RU2289503C2 - Saw-free cutting tool for forming shaped surface in foam material - Google Patents

Abstract

FIELD: processes and equipment for shaping foam materials, namely tools for saw-free three-dimensional working.

SUBSTANCE: tool is in the form of electrically conducting cutting member bent along contour respective to all formed configuration or to part of that configuration and heated by voltage supplied to its ends. Electrically conducting cutting member in cutting zone has relation of its outer dimensions h : l no less than 1 : 1.6 where h - thickness, l - width. Electrically conducting cutting member is made of heat resistant metal sheet material such as Nichrome or stainless steel. Cutting member is provided with additional supports whose thickness is no more than thickness of electrically conducting member. Said additional supports are formed separately from cutting member and they are welded or soldered to it. Supports of cutting members are arranged at their back side along motion direction of worked material. Electrically conducting cutting tool in cutting zone may have rectangular, oval or triangular (in the form of acute-angled triangle) cross section.

EFFECT: improved design of tool having high rigidity, enhanced operational reliability and increased useful time period.

9 cl, 5 dwg

Description

The invention relates to the field of figured processing of foamed materials, for example expanded polystyrene, and, in particular, to tools for sawing bulk processing.

It is known that for straight cutting of polystyrene foam, a wire heated by electric current is used, moving it to produce cutting of polystyrene foam (A. Kobayashi. "Processing of plastics by cutting." P.112, Fig. 127. Cutting pattern. Moscow. Engineering. 1974. Device for saw-free cutting of a polymer shell with a heated wire, patent RU No. 2233781). However, such devices do not allow to obtain products with a curly profile.

Known machines Smirnova S.V. for relief cutting of expanded polystyrene SRP-3200 "Standard", SRP-3210 "Mini", SRP-3220 "Maxi" (Internet site http: //srp-3200.narod/ru/products.htm), in which the cutting tool is heated electric tension string. Processing curly surfaces is achieved by moving the heated string in two or three coordinates in a computer program. The maximum length of the heated string and, accordingly, the maximum length of the workpiece is 2200 mm. The disadvantage of the machine is that the computer software of the machine is a very expensive equipment. In addition, the stretched and heated string with a length of 2200 mm does not allow to obtain straight surfaces at such a length due to the fact that the long string bends from the cutting forces during processing. A significant drawback is that in the event that any inclusions get into the polystyrene foam, the strings break. It should be noted that such machines cannot be installed in a line for the continuous production of, for example, plates of infinite length.

The closest in technical essence to the claimed tool for producing a curved surface in the foam material is the design of the tool of the German company Foam Cutting Systems GmbH, presented in promotional brochures on the website http://www.foamcut.com/ (Appendix to this application for 1 l).

In contrast to the previous analogues, the company’s tool for sawing up foamed material is not a stretched heated string, but a curved heated wire, which is given the profile of the finished part or part of its contour. The wire used has a diameter of 0.1 ÷ 0.4 mm or a rectangular cross-section of 0.75 × 1.0 mm and 1.0 × 1.5 mm. The ends of the wire are fixed on the rods, which together with the carriage can move in the vertical or horizontal directions, as well as receive additional rotational or longitudinal movement, which provide any volumetric configuration. The wire is heated by supplying voltage to its ends.

The design of such a tool significantly increases the possibility of manufacturing various relief objects that cannot be obtained with a tense string. However, the inherent disadvantages of the string remain in this instrument design. The heated wire is deformed when it encounters various inclusions in the foam material, as a result of which the resulting profile of the part is distorted. In addition, when processing tall or long products with a significant distance between the ends of the wire, it is elongated (drawn) with the formation of a deflection and distortion of the profile of the manufactured part. This is clearly seen in the figure “Balusters for construction and decorating”, which shows six small columns or supports of the same profile, which have noticeable deviations in shape in the eye.

The objective of the invention is to provide a tool with increased stiffness, reliability and increased service life for saw-free cutting of foam material, for example polystyrene foam, and obtaining relief surfaces on it.

The task is achieved due to the fact that in the tool for sawing and cutting a curved surface in foamed material, for example polystyrene foam, made in the form of an electrically conductive cutting element, curved along the contour corresponding to the entire configuration or its part, heated by applying voltage to it the ends, according to the invention, the electrically conductive cutting element in the cutting zone is made with a ratio of overall dimensions h: l of at least one 1: 1.6, where h is the thickness, l is the width.

The conductive cutting element is made of heat-resistant metal sheet material, for example, nichrome X20H80 or another grade of stainless steel, and is equipped with additional supports, while the thickness of the supports does not exceed the thickness of the conductive element.

Additional supports are made integrally with or separately from the electrically conductive cutting element and are fixedly connected to the electrically conductive cutting element by, for example, soldering or welding.

The supports of the electrically conductive cutting element are located on its rear side in the direction of movement of the workpiece or electrically conductive cutting element.

