Machines for cutting foam: the principle of operation, types, prices. Homemade foam cutter - buy or do it yourself? The choice of foam for arranging thermal insulation

Styrofoam is a popular building material used as a heater or decorative finish. Despite the apparent ease of processing, it is not recommended to cut it with a tool with a high rotational speed of the cutting element; disc grinders and jigsaws are not suitable. The main reason is the coloring of the foam around the edges. For sawing into pieces at home a small amount of plates, a thin saw or a clerical knife is used, in all other cases it is advisable to do it yourself or buy a machine with one or more filaments.

To create neat edges on products, a thin hot edge or string is used. It smoothly cuts polystyrene foam in a given direction, the dimensions of the working field and productivity depend on its length. The number and nature of the arrangement of threads in machines for cutting foam can be different: the more there are, the higher their efficiency. In advanced models with the ability to work in 2D and 3D modes, up to 12 heated strings are installed. According to the manufacturer's instructions, one person is enough to ensure a continuous process on this equipment.

Types of machines

Depending on the type of construction and performance, all machines are divided into:

Portable models resembling a jigsaw. This variety is the easiest to assemble with your own hands.
CNC machines designed for cutting polystyrene foam in large volumes.

Depending on the processing method, equipment for longitudinal or transverse cutting and models for obtaining complex figured products are distinguished. In different tools, either the thread or the material moves.

Overview of popular models

The products are presented by Russian companies, when choosing a foam cutting machine, its performance, the ability to adjust power and connect to computer control, the size of the working field and the number of threads are taken into account, all these data are indicated in the instructions. Popular semi- and professional equipment include:

The cost of equipment and the main characteristics are summarized in the table:

Model name	Rated power, kW	Machine dimensions, mm	Weight, kg	Price, rubles
SFR-Standard	≤2,5	2400×1250×1200	140	140 000
FRP-05	≤3	1300×700×1300	75	290 000
SRP-3420 Sheet	1,7	2 places: Wooden frame 1300×690×490 Cardboard 340×480×210	90	143 000
SRP-3220 Maxi	1,5	2200×1250×1100	97,7	176 000

Making a machine with your own hands: a guide to action

To create a device at home, you will need: a table, a nichrome thread, a 220/12 V transformer and a rheostat or LATR (adjustable laboratory autotransformer), iron springs. A sheet of plywood, chipboard, OSB boards, walls of old furniture can serve as a support. The width of the working surface is selected taking into account the size of the foam, and the length is 1.5-2 times larger.

Next, marking is carried out: approximately in the middle of the table, but at a distance of at least 15 cm from the edge, racks for the filament are installed (it is advisable to draw up a drawing of the device in advance). In the simplest case, this can be a long screw or a stud fastened with nuts, with the help of which the necessary cutting parameters are adjusted. A cutting thread is attached to one rack at the required height. To the second - a spring, followed by the attachment of the same incandescent element. It is needed to tension the string, since during the heating process the metal expands and it sags. As a tensioner, the use of a conventional counterweight is allowed.

For cutting foam plastic with a string or wire, nichrome metal alloys are best suited. They are used in most household appliances - electric furnaces, hair dryers, irons or are sold separately. A nichrome thread is heated to a temperature of 1200 ° C without a noticeable loss of mechanical and physical properties, unlike ordinary steel or copper wire, investments in this element will definitely pay off.

Next, the main element of the circuit is connected - the current-carrying wire. Reliable connection methods are selected: rigid twisting, through a terminal block or a bolt. Consideration should be given to the significant amount of current flowing, the minimum allowable cross section is from 1.5 mm 2 and above. A 220V to 12V step-down transformer is used as a power source, it is necessary to ensure safe operation when cutting material at home.

The scheme for connecting the IP to a home-made machine is simple: the primary winding - to the outlet, the output ends of the transformer - in series through the rheostat to the heating thread. Ideally, only LATR is used. The calculation of the parameters of the power source is impossible without some knowledge of electrical engineering, but in the simplest case it is taken into account that approximately 2.5 watts of output power is required per 1 cm of the length of a 1 mm thick nichrome filament. When multiplying the length of the thread by 2.5, the desired value for the power source is obtained.

At the final stage, using a rheostat or LATR, the heating temperature of the thread is regulated and the optimal material feed rate is selected (which, in turn, determines the thickness of the cut). If it is necessary to create a machine for figured modeling of foam products on your own, the scheme becomes more complicated. In particular, additional threads are introduced into the drawing perpendicular to the working base. Making a cutting table with your own hands can save a lot, the estimated cost of the necessary elements is 10,000-12,000 rubles, while the price of semi-professional equipment reaches 140,000.

Styrofoam is a versatile material. It is used in construction (insulation), in the production (repair) of household electrical appliances, interior design, advertising. One of the main characteristics of the material is density. The higher this value, the stronger the material. However, this greatly affects the price.

When using the material as a filler for wall insulation, the loosest structure is usually chosen (due to low cost). However, loose foam is difficult to process - when cutting, it crumbles a lot, making it difficult to clean up debris.

A foam cutting knife should be thin and sharp, but this does not prevent the edge from breaking. Even if you work outdoors, flying small balls litter the environment.

Therefore, professional builders cut the foam with nichrome wire or a hot plate. The material is fusible, despite the fire safety.

Important! When choosing a heater, pay attention to the characteristics. It should say "self-extinguishing". Such foam is perfectly cut with the help of temperature, but in case of fire it will not become a source of combustion..

An industrial foam cutting machine can process sheets of any size, cut material both across and along the array.

However, cutting foam at home does not involve such volumes and sizes. For repair work in your home (or garage), a compact thermal knife is quite enough. It can easily cope with both linear cutting and curly adjustment of plates, when laying in areas with complex shapes.

Any tool has a cost, and there is always an opportunity to save money on a purchase.

Do-it-yourself foam cutting tools

For linear cutting, the guillotine is excellent. Only the impact will not be mechanical, otherwise a lot of garbage will be formed. We use a proven technology - cutting foam plastic with a tension heated string.

Required Materials

Nichrome (tungsten) thread
Power supply, preferably adjustable
Any structural materials: beam, metal profile, pipe, for the manufacture of a tension frame
Furniture guides for drawers.

On a table, workbench, or other flat surface, we install vertical racks for attaching the guillotine. With the help of furniture guides, we fix the frame of the cutter so that it moves without distortions. Both sides must move synchronously.

The most critical part of the cutter is the wire mechanism. The first question is where to get the material. Nichrome can be purchased at stores selling radio components. But since we are striving for a shareware design, we will look for an alternative.

