Good day brain artisans! Somehow our team needed a vacuum forming table to create a variety of homemade, but there was no large-sized table for sale. Without thinking twice, we made it with your own hands!

Step 1: Table box

A vacuum table is essentially a hollow box with many small holes through which air is pumped out of the workspace. We chose MDF to create this box, but any durable sheet material will do. So, we create a table box from MDF and drill small holes in the front panel, it is possible on the machine, or we can do it as usual brain drill.

We attach the legs to the box, and install partitions with large holes, about 7.5 cm. These partitions will keep the table flat and will not allow it to sag.

Step 2: Heat Source

Initially, we planned to use nichrome wire as a heater, but it is quite expensive and difficult to obtain. Therefore, we settled on GU10 halogen lamps, which give little light, but give enough heat.

We drill holes in the metal sheet for ceramic lamp holders and install these lamp holders. Further, for ease of installation of the circuit, in order to reduce the amount of soldering, we create from printed circuit boards conductive tracks, we mount them, and already the tracks are soldered into a circuit. For this panel with MDF lamps we make a box with a removable braincap for maintenance, and place the light panel in this box accordingly.

Step 3: Management

The option of the heat source we have chosen allows us to heat not only the entire table, but also, if necessary, only some of its sections when forming small crafts. Of course, connecting the lamps becomes more complicated.

The table control unit consists of several elements:

• The front panel on which an alphanumeric LCD display, LED indication of each heating row, a key for turning on the table, an emergency stop button for the table, and switches for the table operation modes are installed.
• An ATmega644 microcontroller board that works with firmware written in C. A table temperature sensor, a pressure sensor, an LCD display, front panel mode switches, and a heater power control relay (light bulb lines) are connected to this board.
• controller board alternating current, which synchronizes the signal from the microcontroller, the triac and the AC line.
• Relay board, which consists of 6 electromechanical relays controlled by a microcontroller. One of the relays turns on the fan, and the rest of the heater lines.
• Neutral relay board, which consists of 7 relays controlled by a microcontroller and connecting the heater lines to the neutral wire, as well as a temperature sensor in the table space.
• Triac, consisting of two opto-isolated thyristor solid state relays, rated at 20A, 240V, which regulates the fan and the heating of the table space.

Step 4: Installing the supports

On our table box crafts, and by the way, it is 600x900mm in size, we mount supports for the heater panel and install the panel itself with lamps. We also make a frame for plastic and insert it into the bearing supports, seal the junctions of the table box and the frame with insulating porous tape.

Step 5: Vacuum Fan

To the bottom of the box braintable we fix the vacuum source, just a fan. For our vacuum fan, we made an additional plate of MDF and with its help, as well as with the help of neoprene gaskets, we installed it.

Step 6: Final assembly and testing

At the final stage, we connect all the elements, check whether everything is installed correctly and proceed to testing. We insert a sheet of plastic for molding into the frame, turn on the table and mold!

And here is how our table works:

good luck homemade and I hope our guide will help you with this!

The manufacture of a vacuum table is the most important stage in the design of a thermo vacuum press with your own hands. At the design stage, it is necessary to determine the dimensions of the table, choose the material for its manufacture, consider ways of fixing and sealing detachable elements to maintain internal negative pressure (vacuum). The vacuum table is made with the same basic set of tools as.

Further in the text, a vacuum bath will be called a part of the vacuum table - a steel container, inside which the lined workpieces are located, and from which air is pumped out. Under the working dimensions (dimensions) of the vacuum bath, we mean its useful volume, measured by internal dimensions. Let's agree to call the vacuum table the entire structure as a whole, consisting of a vacuum bath, an upper (movable) clamping frame, clamps and other, smaller elements.

External and working dimensions of the vacuum bath.

Consider general principles choosing the size of the vacuum bath, let's designate specific numbers for our press.

The longer the vacuum bath, the more blanks you can fit in it, or veneer a larger workpiece. On the other hand, the longer the bath, the more film has to be consumed in one working cycle, the larger the dimensions of the machine are, which entails a greater consumption of room space. Need to find optimal size. As experience has shown, the optimal working length of the vacuum bath, intended for the manufacture of standard furniture facades and decorative door linings, we can consider the value from 2.4 to 2.6 m. We will make a vacuum bath 2500 mm long, the working length of which will be 2500 - 40 x 2 \u003d 2420 mm (40 mm is the width of the short wall profile pipe).

