Mould for the Spatial Shaping of Plastic Parts made of HDPE or PA or Similar Plastics, in particular HDPE or PA Tubes

Abstract

The invention relates to a mould for the spatial shaping of plastic parts made of HDPE or PA or similar plastics, particularly HDPE or PA tubes, which comprises a body (1), which is provided with at least one contact wall (20) for contacting the mould with the shaped material. At least the contact wall (20) is made of a material with a thermal conductivity lower than 5 W.Math.m.sup.1.Math.K.sup.1.

Claims

1-12: (canceled)

13. A mould for the spatial shaping of plastic tubes, comprising: a tubular body, the tubular body further comprising an internal shaping labyrinth in a form of a spatially shaped tube defining a longitudinal cavity, the tubular body comprising an outer spatial shape corresponding to the spatially shaped tube; the tubular body comprising an open circumference along a longitudinal length thereof that defines a longitudinally-extending through-slot such that a plastic tube to be shaped in the mould is insertable into the longitudinal cavity through the longitudinally-extending through-slot; the internal shaping labyrinth comprising at least one contact wall disposed for contact with the plastic tube inserted into the longitudinal cavity, the contact wall formed of a material with a thermal conductivity lower than 5 W.Math.m.sup.1.Math.K.sup.1; and a plurality of circumferentially-extending flaps spaced apart along the longitudinally-extending through-slot of the tubular body at locations to retain the plastic tube within the longitudinal cavity.

14. (canceled)

15. The mould according to claim 13, wherein the material has a thermal conductivity lower than 1 W.Math.m.sup.1.Math.K.sup.1.

16. The mould according to claim 13, wherein the material has a thermal conductivity lower than 0.5 W.Math.m.sup.1.Math.K.sup.1.

17. The mould according to claim 13, wherein the contact wall is made of one of: wood, plastic, composite material, Teflon, or reinforced polystyrene.

18. The mould according to claim 13, wherein the shaping labyrinth is formed entirely of the material with a thermal conductivity lower than 5 W.Math.m.sup.1.Math.K.sup.1.

19. The mould according to claim 18, wherein the material has a thermal conductivity lower than 1 W.Math.m.sup.1.Math.K.sup.1.

20. The mould according to claim 18, wherein the material has a thermal conductivity lower than 0.5 W.Math.m.sup.1.Math.K.sup.1.

21. The mould according to claim 13, wherein the tubular body is formed entirely of the material with a thermal conductivity lower than 5 W.Math.m.sup.1.Math.K.sup.1.

22. The mould according to claim 21, wherein the material has a thermal conductivity lower than 1 W.Math.m.sup.1.Math.K.sup.1.

23. The mould according to claim 21, wherein the material has a thermal conductivity lower than 0.5 W.Math.m.sup.1.Math.K.sup.1.

Description

DESCRIPTION OF DRAWINGS

[0010] The invention is schematically represented in the drawings, wherein FIG. 1 shows an example of a labyrinth for shaping tubes made of HDPE or PA according to the invention to be fastened to a rod holder of a carrier, FIG. 1a is a sectional view of a labyrinth with a contact surface in the form of a surface layer, FIG. 1b is a sectional view of a labyrinth with a contact surface which is an integral part of the body of the labyrinth, FIG. 1c is a cross-section of a labyrinth with a contact wall which is an integral part of the body of the labyrinth which is an integral part of the carrier (see FIG. 2), FIG. 1d is an example of a labyrinth with holders for fastening to the carrier, FIG. 1e is an example of a labyrinth fastened by means of holders to the carrier and FIG. 2 is an example of a labyrinth for shaping tubes made of HDPE or PA according to the invention with an integrated carrier.

EXAMPLES OF EMBODIMENT

[0011] The invention will be described with reference to an exemplary embodiment of a mould, or a shaping fixture, for shaping products made of HDPE or PA or similar plastics, in which a pre-prepared product, in its essence a semi-finished product, e.g., a straight tube or a multilayer tube, etc., is heated and inserted into a mould and, having been left in the mould for a required period of time, is formed into a desired shapethe resulting product, e.g. spatially shaped (bent) tubes.

[0012] The mould for the spatial shaping of plastic parts made of HDPE or PA or similar plastics comprises a body 1 in which is provided a shaping labyrinth 2. The mould 1 is created either as a single-part mould or a multi-part mould, and so is the shaping labyrinth 2. The shaping labyrinth 2 has a spatial arrangement corresponding to the desired spatial arrangement of the final product, i.e., in this case the specifically desired resulting spatial shape of the HDPE or PA tube being formed. The dimensions of the shaping labyrinth 2 correspond to the dimensions of the shaped tube. For example, the shaping labyrinth 2 is created as a spatially shaped tube with a longitudinal cavity which is provided with a through slot along its length for inserting the shaped tube into the labyrinth 2, or the shaping labyrinth 2 is created as a shaped groove in a suitable body. The shaping labyrinth 2 is made by suitable technology, for example, by cutting from a bent tube, by 3D printing, by machining, etc., or by a combination of two or more technologies, etc.