Old soldering iron. Models made in the USSR, designed for 36-40 volts, can be found in any home workshop. The heater winding is an excellent donor for a nichrome guillotine. True, the length of the wire is not more than a meter.
Iron with classic spiral heater. The wire is thicker, suitable for linear cutting. Curly cutting is acceptable, with low requirements for accuracy.
Spiral heaters from a hair dryer, or a fan heater. The principle is the same, they are not suitable for precise cutting.

note

Tip: When straightening the spiral, do not pull the wire along the spring. Loops may appear and the thread will break. It is better to unwind the turns as from a spool of thread. You can put a spiral on a nail or pencil, and pull the wire across the turns.

The principle of operation of the frame is shown in the diagram.

The wire cutter must be electrically isolated from the frame. Therefore, it can be made of metal. It is important to keep the tension on the wire constant. When heated, nichrome expands, adding up to 3% in length. This causes the string to sag.

Styrofoam (extruded polystyrene foam) is used as thermal insulation for exterior and interior decoration, used for packaging goods or manufacturing prefabricated structures. The material is produced in the form of sheets, which are cut on the spot and adjusted to the dimensions of the surfaces. For quick cutting of foam, you will need a special device that allows you to make a straight or curly cut.

Manual processing of foam plastic is possible at home and in small workshops using a simple device assembled from improvised materials. Extruded polystyrene foam has a fairly dense structure, so you can cut the plates with a metal tool heated to a certain temperature. As a cutting surface, a wire that supplies electric current is suitable, with the supply of which the main difficulty in assembly is associated.

A self-made machine allows you to get tiles or bars of suitable thickness from ordinary foam for packaging with their further use in various structures. With such a device, you can also cut foam rubber or similar materials that are needed for the manufacture or repair of upholstered furniture. The compact dimensions of the device for cutting polystyrene with your own hands using nichrome allow you to install the machine in a small workshop or even on a balcony.

To cut foam at home, you will need a structure that can be assembled from simple materials available at any hardware store. First you need to determine the parameters of each element, taking into account the dimensions of the foam plates that will have to be processed . In most cases, the following details will suffice:

The basis from dense plywood, a chipboard or the massif. You can order new parts or use elements of old furniture (doors, walls, shelves). A base of 400 x 600 mm is sufficient for working with foam.
A string or wire in the form of a thermal knife for polystyrene.
Metal posts, screws, springs or ordinary nails to fix the wire. The installation height of the cutter depends on the expected thickness of the finished boards.
Fixings for parts on the base. A few self-tapping screws are enough to fix the structural elements.

To assemble a thermal cutter, it will take up to one hour of working time. Each of the structural elements can be quickly replaced in the process of repair or expansion of the fixture.

Action algorithm

To make a device for cutting foam or similar materials, you need the most common tools (hammer, screwdriver, pliers). You can work anywhere with enough space (balcony, room, hallway, garage, etc.). No involvement of assistants or third-party specialists is required.

Assembly is carried out in the following order:

Legs can be attached to the base, which will increase stability when cutting foam with a string.

How to choose cutting wire

A suitable cutter can be made from nichrome wire (X20H80), which is used in the design of most household appliances as a heating element. In terms of mechanical characteristics, nichrome is comparable to ordinary steel, while it has a high resistivity and a heating limit up to temperatures of +1200 ºC. Wire diameters up to 10 mm are available for the manufacture of cutting fixtures.

Precise and smooth foam carving is possible when the cutting line is heated to a temperature that is two to three times the melting threshold (+270 ºC). It should be borne in mind that such a process involves the consumption of energy and the absorption of heat by the material itself in proportion to its density. Therefore, for efficient and safe cutting, it is necessary to select a wire of suitable thickness in order to exclude metal melting at maximum heating.

Calculation and preparation of the electrical part

For the safe operation of the device, it is necessary to correctly mount the conductive elements that are connected to the power source through the captive terminals. To cut the material, you can use alternating or direct current. The power of the source is calculated based on the fact that up to 2.5 W will be needed for effective cutting of 10 mm wire (for 500 mm - 125 V).

The voltage is proportional to the resistance and is calculated using formulas or tables. But on average, with a wire diameter of 0.8 mm, a length of 500 mm and a resistance of 2.2 ohms, you will need a 12 V current source with a load current of 12 A. Changing the length up or down will require a similar increase or decrease in voltage at the same strength current.

Power sources and connection diagram

Safe cutting is ensured by connecting to a regular 220 V household network through a car transformer. To adjust the voltage in a single primary winding, a handle is provided, with which the graphite wheel is moved and the voltage is removed from the corresponding section. This parameter can be changed within the range from 0 to 240 V. Connection to the current source is carried out through the terminal box.

When connecting a homemade foam cutting machine to the mains, you need to make sure that the phase does not fall on a common wire. All the necessary parameters and connection diagram can be found on the transformer housing. Before connecting to the network, you need to check the operation of the device using a multimeter.

A simpler option for supplying current to the wire is to use conventional step-down transformers with taps from the secondary windings. In this case you don't have to adjust the voltage, since this value is always constant and sufficient to heat the wire to the desired temperature. You can select the desired value during the initial setup of the transformer, providing a certain number of turns of windings in the circuit.

You can also heat the wire for cutting polystyrene using household appliances. In this case, the following nuances are taken into account:

It must be taken into account that the cutting tool will immediately be hot when energized, so it should not be touched to check the temperature.

To make a thermal knife for polystyrene or foam rubber, it will not take a significant investment of time and effort. For this, a wire of almost any diameter is suitable, but with unknown parameters (diameter, resistance), you need to increase the power gradually, connecting first low-power current sources. Of great importance is the reliable isolation of the contacts and the control of the position of the phase, which cannot be connected to the wire.

Styrofoam is a wonderful material used in many areas of construction and decoration. With its help, they equip hydro- and thermal insulation, create decorative ceiling coverings, baguettes and much more. For all its versatility, it is also cheap. The only problem that arises while working with it is cutting.

Styrofoam cutting: do-it-yourself machine

It is extremely difficult to cut the foam yourself so as to get a clean and even cut. It crumbles and bursts if you use a saw, even a blade or a razor does not solve the problem.

Hot metal can serve as a way out, but how to use it at home? Build a homemade styrofoam cutting machine!

Method number 1.

To implement this venture, you will need:

a table, it is better if each of its sides is no shorter than 2 m;
metal springs with low current resistance;
a transformer that converts current from 220 to 24 volts;
high resistance string, if there is an old heater, remove it from it.

You will also need a string height adjuster. Use a pair of beams as it. A cutting string with a holder will move between them.

