SU643356A1 - Method of making articles of thermoplastic materials - Google Patents

Description

one

The invention relates to a technology for the manufacture of articles from polymer materials, in particular, from a fluoroplastic tube or wire, and can be used in any technical field, for example, for the production of membrane-free pipelines used in instrument making.

Methods are known for the manufacture of products made of fluoroplast, for example corrugated tubes, by putting the tubular billet on the mandrel and subsequent heat-setting at a temperature of 250-300 ° C. It is easy to get a cylindrical helix made of a fluoroplastic tube or wire by winding the workpiece on the mandrel and heat setting 1.

However, it is difficult to manufacture a product of a complex configuration, such as an Archimedes spiral, a conical spiral of variable pitch or a sinusoidally curved, momentless tube by donning or winding the workpiece on the mandrel. The mandrel for such products is complex and expensive, and in some cases the manufacture of the mandrel and the fixing of the workpiece on it is impossible at all.

A known method of making articles from thermoplastic materials by the method of bending a lengthy blank, which is closest to the invention, includes heating the workpiece, forming it by inserting it into the mandrel, the configuration of which corresponds to the configuration of the product, and cooling the product 2.

In a known method, the heating of the preform is carried out prior to its insertion into the mandrel.

However, in the manufacture of products from tubes of small diameter with a complex configuration, for the design of which mandrels with a complex internal cavity are used, the introduction of a preheated preform is not possible.

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The aim of the invention is to provide the manufacture of products of complex configuration from tubes of small diameter.

This is achieved by heating the billet after it has been inserted into the interior of the opcom.

The method of manufacturing products according to this method consists in introducing a polymer preform (a tube of thermoplastic material) into the interior of the mold, the configuration of which corresponds to the configuration of the finished product. Then, the mandrel with the workpiece is heated and after appropriate exposure for the time required to form the product, cool and remove the product.

Example. A momentless supply pipe was made to the instrument for measuring the density of liquid and gaseous media. The shape of the tube is a conic spiral with a variable clamp. As a blank, we used sections of a fluoroplastic capillary with a diameter of 1.5 mm and a length exceeding the tube length of the mandrel by 60 mm. The mandrel is a tube made of red copper with an outer diameter of 4 mm, a wall thickness of 1 mm bent in the shape of an Archimedes spiral (2 turns, the maximum radius is 50 mm), then stretched in a direction perpendicular to the helix plane by a length of 50 mm. The blank is inserted into the tube of the mandrel with a gap. 0.5 mm. The heat setting is carried out in a muffle furnace at 250-300 ° C and held for about 5-7 minutes. After cooling, the capillary is easily pulled out of the mandrel due to elastic

deformations. The shape of the finished product follows the shape of the mandrel.

The use of the invention will allow to manufacture products with a complex spatial form with variable and double curvature.

Claims (2)

1. USSR author's certificate number 376248, cl. On 29 D 23/00, 1968. 2. USSR author's certificate number 434016, cl. B 29 C 17/02, 1969.