Injection moulding

Abstract

An apparatus 13 and method for forming an injection moulded vehicle component comprising an airbag compartment cover mesh insert 40. The apparatus comprises a first member 20 which is moveable with re

Description

TECHNICAL FIELD The present disclosure relates to injection moulding. Aspects of the invention relate to an apparatus for forming an injection moulded vehicle component, and to a method of forming an injection moulded vehicle component. BACKGROUND It is known to provide a mesh within the moulding of a passenger airbag cover. The mesh serves to support the airbag cover during normal use of a vehicle, and helps to control the opening of the airbag cover when the airbag is deployed. The mesh is typically integrated into the airbag cover during an injection moulding process in which all or part of the dashboard of the vehicle is formed together with the airbag cover. If the mesh is not correctly positioned, or if the mesh moves during the injection moulding process, all or part of the mesh may be visible from the exterior of the injection moulded part leading to scrapping of the part. It is an aim of the present invention to address one or more of the disadvantages associated with the prior art. SUMMARY OF THE INVENTION Aspects and embodiments of the invention provide an apparatus for forming an injection moulded vehicle component and a method for forming an injection moulded vehicle component as claimed in the appended claims. According to an aspect of the present invention there is provided an apparatus for forming an injection moulded vehicle component comprising an airbag compartment cover mesh insert, the apparatus comprising a first member and a second member, wherein the first member is moveable with respect to the second member between a closed position and an open position. The first member is configured to hold the mesh insert in a moulding position when the first member is in the closed position, and the first member is configured to release the mesh insert from the moulding position when the first member is in the open position. The present invention is advantageous as the airbag compartment cover mesh insert is held in place in the correct position moulding position by the first member when it is in the closed position, and released from the moulding position when the first member is in the open position so that the mesh insert and injection moulded component may be removed from the apparatus. Optionally the first member may comprise a retention feature which is configured to cooperate with an insert retention feature on the mesh insert when the first member is in the closed position, wherein the retention feature comprises a protrusion configured to pass through a hole in the mesh insert. This is advantageous as the interaction of the retention feature with the insert retention feature on the mesh insert helps to correctly locate the mesh insert in the moulding position. The first member may optionally be configured to clamp a portion of the mesh insert between the first member and the second member when the first member is in the closed position to help hold the mesh insert in position during the injection moulding process. The first member may be at least partially located within the second member which is beneficial for packaging efficiency. The first member and the second member may together form a mesh retention mechanism configured so that the first member is moveable within the second member along a fixed trajectory. In one example, the first member may be biased towards the open position so that the first member releases the mesh insert when not constrained in the second position. Optionally the apparatus may comprise a moveable stop member configured to bias the first member to the closed position to hold the first member in the closed position during the injection moulding process. The apparatus may optionally comprise a support member, wherein the support member is moveable between a loading position and an ejection position, wherein, in use, the support member is configured to: receive and support the mesh insert when in the loading position prior to commencement of the injection moulding operation; and move from the loading position to the ejection position following completion of the injection moulding operation. The support member helps to keep the mesh insert in position before and during the injection moulding process and helps to eject the moulded part once the injection moulding process is complete. The support member may be configured to move from the loading position to a moulding position prior to commencement of the injection moulding operation, and move from the moulding position to the ejection position following completion of the injection moulding operation. Loading the mesh insert onto the support member before moving the support member to the moulding position is beneficial as better access to the support may be provided thereby reducing the risk of misplacement or damage of the mesh insert. In one example the support member may be configured to move the injection moulded item in a direction away from the first member as it moves to the ejection position following completion of the injection moulding operation. Wherein, moving the injection moulded item in a direction away from the first member comprises increasing the distance between the first member and the support member. According to another aspect of the present invention there is provided a method of forming an injection moulded vehicle component comprising an airbag compartment cover mesh insert, the method comprising: positioning a mesh insert within an injection moulding apparatus comprising a first member and a second member, wherein the first member is moveable with respect to the second member; holding the mesh insert in a moulding position by moving the first member from an open position to a closed position; performing an injection moulding operation to form the injection moulded vehicle component, wherein the mesh insert is at least partially embedded within the injection moulded vehicle component; releasing the mesh insert from the moulding position by moving the first member from the closed position to the open position; and removing the injection moulded vehicle component from the injection moulding apparatus. Optionally holding the mesh insert in the moulding position may comprise engaging a retention feature located on the first member with a cooperating insert retention feature of the mesh insert. Engaging the retention feature of the first member with the cooperating insert retention feature of the mesh insert may comprise passing a protrusion located on the first member through a hole located in the mesh insert. 