A transformer is not needed in every case. It depends on what material the string is made of. If it is chrome-plated, a current of 220 volts is also considered acceptable. But when working with such a discharge, you should strictly follow the safety rules, otherwise the matter may end sadly.

If you work with a discharge of 24 volts, then there is no danger to life and health. It is simply not noticeable, and in case of damage, you just need to rinse the affected area with water.

It should also be remembered that when cutting foam with hot metal, toxic fumes are released, so it is imperative to use a protective mask and ventilate the room well, otherwise poisoning will be ensured. And it is best, in general, to work on the street, but this is possible if you have your own yard.

In order to make it easier to assemble a foam cutting machine from the above materials, a schematic drawing is given below:

Method number 2.

In the absence of a suitable table, a chipboard sheet, plywood, board is quite suitable as a base for the device.

The assembly sequence of a homemade machine:

1. Attach the nichrome wire to the springs, put the springs on the M4 screws, and screw them, in turn, into special racks.

2. Press the metal racks into the tabletop, chipboard, or any other surface chosen as the base in advance. The height of the rack and the thickness of the base depends on the needs of the machine owner. If the thickness of the plate is 1.8 cm, and the stand is 2.8 cm high, then in the fully screwed state, the screw will not pass through the base, and when completely unscrewed, it will be able to cut the foam with a thickness of 5 cm.

3. If a thicker thread is required in the future, then the short screws will need to be removed and the long ones screwed in their place.

4. Drill a hole in the base for pressing. Its diameter should be less than the diameter of the rack by half a millimeter. Drive the racks into the holes with a hammer, but before that, to make this procedure easier for yourself, go over the sharp edges of the ends with sandpaper.

5. Before screwing the screw into the rack, cut a groove under its head. To do this, clamp its end with a screwdriver, and attach a thin file under the head and turn on the rotation. This groove is needed in order to fix in one position the wire, which otherwise can move during adjustment.

6. To prevent the wire from sagging, lengthening due to heat, attach it first to the springs, and then to the screws.

7. After all the fasteners are ready, fix the nichrome wire. To ensure that the contact between it and the conductive wire is reliable, use the “twisting with crimping” fastening method. Copper wire must have a cross section of at least 1.45 sq. mm.

8. Remove the insulation from the ends of the wires by about 2 cm. Wind the copper conductors onto the wire in those places where it is attached to the spring. Wrap the end of the wire with pliers around the conductor. Thanks to this winding, the contact of the wire and the conductive wire will have a large area, and when the machine starts working, the junctions will not heat up.

9. To be able to adjust the cutting thickness of the material, make the withdrawal of conductive conductors in the form of a loop. And so that the wires do not get tangled at hand while using the machine, make holes in the base, pass an interfering segment through them and attach to the back of the surface with brackets.

10. Wires are best folded together and twisted in the form of a loose bundle. So they won't get confused.

11. Solder the jumper terminals on the ends of the wires to connect them to the power source.

The device designed according to the above instructions will be quite enough for use at home. In addition, it can be used as a foam cutting machine.

During cutting, the speed of movement of the material should be medium. If you move the foam very quickly, then it will crumble in the same way as when cutting with a saw. If, on the contrary, you move it very slowly, the edges of the cut out figure will melt.

If foam is required to insulate a house during construction, then it is better to purchase a thicker one. Due to the simple manufacture and low demand, such material is much cheaper than thin.

If the Mayak stereo recorder has been lying around in the attic since Soviet times, then don’t buy a transformer, but take it from it. It is just the right one, because supplies 24 volts.

In the case when work is carried out in a power outage, connect three crowns of 9 volts to each other, and use them. Thus, the device will be able to function for 30-40 minutes.

But the use of car batteries for this purpose is strictly prohibited. Despite the low voltage, they have a very high current strength, which can burn the string and it will simply burst. This is in a good scenario, and in a bad one, it will splash with hot metal.

The choice of foam for arranging thermal insulation

There is a special foam designed specifically for the insulation of facades. The packaging usually has a corresponding marking in the form of the letter "F". It has a high, in comparison with conventional material, density and is resistant to mechanical stress. It springs well, making it hard to break.

When cutting foam, for thermal insulation, do not install a string below 50 mm. The fact is that a thinner material will not be effective enough, and when wet it will generally lose most of its wonderful properties. At high humidity, such thermal insulation will be permeable to cold air, like ordinary brickwork.

As an additional material for thermal insulation, use a mineral wool board. In addition to the properties mentioned, it has another important advantage - in the event of a fire, it will not burn.

Foam cutting machine, video:

recn.ru

Do-it-yourself foam cutting machine: how to cut foam

The issue of home insulation is very relevant today. Sheathing the facades of houses with foam plastic is one of the most popular types of insulation. And this is very reasonable, because. the process of such insulation is simple and understandable, and all the necessary materials are always on sale.

But everyone knows that gluing foam is very convenient on a flat wall. With any method of gluing foam to the wall: dry mix adhesive, foam or adhesive foam, it is always very important that the foam sheet fits snugly against the wall and does not create air gaps.

If the wall is even, then no questions arise. But, unfortunately, the walls of old houses do not differ in ideal evenness. Yes, and different design features of the structure sometimes create drops on the plane of the wall.

Partially, this drawback can be leveled by laying the foam on a thicker layer of glue. But the maximum allowable thickness of the adhesive layer often cannot cover the magnitude of the differences in the plane of the walls. In addition, too large differences lead to unjustified overspending of glue.

The next way out of the situation remains - cutting the foam in thickness. But doing this with a hacksaw is very inconvenient and time consuming, especially if you need to cut a large amount of foam. In addition, during cutting, a large amount of debris in the form of foam balls is formed. Yes, and the surface is uneven and the accuracy of such cutting is very conditional.

In order to quickly and evenly cut the foam of the desired thickness, you can use a foam cutting machine. This device can be made independently, absolutely with your own hands.

The principle of operation and the device of the machine for cutting foam

The principle of operation of the machine is based on the fact that the foam is easily melted under the influence of temperature. Thus, if you draw a thin heated wire over it, it is easily cut, while forming a perfectly flat, smooth surface.

For the manufacture of the machine, the following components are needed:

LATR (laboratory autotransformer) or car battery;
nichrome thread;
racks for attaching nichrome thread;
spring (1-2 pcs.);
tabletop board;
copper wire.

A nichrome thread (spiral) is used as a cutting object. You can either buy it in a store or extract it from old household appliances in which they were used as filaments (a hair dryer, for example). The thickness of the spiral can be 0.5-1 mm. The most optimal thickness is 0.7 mm. The length depends on the width of the foam to be cut.

