Installation for cutting foam. Foam cutting machines: types, principle of operation

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 cutting 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. The 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 sought-after material, therefore, a lot of products are made on a CNC foam cutting machine, which are used for pipe insulation and are in demand in the form of all kinds of decorative elements.

Despite the apparent simplicity and ease of processing, it is not recommended to cut the polymer material mechanically using a saw or grinder, as it crumbles. At home, if the cleanliness of the edge is not required, for example, for cutting plates, then they use a hacksaw with a fine tooth or a knife.

Attention. The advantage of polystyrene is its low weight, so volumetric elements are fixed to the wall, or put up in the form of decorative inscriptions.

Words made up of letters are a wonderful decor for the interior of the room. In this case, any boring composition of letters can be replaced by another.

Features of cutting polymer material

To make blanks from foam and polystyrene, the device is made by hand, or they buy a CNC foam cutting machine. For cutting foam, nichrome is more often used, less often a titanium alloy: due to the increased cost. An alloy of nichrome and titanium is used in the form of wire with a diameter of 0.1 mm to 0.5 mm, while the length of such heated strings affects the performance of the equipment. There are no special requirements for home-made machines, since the cutting of polymeric material has to be done manually.

Machines come with one string, in the form of a jigsaw, as well as with two or more filaments, depending on the configuration of the product. Most often, with one string, individual parts of foam plastic machines are made home-made, while making them is not particularly difficult. CNC machines are used for cutting foam plastic in cases where parts of complex configuration are manufactured in 2d or 3d mode and a large volume of products is needed.

Types of machines

SFR device for shaped cutting. For control - a regular computer port. On such a milling unit there is a swivel head and up to 8 heating elements.
SRP-3420 The unit cuts foam in the form of rectangular blanks for further processing.
FRP-05 is a small machine with one nichrome string. Can process a part in 3 planes (3d mode)
SRP-3220 - Maxi. The machine produces pipe insulation and packaging products.

CNC machine SFR-Standard

Consider the principle of operation of the SFR machine according to the Penop program. The menu contains software control of the machine through certain commands with buttons. In order for them to be with quick control, for this they are duplicated and placed on the toolbar. The functionality of the program allows you to create files with the desired profiles of future figures, their size and scale. Also, the program automatically selects the cutting power and speed, the temperature of the threads and other parameters of the machine when cutting polymeric material.

It allows you to set and save the selected parameters, so the machine is cutting without additional settings. When drawing a detail profile, the main thing is to keep the lines closed: so that the beginning of the next element is the end of the previous one. This is necessary in order for the machine to cut the specified profile of the workpiece without failure.

Getting 2d shapes

When manufacturing two-dimensional parts on the SFR-Standard unit, files in the PLT format are in demand. To open the required file, you need to select the item "processing figure 2d" in the menu.

After the file is loaded into a separate program window, for more productive settings and management, you can use the "edit" button. With its help, the missing details are adjusted, the corners are smoothed, the scale of the figure is changed. After loading the created files and setting certain parameters for the machine, further control is carried out using three buttons:

software launch;
pause;
stop.

Making 3d parts

The heated strings move along the X and Y axes with the help of drives controlled by a computer system. Precise mechanisms allow cutting material with high precision, high purity and any configuration.

CNC milling machine 3d milling cutter makes it possible to obtain models for casting parts with complex configurations, for example, various volumetric elements in the form of letters, decorative figures. In addition, similar figures and letters can be obtained after milling at high speeds.

It's important to know. With the help of a turntable, various projections of the same shape are cut, which makes such 3d parts attractive figures.

Advantages of foam cutting machines

Such numerically controlled devices for cutting foam plastic shapes create parts of any complexity in a short time and relatively cheaply. 2d and 3d figured cutting of polystyrene is used for the manufacture of three-dimensional logos from letters and graphics. And also for models of various goods, exhibition stands, insulation for pipes, and all kinds of decor.

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 polystyrene, 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, such as 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. With an electric foam cutter, you can always cut sheets of the desired thickness from a thick plate. The machine also allows you to turn the 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 cutter for foam plastic 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.

Machine design

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 home craftsman's laziness, so I implemented the simplest design that provides secure fixation and smooth adjustment of the string height during cutting above the surface of the machine base.

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 mm 2. You can select the wire section for connecting nichrome wire from the table. I had a wire with a cross section of about 1 mm 2 at my disposal. Therefore, each of the wires had to be made of two with a cross section of 1 mm 2 connected in parallel.

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 torch wire does not reach the correct temperature. Electrical appliances can also be connected in parallel.

The disadvantages of the last scheme for connecting a nichrome spiral include the need to determine the phase for proper connection and low efficiency (coefficient of performance), kilowatts of electricity will be wasted.

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 area. 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.

