Pulled styrol cutter

Abstract

A method for heating a heater wire to cut foamed styrol and the like has been often used. The heater wire is thin and bends easily, and thus a tension support tool for linearly supporting the wire has been necessary. Due to this, the extent of processing is limited by the size of the tension support tool. Furthermore, processing for carving a surface, such as in sculpting, is difficult with the heater wire having a straight line shape, and only a heat knife such as a soldering iron could be used.　In the present invention, the tension support tool is eliminated, separate handles are formed at both ends of the heater wire, and the heater wire is pulled by hand. Thus, a cutter that enables processing to the maximum extent is achieved. Furthermore, by bringing the two handles together to curve the heater wire, and supporting the heater wire midway therealong if necessary, a cutting tool for sculpting foamed plastic is achieved.　

Description

Pull-type Styrofoam Cutter

[0001] The present invention relates to a cutter using a heater wire for cutting expanded polystyrene or the like.

[0002] When foamed plastics such as styrofoam are cut with a blade, a large amount of fine fragments are generated. For this reason, a method of cutting by heating an electric resistance wire (hereinafter simply referred to as a heater wire) is widely adopted. Since the heater wire is very thin and easily bent, a device for holding the heater wire (hereinafter referred to as a tension supporter) having an arc or U-shape that supports the heater wire in a straight line as disclosed in Patent Document 1 has been required.

[0003] Patent Document 2 and Patent Document 3 disclose cutters that allow children to safely process work or strip and scrape wire insulation, but both of these apply tension to the heater wire via an electrode or a tension supporter. Therefore, when it is desired to scrape a surface like in engraving, it has been necessary to attach an attachment with a slightly curved heater wire to the tension supporter as disclosed in Patent Document 4, or use a hot knife like a soldering iron disclosed in Patent Document 5, or a heat cutter manufactured by Ishizaki Electric Mfg. Co., Ltd. with a thickened blade.

[0004] Patent Documents 6 and 7 describe a cutter having a shape in which separate handles are provided at the ends of a heater wire as in the present application. The cutter of Document 6 changes the shape of the loop by bringing the handles into close contact and relatively shifting their positions, thereby cutting foamed plastic. In the cutter of Document 7, slack in the heater wire occurs when the two handles approach each other, which can induce accidents. As a safety measure, the cutter has a structure that constantly winds up the heater wire by the action of a coil spring to prevent slack.

[0005] Patent Document 8 discloses a hot wire cutter for cutting ice cakes. The cutter has two handles that move within a large circle formed by a heater wire coated with an insulator. When the handles are separated from each other, the section of the heater wire between them becomes exposed, allowing the ice cake to be cut. Therefore, the tool is designed with safety considerations to prevent the handles from contacting each other.

[0006] Utility Model Registration No. 3087060, Utility Model Application No. 62-054619, Patent Application No. 2009-074319, Utility Model Registration No. 50-93893, Patent Application No. 57-202368, Patent Application No. 49-132647, Korea 2010-0121931, AUS 2019-0232519A1

[0007] Tension supports must be structurally robust, so increasing their size would increase their weight and material costs, which meant they tended to be small. This also meant they had limited headroom, making large-scale machining impossible. Moreover, they were still quite large when not in use. Furthermore, when tension was applied to the heater wire, it could not extend beyond the electrodes or tension supports, so machining was limited to within that width or only shallow from the surface.

[0008] The attachment in Patent Document 4, like the present application, brings both ends of the heater wire close together to form a U-shaped cutting tool. However, the large tension support used to attach it prevents deep machining beyond the surface of the polystyrene. Furthermore, there is no description of reinforcing the heater wire with support terminals or shortening it, as shown in Embodiment 2 of the present application. As a result, the heater wire is easily bent at its full length, and even when it can be machined, it can only be machined at a very slow speed.