However, the support portion of one side of the electrically conductive cutting tool is offset from the support portion of the other side of the electrically conductive cutting tool in the feed direction when machining the part.

The cross section of the electrically conductive cutting element in the cutting zone is made in a rectangular shape, but it can, for example, have the shape of an acute-angled triangle or an oval shape.

The essence of the utility model is illustrated by drawings, which depict:

- Figure 1. U-shaped conductive cutting element;

- Figure 2. U-shaped conductive cutting element with offset supports of the sides;

- Figure 3. V-shaped conductive cutting element;

- Figure 4. U-shaped conductive cutting element with additional supports;

- Figure 5. The scheme of the tool.

A tool for sawing and cutting a curved surface in a foam material, for example polystyrene foam 1, is an electrically conductive cutting element 2, curved in the form of a contour corresponding to all or part of the obtained configuration. In order to avoid deformation of the electrically conductive cutting element during operation and to increase its rigidity, it is made of heat-resistant metal sheet material, for example, nichrome X20H80 or another grade of stainless steel, while the electrically conductive cutting element in the cutting zone is made with a dimension ratio h: l of at least 1: 1.6, where the heating of the electrically conductive cutting element is carried out by applying voltage to its ends.

Depending on the purpose, the electrically conductive cutting element may have a different configuration (Figs. 1, 2, 4), such as, for example, U-shaped for the manufacture of grooves and ridges, V-shaped (Fig. 3) to obtain a relief volumetric configuration or oval ( not shown).

To impart rigidity, increase resistance to bending and deformation, the electrically conductive cutting element is equipped with additional supports 3 (Fig. 4, photo - Appendix 2), while the thickness of the supports does not exceed the thickness of the electrically conductive cutting element.

Additional supports 3 are made in one piece with an electrically conductive cutting element. At the same time, it is possible to separately manufacture additional supports 3 followed by a fixed connection with an electrically conductive cutting element by, for example, soldering or welding (not shown).

The supports of the electrically conductive cutting element are located on its rear side in the direction of movement of the workpiece to reduce the resistance to movement of the cutting tool or workpiece.

In order to redistribute the load on the electrically conductive cutting element 2 (FIG. 2) during the cutting process, the supporting part of one side of the electrically conductive cutting tool is shifted relative to the supporting part of the other side of the electrically conductive cutting tool by a value B in the feed direction when machining the part. The amount of displacement B is determined based on the selected cutting conditions.

The tool works as follows.

There are two options for the tool. The first, when the tool is stationary, and the workpiece moves, and the second, in which the workpiece is stationary, and the tool moves.

Figure 5 presents a diagram of the operation of the device with a stationary tool. Before starting work, voltage is applied to the ends of the electrically conductive cutting element. The tool is heated to a predetermined operating temperature, and then the workpiece is fed to the tool by a conveyor. The heated tool performs non-sawing cutting and forms a curved surface (configuration) in the workpiece that corresponds to the contour of the electrically conductive cutting element.

The technical result achieved is that due to the manufacture of an electrically conductive cutting element from sheet material with a given ratio of overall dimensions of its cross section h: l of at least 1: 1.6 and the introduction of additional supports, the tool stiffness significantly increased, its reliability increased and increased tool life.

Claims (9)

1. A tool for sawing and cutting a curved surface in a foam material, such as polystyrene foam, made in the form of an electrically conductive cutting element, curved along the contour corresponding to the entire configuration or its part, and heated by applying voltage to its ends, characterized in that an electrically conductive cutting element in the cutting zone is made with a ratio of overall dimensions h: l of at least 1: 1.6, where h is the thickness, l is the width. 2. The tool according to claim 1, characterized in that the electrically conductive cutting element is made of heat-resistant metal sheet material, for example, nichrome X20H80 or stainless steel. 3. The tool according to claim 1, characterized in that the conductive cutting element is equipped with additional supports, the thickness of which does not exceed the thickness of the conductive element. 4. The tool according to claim 3, characterized in that the additional supports are made in one piece with an electrically conductive cutting element. 5. The tool according to claim 3, characterized in that the additional supports are made separately from the electrically conductive cutting element and are motionlessly connected to it by, for example, soldering or welding. 6. The tool according to claim 4 or 5, characterized in that the supports of the electrically conductive cutting element are located on its rear side along the movement of the workpiece when cutting it. 7. The tool according to claim 1, characterized in that the supporting part of one side of the electrically conductive cutting tool is offset from the supporting part of the other side of the electrically conductive cutting tool in the feed direction when machining the part. 8. The tool according to claim 1, characterized in that the cross section of the electrically conductive cutting tool in the cutting zone is made in a rectangular shape. 9. The tool according to claim 1, characterized in that the cross section of the electrically conductive cutting tool in the cutting zone is made, for example, in the form of an acute-angled triangle or oval.

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