An important element of the device for cutting foam is LATR. But if it is not there, then it can be done using an old transformer and a device for charging car batteries.

You can also use a computer power supply that uses wires that give 12 watts (yellow and black) to connect to the spiral.

To operate such a machine, it is enough to have an output voltage of 6-12 watts.

It is necessary to correctly adjust the length and thickness of the filament and to match the voltage. If the thread is too hot, it may break. Well, if the thread is slightly heated, then cutting will be slow.

A car battery can also be used as a power source. They can be used in conditions where there is no electricity on the site.

Machine for cutting foam in the field. Connecting to a car battery.

For different tasks, you can make different designs of the foam cutting device.

Basically, these devices will differ in the length of the spiral. To cut foam into bars, a short spiral length is needed.

You can install two spirals and cut the sheet into several bars in one pass.

Two spirals cut the sheet into three parts in one pass. The stand is stuffed with guides for smooth feeding of the foam.

But, in extreme cases, foam plastic can be cut into bars with a hacksaw. It is much more difficult to cut the foam in thickness, and even with a given size. Therefore, we will consider how to make a machine for cutting foam in width.

Step-by-step instructions for self-manufacturing the machine and cutting foam

Step 1. Preparation of the countertop. As a tabletop for a do-it-yourself foam cutting machine, you can take any piece of chipboard of the right size. The surface on which the foam will move must be smooth. Holes for racks are drilled in the table top. It is convenient to use metal pins with a thread with a diameter of 10-12 mm as racks. The height of the racks should correspond to the thickness of the foam sheets plus a margin in height. The pin is fixed with nuts.

To give the structure stability, bars are attached to the tabletop from below, which will also serve for the safe passage of an electric wire.

Step 2. Connecting the current supply wires. From below, under the tabletop, the wires are connected to metal rod-racks: the wire is wound around the lower end of the pin and pressed with a bolt.

The other end of the wires must be connected to a power source, depending on the method chosen. The best connection will be through a plug, which will be connected to the LATER socket. It is possible to connect via self-clamping terminals, as well as by twisting and soldering. It depends on the selected power supply.

In any case, the connection must be made in accordance with the rules for working with electrical installations and devices, be convenient for work and safe during operation.

Step 3. Fixing the nichrome spiral. Nichrome spiral is fixed between two racks. A spring is attached to one end of the spiral (there may be two of them).

The spring is needed in order to pull the nichrome thread during operation. The fact is that when heated, the nichrome thread lengthens and sags. The thread in this state will not give a quality cut. Therefore, the thread is fixed in an initially stressed state, so that the spring is slightly stretched.

To fasten the nichrome thread to the pin, washers with an inner diameter slightly larger than the diameter of the pin are used. A small hole is made in the washer for attaching the spiral itself. A small sharpening is also made on the side of the inner diameter so that the washer can be fixed on the thread of the pin.

A spring with a spiral attached to it is inserted into one washer and put on the first pin. The second washer is put on the second pin and a nichrome spiral is threaded into the drilled hole. Next, it is pulled so that the spring is stretched, and fixed.

Step 4: Cutting the Styrofoam To dissolve a sheet of foam into two sheets of a given size, the spiral is set to the desired height. The required distance is measured with a ruler.

The machine is then connected to a power source. The thread heats up and now you can cut the foam, smoothly moving it forward along the countertop.

The cutting speed depends on the temperature of the filament, which in turn depends on the voltage applied and the thickness of the filament itself. Do not try to apply more voltage to achieve high speed, because. this can cause the filament to burn out quickly. Here, a balance between tension, thickness and length of the thread must be selected empirically. The thread should not overheat during operation. When heated, it becomes red or scarlet. But it should not turn white - this indicates that the thread is overheating and that it is desirable to reduce the voltage, otherwise the thread will not last long in this mode. Of course, smooth adjustment is easily done if LATER is available. But if it is not there, then a laboratory power supply can also be made from a computer power supply, the video below has more information. After you have made this foam cutting machine with your own hands, you need to make sure that the machine is safe.

It must be remembered that all activities must comply with safety regulations for working with electrical appliances. The power supply must be grounded, all connections must be carefully insulated. All work on the assembly of the machine must be carried out with de-energized wires. The machine is connected to the mains only while working with foam. After work, it must be immediately turned off. While working with the machine, touching the metal parts and the nichrome thread itself should be avoided.

Step 4: Cut the Styrofoam at an Angle Sometimes it becomes necessary to cut the foam in such a way that one side is higher and the other lower.

To do this, the spiral is set at a slope with the desired parameters. In this way, foam sheets of various sections can be obtained.

Useful video

o-builder.com

Homemade foam cutting machine Design, calculation, electrical circuit

Heat and sound insulating building materials on the market are presented in a wide range, these are foamed polyethylene, mineral and basalt wool and many others. But the most common for insulation and soundproofing is extruded polystyrene foam and foam plastic, due to its high physical and chemical properties, ease of installation, low weight and low cost. Polyfoam has a low coefficient of thermal conductivity, a high coefficient of sound absorption, and is resistant to water, weak acids, and alkalis. The foam is resistant to the effects of ambient temperature, from the lowest possible to 90˚C. Even after decades, the foam does not change its physical and chemical properties. The foam also has sufficient mechanical strength.

Styrofoam also has very important properties, these are fire resistance (when exposed to fire, the foam does not smolder like wood), environmental friendliness (since the foam is made of styrene, even food products can be stored in containers from it). Fungi and foci of bacteria do not appear on the foam. An almost ideal material for insulation and soundproofing in the construction and renovation of houses, apartments, garages, and even packaging for food storage.

Styrofoam is sold in building materials stores in the form of plates of different thicknesses and sizes. When repairing, foam sheets of different thicknesses are often needed. If you have a machine for cutting foam, you can always cut foam sheets of the desired thickness from a thick plate. The machine also allows you to turn shaped foam packaging from household appliances into plates, as in the photo above, and successfully cut thick sheets of foam rubber for furniture repair.

How easily foam is cut on a homemade machine, the video clip clearly demonstrates.

If you want to make a machine for cutting foam and foam rubber, many are stopped by the difficulty of organizing the supply of supply voltage to heat the nichrome string to the desired temperature. This obstacle can be overcome if you understand the physics of the issue.

The design of the foam cutting machine

The basis of the device for cutting foam was a sheet of chipboard (chipboard). The size of the plate must be taken based on the width of the foam plates that are planned to be cut. I used a 40x60 cm furniture door. With this size of the base, it will be possible to cut foam plates up to 50 cm wide. The base can be made from a sheet of plywood, a wide board, and the cutting string can be fixed directly on the desktop or workbench.