[0009] The soldering iron-like hot knife described in Patent Document 5 took nearly three minutes to reach a usable temperature. Furthermore, it burned almost all of the styrofoam in the space being cut, resulting in a lot of odor and smoke. The heat cutter, with its thick heating wire (3-5 mm wide), required the use of a pre-prepared molded heater, which resulted in a long heating time, a heavy power supply, and therefore a high cost.

[0010] In the cutter described in Patent Document 6, after the cutting loop shown in the figure is formed, even if the handles are slid back and forth, it is generally not conceivable that the shape of a hard wire like nichrome wire will change as desired, other than becoming distorted. However, since sliding is necessary to deform and maintain that shape, it is considered that it cannot be formed by fingertips as in the present invention. Furthermore, since the handles have sliding grooves and rail protrusions, they do not easily separate, but even if they do, they are not easy to hold, and the heating wire is not long, so it is not suitable for cutting.

[0011] The cutter described in Patent Document 7 cannot cut by creating loops because the heater wire is always in a straight line. Furthermore, if the heater wire is wound or straightened, the resistance value changes each time, as the heater wire is considered to have no insulating coating. Therefore, a fairly sophisticated voltage control device is required to achieve uniform heating.

[0012] The cutter in Patent Document 8 can create a loop by bending the handles 90 degrees apart, but it cannot maintain this loop as in Patent Document 6. Furthermore, if the loop becomes a circle, the heating wires come into contact with each other, so it is only a tool for straight cuts. In addition, to increase the cutting depth, even in cases where it is not normally necessary to adjust the heating wires, this cutter requires making the already large circle even larger, which means lengthening the heating wires, and therefore the power supply voltage had to be changed accordingly.

[0013] The tension support was eliminated and separate handles were prepared, connected by a heater wire and a reinforced lead wire. The heater wire was the same as before, or slightly thicker, but it was designed to reach thermal equilibrium within a few seconds of turning on the power, allowing for stable processing.

[0014] Furthermore, the handles were brought side by side, the heating wire was curved to form an arc, and because of its length, it was supported in the middle when necessary to provide stiffness, and then heated and used for cutting.

[0015] By pulling both handles, the heating wire straightened out, and it could be cleanly cut by applying it to styrofoam. Making the reinforced lead wire longer allowed for maximum processing without changing the heating wire or power supply, and it became smaller when stored. The reinforced lead wire prevented accidents such as the handles touching each other.

[0016] The curved heating wire could be used to shave styrofoam like a spoon, maintaining its large curve. Processing could begin immediately after powering it on, and once the power was turned off, the heating wire cooled down quickly and became touchable, allowing for the creation of various curves by changing its bend with one's fingertips.

[0017] This is a plan view showing one example of the polystyrene foam cutter of the present invention. This is a plan view showing one example of the cutting tool of the present invention. This is a plan view showing another example of the cutting tool. This is a plan view showing yet another example of the cutting tool. This is a side view of the combined cutting tool of Figure 4.

[0018] In Example 1, the polystyrene foam cutter of the present invention is illustrated in Figure 1. In Examples 2 to 4, cutting tools that utilize this cutter as an alternative to carving tools or hot knives are illustrated in Figures 2 to 5. These are all examples of the present invention and the present invention is not limited to them.

[0019] The polystyrene foam cutter of the present invention is explained in Figure 1. A heater wire 5 is connected between electrodes 4 provided on the controller / handle 1 and the second handle 3, which has a hole 2 for inserting a finger. As shown in Figure 1, the heater wire is wrapped around the electrode 4 and twisted to secure it. Screws and nuts may also be used for the connection (figure omitted). Furthermore, a covered copper wire with a diameter of 1 mm is used to connect from the controller / handle 1 to the electrode 4 of the second handle 3 as a lead wire from the other electrode of the power supply. This lead wire is called a reinforced lead wire 6.

