RU2456159C1 - Method of producing shaped shells from tubular workpiece, - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to hot injection and may be used for fabrication of long article package supports. Proposed method comprises placing initial polymer tubular billet on spatial carcass mandrel with ledge supports and billet plastic deformation. For this, billet is heated to elastic state at sections between mandrel carcass supports, external forming tool is pressed against heated sections to shape the latter as required.

EFFECT: whatever depressions on tubular billet.

4 dwg

Description

The invention relates to the field of thermoforming of products, in particular, a method for manufacturing shaped shells from a tubular polymer part for lodgements having an outer surface with positive and negative curvature, used for packing long items and transporting long items, such as pipes, is considered.

A method of manufacturing a lodgement part relates to the field of plastics processing, namely, the manufacture of shells from various thermoplastics (PP, PE, PVC, etc.) with a given surface geometry, and can be used for the manufacture of lodgements for pipe packaging and transportation devices (RU No. 2306246, 2005).

The closest to the proposed invention, the essential features is the method for manufacturing a negative curvature of the tubular thermoplastic casings, wherein the tubular element is clamped in the disks and between the discs after heating takes the form of negative curvature close to catenoid (RU №2388601, B29C 51/02, publ May 10, 2010) (selected as a prototype).

The known method is that both ends of the tubular element, or oriented heat-shrinkable thermoplastic tubular with its ends embedded in rigid metal disks with spacers separately heated to highly elastic state, and then the entire device is heated and prior to the highly elastic state and the heating is stopped abruptly. With this treatment, the tubular oriented or heat-shrinkable element is tightly clamped tightly in the disks, and between the disks it takes on a negative curvature shape close to the catenoid. After removal from the framework, both the catenoid itself and its components can be used, separated by mechanical processing into other shells of negative curvature.

The disadvantage of this method is the impossibility of obtaining between the supporting disks of a surface with a different geometry, for example with convex (protruding) sections, that is, it is impossible to obtain a tubular product with both negative and positive curvature on separate external surface sections.

The technical result when using the invention is the expansion of technological capabilities due to the receipt on the tubular element of the recesses of various shapes, separated by protrusions, that is, surfaces with different geometries.

Said technical result is achieved by a method for manufacturing profiled tubular form shells of an oriented or heat-shrinkable tubular thermoplastic tubular preform thermoplastic is mounted on a mandrel and heated to an elastic state over the entire surface at the same time as the mandrel is used a collapsible frame, assembled from longitudinal and cross members providing protrusions during molding, and the recesses between the protrusions form an imprint of the external forming tools.

The proposed method is illustrated by drawings,

where in Fig.1 is a diagram of the installation for giving the tubular product a profile shape;

figure 2 - section aa in figure 1;

figure 3 - the finished product.

According to the present invention, there is considered a method of manufacturing profile shells from a tubular part, the surface of which is characterized by the presence of recesses of various shapes, separated by protrusions, that is, surfaces with different geometry and surface curvature. Such shaped tubular products are used as lodges for packaging, transportation and storage of long loads, for example pipes in bags, in order to prevent mechanical damage to their surface, which can be used in various industries, including gas, oil, military and chemical.

The method consists in installing a tubular polymer billet on a spatial frame in the form of at least two disk-shaped elements under the protrusions on the billet located on the rod, heating the billet to an elastic state, plastic deformation of this tubular billet, and removing the rod from the supports. In this spatial frame together with the workpiece placed thereon is set in rotary bearings, heating the preform to an elastic state is performed on portions between disk member spatial frame, and recesses on the heated areas of the workpiece are formed by pressing the outwardly located molding tool and obtaining a print of the pressed part of the tool on the surface of the workpiece.

Below is an example implementation of this method.

The blank of the lodgement case (product) from the plastic pipe 1 is placed on a prefabricated mandrel 2, which is installed in the rotary supports 3. The forming tool 4 is a part whose cross section repeats the cross section of the product intended for packaging. Heaters 5 are placed around the plastic pipe 1. Hair dryers with a power of 1500-2000 W (or other heaters providing a directed flow of air heated to the temperature of plastic deformation of the polymer used) are used as heaters. The finished part 6 with recesses 7 is shown in figure 3. As a rule, several forming tools are used, fixed on the bar 8, figure 1 shows six forming tools located with a given step opposite each other. Forming tools are associated with a drive for moving them in the direction of the heated plastic pipe 1 until they come into contact with its surface and change its shape by pressing molding tools into the body of pipe 1. This drive can be mechanized or manual. The forming tool (metal, ceramics and other materials) can be a ball, disk, oval disk, can be made in the form of an ellipsoid or any other shape.

The manufacturing method is carried out in the following sequence:

The mandrel is assembled in the form of a removable (or non-removable) rod element, on which rings or a given shape of disks are placed, which are elements of the formation of protrusions on the future product, then the workpiece in the form of a plastic polymer pipe 1 (future lodgement case) is put on the mandrel 2, and the mandrel is installed in the rotary supports 3, then the heaters 5 produce heating of the surface of the workpiece, where the recesses should be made. After the elastic state of the surface is reached, heating stops, the workpiece is rotated 90 ° and molding tools 4 are pressed into it, fixed on the bar 8. After cooling the workpiece, the tools are returned to their original position, and impressions in the form of recesses 7 remain on the surface of part 6.

The resulting part (photo in figure 4) is used as a tool tray for laying pipes. The shape of the recess may be triangular, rectangular, and another type of shape corresponding to the shape of the tool. The number of recesses, protrusions and the pitch between them may vary. Fittings can be installed inside the tool tray to increase longitudinal stiffness. To increase the radial stiffness of the tool tray during operation, transverse inserts, for example rings or disks, of solid material, which remain in the part, are installed in the tubular billet before molding. As a pipe, a non-circular profile can be used. The shape of the prints, their size, quantity and pitch are changed by replacing the forming tool with a corresponding other product.

The present invention is industrially applicable and can be manufactured using known devices.

Claims (1)

A method of making core polymeric shells, comprising setting the tubular polymer preform to a space frame in the form of at least two disc-like elements under the projections on the workpiece disposed on the web, heating the preform to an elastic state, plastic deformation of the tubular blank and extraction rod supports, wherein that the spatial frame together with the polymer preform placed on it is installed in the pivot bearings, heating the preform to an elastic state o uschestvlyayut the sections between the disc-shaped elements of a spatial frame, and the recess portions on the heated billet is formed by pressing the outwardly located molding tool to obtain a print of the pressed part of the tool to the workpiece.

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