Vacuum clamps. vacuum tables. Necessary materials and tools

Using the power of a vacuum pump.

The desktop itself milling machine- this is a horizontal surface that is designed to work with the part (it is fixed and securely based on it). This part of the milling machine is considered one of the most important - if the workpiece is not securely and evenly fixed relative to the movement of the cutter, then accurate and efficient processing will become unrealistic. 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 face of the part to be made. 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 it very small parts 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 you to achieve high precision in processing, avoid errors. Collaboration with the coolant system is not allowed.

board type FLIP POD. This a large number of separate suction cups-valves, which are designed for reliable fastening of 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 offer 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.

Often, CNC (Computer Numerical Control) machines are sold with a vacuum table. It is designed for fastening sheet parts with their subsequent processing. As a rule, the processing of such blanks is curvilinear in nature.

At the same time, parts can be made from the most different materials- Chipboard, veneer, plywood. Most often, vacuum tables are used for milling machines that process solid sheets (for example, in the manufacture of furniture).

What does a vacuum table look like?

This device is a surface for processing with a coating divided into sectors. Special suction cups and grooves are evenly distributed over the area of the device, which fix the workpiece in the required position. The larger the area of the vacuum table, the more functional and expensive it is.

Workpieces are fixed thanks to a special vacuum pump. It is he who is responsible for the reliable fastening of the workpiece to the surface of the table. Thanks to this invention, the curvilinear processing of sheet parts with large dimensions has become possible.

It is noteworthy that vacuum cleaners are used preferably for processing wooden blanks. If there is a need to perform similar work with metal, then magnetic tables are used for this purpose.

It should be noted that depending on the size and functionality, the price of vacuum tables can fluctuate significantly. At the same time, even the cheapest factory vacuum table will cost the buyer at least 150-170 dollars.

You can also buy a used device, but the quality of such a table will always be in question. It is because of the factors listed above that many craftsmen create vacuum tables at home.

How to make at home?

Vacuum Retainer for Plastic Molding

It is possible to make such a device at home, but this is not an easy task. You need to understand the specifics of the device and the principles of its structure. Any stable sheet material, such as MDF, is suitable for forming a vacuum table. We create the contours of the table according to the type of box and drill holes on the front side of the panel using an ordinary drill.

We attach special legs to the same box and install partitions with holes with a diameter of 7 to 8 centimeters. We do all this to add stability to our table and prevent it from deforming during use.

Energy source (for plastic molding)

Non-chromium type wire is often used as a heater. This approach entails rather high costs, besides suitable material quite hard to find. Alternatively, halogen lamps can be used. It is better to sacrifice the level of heat, but get affordable and efficient heaters for a homemade vacuum table.

Halogen lamp sockets should be installed in pre-drilled slots in the sheet metal. From printed circuit boards we make tracks for current wiring, install them on the base and only then solder them. Otherwise, you will have to spend a lot of time soldering the tracks. The panel with bulbs should be in a box with a cover that will allow maintenance of the device.

This approach to creating a heat source allows you to heat the entire area, and if necessary, only individual sections. But to make such a "smart" device, you need to pay more attention to connecting lamps.

Control system

Key controls of the vacuum table:

Symmetrical thyristor with operating parameters from 20A and 240V. Its function is to regulate the heating process and coordinate the operation of the fan.
Front panel with liquid crystal display. The table interface should display the status of each heating row. The panel also contains a device activation key and an emergency shutdown button.
Board with electromechanical relays (6 pieces). 5 relays activate the heater lines, and the sixth - the fan.
Table temperature indicator.
Neutral relay board. It consists of electromechanical relays (7 pieces). Their function is to connect the heater lines to the neutral cable.
Microcontroller with board (ATmega644). It is to this device that a temperature sensor, a pressure indicator, a display, a mode switch, a relay board are connected.
Node control over alternating current. Its function is to match the signal of the microcontroller, symmetrical thyristor and lines with alternating current.

Installation of supports for heaters is carried out on a box that was previously prepared. After that, install the heater panel. It is also necessary to install a special frame for plastic. We insert it into the supports on special bearings. To better fix the frame around the perimeter of the table, use insulating tape.

The key element of the vacuum table is the fan, which must be attached to the underside of the box. It is worth noting that the vacuum source can be mounted using an additional plate and neoprene type gaskets.

After the final creation of all the key elements of the vacuum table, you can proceed to its installation. Before testing, you should check the quality of all connections, the continuity and safety of the electrical equipment of the machine and the table.

