GB2112316A

GB2112316A - Moulding articles with inserts

Info

Publication number: GB2112316A
Application number: GB08138965A
Authority: GB
Inventors: Derek William Pearce
Original assignee: Plessey Co Ltd
Current assignee: Plessey Co Ltd
Priority date: 1981-12-24
Filing date: 1981-12-24
Publication date: 1983-07-20
Also published as: GB2112316B

Abstract

A moulding process for moulding articles comprising inserts includes a first stage in which one or more inserts 14, 16, 18 are held in defined positions within a first mould 10, 12 by recesses 20, 22, 24 in the first mould post 12 and in which moulding material is injected to secure the inserts in the defined positions, and a second stage in which the part moulded article is transferred to a second mould, Fig. 4 (not shown), into which further moulding material is injected to further enclose the inserts and form the final moulded article. In the second mould the inserts are held in position by the previous moulding material. <IMAGE>

Description

SPECIFICATION Improvements in or relating to moulding processes The present invention relates to moulding processes and more particularly to processes for moulding articles incorporating one or more parts within a moulded structure.

Previously when an article is required to be assembled from a plurality of parts it is assembled by positioning each part in its respective position with appropriate spacing pieces and mechanically securing the assembly together by for example a screw. This is an extremely time consuming operation requiring other manual assembly or automatic assembly by a complex and therefore expensive machine.

It is an object of the present invention to provide a method of moulding a structure incorporating one or more parts in a two stage process.

The present invention therefore provides a moulding process including a first stage in which one or more parts to be moulded in a body are held in defined positions within a first mould by projections within the first mould and in which moulding material is injected to secure the one or more parts in the defined positions and in which after the moulding material has been allowed to set, in a second stage the part moulded article is transferred to a second mould in which the one or more articles are not required to be held in position and in which further moulding material is injected into second stage mould to further enclose the one or more articles.

Preferably at the second stage the mould is designed such that moulding is injected into the mould to produce a moulded surface flush with a surface of the one or more articles.

Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings in which:~ Figure 1 shows the moulding tool for the first stage of the process together with three articles for inclusion in the moulding.

Figure 2 shows a composite sub assembly formed from the moulding tool of figure 1.

Figure 3 shows the composite sub assembly of figure 2 with a further component attached.

Figure 4 shows the moulding tool for the second stage of the process together with the sub assembly of figure 3 and; Figure 5 shows the completed moulding after the second stage moulding process.

Referring now to figure 1 of the drawings there is shown an upper section 10 and lower section 12 of a moulding tool which sections can be moved together to form a cavity by means not shown. Such means may be a hydraulically operated or hand operated press. In the first stage of the process articles or inserts 14, 16 and 18 are placed in the lower section of the moulding tool and are held in position by recesses 20, 22, 24 in the tool which abut against portions of the articles. The press is then operated to close the two sections of the mould together, thus forming one or more cavities 26, 28, 30, 32 which are then completely filled with moulding material.

After leaving time for the moulding material to set, or cooling in the case of a thermo setting plastic the sub assembly is removed from the mould.

The sub assembly is shown in figure 2, the moulding material formed within each cavity 26, 28, 30, 32 being referenced respectively 261, 281, 301, and 321. this moulding material holds together with inserts 1 4, 1 6 and 1 8 in defined respective positions. Inserts 14, 1 6 and 18 could for example be hollow and mould material could be continuous along the length of the centre of the sub assembly.

It may be required, at this stage in the process, to do further work on the sub assembly of figure 2 for example to machine it or assemble further components to it by known means. Figure 3 illustrates an example of this in which a hole 34 is drilled and tapped into one of the inserts 1 8 and a further component 36 is placed in position preparatory to being secured by a screw (38) (see figure 4).

Figure 4 shows the second stage moulding tool which has upper 40 and lower 42 sections. The sub assembly of figure 3 is placed in the bottom section 42 of the moulding tool and the two sections of the tool are closed by for example a hydraulic press (not shown). Further cavities 44, 46, 48, 50, 52 are formed which are filled with moulding material. The inserts 14, 16 and 18 are held in position by the previous moulding material and therefore do not move relative to each other.

It can be seen with reference to the finished composite moulded assembly shown in figure 5 that articles or inserts such as 1 8 may be formed flush as with the bottom surface 54 of the assembly and may be buried completely as in the upper portion of the moulding. The first moulding process holds the articles or inserts in position and the second stage is used to form the completed moulding with the articles secured in their required positions.

Using only a single stage process this would be extremely difficult because it would not be easy to grip the inserts to hold them in their respective positions.

Claims

1. A moulding process including a first stage in which one or more parts to be moulded in a body are held in defined positions within a first mould by projections within the first mould and in which moulding material is injected to secure the one or more parts in the defined positions and in which after the moulding material has been allowed to set, in a second stage the part moulded article is transferred to a second mould in which the one or more articles are not required to be held in position and in which further moulding material is injected into the second stage mould to further enclose the one or more articles.

2. A moulding process as claimed in claim 1 in which at the second stage the mould is designed such that moulding is injected into the mould to produce a moulded surface flush with a surface of the one or more articles.

3. A moulding process substantially as described with reference to the accompanying drawings.