Stretching a nichrome string between two nails is the limit of the laziness of a home craftsman, so I implemented the simplest design that provides secure fixation and smooth adjustment of the string height during cutting above the surface of the base of the machine.

The ends of the nichrome wire are attached to the springs, dressed on M4 screws. The screws themselves are screwed into metal racks pressed into the base of the machine. With a base thickness of 18 mm, I picked up a metal stand with a length of 28 mm, so that when fully screwed in, the screw does not extend beyond the bottom side of the base, and when the maximum unscrewed state provides a foam cutting thickness of 50 mm. If you need to cut sheets of foam or foam rubber of greater thickness, then it will be enough to replace the screws with longer ones.

To press the rack into the base, first a hole is drilled in it, with a diameter of 0.5 mm less than the outer diameter of the rack. In order for the racks to be easily hammered into the base, the sharp edges from the ends were removed on an emery column.

Before screwing the screw into the rack, a groove was machined at its head so that the nichrome wire could not move arbitrarily during adjustment, but occupied the required position.

To make a groove in a screw, first its thread must be protected from deformation by putting on a plastic tube or wrapping it with thick paper. Then clamp the drill in the chuck, turn on the drill and attach a narrow file. In a minute, the groove will be ready.

To prevent sagging of the nichrome wire due to elongation when heated, it is fixed to the screws through springs.

A suitable spring from a computer monitor, used to tension the ground wires on the kinescope, turned out to be suitable. The spring was longer than required, I had to make two of it, for each side of the wire attachment.

After preparing all the fasteners, you can fix the nichrome wire. Since the current consumed during operation is significant, about 10 A, for reliable contact of the current-carrying wire with nichrome wire, I used the method of fastening by twisting with compression. The thickness of the copper wire at a current of 10 A must be taken with a cross section of at least 1.45 mm2. You can select the wire section for connecting nichrome wire from the table. I had a wire with a cross section of about 1 mm2. Therefore, each of the wires had to be made of two with a cross section of 1 mm2, connected in parallel.

After removing the insulation from the ends of the wires to a length of about 20 mm, the copper conductors are wound onto a string of nichrome wire at the point of its attachment to the spring. Then, holding the nichrome wire by the loop with pliers, the copper wire wrapped around the free end of the nichrome wire in the opposite direction.

This method of connecting the current-carrying copper wire to the nichrome wire will provide a large area of their contact and eliminate strong heating at the junction during the operation of the foam cutting machine. This was confirmed by practice, after prolonged cutting of the foam, the PVC sheath of the current-carrying wire did not melt, the copper wire in the connection zone did not change its color.

To be able to adjust the cutting thickness of the foam plastic on the fixture, the outlet of the current-carrying conductors is made with a loop. So that the wires do not interfere with work, they are passed through the holes in the base and fixed on its reverse side with brackets. The same brackets are nailed to the corners of the base as legs.

The current-carrying wires, so as not to get tangled, are twisted together. At the ends of the wires for connecting to a power source, captive terminals are soldered.

Nichrome wire in appearance is not much different from steel wire, but it is made from an alloy of chromium and nickel. The most common wire brand X20H80 containing 20% chromium and 80% nickel. However, unlike steel or copper wire, nichrome wire has a higher resistivity and withstands, while maintaining high mechanical strength, heating temperatures up to 1200˚С. Nichrome wire is available in diameters from 0.1 mm to 10 mm.

Nichrome wire is widely used as heating elements in household and industrial products such as electric hair dryers, irons, hotplates, radiant heaters, soldering irons, water heaters, and even electric kettles. And this is not a complete list. The so-called heaters of the TEN type are also made of nichrome wire, only the spiral is placed in a metal tube, which is filled with quartz sand to isolate and transfer heat from the spiral to the tube walls. He gave a list of devices not by chance, just from a failed heating element, you can take a nichrome wire for the manufacture of a machine, of course, if it has not had time to burn out from long work.

Cutting foam on the machine is to melt it along the line of passage, heated nichrome wire. The melting point of the foam is about 270˚C. in order for the foam to melt in contact with the wire, its temperature must be several times higher, since heat will be consumed not only for melting, but also absorbed by the foam itself due to thermal conductivity, reducing the temperature of the wire. The amount of heat absorbed by the foam will directly depend on its density. The denser the foam, the more heat energy will be required.

From the above, it follows that, depending on the density of the foam, it is necessary to choose a wire of the appropriate diameter for cutting it so that the nichrome wire does not melt from the heat generated on it. The higher the density of the foam, the larger the diameter of the nichrome wire should be. It is worth noting that the machine on which the wire for cutting dense foam is installed will successfully cut loose foam, only it will need to be advanced faster.

The length of the nichrome wire for the fixture is selected based on the dimensions of the foam plates intended for cutting, and does not depend on the density of the foam.

As a result of the experiments, it was determined that for efficient cutting of foam, the power that must be supplied per unit length of wire should be in the range of 1.5-2.5 W per centimeter of wire length, for this mode of operation, nichrome wire with a diameter of 0 .5-0.8 mm. It allows you to generate enough heat to quickly cut foam of any density, while maintaining its mechanical strength. Therefore, nichrome wire with a diameter of 0.8 mm was used to manufacture a foam cutting machine.

Calculation of the parameters of the power source for heating the wire

It should be noted that for heating the nichrome wire of a foam cutting machine, a power source of both alternating current and direct current is suitable.

Taking into account the fact that no more than 2.5 watts of power should be allocated per centimeter of the wire length and a wire length of 50 cm, it is possible to calculate the power of the power source. To do this, you need to multiply the amount of power released by the length of the wire. As a result, it turns out that to heat up the wire of the foam cutting machine, you will need a power source with a power of 125 watts.

Now you need to determine the voltage of the power supply. To do this, you need to know the resistance of the nichrome wire of the foam cutting machine.

Wire resistance can be calculated from resistivity (resistance of one meter of wire). The specific resistance of the wire made of nichrome grade Kh20N80 is shown in the table. For other brands of nichrome, the values differ slightly.

As can be seen from the table, for a wire with a diameter of 0.8 mm, the resistivity is 2.2 ohms, therefore, the 50 cm long nichrome wire that was chosen for the foam cutting machine will have a resistance of 1.1 ohms. If you choose a wire with a diameter of 0.5 mm, then the resistance of a piece of wire 50 cm long will be 2.8 ohms.