[0020] The controller / handle 1 has a push-button switch 7 for connecting the power supply and a lamp 8 to indicate power is supplied, and is properly wired internally to a power cord 9 from an external power source. When you hold handles 1 and 3 with both hands, pull the heater wire 5, and press the push-button switch 7, current flows through the heater wire 5. At the same time, the lamp 8 that indicates this lights up.

[0021] If we use a 5V smartphone power supply as an external power source and use a 0.4mm diameter iron-chromium wire for the heater wire 5, it will have a resistance of 2.2Ω over a length of approximately 20cm, so a current of 2.3A will flow. The heater wire 5 will heat up and reach a processing temperature in 2-3 seconds. Even as time passes, it will be cooled by air and heat will be absorbed by the workpiece, so even if the power is applied for 5-10 seconds repeatedly, the temperature will not rise significantly from that point; it will reach what could be called an equilibrium state.

[0022] When the heater wire 5 is placed against the styrofoam (no diagram shown), the heat is lost from that part, causing it to cool slightly, but the styrofoam begins to cut. The part of the heater wire that is not in contact with the styrofoam remains hotter, so moving it back and forth like a saw makes it easier to cut.

[0023] The materials that can be cut are expanded polystyrene, expanded polyethylene, expanded polypropylene, etc. The dimensions are 20 cm, which is the length of the heater wire 5, and the depth is the length of the reinforced lead wire 6. Lengthening the heater wire 5 would require changing the power supply, but the depth can be increased by lengthening the reinforced lead wire 6.

[0024] The reason it's called reinforced lead wire 6 is that, when you let go of the handle, the heater wire tends to curl, and depending on how you position the handle, the lead wire needs to have a certain degree of rigidity to prevent accidents such as short circuits caused by contact between electrodes or in the middle of the heater wire. In reality, the lighter the better, so a thin metal wire that doesn't get too close when you let go of the handle would suffice.

[0025] To further prevent accidents, it would be good to make the insulation of this reinforced lead wire 6 stronger. The temperature of the heater wire is thought to be around 150-200°C, and the temperature drops quickly upon contact, so a glass fiber coating should be sufficient, or a heat-resistant fluororesin coating or enamel coating on the copper wire would also be acceptable. The current flowing through it is only a few amperes, so metal wires such as brass, iron, or aluminum would also be fine.

[0026] This second handle 3 simply connects the heater wire and the reinforced lead wire with an electrode screw or similar, so if the electrode and the reinforced lead wire with the necessary insulation are made extra long, you can hold it there and apply tension to the heater wire. It is a small second handle without the molded box. One possible application is to make a small hole in styrofoam and pass this small second handle 3 through it, allowing you to use the entire length of the heater wire as a cutting tool and process it from there.

[0027] Figure 2 shows a cutting tool that can process polystyrene foam like a sculpture. The handles 1 and 3 of the polystyrene cutter in Figure 1 are brought together, and the tip of the heater wire 5 extending from the electrode 4 is shaped like a spoon, with the arc gently folded in half. The handles 1 and 3 are integrated by a connector 10, and at the same time, the heater wire 5 is supported in the middle by two 1.2 mm diameter nichrome wire support terminals 11 provided on the connector 10. The connector 10 can also be a screw or the like.

[0028] When this cutting tool is heated by pressing switch 7 and moved against styrofoam, it can shave off pieces as if scooping hard ice cream with a spoon. Unlike tools with fixed ends, the heater wire 5 is too long if simply bent, so it is supported by the support terminal 11 to shorten it. However, it still bends if moved too quickly, so it must be moved much slower than a cutter. Once the power is turned off, it cools down immediately, allowing you to bend the spoon shape by hand or create corners with pliers.

[0029] The tip of the support terminal 11 can be U-shaped as shown in Figure 2, and can be designed to hook onto the heater wire just enough to prevent it from coming off as it cuts through the polystyrene foam. For a more secure fixation, it can be wrapped around the wire or joined with screws and nuts (not shown in the diagram). The excess heater wire 12 between the support terminal 11 and the electrode 4 can also be used as a cutting tool separate from the curved portion.