Despite the huge amount of insulating materials (which, by the way, is constantly growing), as well as the increasing popularity of mineral wool, polystyrene still occupies a leading position and does not plan to give them up. If it is planned to insulate the floor in an apartment or basement, then cutting polystyrene foam is completely done with the help of improvised tools, but if we are talking about significant volumes or unusual tasks, then a special device is needed - a foam cutting machine.

Foam Cutting Machine

Machine classification

In today's market, such machines are presented in a fairly large variety. In this case, you can purchase a special laser cutting machine or, alternatively, try to make something similar with your own hands.

By the way, all machines are conditionally divided into the following categories:

portable units (vaguely resemble a knife);
CNC units;
for cutting across or horizontally.

Design features and principle of operation

Even despite the fact that the machines exist in a variety of modifications, the principle of operation for all of them is in general the same. The edge heated to a high temperature passes through the foam layer in the desired direction, like a hot knife through butter. In most cases, a fishing line is used as such an edge. In the simplest models, there is only one such heating thread, while in more advanced devices there can be several at once (up to six strings).

Note! If cutting of molded elements is planned, then special attention should be paid to the length of products that can be processed.

As an example: the SRP machine, which is also used for cutting the described material, is equipped with strings over 2 meters long, and in one run it can cut about 12 linear meters. meters of material.

Specialized machines and their prices

Often, foam is used not for insulation or soundproofing structures, but for the manufacture of advertisements or in interior design. This is possible due to the use of special machines designed for curly cutting. Characteristically, with the help of such equipment it is possible to process the material simultaneously in 2 or even 3 projections. If desired, you can produce the most complex elements, such as gears, chess, miniature models of cars, various figures, any decorative ornaments.

Below are the most popular devices on the domestic market, as well as the average market price for them.

FRP-01

This unit owes its huge popularity to the simplicity of its design and versatility. It is possible to produce molded elements, figures and letters for signboards, insulation boards and so on. The control of the device operation is carried out by means of a computer program included in the kit.

The approximate cost of the unit is 110-115 thousand rubles.

Machine FRP-01 for cutting foam

SRP-K "Kontur"

Another great model that allows you to make various parts of facade decoration and formwork for pouring mortar. In this case, the control is manual, but the power consumption is relatively low (about 150V), and it is very convenient to transport it.

The average market value is somewhere 42.5 thousand rubles.

Self-made cutting machine

There are a number of ways to build a foam cutting machine - from the simplest (hand tools) to the extremely complex in execution. Let's briefly consider each of them.

Method one. Manual cutting of styrofoam

The simplest and at the same time affordable method is cutting the material with a knife. It is important that the knife used for this has serrations and is lubricated with automotive oil before starting work (this will reduce noise and optimize the procedure itself). It is also worth noting that this is the slowest of the methods, so it is only advisable in the case of a small amount of material.
Styrofoam can also be cut with a hot string. To do this, hammer in a couple of nails, pull a nichrome wire between them and connect the power supply to it. The main advantage of this method is high speed (one meter is cut in 7-8 seconds) and a neat cut. But there is a significant disadvantage: such a procedure is harmful to human health.
The third method is known as "cold string" cutting. In this case, a steel string is used in the same way as a two-handed saw blade. This method is quite productive.
Similarly, you can cut the foam with a conventional hacksaw.
Finally, there is a professional hand instrument, finished similar to the hot string mentioned above, only more advanced. With such a tool, the work is done efficiently and quickly, it is possible to use curly nozzles.

Video - Cutting polystyrene foam with nichrome

Method two. Homemade machine on the table

Be that as it may, cutting polystyrene foam manually, even with one of the above tools, is quite difficult. The material may burst or crumble, nothing can be done about it. The hot string partially solves the problem, but what if the amount of work is too large? There is a way out - you can build a stationary cutting machine at home.

First, everything you need is prepared. When creating such a device, you will need:

a large table (ideally, each side should be at least 2 meters);
a string with increased resistance (in the presence of an old electric heater, it can be removed from it);
iron springs, which are characterized by low electrical conductivity;
laboratory transformer (LATR), which turns a 220-volt current into a 24-volt one.

In addition, you will also need a string height controller. They can be, say, a pair of beams, and it is between them that the cutting string will move along with the holder.

Note! A transformer is not always required. This moment depends solely on what material is used in the manufacture of the thread. And if it is chrome-plated, then a current of 220 volts can also be used. Although we note that when working with such power, you must strictly adhere to the safety rules, otherwise the consequences can be the most sad.

If the foam cutting machine will operate from only 24 volts, then there can be no danger to the body. You simply won’t feel such a current, and after an accidental lesion, you just need to rinse the affected skin area with water.

We also recall that if the foam is cut with hot metal, then toxic substances will inevitably be released. For this reason, work must be done exclusively in a special mask, and the room must be well ventilated; otherwise you can get poisoned. While cutting outdoors is preferable, this can only be done if you have your own yard.

To make it more convenient for you to assemble the structure from prepared parts, we have given below a detailed diagram of the future machine.