A similar type of table, but without heating lamps, is also suitable for a milling machine. Thus, we have described for you the independent development and installation of the most complex type of vacuum tables designed for plastic processing. To work with metal or wood, it is enough to correctly make only the lower part of this device.

Instead of a fan, as a source of vacuum can be used powerful pump. In the place where the plastic table has heating elements, you should have a milling machine.

Video: vacuum table.

Important nuances

A special vacuum generator can be used as a vacuum source. It looks like a small box with an air outlet and a vacuum inlet. Also, for devices of this type, an indicator must be installed to measure vacuum indicators.
The ejector and the level of its performance depends on the speed and volume of air that fly past it. That is why, it does not benefit much compared to a conventional vacuum pump. Indeed, to create a high-quality vacuum, a high-quality compressor should also be used. The fact is that a rather weak compressor is enough to fix a large part over the entire area of \u200b\u200bthe table, but to fix a small plate, you need to use a more powerful unit.
A conventional industrial vacuum cleaner is not well suited for creating vacuum clamps, as it is not well suited for working with a completely closed hose. That is why it is recommended to use a special vacuum pump.

With details large sizes a large vacuum table is needed. Such equipment is very expensive due to the complexity of transportation and is not always suitable for certain tasks, but you can design a table yourself, under custom size and needs.

Vacuum tables for CNC are designed for milling machines with large sheets of wood or metal. Most CNC machines use curved machining. To work on milling machines, you need a surface that securely fixes the workpieces. vacuum table presses products to the surface, preventing them from moving, making work on the milling machine more accurate and comfortable. In addition, high-grade equipment provides heating to the desired temperature. It is more versatile than a magnetic table, which is only suitable for processing metal products.

Quite often, CNC milling machines come with a vacuum table, but if it is not available or is not large enough, another device is required. In this case, you can buy a used device of dubious quality or make it yourself.

Necessary materials and tools

To make a vacuum table for a milling machine, you need to find all the components. To create functional equipment you will need:

wooden or a metal sheet appropriate size;
metal profile;
Vacuum pump;
a heating element;
Control block.

From the tool you will need: drill, screwdriver, spanners, soldering iron. Other tools are optional, subject to availability.

Manufacturing steps

After acquiring all the necessary materials and tools, you can proceed to self assembly table.

Production of a working surface and a box

At the beginning of the manufacture of a vacuum table for CNC with your own hands, you need to create a work surface. For this, a pre-prepared sheet of material is taken. Holes are drilled in it neatly, in a checkerboard pattern with a drill or screwdriver. Later, from the back, the surface will adjoin the vacuum pump, which serves to securely fasten the products. To increase the reliability of the structure, partitions are installed. They do not allow the table to deform during operation.

Box

The most significant here is the height, since the table is designed for a CNC machine. A stable structure is assembled from metal and wooden parts for fixing working surface. The surface above the work area will act as a holder for the heating element. It is desirable that the box be collapsible: this will facilitate further work, setting up equipment or transporting the table in the future.

The desktop should be as stable and reliable as possible. Therefore, in the design it is desirable to avoid short-lived or moving joints. Adjustable height feet can be used to facilitate instrument repositioning. This will allow you to work on uneven surface providing stability.

A heating element

Vacuum forming plastic also requires a special table. During operation, the product is affected by a vacuum field and a heating element that heats the plastic to the required temperature. To do this, a heating panel is installed above the table. As a heating element, nichrome filament has proven itself best. However, due to the high cost of the material, as well as the difficulty in finding it on free sale with self-manufacturing usually halogen lamps are used.

Among the advantages of using it should be noted uniform heating, as well as quality lighting working area.

A sheet of metal is taken as a blank. Holes for lamps are also drilled in it, after which the heating elements are fixed and the electrical part is installed. All lamps must be connected in parallel. With more complex design the electrical part is output to the controller or separate switches for heating certain parts working area. The connection is made by soldering and copper wires. In order to reduce the wiring, more pleasing appearance, more convenient operation and more reliable wiring, it is recommended to use printed circuit board or several small boards. The design of the light panel must also be dismantled for maintenance.

Vacuum pump

The most important piece of equipment. Serves to create a vacuum and securely fix the part. It is best to use a specialized vacuum generator with a pressure gauge. In the absence of a specialized vacuum pump, several vacuum fans will do. It is possible to replace industrial vacuum cleaners, but in practice their efficiency is lower.