[0030] If the heater wire 12 is in the way, it can be left straight or made into a small coil and placed inside the handle so that it is not touched by the hand. In other words, it is a voltage division of the power supply voltage by the heater wire. If the reinforced lead wire 6 is not returned to the original shape of Figure 1 or is no longer needed, it can also be made into a short, ordinary lead wire and placed inside the handle in the same way.

[0031] This results in a new cutting tool 13 with two electrodes, as shown in Figure 3. In other words, it is a handle that also serves as a controller for the two electrodes. By making the cutting heater wire 14 into a 10 cm arc and extending it in front of the extended electrode 15, the electrode 15 does not get in the way, allowing for deep hole machining. The electrode 15 can be made shorter or longer depending on the purpose, and the two electrodes can be of different lengths. However, since half of the heater wire 12 is inside the handle of this cutting tool 13, the handle will get a little hot if used for a long time.

[0032] Therefore, for this heater wire 14, I used an iron-chromium wire that is 11 cm long and 0.3 mm in diameter. The resistance value is 2.2 Ω, so it can receive almost all of the power from a 5V 2.4A USB power supply for smartphones. Consequently, there is no excess heater wire, and the handle does not get hot. However, because this heater wire 14 is thin, it feels considerably less stiff to the touch compared to the previous heater wire 5. Nevertheless, it can be used without bending at all.

[0033] The polystyrene foam is cut or melted the moment it is touched, so even when moved at a practical speed, there is little contact resistance and it does not bend. Although the heater wire 5 in Figure 2 can also cut it, the speed at which it does so is considerably slower. Therefore, the length at which the heater wire can stand on its own depends not only on its thickness, but also on the temperature during cutting and the speed at which it is moved. In short, the higher the temperature, the faster and more freely you can process the material with a thin, weak heater wire.

[0034] However, there is a concern that it may ignite if the temperature exceeds the ignition point. According to the catalog, when a 2.4A current is passed through this 0.3mm heater wire and the heater wire is straightened and placed horizontally in the air, the temperature at which it reaches equilibrium (hereafter referred to as the reached temperature) is 600°C. Because I was worried, I repeatedly conducted experiments such as dipping the cutter into styrofoam and performing cutting tests while continuously heating it for one minute, but there was absolutely no sign of it igniting.

[0035] If this heater wire 14 is moved any faster, it frequently bends upon contact with the hard styrofoam. This means that the thin heater wire cools down quickly, losing heat in a short time and dropping to a temperature of around 100°C, which is too low to melt the material. A plausible explanation is that although this 0.3 mm heater wire heats up to a temperature above its ignition point, the temperature drops below the ignition point the moment it touches the material, preventing it from catching fire and allowing the processing to continue.

[0036] However, when 3.4A is passed through this heating wire, the temperature reaches approximately 900°C, causing it to glow bright red. Even when this red heating wire is brought into contact with or submerged in styrofoam, it does not ignite. This change is clearly visible when the red wire turns black. Furthermore, when the heating wire was rubbed against styrofoam that had been ignited with a burner, sometimes heated and sometimes not, it was difficult to determine precisely because melted styrofoam stuck to it, but at least it did not intensify the flame. Even when the heated heating wire was inserted into the butane gas being emitted from the burner, it did not ignite. This is despite the fact that the heating wire could ignite paper.

[0037] This phenomenon seems similar to the use of wire mesh guards to prevent explosions in coal mines, or the way the lit alcohol flame of a platinum hand warmer doesn't spread to clothing outside a perforated case. In other words, this heating wire acts like a wire mesh, generating polystyrene gas (ignition?), but the gasification and convection lowers its own temperature, which in turn lowers the temperature of the gas, thus preventing it from burning.