Equipment necessary for the production of foam Previously, we talked about the equipment that is necessary for the production of foam, in addition to this article, we advise you to familiarize yourself with this information.

Method three. Homemade machine (in the absence of a suitable table)

If you do not have a table of suitable dimensions, then you can make a base for the unit from plywood, a regular board or chipboard. The algorithm of actions in this case should be as follows.

Preparing everything you need

The principle of operation of the machine described above is also based on the use of hot metal. If you run a hot wire over the material, it will be easy to cut, and the cuts will be perfectly even. In the workflow, in this case, you will need:

The cutting element will be a nichrome spiral. As already noted, it can either be purchased or removed from the old heater. Tellingly, the thickness of this spiral can vary between 0.5-1 mm, although it would be better if it is 0.7 mm. As for the length, it depends on the dimensions of the material that will be cut.

Note! An important element is the laboratory transformer. If you don't have one, you can make something similar out of an old transformer and a car battery charger.

There is another option - you can take a power supply from a PC, where 12 volt wires (black and yellow) are connected to the spiral.

For a homemade machine, an output voltage of 7-12 volts is sufficient. Another important point: the thickness/length of the filament must be adjusted to match the voltage. If the heat is too strong, the thread may even burst. At the same time, if the warm-up is weak, the cutting procedure will noticeably slow down.

Finally, the battery itself from the car can serve as a power source. This is useful in cases where there is no electricity.

Assembly directly

Below is a step-by-step assembly instruction for the unit.

Step one. We take a thread from nichrome and attach it to the springs. The springs themselves are put on the M-4 screws, and those, respectively, are screwed into the prepared racks.

step two. We pre-press the iron racks into a chipboard sheet, countertop, plywood (or another surface that will serve as the basis for a foam cutting machine). The thickness of the base, as well as the height of the posts, should be determined by what the needs of the user are. With a base thickness of 18 millimeters and a support height of 28 millimeters, the screw, being completely screwed in, will not be able to pass through the base; and vice versa, being completely unscrewed, it will be able to cut material with a thickness of 50 millimeters.

Note! If further cutting of thick sheets is required, we will remove the small screws and screw in longer ones instead.

Step Three. We make holes in the base for the purpose of pressing. It is important that the diameter of these holes is approximately 0.5 mm smaller than the diameter of the stand itself. Next, using a hammer, we drive the racks into the holes, but we pre-treat the sharp end edges with sandpaper (this will greatly simplify this procedure).

Step Four. Before screwing the screw into the rack, we take some suitable tool and cut a small groove under it (the screw) with a hat. To do this, we clamp one end with a screwdriver, put a file under the hat and initiate rotation. What is this groove for? First of all, in order to fix the wire motionless, otherwise it may move during the adjustment process.

Step Five. We fix the wire: first to the springs, and only then to the screws themselves. This is necessary so that it does not sag, heating up and, accordingly, lengthening somewhat.

Step Six. Having finished with all the fasteners, we take the nichrome wire and fix it. The fastening method that we use here is called “crimped twisting”: it allows you to create the most reliable contact between the cable that conducts current and the wire. It is also important that the cross section of the copper cable is at least 1.45 mm².

step seven. We clean the insulating layer from the ends of the cables by about 2 centimeters. We wind copper conductors onto the wire where it is already fixed on the springs. One of its ends, using pliers, firmly hold and wrap the conductor with it. Such a winding allows you to achieve the maximum area of \u200b\u200bcontact of the wire with the wire, and when the machine finally starts working, the connections will not overheat.

Step eight. Next, we make a withdrawal of conductors that conduct electric current in the form of a loop, so that in the future it will be possible to regulate the procedure for cutting foam. In addition, we make holes in the base and pass wires through them so that they do not get confused during operation. After that, we fasten them on the other side using staples.

Note! Experts advise laying the cables together and twisting them, forming a bundle that is not too tight. In this case, they certainly will not get confused.

Step nine. We solder the terminals to the ends of the wires, which will be connected to the energy source used.

So, the foam cutting machine is almost ready. Note that the design created according to the above scheme is quite enough for home use. Moreover, if desired, it can also be used as a device for curly cutting polystyrene foam.

Video - Creating a device for cutting polystyrene foam

During the cutting process, an average speed of movement of the foam is required. If it moves too fast, it will most likely crumble, and if it moves too slowly, the ends of the sheets will begin to melt.
If work is being done on a site without electricity, then you need to connect 3 9-volt crowns together and use them as an energy source. In this case, the machine will be able to work for about 35-40 minutes.
It is undesirable to use car batteries for this, since they, despite the insignificant voltage, are also distinguished by a large current that can damage the string. And it’s good if it simply bursts, because it can happen that it splashes with hot metal.
The foam that will be used to insulate the bath must be thick. Moreover, thick material is easier to produce (and it is not particularly popular), which means that it will cost less than thin material.