The width of the tub is directly related to the width of the PVC film used. Depending on the film manufacturer, there may be various meanings width, the most common is 1.4 m, and we will focus on it. We choose the width of the bath equal to 1400 mm, the working width will be 1400 - 40 x 2 = 1320 mm. When facing high blanks, for example, for curved (radius) facades, the width of the bath must be reduced (make it smaller than the width of the film), but to work with such blanks, a press of a different design is needed, so these issues will not be considered.

The working height of the bathtub must be calculated taking into account the fact that there must be a small free space between the upper surface of the facades and the covering film. In other words, the film stretched over the blanks should not touch them before the air is pumped out. The calculation is the following. Firstly, the vacuum (breathable) table top that will be placed first on the vacuum table will be made of MDF boards 10 mm thick. Secondly, the linings for the facade blanks will be small pieces of MDF board 16 mm thick (this is the simplest, most common and best option linings). Thirdly, the thickness of the coated blanks will be from 8-10 mm (door linings) to 16-32 mm (facades and other furniture elements). Fourthly, the sealing rubber will add about 2 mm to the depth of the bath. Eventually, maximum height the entire "pie" inside the bath will be: 10 + 16 + 32 = 58 mm. For the manufacture of a vacuum bath, we use a profile pipe with a cross section of 60x40 mm, placing it on the short side. At the same time, the height of the free space will be at least: 60 + 2 - 58 = 4 mm, which is quite enough.

Making a vacuum table.

Vacuum bath.

The bottom of the vacuum bath will be a sheet of steel 2 mm thick. To minimize sheet deflection under negative internal pressure, and to give the table surface an even shape (close to an ideal plane), it is necessary to make a stiffening frame. For the manufacture of the frame, we will use the same profile pipe 60x40x2. The pre-cut pipe, in accordance with the project, is laid on the slipway, rigidly fixed with clamps, and all joints are welded. After making the stiffening frame, a steel sheet is welded on top of it. This is the most important step welding work, it requires a continuous weld to be sealed (double penetration is recommended).

In order to avoid warping of the sheet under the influence of prolonged high temperatures, you can use the following: alternative method welding the sheet to the stiffening frame. Before styling steel sheet on the stiffening frame, along its perimeter, it is necessary to apply a sealing compound that can withstand high temperatures (for example, high-temperature silicone sealant), and welding should be carried out not with a continuous seam, but with small regular fixing tacks with a pitch of about 50 mm. This method It is designed that short-term, local impacts of welding cannot damage (burn out) the entire sealant, but only a small part of it in the immediate vicinity of the tacks, while most of the sealant after curing will perform its direct function.

Vacuum table dimensions.

Detailing the stiffening frame and the procedure for assembling the vacuum bath: the stiffening frame is welded, a steel sheet is welded to it, a stationary (lower) frame is hermetically welded along the perimeter of the steel sheet with a part of the swivel joint for attaching the lifting (upper) frame.

Photo of the vacuum table from below.
The stiffening frame is made partly from an angle profile.

Lifting (clamping,top)frame.

Frame material - profile pipe 60x40x2 mm. The dimensions of the pressure frame must be exactly the same as those of the vacuum bath. If it was not possible to find a sufficiently even (not bent, not twisted) profile, then it is necessary to select in advance in pairs several of the most even whips, from which parts of the vacuum table that are tightly adjacent to each other will be made.
The pressure frame will rise thanks to the adjustable swivel joints. The hinges are adjusted after gluing the sealant - strips of sheet rubber of medium hardness, about 2 mm thick.

Welded washers are needed to increase the friction area. The swivel pin is a D12 steel bar with threaded ends.

Gas lifts can be used to hold the pressure frame up. For safety reasons, it is recommended to install four gas lifts (two per side) and make sure that any three of them are able to hold the frame. If the opening angle of the frame (45°) turns out to be insufficient, the frame will cause significant inconvenience in work, it can be raised as far as possible up to an angle of slightly more than 90°, using the thermal module parked behind as a support (gas lifts are not used).

Clamps.

To securely and tightly hold the film during vacuum pressing, it is necessary to firmly and evenly press the upper frame to the perimeter of the vacuum bath, achieving a ubiquitous fit. rubber seal. For these purposes, you can use various ready-made clamps, clamps, or you can make them yourself.
For the manufacture of homemade clamps, working on the principle of an eccentric, you will need the following steel rolled metal: half a meter of a DU50 pipe (outer diameter of about 60 mm), two meters of a rod with a diameter of 10 mm, and about the same amount of a profile pipe with a cross section of 20x20x2 mm.

Firstly, the DU50 pipe is cut into 8 equal 60 mm segments. Each section of the pipe is finished with a semicircular central cut having a width of 10-11 mm and an arc length equal to 3/4 of the length of the outer circumference of the pipe. We will get 8 pieces of eccentric rotary cylinders, to which it is necessary to weld a handle 220 mm long from a square profile 20x20 mm.