[0038] There is no documentation on the temperature reached by the heater wire in a styrofoam cutter with a straightened heater wire. So, I purchased actual products from a manufacturer specializing in heating equipment and measured them. In a battery-powered cutter, two 0.3 mm diameter nichrome wires, the same as in this invention, are used as heater wires and have internal resistance, resulting in 2.3V x 1.3A. In a cutter using a transformer from 100V, the voltage is 3.4V x 1.3A, and in both cases, the temperature reached is approximately 300°C.

[0039] On the other hand, internet research indicates that the ignition point of polystyrene foam is 260-416°C. This means that while manufacturers may have carefully manufactured their products at low temperatures to prevent fires from starting around the heating element, the temperature range still overlaps with the ignition temperature range. Furthermore, given that it has been commercially available for a long time, and has been used in various ways, there may have been instances where heat accumulated, leading to high temperatures and fires. It would not be surprising if warning labels were issued to prevent such incidents.

[0040] However, such a thing does not exist, and on the other hand, knife-type cutters are sold on the internet claiming to reach 500-600°C. Therefore, although it cannot be explained, it seems that there is a combustion system mechanism that prevents polystyrene foam from catching fire even when heated by a heater wire at a temperature far exceeding its ignition point. Therefore, based on the fact that no problems occurred for a long period of time with the heater wire 14 in Figure 3, and the results of my own experiments, the inventor believes that it is safe to use on polystyrene foam, and by extension, on foamed plastics.

[0041] This heater wire 14 can also be used in place of the heater wire 5 of the cutting cutter shown in Figure 1. The heater wire 5 reached a temperature of approximately 400°C. The length of the heater wire is shortened from 20 cm to 11 cm, but the temperature reached is 600°C, allowing for very fast processing. If the length is to remain the same, the power supply voltage must be changed to 10 V, meaning a separate power supply must be obtained. The main purpose of this invention was the structure, but the high-temperature cutting performance of the heater wire is valuable not only for the cutter of this invention but also for conventional cutters using tension supports.

[0042] Figures 4 and 5 show an improved version of the cutting tool 13, which is separated into a heater section and a handle. To properly engrave polystyrene foam, various types of cutting tools are needed, which would require either owning multiple of these tools or preparing heater wires 14 bent into the shapes of various cutting tools, and then loosening the screws to replace them each time.

[0043] Therefore, it is convenient to prepare a plurality of new replacement bases 16 in advance, connect the heater wires 14 to the electrodes of each replacement base in the shape of the required blade, prepare them in advance (only two types are shown in the drawings), and allow the replacement base 16 of the required shape to be replaced when necessary. In the present specification, a replacement base with the heater wires 14 connected thereto may also be referred to by the same name.

[0044] A replacement base holder 17 for receiving the replacement base 16 is provided with a hole into which the base end of the replacement base 16 is fitted and a fixing knob 18, and is further provided with a charging part 19 for coming into contact with the extended electrode 15 of the replacement base to conduct electricity. Since the replacement base 16 in Fig. 4 shows the back side, it may be turned over, inserted into the replacement base holder 17 and fixed.

[0045] Of course, if the extended electrode 15 of the replacement base is wired to the back side, it can be inserted directly from the front side. In other words, the electrodes and the charging parts are not limited to the arrangement shown in the drawings, and may be extended, arranged at other positions, or wired so that the replacement base can be easily replaced. The replacement base holder 17 also serves as a controller, and this is self-evident, so the fact that it also serves as a controller will not be particularly mentioned hereinafter.

[0046] For the state where the replacement base 16 is inserted into the replacement base holder 17, it is sufficient to ignore the silicone sponge 20 from the side view of Fig. 5 and consider that the two are in contact with each other. Various methods can be conceived for the contact method between the replacement base 16 and the replacement base holder 17, and after that, it is only necessary to press the switch 7.

[0047] Fig. 5 shows an embodiment in which the switch is omitted. It is a side view of the state where the replacement base 16 is inserted into the replacement base holder 17, and the silicone sponge 20 is sandwiched between the two. This elastic body 20 is compressed when pressed, and at that time the electrode 15 of the replacement base comes into contact with the charging part 19 of the replacement base holder to conduct electricity, so it functions as a switch. Only one contact is required for conduction. Further, the elastic body separating the two may be ordinary rubber, a spring or the like.