Using the transformed formulas of the Ohm and Joule-Lenz laws, we get a formula for calculating the magnitude of the supply voltage for a foam cutting machine. The value of the supply voltage will be equal to the root of the product of the power consumption and the resistance of the wire. As a result of the calculations, it turns out that a power supply with a voltage of 11.7 V is needed. In this case, the current consumption from the source will be 11.7 A. In order to find the current value, you need to divide the power consumption by the voltage value. By dividing 125 W by 11.7 V, we get a current of 11.7 A.

As a result of the calculations, it was determined that in order to heat the nichrome wire of the foam plastic cutting machine, an AC or DC power supply is required, outputting a voltage of 11.7 V and providing a load current of 12 A.

When reducing or increasing the length of the wire, the power supply voltage will need to be proportionally reduced or increased accordingly. In this case, the current will not change.

The calculation performed is an estimate, since the transition resistance at the wire connection points and the resistance of the current-carrying conductors are not taken into account. Therefore, the optimal wire heating mode ultimately has to be set directly when cutting the foam on the fixture.

Electrical diagram of the power supply of the foam cutting machine

You can apply power to the nichrome thread of a foam cutting machine using several circuits.

Scheme of a foam cutting machine using LATR

The simplest version of the power source for a foam cutting machine is an autotransformer with the ability to smoothly adjust the output voltage. But this circuit has a significant drawback, it does not have galvanic isolation from the supply network, since the LATR output is directly connected to the mains. Therefore, when using LATR, it is necessary to connect it in such a way that the common wire is connected to the neutral wire of the mains.

Wiring diagram for connecting a nichrome spiral of a foam plastic cutting machine to LATR.

What is LATR and how it works

The industry produces laboratory autotransformers, which are commonly called LATR (adjustable laboratory autotransformer). They are connected directly to a 220 V household power supply and, depending on the type of LATR, are designed for different load currents.

LATR is a toroidal transformer with one primary winding, along the turns of which, when the handle located on top is rotated, a graphite wheel moves, which allows you to remove voltage from any part of the winding. In this way, at the output of LATR, you can change the voltage from 0 to 240 V.

The wires to the LATR are connected using a terminal block, on which its electrical circuit is drawn and the inscriptions "Network" and "Load" are applied. A cord with a plug is connected to the “Network” terminals for connecting to a household network. The product is connected to the “Load” terminals, which must be powered with a voltage different from the household power supply.

Attention! One of the mains wires, bottom terminals in the photo, is connected directly to one of the load wires. Thus, if a phase gets to the lower terminal, then touching this circuit will be dangerous for humans.

Therefore, in the case of using LATR to heat the nichrome wire of a foam plastic cutting machine without an isolation transformer, it is necessary to check the absence of a phase on the common wire with a phase indicator. If there is a phase on it, remove the LATR power plug from the outlet and, turning it 180 degrees, insert it again. Recheck the bottom wire for the presence of a phase.

Usually there is a label on the LATR case, which provides data on its load capacity. On the LATR, which is shown in the photo, the label is installed directly on the adjusting knob.

From the label it follows that this is a LATR type LOSN, the output voltage can be adjusted in the range from 5 to 240 volts, the maximum load current is 2 A.

If the rated current does not exceed 8 A, then it is quite possible to power the nichrome wire through the LATR type RNO 250-2.

This LATR allows you to connect a load with a current consumption of up to 8 A, but given the short duration of the device for cutting foam, it will fully withstand the load current and 10 A.

Before using LATR as a power source, it is necessary to check its performance. To do this, you need to connect a power cord to the “Network” terminals of the LATR, and to the “Load” terminals a multimeter or a pointer tester, switched on in the alternating voltage measurement mode, to a limit of at least 250 V. Set the LATR voltage adjustment knob to the minimum voltage position. Insert the plug into the socket.

Slowly turn the LATR knob clockwise to make sure that the output voltage increases. Return the LATR handle to the zero position. Remove the plug from the network and connect the wires coming from the nichrome thread to the "Load" terminals. Insert the power cord plug into the socket and use the phase indicator to check the absence of a phase on the nichrome wire. Having dealt with the phase, you can slowly turn the LATR handle to apply voltage to the nichrome wire. It should be taken into account that the wire heats up gradually, within a few seconds.

Attention! It is strictly forbidden to touch the wire with your hand to check the degree of its heating when the supply voltage is applied to it! The temperature of the wire is very high and you can get burned!

When the wire heats up to a slightly noticeable glow, you can start cutting the foam on the machine.

Scheme of a foam cutting machine using a step-down transformer LATR

If the amount of current consumed by the nichrome wire of the foam plastic cutting machine is greater than the LATR can provide, then it will be necessary to additionally turn on the step-down transformer after it according to the electrical diagram below.

As you can see, unlike the previous circuit, the network winding of the power transformer is connected to the LATR output, the nichrome spiral is connected to the secondary output winding of the transformer. In this circuit, thanks to the isolating step-down transformer, the nichrome coil is not galvanically connected to the electrical network and is therefore safe to operate. In addition, it became possible to more smoothly adjust the output voltage and, consequently, to more accurately set the foam cutting temperature on the machine.

The power of the transformer and the voltage on its secondary winding are taken on the basis of calculations performed according to the above method. For example, for the proposed design of a foam plastic cutting machine, with a nichrome wire diameter of 0.8 mm and a length of 50 cm, the power supply was a LATR with an output current of 2 A with a 150 W step-down transformer connected after it with a voltage on the secondary winding of 12 V.

To power the nichrome spiral of the foam cutting machine, you can use a transformer with taps in the secondary winding. This is the easiest, most reliable and safest option, especially if the foam cutter will be used regularly. Indeed, when cutting polystyrene on a fixture, it is not necessary to regulate the heating temperature of the nichrome wire. The temperature is selected once when setting up the machine. Therefore, having selected the desired voltage, the wires from the leads of the nichrome wire are soldered to the leads of the secondary winding of the transformer forever.

Despite the simplicity and reliability of this circuit, there are no standard ready-made transformers with taps, and even for the required voltage. You will have to find a suitable transformer for voltage and current on the secondary winding and unwind the extra turns. You can disassemble the transformer and unwind part of the secondary winding, wind it again, but with taps. But this work requires knowledge and experience.

Scheme of a foam cutting machine using a step-down transformer and current-limiting capacitors

It is possible to establish a stable output current from the secondary winding of the transformer using ordinary capacitors included in the primary winding of the transformer.

The capacitor must be designed for a voltage of at least 300 V and have a capacity of about 50 microfarads, depending on the type of transformer and the current consumption of the nichrome coil. On this principle of stabilizing the current on the secondary winding, I developed a charger circuit for car batteries. The transformer must be of adequate power and have a 10% voltage margin.