When connecting, it is important to minimize the air flow, that is, to insulate from the inlet to the work surface. A pressure gauge is needed to measure results: too much vacuum can damage the part, work surface or equipment. With a more complex design of the tables, the heating part regulators and the pressure gauge are installed in the control unit.

Control block

The electronic part of the vacuum table is needed to effectively regulate the heating of the working area and create a more stable fixation of parts. There are many options for implementing the control unit, the milling machine and the numerical control installed in the working equipment play the biggest role here. The most optimal is selected based on the tasks, budget, availability of specific elements. For optimal performance requires a microcontroller with a display and one relay per control unit.

For comfortable work temperature and pressure sensors are used. With a minimum configuration, one sensor and 2 relays are required: one for turning the pump on / off, the other for control heating panel. To delimit the working area, use the clamp and heat only for part of the table, it is necessary to use a larger number of relays and, accordingly, a more efficient controller. Installing a reliable control unit will make work more comfortable, and will allow you not to be distracted by the pressure gauge.

Vacuum workpiece clamping: pumps or blowers?

Currently, in various industries of processing metal, wood or plastic products, instead of mechanical devices, the so-called "vacuum clamp" is used to hold the workpiece on the desktop. With this method of holding, a force is used that presses on the workpiece, pressing it against the table, from which air is pumped out and a vacuum is created. This force, pressing the workpiece, appears immediately after the start of pumping air out of the table and disappears when the air enters there again.

The clamping force can be estimated in the usual values and calculate what it can be. Since it is a consequence of the vacuum created in the table on which the workpiece is located, or rather the difference in air pressure inside and outside the table, its maximum value is equal to the product of one atmosphere and the area of the pressed workpiece. Since it is impossible to pump out air deeper than one atmosphere, then the “working pressure” for creating this force cannot be more than 10 tons per 1 square meter.

What devices allow this method to be implemented?

The most correct, reliable and effective is to use vacuum dry rotary vane pumps. These pumps, although they do not create the theoretically possible maximum vacuum that guarantees the coveted 10 tons per square meter, are capable of pumping out 88% of the air to create a pressure drop of up to 8.8 tons per square meter. At the same time, unlike, for example, oil ones, which have a better residual pressure indicator, they are more convenient in operation and are better adapted to work at intermediate pressure values (below atmospheric, but above the limiting residual pressure). In addition, like all vacuum pumps, they are not afraid to work with completely closed suction and discharge pipes.

The second in terms of correctness and popularity of application (which, by the way, is constantly growing and is already comparable to the popularity of pumps) are vortex blowers. If you connect a vortex blower with a suction pipe to a vacuum table, then it, working as a pump, is also able to create a vacuum, but it is 2-3 times worse in terms of vacuum depth than when pumping out with a rotary vane vacuum pump. That is, the blower (with the exception of special high-pressure series) is in principle not capable of creating a vacuum deeper than 0.4-0.5 atmospheres. In addition, it cannot work for a long time with closed pipes, as it will fail if it overheats. This is where their weaknesses end and one can understand why in many cases they are preferred to rotary vane pumps.

There are many types of material processing on vacuum tables, when, in principle, a large clamping force is not required, or when, due to the large area of the workpiece, even a small pressure can create sufficient clamping force. This applies primarily to the processing of plastic and wood panels. The second important argument in favor of blowers is the size of the table and the impossibility of creating an absolutely hermetic evacuated volume - there is almost always a reverse movement of air into the system. Therefore, the pumping speed comes first - it is it that compensates for the leakage. Pumps with capacity over 150 cubic meters per hour is always more expensive than blowers with the same pumping speed and heavier than them. And when customers see the maximum performance in the characteristics of the blower (one and a half to two times higher than the actual one at the duty point), the blower, as an alternative to a vacuum pump, seems even more attractive.

Let's summarize. In which case to choose a pump, and in which blower?

If the dimensions of the table do not exceed 3-4 meters in length, the details are small, of complex shape, the vacuum table is made with high quality (with a good fit of parts and without possible leakage), it is required to obtain a pressure drop of at least 5 tons per square meter, then best solution will rotary vane oil-free pump.

When the tables have linear dimensions of more than 5 meters, the workpieces being processed are also large, have a small specific gravity, the tangential load (shifting the workpiece) is small and is compensated by a clamping force of about 10 tons on the entire part, which has an area of several square meters, the rigidity of the table does not guarantee the preservation of its shape during vacuuming, the tightness of the system is low, and the cost comes to the fore, then preference is given to blowers.