[0048] The cutter shown in FIG. 1 can also be incorporated into this exchange table 16 (the drawing is omitted). That is, the controller / handle 1 in FIG. 1 is replaced with the exchange table 16 and an exchange table handle 17. When the exchange table handle 17 with the exchange table 16 inserted therein and the second handle 3 are pulled, the heater wire 5 becomes straight. Since a pulling force is applied, the exchange table and the exchange table handle are structurally required to be provided with corresponding provisions.

[0049] According to the above selection when using a 5V 2.4A power supply for smartphones, a ferrochrome heater wire with a diameter of 0.3 mm and a length of 11 cm is convenient for cutting. This can also be used for cutting, but alternatively, a longer one with a diameter of 0.4 mm and a length of 20 cm is also suitable. Although it cannot cut quickly, moving it like a saw allows effective use of the high-temperature portion. These sufficiently provide the functions of a polystyrene foam cutter.

[0050] Even so, by further adjusting the voltage and current to increase or decrease them compared to a smartphone power supply, the above heater wire can be changed to be stronger, longer, and higher in temperature, which can also expand the scope of application. For the power supply, voltage division by the heater wire shown in Embodiment 2, or other voltage and current adjustment circuits such as inverters using transformers or semiconductors connected to a completely separate external power supply may be used. An optimal voltage can also be obtained directly from a commercial power supply. A battery is also possible.

[0051] However, increasing the thickness of the heater wire to increase the self-supporting length is not a very advisable approach. This delays the time to reach an equilibrium state, and increases the amount of heat generated, which requires a large power supply, electrodes with high heat insulation properties, and heat insulating materials. Since it cools slowly, there is also a risk of burns or fire. Furthermore, more resin adheres to it, which increases the burnt odor from the heater wire. Above all, it also becomes difficult to bend.

[0052] In this specification, the expressions "bending the heater wire by hand" and "changing the shape with a fingertip" mean that the heater wire can be easily bent and stretched, and do not exclude fabrication with tools or machines, such as using pliers or a mold, or mass-producing the same shape. Furthermore, the terms "cutter" and "cutting tool" include the same applications as each other, and the description referring to a "styrene cutter" or "polystyrene foam cutter" is naturally included in the category of "foamed plastic cutter".

[0053] While the previous explanation of heater wires referred to iron-chromium wire, other types of wires with similar resistance values, such as nichrome wire, are also included. Furthermore, since the amount of heat generated is related to voltage, current, and resistance, it is more accurate to describe it as power adjustment rather than voltage and current adjustment, given the current advancements in electronic technology.

[0054] Although the structure of the present invention is very simple, in industrial applications, the second handle 3 can be fixed further away from the hand to accommodate large, wide foamed plastics.

[0055] At home, it can be used as a waste disposal tool to easily dispose of large styrofoam boxes that come with frozen foods or as cushioning for large appliances. After use, the cutter can be stored compactly.

[0056] The cutting tool of this invention generates less heat than a hot knife such as a soldering iron, heats up quickly, can be used immediately after power is applied, and produces less odor.

[0057] Furthermore, since the cutting tool is the same as a cutter, it is inexpensive, and it can remove more material than a soldering iron, making it easier to use. Therefore, it is possible to try large-scale carvings and other projects, increasing the ways in which both adults and children can enjoy crafting.

[0058] The cutters and cutting tools of this invention can be used anywhere in the world, along with their convenience, by using a smartphone charger or battery as a power source.