Secondly, the steel bar is cut into 16 pieces: 8 pieces 190 mm long (for studs) and 8 pieces 55 mm long (for pivots). It is necessary to weld an M12 nut (or M10 with a drilled thread) to one end of the stud so that it can rotate freely on the pivot, and cut the M10x50 thread at the other end.

Thirdly, to complete the manufacture of the clamp, we weld the ends of the kingpin (with a nut with a welded stud previously put on it) to the inner surface of the eccentric rotary cylinders.

To install the clamps on the vacuum table of the press, at eight points of the table, according to the project, they drill through holes 10 mm in diameter. After that, the upper holes are enlarged, giving them an oblong shape. The clamps are adjusted by setting combination nuts in the right place of the thread of the stud, followed by fixation with locknuts. This operation is performed at the last stage of manufacturing a vacuum table, after gluing a rubber seal.

Elements and dimensions of the swivel clamp.

Hooks for clamps are made of steel angle 50x50x3.

If it was not possible to achieve a flat surface of the table.

If during the welding process the sheet has undergone significant deformations that go beyond the permissible values, then pick up a grinder and cut off the welds, there is no need to redo everything again. It is possible to provide a perfectly flat plane of the vacuum table with additional measures, namely by using epoxy leveling compounds, which are used in the manufacture of poured floors. To do this, the vacuum table is set strictly according to the level, the required volume of bulk mass is determined (for example, using a test filling with water), the bottom of the vacuum bath is cleaned of rust, and primed. Fill with the prepared epoxy mixture according to the manufacturer's instructions. For reasons of economy, the mixture can be diluted with some cheap filler, for example, quartz sand. To speed up the curing of the mixture after pouring, the table can be heated from above in a controlled manner with the heat from the thermal module. It makes sense to carry out this filling leveling operation after the complete readiness of the vacuum press, the production of test samples of the product, and the decision on the need to improve the geometry of the working surface.

Estimated material for the vacuum table.

Upon completion of the main scope of work, the vacuum table is installed on the frame (on specially provided supports) and fixed at the corners with four bolts, as shown in the figure, after which they proceed to minor work: installing and adjusting the clamps, adjusting the lifting frame hinge, gluing the seal.

The metal structure begins to take shape of the future thermal vacuum press, but it still lacks many elements: a vacuum system, a thermal module, an electrical control unit, which will be discussed in the following articles.

The vacuum table makes it much easier and faster to install on the table milling machine CNC sheet materials. It can be both MDF sheets and acrylic ... Moreover, if the sheet is curved, then the vacuum fastening allows it to be leveled for the duration of work.
If MDF is regularly processed on the machine, then the machine is probably equipped with a powerful hood (a vacuum cleaner for collecting chips and wood dust - see photo below). Such a hood with a power of 2.2 kW is able not only to remove sawdust from the cutting zone, but also to ensure the operation of the vacuum table.

ATTENTION! Safety of work is guaranteed only under certain conditions: the size of the cutters must not exceed the allowable workpiece clamping force, the cutting mode is only tested with the existing vacuum table. Otherwise, it is possible to tear off the workpiece during processing, which is fraught with injuries with severity up to a fatal outcome.

The vacuum table is made of two layers of MDF 20mm thick. Upper layer- front - is needed for suction of sheets of the processed material. The channels on it are divided into six zones (see photo below), which, if necessary, can be muffled one at a time, depending on the size and configuration of the workpiece being processed. The cross section of the channels is chosen so that, if necessary, each zone can be sealed along the contour using a D-shaped household rubber sealing tape (tape for sealing windows and doors). The tape is equipped with a self-adhesive layer and is well fixed in the channels. The depth of the channels is chosen so that the workpiece, when the vacuum table is turned on, lies on the surface of the table, pressing down on the sealing tape.

The lower layer of the vacuum table serves to supply vacuum separately to each zone of the upper layer of the table.
In the channels of the upper layer, vertical holes are made for bypassing the rarefaction from the channels of the lower layer to the channels of the upper layer. There are 4 such holes. for each zone. However, the more of them, the better.

The easiest way to connect a vacuum table to a vacuum cleaner is with a ubiquitous pipeline, such as a sewer (see photo below). It is both cheaper and technologically advanced. The photo shows that a sewer pipe with a diameter of 110 mm was used to supply vacuum to the machine. Vacuum is supplied directly to the machine by six corrugated hoses with a diameter of 50 mm. Each corrugated hose is attached to the vacuum table by means of a fitting screwed into the table.
All connections are hermetically sealed with either standard seals or clamps (preferably with a sealant).