If you tell us the specific value of the down force, then we can call you and offer specific model pump or blower.

Vacuum clamping machines and fixtures are used in almost all industries. We offer solutions for each of them: from small-sized vortex blowers for holding sheets of paper or plastic in cutting plotters to specialized units capable of withstanding repeated ingress of cutting fluid into the vacuum system.
The performance of the vacuum pump used for vacuum clamping determines the speed of pumping the system to the required pressure and, mainly, the ability to compensate for air leaks through leaks or cuts formed during material processing.
The pressure drop created by the vacuum pump determines the workpiece clamping force. High differential pressure pumps are recommended for applications where maximum down force is required at small area workpiece contact and vacuum gripper.

MSH Blowers for CNC Vacuum Tables

This type of equipment allows high performance with a relatively small pressure difference. Devices of this type are used to press workpieces with a large contact area to the vacuum tables of CNC machines, for example, they can be used to press plastics, vinyl film, plywood, etc. sheet materials. An important advantage vortex blowers with high productivity is that when the tool cuts through the material, as a rule, it remains possible to continue processing, because. air leaks through the slot are compensated by increased productivity. Vortex blowers are extremely unpretentious in operation, have no wearing parts, can be supplied with frequency converters, additional filters, silencers and reversers.

Elmo Rietschle rotary vane oil-free vacuum pumps for vacuum clamping systems

Machines of this type are most widely used in vacuum clamping systems. Not only do they provide enough differential pressure to hold down most types of workpieces and sheet materials, but they can also be quite greater performance. Rotary vane oil-free vacuum pumps operate without the use of lubricants in the working chamber. These pumps are easy to operate and maintain. As standard, pumps of this series already have built-in air filters and mufflers.

Water ring vacuum units ROBUSCHI (Italy) with closed water circulation for vacuum pressing

Used as an alternative to dry rotary vane pumps. These installations can provide almost any capacity required for vacuum clamping. They hardly require Maintenance, resistant to ingress of dust, coolant, can work for a long time with atmospheric suction pressure. At a lower cost for most sizes than rotary vane vacuum pumps, they require no consumables and pay for themselves very quickly.

Vacuum gauges and vacuum switches

In our company you will always find a wide range of vacuum gauges and vacuum relays necessary for monitoring the operation and control of vacuum clamping systems. Our product range includes: mechanical and digital vacuum gauges, mechanical and electronic relays vacuum, as well as other accessories: filters for vacuum systems, inverse and shut-off valves, vacuum receivers, safety valves, fittings, vacuum hoses.

Working with MSH Techno Moscow (MSH Techno), you can be sure that a wide range of supplied equipment will allow you to choose exactly what is really best suited for your tasks. If you have any questions about the equipment presented on our website, we will be happy to answer them!

Systematic Automation has been manufacturing vacuum tables for over 30 years.

Practically perfect surface(tolerance no worse than ± 25µm / sq.ft) - the result of a unique manufacturing technology and the use of high quality equipment. Annually

Systematic Automation manufactures thousands of vacuum tables every year for a variety of unique applications: assembly, CNC, moulding, cutting, digital printers, photography, engraving, textile, inkjet, research equipment, laboratory equipment, laminating, laser engraving and cutting, plotters, sail making, screen printing, ultrasonic cutting machines, presses, carpet cleaning.

Design of vacuum tables

The top of the table is made from durable aluminum alloy 3mm thick. Usage epoxy resin in construction, provides good protection against dents and bends.

The basis of the vacuum table has a "honeycomb" structure and is made of a material that reduces the effect of temperature differences on the uneven surface of the table. The honeycomb design ensures uniform airflow across the entire surface of the table.

The 25x25mm "collector" is located around the honeycomb base, due to which the best possible distribution of vacuum between all the holes in the table is achieved.

Hole size

In the standard version, the holes in the table have a diameter of 1.6mm, and are located in 12.5mm increments, which is optimal for most jobs.

Materials such as 127µm thick polycarbonate or vinyl will not deform against 1.58mm holes with the full force of a standard vacuum pump (see specification).

Optionally, holes can be custom-sized (min. 0.79mm). 0.79 mm holes are countersunk on the underside for minimum losses air streams.

Fastening

All tables have a 9.5mm flange around the perimeter for fastening. If the fitting for connecting the vacuum pump is not located below, but on the side, then the flange on this side will be absent. If necessary, holes for fastening will be drilled in the flange, in accordance with the customer's drawing.