[0013] The mould is further adapted to hold the shaped tube in the shaping labyrinth 2, for example by means of flaps 3 arranged appropriately along the length of the labyrinth 2, and despite the presence of the flaps 3 the labyrinth 2 is able to accommodate the shaped tube by inserting a tube from the outside of the labyrinth 2. The shaping labyrinth 2 comprises a contact wall 20 with a shaped tube on its inner side, the contact wall 20 being a functional shaping wall 20 of the labyrinth 2, which is decisive for the future shape of the tube being formed.

[0014] In the exemplary embodiment in FIGS. 1 and 1a, the contact wall 20 of the shaping labyrinth 2 is formed by a coating or insert made of a material with a thermal conductivity lower than 5 W.Math.m.sup.1.Math.K.sup.1, more preferably with a thermal conductivity lower than 1 W.Math.m.sup.1.Math.K.sup.1, most preferably with a thermal conductivity lower than 0.5 W.Math.m.sup.1.Math.K.sup.1. The coating or insert is formed by a suitable technology, such as coating, 3D printing, pressing, etc., or by combining at least two different technologies.

[0015] In the exemplary embodiment in FIG. 1b, the entire shaping labyrinth 2 is made of a material with a thermal conductivity lower than 5 W.Math.m.sup.1.Math.K.sup.1, more preferably with a thermal conductivity lower than 1 W.Math.m.sup.1.Math.K.sup.1, most preferably with a thermal conductivity lower than 0.5 W.Math.m.sup.1.Math.K.sup.1. The labyrinth is made by a suitable technology, such as machining, 3D printing, cutting the shaped tube from a suitable material, etc., or by combining at least two different technologies.

[0016] In the embodiments of FIGS. 1, 1a, 1b, 1d and 1e, the shaping labyrinth 2 is provided with fastening means 21 for fastening it to the carrier 4, which is shown in FIG. 1e. FIGS. 1, 1a, 1b, 1d and 1e show a particularly preferred embodiment of the labyrinth 2, wherein the labyrinth 2 is for production simplification divided into sections which are provided with special flanges 22 for joining individual adjacent sections of the labyrinth 2. The embodiments of the flanges 22 and their principle, however, are not the subject-matter of the present invention.

[0017] In an exemplary embodiment of FIGS. 1c and 2, the entire mould, i.e., including the body 1 and the shaping labyrinth 2 are made of a material with a thermal conductivity lower than 5 W.Math.m.sup.1.Math.K.sup.1, more preferably with a thermal conductivity lower than 1 W.Math.m.sup.1.Math.K.sup.1, most preferably with a thermal conductivity lower than 0.5 W.Math.m.sup.1.Math.K.sup.1. The body 1 and the labyrinth 2 are made by a suitable technology, such as machining, 3D printing, cutting from a suitable material, etc., or by combining at least two different technologies.

[0018] An example of a material with a thermal conductivity lower than 5 W.Math..sup.1.Math.K.sup.1 is wood, plastic, especially polymer, reinforced polystyrene, Teflon, a composite, especially polymeric matrix composite, etc. From the point of view of the durability of the mould, or, more specifically, of its contact wall 20, it is desirable and advantageous if the material used with a thermal conductivity lower than 5 or 1, or 0.5 W.Math.m.sup.1.Math.K.sup.1 has a temperature resistance at least at the level to which a shaped product of HDPE or PA or similar plastics is heated prior to being inserted into the mould according to the present invention.

[0019] The mould according to the present invention operates in such a manner that it substantially reduces heat dissipation from the shaped tube during the cooling of the tube, and therefore it is not necessary to use a tempering furnace to slow the cooling process of the product for the recovering of the crystalline or semicrystalline structure and for the relaxation of the internal tension of HDPE or PA material, nor is it necessary to prolong production time by waiting for HDPE or PA material shape stabilization in the mould in air. This results in reducing the overall cost by the acquisition cost and operating costs for the tempering furnace, shorten the production times and increase production throughput.

[0020] In the case of a mould for forming other shapes, the contact walls 20 for the contact with the material being shaped are provided with at least a coating of a material with a thermal conductivity lower than 5 W.Math.m.sup.1.Math.K.sup.1, more preferably with a thermal conductivity lower than 1 W.Math.m.sup.1.Math.K.sup.1, most preferably with a thermal conductivity lower than 0.5 W.Math.m.sup.1.Math.K.sup.1, or the contact walls 20 or part on which the contact walls 20 are located are directly made of a material with a thermal conductivity lower than 5 W.Math.m.sup.1.Math.K.sup.1, more preferably with a thermal conductivity lower than 1 W.Math.m.sup.1.Math.K.sup.1, most preferably with a thermal conductivity lower than 0.5 W.Math.m.sup.1.Math.K.sup.1.

INDUSTRIAL APPLICABILITY

[0021] The invention is applicable for series production of products made of HDPE or PA or similar plastics by further shaping of previously produced semi-products. It is especially advantageous for the spatial shaping of HDPE or PA tubes from HDPE or PA straight tubes.