Scheme of a foam cutting machine using a step-down transformer and a thyristor power controller

Another, somewhat unusual scheme for the heating temperature controller of a nichrome wire, using a thyristor. It is similar to adjustment using LATR with a transformer, but small-sized. The classic thyristor regulator circuit is not suitable for this circuit, as it distorts the shape of the sinusoidal current.

Therefore, a special thyristor regulator circuit is needed, which produces a sinusoidal signal at the output and is designed to work with an inductive load.

It is also possible to turn on the thyristor regulator after the secondary winding of the transformer. In this case, when choosing a regulator circuit, it should be taken into account that it must be designed for the current that is necessary to heat the nichrome wire.

Scheme of a foam cutting machine using any electrical appliances

If none of the above electrical circuits for heating nichrome wire for a foam cutting device can be implemented, then I propose a non-standard heating circuit.

When you connect any electrical appliance, it consumes current from the mains. The magnitude of the current directly depends on the power of the electrical appliance. The more power, the more current will flow through the wires. The resistance of a piece of nichrome wire of a foam plastic cutting machine is slightly greater than the resistance of copper wires and, therefore, turning the machine into a break in one of the wires of an electrical appliance will not affect its operation, and the nichrome wire will heat up. This is what you can use.

When using the connection of the foam cutting machine according to this scheme, it is imperative to ensure that the nichrome wire is not connected directly to the phase wire of the mains. Physically, the connection is best done using an adapter, like the one described for measuring the current consumption.

Suitable for operation in the circuit are continuous electrical appliances, such as a heater, a vacuum cleaner. You can estimate how much current electrical appliances consume according to the table on the site page "Selecting the wire cross section of the cable for electrical wiring."

If the electrical parameters of the nichrome wire are not known, then you must first try to connect a low-power electrical appliance, for example, a 200 W electric light bulb (a current of about 1 A will flow), then a 1 kW (4.5 A) heater, and so increase the power of the connected devices until the nichrome the wire of the foam cutting machine will not heat up to the desired temperature. Electrical appliances can also be connected in parallel.

The disadvantages of the last connection scheme for a nichrome spiral of a foam cutting machine include the need to determine the phase for the correct connection and low efficiency (efficiency), kilowatts of electricity will go useless.

ydoma.info

Do-it-yourself foam cutting machines (drawings, video)

The foam cutting machine is an essential piece of equipment for many businesses and home workshops. With their help, the production of various blanks used in construction, repair, decoration, interior design, etc. is carried out.

Photo of foam cutting machine

If you study the range of factory models of foam cutting machines or simply PSA, then there are several types:

Mobile. Such PSAs are more like an ordinary knife designed for do-it-yourself foam work. A mobile machine can make various simple workpieces. Quite often they are found in everyday life when processing polystyrene foam, polystyrene foam;
Machine tools for transverse and horizontal processing. These PSAs are cut in a certain direction, that is, it is problematic to achieve complex figures. But the machine provides highly efficient production, cutting of large materials is carried out;
CNC machines. PSA equipped with a CNC module are modern models of machines for processing expanded polystyrene, foam plastic. With it, you can make the most diverse in terms of parameters, complexity and configuration of machines, 3d models. The current furniture, repair and construction production is not complete without the use of CNC PSA.

Scheme-drawing machine for cutting foam

If you want to buy a PSA or make it yourself, first you need to understand the features of the device.

The work of most types of machines for working with foam is based on a single principle;
The cutting part of the machine heats up, affects the material being processed;
The cutting element moves according to the drawings;
The process is similar to the passage of a hot knife through butter, that is, the process is carried out easily, with minimal damage to the foam or polystyrene foam;
The simplest model of the machine has one cutting string. Such an installation is easy to do with your own hands, having the appropriate drawing at your disposal;
To work with complex 3d figures, perform high-precision cuts, use the SRP with a CNC module. The machine itself can have up to 6 cutting strings;
The advantage of the machine is that additional processing of the edges is not required due to a clean cut. This simplifies production, minimizes the cost of fine-tuning parts.

Device Features

If you want to make a cutting device for foam plastic with your own hands, this can be done in two ways - by vertically and horizontally cutting a foam sheet;
To make a vertical cut, the cutting line is set perpendicular to the work table;
For a horizontal cut, you need to make an appropriate construction, opposite to the first example;
To get a smooth, neat cut, you will need a competent drawing and a template for further processing;
The drawing is widely presented on the net, which allows anyone to make the machine at their discretion, based on personal needs or materials available for assembly of the PSA;
It is recommended to use a nichrome thread as a cutting element. Almost every drawing provides for its use;
For processing complex parts, obtaining 3d models, the current production of machine tools has reached a high level. Special models of CNC units are widely used, designed specifically for curly cutting. The workpiece is processed in several projections at once. Due to such equipment, it is possible to establish the production of models of cars, people, aircraft, animals and much more. Moreover, in fact, 3d products are obtained that accurately repeat all the bends, lines, configurations of the copied product.

We make a machine with our own hands

The production of special machines for cutting foam plastic has been put on active flow. At the same time, the cost of equipment for many potential buyers seems high. In addition, having the opportunity to assemble a foam cutting machine without too much help, with their own hands, many simply refuse the idea of \u200b\u200bpurchasing. The estimated price of a factory machine is from 40 thousand rubles. But there are models worth 100 thousand rubles and more.

Yes, for that kind of money you can get an excellent foam cutting machine equipped with a CNC module. The CNC machine is far superior to home-made simple devices. At the same time, not everyone has a real need for CNC and automated cutting of foam. Therefore, we will give an example of how you can make an excellent unit for processing polystyrene foam or polystyrene with your own hands. It will not be superfluous to consolidate the skills with video lessons.

Drawing. It is not necessary to use a drawing specifically for this machine model. Here it is not needed, since the design is quite simple. But for clarity, you can draw a drawing yourself, rely on the selected parameters. Another option is to choose a drawing of a more serious installation. It all depends on what you want from your foam cutting machine.
Select or assemble a table on which the Styrofoam cutting operations will be performed. The surface should be covered with thermal insulation or electrical material. Polyamide film has proven itself in this component.
Attach the insulator to the center of the long side of the work surface. One from each end. Ceramic or glass elements can be used as insulators. Between these structural components, you will then stretch the thread, which will act as a cutting tool.
Choose a line. If you have an old electric stove, an unnecessary soldering iron or an iron, you will find a nichrome thread inside them. It has sufficient power.
Remove the spiral from the tool, carefully straighten it to get a smooth thread.
It is not recommended to use nichrome threads with a thickness of more than 0.5 mm for a homemade machine.
Be sure to connect the thread to the network through a rheostat or step-down transformer. This will protect your main working element of the machine from combustion.
A nichrome line is connected to the reel on the insulating material. An electrical cable is connected to the fishing line, through which power will be supplied to the machine. Try to ensure that the contact between the electrical cable and the thread is of the highest quality.
Under the table, stretch the thread to another insulator and pass through it. The end of the thread will hang from the insulator, so a weight should be provided here. The weight of the load determines the tension of the heated thread when processing the foam. Here you have to “play around” a bit to determine the optimal weight parameters. Movable sliding fixation is the most beneficial when creating such a machine with your own hands. This is due to the fact that this way you will get a better and cleaner cut line, you can adjust the position of the thread as needed.
Near the second insulation coil, a second electrical cable is mounted to the thread, which goes to the rheostat and is connected to the slider terminal.