Standard parameters Options FAQ Video

External dimensions of standard vacuum tables. Vacuum holes are located 25mm from the edge.

127x152x30mm. (5″ x 6″ x 1 3/16″)
203x203x30mm. (8″ x 8″ x 1 3/16″)
304x203x30mm. (12″ x 8″ x 1 3/16″)
304x304x30mm. (12″ x 12″ x 1 3/16″)
304x406x30mm. (12″ x 16″ x 1 3/16″)
304x609x30mm. (12″ x 24″ x 1 3/16″)
304x762x30mm. (12″ x 30″ x 1 3/16″)
355x355x30mm. (14″ x 14″ x 1 3/16″)
406x279x30mm. (16″ x 11″ x 1 3/16″)
457x279x30mm. (18″ x 11″ x 1 3/16″)
508x406x30mm. (20″ x 16″ x 1 3/16″)
508x431x30mm. (20″ x 17″ x 1 3/16″)
508x457x30mm. (20″ x 18″ x 1 3/16″)
508x508x30mm. (20″ x 20″ x 1 3/16″)
558x558x30mm. (22″ x 22″ x 1 3/16″)
609x457x30mm. (24″ x 18″ x 1 3/16″)
609x558x30mm. (24″ x 22″ x 1 3/16″)
609x711x30mm. (24″ x 28″ x 1 3/16″)
660x355x30mm. (26″ x 14″ x 1 3/16″)
660x482x30mm. (26″ x 19″ x 1 3/16″)
660x508x30mm. (26″ x 20″ x 1 3/16″)
660x762x30mm. (26″ x 30″ x 1 3/16″)
660x863x30mm. (26″ x 34″ x 1 3/16″)
685x1016x30mm. (27″ x 40″ x 1 3/16″)
711x812x30mm. (28″ x 32″ x 1 3/16″)
762x508x30mm. (30″ x 20″ x 1 3/16″)
762x863x30mm. (30″ x 34″ x 1 3/16″)
762x1016x30mm. (30″ x 40″ x 1 3/16″)
914x914x30mm. (36″ x 36″ x 1 3/16″)
1219x1219x30mm. (48″ x 48″ x 1 3/16″)
1219x2438x38mm. (48″ x 96″ x 1.50″)
1828x3657x38mm. (72″ x 144″ x 1.50″)
Custom size tables available. Specify.

vacuum pump
vacuum valve
Vacuum table air supply valve
Pressure regulator.
Pedal
Stops for positioning products on a vacuum table.
Retractable vacuum tables
Plastic (Formica) tabletop
Independent vacuum zones controlled by valves.
Anodized table surface
Location of vacuum holes according to customer's drawing
Table shape and size according to customer requirements

Q: How can I fix the vacuum table?
A: The table has a 9.5mm bottom and top flange around the perimeter. You can use them for clips or drill holes for mounting.

Q: Is it possible to use threaded connection for a vacuum line?
Oh yeah. Specify the required size.

Q: I already have a vacuum pump. Will it work with your vacuum table?
A: Most likely it will work. In any case, you can order the pump later. If you decide to use your pump, you can immediately order an adapter / adapter. Please specify dimensions when ordering.

Q: I work with materials that can get scratched. Can they be avoided when working on a vacuum table?
A: Yes, you can use the switch valve to blow air out of the table. This will result in an effect air cushion. Optionally, you can adjust the amount of air supplied. The valve requires compressed air at a pressure of min. 4.2 bar.

Q: How much Smooth surface vacuum table?
A: Tolerance no worse than ±25µm/sqft

Q: How should I secure the table to prevent it from bending?
A: As a rule, the bottom (surface) of the table is flat and parallel to the top, so it is possible to mount the table on the machine base.
When setting the table on a surface, pay attention to the absence of gaps, which indicate an uneven surface. Use shims to eliminate table "wobble" due to gaps. Check parallelism. If necessary, use additional spacers to eliminate the possibility of table deflection under pressure and violation of the plane of the working surface of the vacuum table.

Q: Is there a way to place items on the table in exactly the same place?
A: Yes, it is possible. Optionally, you can order a system of stops for positioning products. As a rule, these are three steel pins that are “pulled out” from the table during the laying of the product and “recessed” into the table as soon as the vacuum is turned on. It is possible to accommodate more than three pins.

Find out the price!

The manufacturer reserves the right to make changes to the design and specifications of the stencil equipment without notice.