2 In one example, holding the mesh insert in the moulding position may comprise clamping a portion of the mesh insert between the first member and a second member. Optionally positioning the mesh insert within the injection moulding apparatus may comprise positioning the mesh insert on a support member when the support member is located in a loading position. The method optionally comprises moving the support member to a moulding position prior to commencement of the injection moulding operation. The method may comprise moving the support member of the to an ejection position following completion of the injection moulding operation. Within the scope of this application it is expressly infended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in any way and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a schematic representation of an injection moulding machine; Figure 2 shows a schematic representation of an apparatus for use with the injection moulding machine of Figure 1 in a first configuration; Figure 3 shows a schematic representation of the apparatus of Figure 2 in a second configuration; Figure 4 shows a schematic representation of an airbag compartment cover mesh insert; Figure 5 shows a schematic representation of an alternative apparatus for use with the injection moulding machine of Figure 1 in a first configuration; Figure 6 shows a schematic representation of the apparatus of Figure 5 in a second configuration; and Figure 7 shows a flow chart describing a method of forming an injection moulded vehicle component comprising an airbag compartment cover mesh insert. DETAILED DESCRIPTION Figure 1 shows a schematic representation of an injection moulding machine 10 comprising a pair of platerns 11, 12 between which is located a mould tool 13. The mould tool 13 defines a mould cavity 14 which defines the shape of the injection moulded component to be formed. In use, a flowable plastic material is injected via an injection channel 15 into the mould cavity 14. A hopper 16 stores plastic granules which are fed to a channel 17 in which the plastic granules are melted and fed onward by a screw mechanism to the injection channel 15. One of the platerns 11 is fixed in position and the other of the platerns 12 is moveable along tie bars 18. Once the moulded component is formed, the moveable platern 12 is moved along the tie bars 18 to allow the moulded part to be released from the injection moulding machine 10. The moveable platern 12 is then moved back into position before the next moulded component is formed. The mould tool 13 comprises a plurality of members which are moveable with respect to one another. An example of such a multimember mould tool 13 is described with reference to Figures 2 and 3. Figure 2 shows a schematic representation of a sectional view through the mould tool 13 in its moulding configuration where, in the moulding configuration, the plurality of members define the mould cavity 14. Figure 3 shows a schematic representation of a sectional view through the mould tool 13 in its loading configuration where, in the loading configuration, the plurality of members have a different configuration with respect to one another than in the moulding configuration. The mould tool 13 comprises a pair of first members 20 and a pair of second members 21. The first members 20 comprises sliders which are received within slots formed within each second member 21. The first members 20 are moveable with respect to the second members 21 and are biased away from the second members 21 by resilient members 22. In this example, the resilient members 22 comprise helical springs. However, it will be understood that any suitable resilient member may be used. The mould tool 13 also comprises a pair of core members 23 located on either side of the second members 21, a support member 24, a pair of stop members 25 located on either side of the support member 24, and a cap member 26 which extends across all of the other mould tool members and which defines one side of the mould tool 13. A schematic representation of an airbag compartment cover mesh insert 40 is shown in position in the mould cavity 14 in Figure 2, and ready for placement on the support member 24 in Figure 3. Figure 4 shows a schematic plan view of the mesh insert 40 before it has been folded into the configuration shown in Figures 2 and 3. The mesh inset 40 comprises a first plurality of holes 41 located towards the centre of the mesh insert 40, and a second plurality of holes 42 located of either side of the first plurality of holes 41. As will be described in greater detail below, the first and second plurality of holes 41, 42 form insert retention features which are configured to cooperate with retention features of the support member 24 and first members 20 respectively. The outermost portions of the mesh insert 40 form clamp portions 43 when the mesh insert is folded into the configuration shown in Figures 2 and 3. Referring once again to Figures 2 and 3, the first members 20 each comprise a retention feature 27 in the form of a pin which are each configured to cooperate with one of the second plurality of holes 42 of the mesh insert 40. Similarly, the support member comprises a plurality of bosses 29 which are each configured to cooperate with one of the first plurality of holes 41 of the mesh insert 40. When the mould tool 13 is in the moulding configuration shown in Figure 2, the pins 27 of the first members 20 pass through the holes 42 in the mesh insert 40 and press against the clamp portion 43 of the mesh insert 40 so that the clamp portions 43 are clamped between the pins 27 and the second members 21. This arrangement helps to keep the mesh insert in place during the injection moulding operation. Referring now to Figure 3, prior to the injection moulding operation, the support member 24 is in a loading position ready to receive the mesh insert 40, and the stop members 25 are withdrawn so that the first members 20 are biased away from the second members 21 to an open position. The mesh insert 40 is placed on a support surface 28 of the support member 24 so that the bosses 29 engage with the first plurality of holes 41 in the mesh insert 40. After the mesh inset 40 has been loaded, the support member 24 moves to a moulding position as shown in the moulding configuration of Figure 2, and the stop members 25 advance towards the first members 20 and the support member 24 to bias the first members 20 towards and into the second members 21 against the bias of the resilient members 22. The opposing surfaces of the stop members 25 and the first members 20 are shaped so that when the stop members 25 move towards the first members 20, the first members 20 are pushed to a closed position in which the pins 27 of the first members 20 hold the mesh insert 40 in the moulding position. As discussed above, when all of the members of the mould tool 13 have reached the moulding configuration of Figure 2, and the first members 20 are in the closed position, the pins 27 of the first members 20 pass through the holes 42 in the mesh insert 40 and press against the clamp portion 43 of the mesh insert 40 so that the clamp portions 43 are clamped between