Before assembling the table, all its channels should be treated with PVA glue or a primer to ensure that the MDF is impermeable to air (MDF does have good air permeability).
The top layer of the vacuum table is screwed to the bottom with self-tapping screws. So that the caps of the self-tapping screws do not interfere with the work with the table, holes are made in its surface into which the caps are recessed.
After assembling the table, its surface should be machined with a milling cutter to ensure that the surface is flat.

Summary

As can be seen from the photo, a 2200 W vacuum cleaner is used in this design. Such a vacuum cleaner has a tee at the inlet for connecting three air ducts with a diameter of 100 mm. In the course of all work, one hole of the tee was occupied by a vacuum table, the second - exhaust system with a 50 mm inlet. The third hole was half open to prevent overheating of the vacuum cleaner due to low air flow, because the vacuum table does not provide air consumption at all, the hood has an inlet of only 50 mm, i.e. the cross section of the inlet would be only 50 mm instead of 3 holes with a diameter of 100 mm. With this connection, the power of the vacuum cleaner turned out to be sufficient for the operation of the vacuum table and the system for suction of chips from the cutting zone.
The clamping force of the workpiece on the table depends strongly on the clamping area. A workpiece made of MDF with a size of 600x900 mm can be processed with a milling cutter with a diameter of 6 mm with a full diameter to a depth of 6 mm in one pass at a feed rate of 2000 mm/min. In this mode, such a vacuum table is able to hold the workpiece.
For greater reliability, it is recommended to use stops along the edges of the workpiece so that the workpiece cannot be moved during processing. Such a solution will be useful, for example, in case of failure of the vacuum table during operation or in case of unauthorized excess of the cutting force. At the same time, the complexity of installing the workpiece on the machine table will not change, and possibly decrease (the stops will allow you to put the workpiece in the same place).
In addition, it should be borne in mind that the workpiece on the vacuum table can easily be torn off by vertical force. When planning processing, this should be taken into account and cutters that create lifting force during operation should not be used.

Using the power of a vacuum pump.

The desktop of the milling machine itself is a horizontal surface that is designed to work with the part (it is fixed and securely based on it). This detail of the milling machine is considered one of the most important - if the workpiece is not reliably and evenly fixed relative to the movement of the cutter, then accurate and efficient processing will become unreal. Both the table and the cutting tool can move.

Work table of a milling machine with a numerical software it is supplied with grooves of the longitudinal type, where a number of clamps are placed to secure the workpiece for processing or other necessary devices. But fastening with clamps has several disadvantages:

There must be a mechanical clamping of the workpiece, while the tightening force is set to the maximum.

Deformation and mechanical damage to the front part of the manufactured part. Such consequences are absolutely undesirable for working with glass boxes equipped with lighting - even the smallest scratches and cracks in them can completely spoil the appearance.

If the workpiece differs in some non-standard dimensions and shapes, then it is not always possible to find the required location due to the lack of symmetrical holes.

Difficulty with placement soft materials, which can bend when the cutter touches them (these are composite models with rather large dimensions). A large number of clamps cannot be installed on the table, so working with these types of workpieces is very complicated.

All the inconveniences listed above are solved quite simply - it is worth installing a vacuum table. It helps to securely fix the workpiece in the right place for precise milling, while mechanical clamps are not used. The very essence of the work is that air is pumped out, and thereby the pressure between the work table and the surface of the workpiece decreases. Thus, a kind of “suction cup” is obtained, firmly pressing the part by means of atmospheric pressure. This helps to firmly and securely fix the workpiece in the desired position.

However, the vacuum table also has disadvantages:

- the inability to fix very small parts on it or parts that are not sheet materials.

Usually, all manufacturers, when equipping the machine with a vacuum table, also leave the possibility of fastening with clamps, however, they are much smaller and they are no longer located as often as in a conventional table.

- The compressor that maintains the vacuum is required to be quite powerful from 5kW, which usually leads to an increase in energy consumption by a milling machine almost twice.

Therefore, each manufacturer must carefully consider the pros and cons of vacuum fastening and make a choice for himself.

Varieties of vacuum tables

Vacuum tables are divided into several varieties depending on the type of fastening of workpieces:

Trellised. This type is most common, since it is easier to install, and the cost is democratic. Thanks to the unique lattice design, it allows you to place required amount insulating material to enclose the workpiece around its perimeter. From the resulting circuit, the pump pumps out air, thereby reliably pressing the part to the surface of the desktop.