[0059] 1 Controller / Handle 2 Finger Holes 3 Second Handle 4 Electrode 5 Heater Wire 6 Reinforced Lead Wire 7 Push Button Switch 8 Lamp 9 Power Cord 10 Connector 11 Support Terminal 12 Excess Heater Wire 13 Dedicated Cutting Tool 14 Cutting Heater Wire 15 Electrode 16 Replacement Stand 17 Replacement Stand Handle 18 Fixing Knob 19 Charging Section 20 Silicone Sponge

Claims

1. A foam plastic cutter characterized by comprising a thin, bare electrical resistance wire (hereinafter simply referred to as a heater wire), two handles for holding it, namely a controller / handle and a second handle, a reinforced lead wire and a power supply, the heater wire being connected to the electrodes of each handle, the reinforced lead wire originating from the controller / handle and connecting the other power supply to the electrode of the second handle, and a structure that keeps the distance between the two handles loose, allowing the heater wire to be straightened and cut by pulling the two handles, or conversely, the heater wire to be bent by bringing the two handles closer together, with the help of electrodes or support terminals to support a length that can be maintained by its own rigidity, and if necessary, the heater wire to be further processed into an angular or curved shape and cut, or both cutting and cutting can be performed.

2. The foam plastic cutter according to claim 1, characterized in that the two handles are brought together and integrated with a connector or the like, or the handle also serves as a single controller with two electrodes, the heater wire is connected to the two electrodes by bending or other means, without support terminals, to a length that can be maintained by the rigidity of the heater wire itself, and the voltage applied to the electrodes is adjusted by a power adjustment circuit such as an electronic circuit using resistors, transformers or semiconductors to reduce the original voltage to the ratio of the length to the original length.

3. A foamed plastic cutter according to claims 1 or 2, characterized in that it comprises a handle that also serves as a controller with two electrodes, a heater wire and its power supply, or a new heater wire and a new power supply, the heater wire is connected to the two electrodes by bending it without support terminals, and when the heater wire is heated by the power supply, the temperature reached by the heater wire, i.e., the temperature reached when placed horizontally and in a straight line in the air, is in the range of 400 to 900°C.

4. The foam plastic cutter and its replacement stand handle and replacement stand according to claims 1 to 3, characterized in that the handle which also serves as a controller having two electrodes is composed of a replacement stand and a replacement stand handle which also serves as a controller (hereinafter simply referred to as the replacement stand handle), the heater wire is bent or otherwise connected to the two electrodes of the replacement stand, and multiple such connections, along with the replacement stand handle which holds the replacement stand when attached and supplies the necessary power to the two electrodes, have the function of quickly replacing heater wires of different shapes.

5. The foam plastic cutter and its replacement base handle and replacement base according to claims 1 to 4, characterized in that the handle having the two electrodes is composed of a replacement base and a replacement base handle, and when the replacement base to which the heater wire is connected is attached to and held by the replacement base handle, the electrodes face the charging part that supplies power to the replacement base handle, and are normally separated by an elastic body such as a spring or silicone sponge, but when the replacement base and replacement base handle are brought closer together by pushing them with a finger or the like, the electrodes and the charging part come into contact and supply the necessary power to the heater wire, thus having a switch function.

6. The foam plastic cutter and its replacement handle and replacement stand according to claims 1 to 5, comprising a replacement stand and a replacement stand handle, a heater wire and a reinforced lead wire and a second handle according to claim 1, wherein one end of the heater wire and reinforced lead wire is connected to one electrode of the second handle, and the opposite ends are connected to the two electrodes of the replacement stand, the replacement stand is joined to the replacement stand handle, and the heater wire is straightened or brought close together to form a curve for cutting or shaping.

7. A foam plastic cutter comprising a power supply, a heater wire, and a handle with a tension support, wherein the heater wire is energized and heated without control from the power supply to cut or cut foam plastics such as polystyrene, characterized in that the heater wire is heated by the power supply, but the temperature reached by the heater wire is in the range of 400 to 900°C.

8. The foamed plastic cutter according to claims 1 to 7, characterized in that the heating wire is an iron alloy wire such as iron-chromium or nichrome, with a diameter of 0.1 to 1 mm.

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