the pins 27 and the second members 21. After the injection moulding operation is complete, the members forming the mould tool 13 return to the loading configuration of Figure 3 such that the support member 24 moves from its mounding position to an ejection position and the stop members 25 withdraw to allow the first members 20 to be pushed back to their open position by the resilient members 22. The movement of the support member 24 pushed the moulded part away from the mould tool members thereby facilitating removal of the moulded part from the injection moulding machine 10. The support member is once again in its loading position ready to receive the mesh insert 40 of the next part to be formed. Figures 5 and 6 show an alternative mould tool 113 that may be used with the injection moulding machine 10. The mould tool 113 is similar in many respects to the mould tool 13 described above. However, in this example, there is no support member such that the mesh insert 40 is supported by the first members 120 when the mould tool 113 is in its loading configuration as shown in Figure 6, and by the first members 120 and the stop member 125 when the mould tool 113 is in its moulding configuration as shown in Figure 5. The mould tool 113 comprises a pair of first members 120 and a pair of second members 121. The first members 120 comprises sliders which are received within slots formed within each second member 121. The first members 120 are moveable with respect to the second members 121 and are biased away from the second members 121 by resilient members 122. In this example, the resilient members 122 comprise helical springs. However, it will be understood that any suitable resilient member may be used. The mould tool 113 also comprises a pair of core members 123 located on either side of the second members 121, and a stop member 125 located between the first members 120 (in the moulding configuration at least). The first members 120 each comprise a retention feature 127 in the form of a pin which are each configured to cooperate with one of the second plurality of holes 42 of the mesh insert 40. Similarly, the stop member 125 comprises a plurality of bosses 129 which are each configured to cooperate with one of the first plurality of holes 41 of the mesh insert 40. When the mould tool 113 is in the moulding configuration shown in Figure 5, the pins 127 of the first members 120 pass through the holes 42 in the mesh insert 40 and press against the clamp portion 43 of the mesh insert 40 so that the clamp portions 43 are clamped between the pins 127 and the second members 121. Prior to the injection moulding operation, as shown in Figure 6, the first members 120 are in an open position and receive the mesh insert 40. The stop member 125 is withdrawn so that the first members 120 are biased away from the second members 121. After 5 the mesh inset 40 has been loaded, the stop member 125 advances towards the first members 120 to bias the first members 120 towards and into the second members 121 against the bias of the resilient members 122. The opposing surface of the stop member 125 and the first members 120 are shaped so that when the stop member 125 moves towards the first members 120, the first members 120 are pushed to the closed position in which the pins 127 of the first members 120 hold the mesh insert 40 in the moulding position. When all of the members of the mould tool 113 have reached the moulding configuration of Figure 5, and the first members 120 are in the closed position, the pins 127 of the first members 120 pass through the holes 42 in the mesh insert 40 and press against the clamp portion 43 of the mesh insert 40 so that the clamp portions 43 are clamped between the pins 27 and the second members 21. In this configuration, the stop member has taken up position between the first members 120 so that the mesh inset 40 rests on a surface 128 of the stop member 125 and the bosses 129 of the stop member 125 engage with the first plurality of holes 41 in the mesh insert. After the injection moulding operation is complete, the members forming the mould tool 113 return to the loading configuration of Figure 6 such that the stop member 125 withdraws to allow the first members 120 to be pushed back to their open position by the resilient members 122, the moulded part can then be removed from the injection moulding machine 10. Figure 7 shows a flow chart describing a method 50 of forming an injection moulded vehicle component comprising an airbag compartment cover mesh insert 40. In a first step 51, the method comprises positioning the mesh insert 40 within an injection moulding apparatus 13,113 comprising a first member 20,120 andasecond member 21,121, wherein the first member 20,120 is moveable with respect to the second member 21,121. IN a second step 52, the method comprises holding the mesh insert 40 in a moulding position by moving the first member 20, 120 from an open position to a closed position. In the next step 53 an injection moulding operation is performed to form the injection moulded vehicle component. The mesh insert 40 is thereby at least partially embedded within the injection moulded vehicle component. In the next step 54, the mesh insert 40 is release d from the moulding position by moving the first member 20, 120 from the closed position to the open position, and in a final step 55 the injection moulded vehicle component is removed from the injection moulding apparatus 13,113. It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application. In particular, it is not necessary that the mesh inset 40 comprises holes 41, 42 that engage with pins 27 or bosses 29 respectively and one or both sets of holes 41, 42 may be omitted along with the corresponding pin / boss. If holes 42 are provided for engagement with pins 27, it is not necessary for the mesh insert 40 to have clamp portions 43 as the mesh insert40 may be help in place by the pins 27 / holes 42 alone. The holes 41 / bosses 29 may be omitted in either case. It is not essential that the first member 20, 120 comprises a slider which moves within a slot formed in the second member 21, 121. In an example the first members 20,120 may extend along the length of their respective second members 21,121 and may comprise a plurality of pins 27,127. In this example the whole of each first member 20,120 moves with respect to its associated second member 21, 121. It is not necessary for each of the members forming the mould tool 13, 113 to move in unison. In one example the support member 24 of the mould tool 13 may move from the loading position to the moulding position before the stop members 25 move into their moulding configuration. Similarly, the stop members 25 may withdraw away from the support member 24 before the support member moves from its moulding position to the ejection position. Alternatively the members of the mould tools 13,113 may move in unison, or may move with staggered, but overlapping movement times.