Vacuum tables VAC-MAT type. Represent the rigid strong framework made of polymer. It divides the space between the workpiece and the compactor into a number of sectors isolated from each other, from which air is then simultaneously pumped out. Thus, the vacuum is maintained even with a through type of milling, the compartments are not amenable to depressurization.

Slotted variety. They are indispensable when working with small workpieces, or with those parts on the surface of which there are many holes. Such a table is equipped with a number of grooves and compartments, some of which can be combined (if the holes match those on the workpiece).

Porous boards. They are recommended for working with very thin material (like foil sheets, for example). It can accurately reproduce the shape of the workpiece, the degree of impact depends on what area the "substrate" occupies. This vacuum material allows to achieve high precision in processing, to avoid errors. Collaboration with the coolant system is not allowed.

board type FLIP POD. This is a large number of individual suction cups, valves, which are designed to securely fasten even fairly massive workpieces. Such a system of vacuum tables does not involve covering the perimeter of the workpiece with a compactor, which makes it possible to process cutting tool edge of the part.

Almost all manufacturers of CNC milling machines program management offer to optionally complete their products with a special vacuum table. It is installed quite simply, no special operations are needed to carry out and reconfigure the equipment - you only need to connect a compressor or a vacuum pump.

Vacuum tables for CNC machines - a vacuum surface designed for fixing workpieces and sheets ready for milling and curved cutting. Its dimensions may be different, depending on the dimensions of the existing machine, and the working surface is evenly divided into sectors.

The sections of the milling machine are equipped with grooves for uniform distribution vacuum over the entire area of ​​the table and holes that act as suction cups that ensure the immobility of the material.

Types of vacuum tables for CNC

Modern industrial stores offer to buy a vacuum table for a CNC router, made using a special technology and allowing you to work with various materials: wood, metal, thanks to the reliable attachment of the workpiece to the work surface. Also, the device allows you to easily change tools, which speeds up the workflow and improves the quality of the finished product.

Today you can buy such a vacuum table for CNC:

• Lattice.
• Turning.
• Slotted.
• With inserts made of porous materials.

Lattice vacuum table

Lattice vacuum table for CNC milling machine is popular with enterprises of various sizes, because such equipment creates closed loop work piece. During the processing of the material, it is laid on work surface and a vacuum is applied, as a result of which the sheet sticks to milling table throughout the anchorage area.

If there is a second lattice table and if it is necessary to increase the working area, it is possible to connect the vacuum boards to each other. Also, the device allows you to work with round blanks.

Rotary vacuum table for CNC

According to the principle of work rotary machine does not differ from the lattice, however, it is able to rotate, which simplifies the workflow. Connecting a vacuum hose in this case is acceptable both in the central part of the table and in the end part of the board. As a result, it is possible to produce longitudinal, vertical and transverse movements on the treated surface.

Additionally, Rotary table allows you to create the necessary angle of inclination to process a rounded or spiral object in various planes, perform milling, rounding, or transitions.

Slotted vacuum table

The slotted vacuum table is designed to work with products that have many holes and small details. Such a device has a high coefficient of friction, resulting in an increased vacuum force and reduces the risk of shifting the processed object from the designated location.

In the process of work, a frame (flat) with holes under the work object is laid out on the surface of the table. Further, the resulting frame becomes an auxiliary fastening material.

Modern manufacturers offer to buy a slotted vacuum table for CNC at a bargain price, so many enterprises use it as a main or auxiliary board.

Tables with porous inserts

Vacuum tables with a porous insert allow you to work with an object without the use of foil and other thin materials, as well as without reconfiguring the table for another type of work. The porous blocks of the device can be made of aluminum, bronze or steel material, as well as from compressed porous raw materials.

This board is designed to work with any shape of the object, but the strength of the fastening will depend on the area of ​​the processed material, the table and the final quality of the work performed.

How to make a vacuum table for CNC with your own hands

Despite the offers of stores, some people prefer to make such a device on their own. However, given the complexity of the procedure, the master will need to stock up on patience and materials.

To make a vacuum table for CNC with your own hands, you will need drawings, tools and an understanding of the principle of operation of the device. Usually, MDF and metal sheets are used for this (for the manufacture of a table box), in which holes are drilled with a drill and legs are attached to the resulting box. Then, non-chromium wire or halogen lamps are placed there, used as a heater.

Also, you will need to place in the device:

• Fan.
• Neutral relay.
• AC controller.
• 6 electromechanical relay boards.
• Symmetrical thyristors from 20A and 240V.
• Front panel with LCD display.
• Temperature sensor, mode switch, pressure indicator, etc.

Despite the complexity of manufacturing the structure, some craftsmen still perform its installation. However, buying a vacuum table is much more reliable, because it uses original spare parts and technologies that increase the service life.