The machine can only be started after the slider has been set to the maximum resistance level. If this is not done, literally immediately after turning on your thread will burn out, you will have to look for a new one.

The power of the unit depends on the parameters of the current and the thickness of the thread used. The only drawback of a homemade foam machine is that when heated, the material emits an unpleasant odor and harmful substances. Therefore, it is highly recommended to use the machine only where there is an effective ventilation system.

During construction and finishing work, the question arises of how to cut the foam so that it does not crumble. To do this, use special tools and techniques that are selected based on the size of the foam plate. These cutters can be purchased at the store or you can make your own. To make a tool with your own hands, you do not need special knowledge or skills.

DIY nichrome cutter

Styrofoam is cut with a string heated to +120 ... + 150 ° С and melting the material. Thanks to this, the cut is even, and the foam does not crumble. On such devices, a nichrome thread is installed through which electricity is passed. You can make a simple cutter with your own hands. It differs from the machine in portability and compactness, so the heating temperature of the nichrome wire cannot be adjusted on it.

Necessary tools and materials

To make a cutter with nichrome wire for cutting foam, you will need the following tools and materials:

a small wooden block;
screwdriver and drill;
2 pencils;
2 pieces of copper wire;
round nose pliers;
hot glue or PVA;
insulating tape;
battery connector;
switch;
1 m wires;
soldering iron;
nichrome thread.

The latter is sold in a radio parts store. It can also be taken from old heating elements from a hair dryer, boiler, boiler, etc.

Homemade foam cutter

A homemade cutter is designed for minor work. It is not possible to cut the entire sheet of polystyrene foam with them. To carry out cutting foam at home, you must:

Make 2 holes in a wooden block 10-11 cm long. They should match the diameter of the pencils. You need to retreat 1-1.5 cm from the edge. The recess should be slightly deeper than half of the bar in order to fix the pencils. Due to this distance, it is possible to cut a sheet of foam plastic of almost any thickness.
Glue both pencils into the holes with hot glue or PVA.
In each of the pencils, make a small hole for the copper wire on top.
Bend the copper wire with round-nosed pliers so that small rings are formed at its ends. After that, install in the holes in the pencils.
Glue the battery connector perpendicular to the wooden block. Additionally, it will play the role of a handle.
Stick a switch on the bar so that you can de-energize the string.
Then connect 2 wires to the connector. After that, connect to the switch, and then bring each one to a separate pencil. So that the wire does not sag and does not interfere with work, it is fixed with electrical tape. To ensure a reliable connection quality, you need to solder the wires to the connector. The joints must be insulated with heat shrink tubing or electrical tape.
Clean the other end of each wire from the braid and screw it to the copper wire. Solder the connection.
Thread the nichrome thread into the rings of copper wire and fasten to them. The string should be taut between the pencils. When heated, it stretches and sags a little. The stronger the tension, the less sag.
Insert the batteries into the connector and start cutting the foam sheets.

Thus, you can make a simple do-it-yourself foam cutting device. And another version of the manufacture of the machine, see the video:

DIY foam cutting machine

Cutting machines are more convenient because the cutting thread is fixed in them and only the foam needs to be moved. This allows you to increase the accuracy of movements. In the manufacture, you will need the same tools and equipment as in the previous case.

First you need to make a table, which is a wooden base with small legs. The table must be flat and smooth to prevent deformation of the foam. The dimensions of the base are chosen arbitrarily. A bar is screwed perpendicular to the tabletop, and a wooden crossbar is attached to it at an angle of 90 °. Then it is necessary to strengthen the structure with a jumper.

An angular ruler marks the place where the filament will go. If the surface is fairly flat, this can be done with a plumb bob. To do this, a self-tapping screw with a wide head is screwed into the end, and a thread with a load is wound onto it. A hole with a diameter of 6 mm is drilled in the selected place. To prevent the string from burning the wood, a plate of textolite or metal is installed. The material should be placed flush with the surface.

A wire is threaded into the hole, the lower end of which is put on a self-tapping screw. The screw is screwed in next to the hole. The length of the spiral should be such that when heated, the latter becomes red. Since the wire lengthens at high temperatures, a compensating spring must be used to avoid sagging. A spring is mounted on the upper self-tapping screw, and a nichrome thread is attached to it.

An energy source is connected to the ends of the thread, which can be a battery with a voltage of 11.7-12.4 V. To regulate this indicator, a thyristor regulator circuit is used. The regulator can be taken from an electric grinder. You can also control the voltage using a spiral on a polystyrene foam cutting machine.

This spiral is mounted on a wooden bar, to which the upper edge of the filament is attached. Connected to the wire in series. Its function is to lengthen the nichrome thread and, accordingly, reduce the voltage. This can be achieved by changing the place of connection to the nichrome spiral. The shorter the distance, the more the thread heats up and the more the foam melts.

If a transformer is connected to the machine, it must be galvanically isolated. In this case, a transformer with taps must be used.

For smooth and even cuts, you need to make a guide rail. It is made from a bar or any other even material.

With the help of such a simple machine, foam cutting is carried out with your own hands. Additionally, you can make different devices. You can make a miter box with your own hands or a tray during the repair, which will help you cut the material evenly at the right angles.

3D foam cutting technology

Expanded polystyrene products have become widely used for marketing and decorative purposes. Company logos are made from expanded polystyrene, names, various figures, decorative elements, etc. are cut out. Therefore, 3D cutting has gained wide popularity. The use of foam allows you to save money and at the same time get a high-quality and durable product.

Volumetric cutting is carried out on special machines. They cut the material using long strings or a laser and allow you to give the foam any shape.

Figured cutting of foam

Figured cutting of expanded polystyrene is carried out on special machines. Some of them are equipped with CNC. When working on the machine, the thickness of the foam sheets does not matter. However, for simple cutting, you can use a simple do-it-yourself cutter.