Claims

1. Apparatus for forming an injection moulded vehicle component comprising an airbag compartment cover mesh insert, the apparatus comprising a first member and a second member, wherein the first member is moveable with respect to the second member between a closed position and an open position, wherein the first member is configured to hold the mesh insert in a moulding position when the first member is in the closed position, and wherein the first member is configured to release the mesh insert from the moulding position when the first member is in the open position.

2. An apparatus according to claim 1, wherein the first member comprises a retention feature which is configured to cooperate with an insert retention feature on the mesh insert when the first member is in the closed position, wherein the retention feature comprises a protrusion configured to pass through a hole in the mesh insert.

3. An apparatus according to any preceding claim, wherein the first member is configured to clamp a portion of the mesh insert between the first member and the second member when the first member is in the closed position.

4. An apparatus according to any preceding claim, wherein the first member is at least partially located within the second member.

5. An apparatus according to any preceding claim, wherein the first member is biased towards the open position.

6. An apparatus according to any preceding claim, comprising a moveable stop member configured to bias the firstmember to the closed position.

7. An apparatus according to any preceding claim, comprising a support member, wherein the support member is moveable between a loading position and an ejection position, wherein, in use, the support member is configured to:receive and support the mesh insert when in the loading position prior to commencement of the injection moulding operation; andmove from the loading position to the ejection position following completion of the injection moulding operation.

8. An apparatus according to claim 7, wherein the support member is configured to move from the loading position to a moulding position prior to commencement of the injection moulding operation, and move from the moulding position to the ejection position following completion of the injection moulding operation.

9. An apparatus according to claim 7 or 8, wherein the support member is configured to move the injection moulded item in a direction away from the first member as it moves to the ejection position following completion of the injection moulding operation.

10. A method of forming an injection moulded vehicle component comprising an airbag compartment cover mesh insert, the method comprising:positioning a mesh insert within an injection moulding apparatus comprising a first member and a second member, wherein the first member is moveable with respect to the second member;holding the mesh insert in a moulding position by moving the first member from an open position to a closed position;7performing an injection moulding operation to form the injection moulded vehicle component, wherein the mesh insert is at least partially embedded within the injection moulded vehicle component;releasing the mesh insert from the moulding position by moving the first member from the closed position to the open position; andremoving the injection moulded vehicle component from the injection moulding apparatus.

11. A method according to claim 10, wherein holding the mesh insert in the moulding position comprises engaging a retention feature located on the first member with a cooperating insert retention feature of the mesh insert.

12. A method according to claim 11, wherein engaging the retention feature of the first member with the cooperating insert retention feature of the mesh insert comprises passing a protrusion located on the first member through a hole located in the mesh insert.

13. A method according to any one of claims 10 to 12, wherein holding the mesh insert in the moulding position comprises clamping a portion of the mesh insert between the first member and a second member.

14. A method according to any one of claims 10 to 13, wherein positioning the mesh insert within the injection moulding apparatus comprises positioning the mesh insert on a support member when the support member is located in a loading position.

15. A method according to claim 14, comprising moving the support member to a moulding position prior to commencementof the injection moulding operation.

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