Injection mould with multi-part mould insert frame

Abstract

In an injection mould comprising a mould insert frame (3) for receiving a multiple-nozzle head (4) and a plurality of mould inserts (7) each having a cavity formed therein, each of which can be supplied with plastic melt via the multiple-nozzle head (4); wherein the mould insert frame (3) has a central aperture (4), which extends in an axial direction (A) and in which the multiple-nozzle head (3) is received, and a plurality of peripheral apertures (5), which are arranged around the central aperture (4) and extend in the axial direction (A) and in each of which one of the plurality of mould inserts (7) is received; there is provision that the mould insert frame (3) comprises a central frame part (31, 31') with the central aperture (4) and at least one peripheral fixing part (32, 32') which can be removed from the central frame part (31, 31'); wherein the plurality of peripheral apertures (5) are formed by the central frame part (31, 31') and the at least one peripheral fixing part (32, 32'); wherein a separation (T) between the central frame part (31, 31') and the at least one removable peripheral fixing part (32, 32') runs through the respective peripheral aperture (5) in such a way that, with a peripheral fixing part (32, 32') removed, the mould insert (7) can be taken out from the central frame part (31, 31') from the multiple-nozzle head (3) in a direction (R) perpendicular to the axial direction (A).

Description

[0001] Injection mold with multi-part mold insert frame

[0002] Technical area

[0003] The invention relates to an injection molding tool with a mold insert frame for receiving and mounting a multiple nozzle head and a plurality of mold inserts arranged around the multiple nozzle head.

[0004] Technical background

[0005] Injection molds with multiple mold inserts, which are supplied with a plastic melt via a multiple nozzle head, typically have a mold insert frame in which the multiple nozzle head and the multiple mold inserts are accommodated and mounted. For this purpose, the mold insert frame has a central recess extending in a vertical direction for the multiple nozzle head and several peripheral recesses for the mold inserts, arranged evenly around the central recess and also extending in the axial direction. The axial direction is also the closing or opening direction of the injection mold.

[0006] The multiple nozzle head comprises a primary melt channel, which branches at one end of the multiple nozzle head into several secondary melt channels, which run essentially perpendicular to the axial direction and open laterally into the mold insert. The secondary melt channel is connected at a proximal end to the primary melt channel and at a distal end to a pre-chamber via a nozzle tip attached to the nozzle head. The pre-chamber is formed partly by the multiple nozzle head and partly by the respective mold insert, which are sealed together. The nozzle tip usually extends into a corresponding recess in the mold insert. Accordingly, the mold inserts can be very precisely positioned and fixed relative to the multiple nozzle head using the respective recesses.

[0007] During normal operation of the injection mold, it may happen that individual mold inserts require maintenance and cleaning. To remove the mold insert to be cleaned, the corresponding mold insert, together with the multiple nozzle head and all other mold inserts, must be lifted axially out of the injection mold or the recesses in the mold insert frame. The defective mold insert can then be removed from the multiple nozzle head in a direction perpendicular to the axial direction. Assembling and reassembling the mold inserts and the multiple nozzle head into the injection mold is extremely time-consuming and requires a great deal of skill, because all mold inserts must be precisely aligned with the multiple nozzle head before all elements can be inserted into the corresponding recesses in the insert frame. Furthermore, there is a high risk of damaging the nozzle tips or other components.

[0008] To facilitate the installation and removal of a mold insert, WO20227817A1 proposes designing the nozzle tip so that it can be removed axially. The mold insert can be removed axially together with the nozzle tip. However, if solid plastic is still present in the nozzle, and in particular in the nozzle tip and the corresponding pre-chamber, cold removal of the mold insert is hardly possible. Another problem is the seal between the nozzle tip and the multiple nozzle head. Even very slight play in the nozzle tip inevitably leads to leaks. Furthermore, instead of a conventional multiple nozzle head available on the market, a specially designed multiple nozzle head with a nozzle tip that can be removed axially must be used.

[0009] EP0743157 and WO09124865 each describe systems with individually removable nozzle tips for subsequent removal of the mold insert. In EP0743157, an upper part of the mold insert must also be removed beforehand, which can lead to further leaks. Even with these systems, cold removal of a mold insert is hardly possible if solid plastic residues are present.

[0010] Description of the invention

[0011] One object of the invention is to provide an injection molding tool that does not have the aforementioned disadvantages. This object is achieved by an injection molding tool having the features of claim 1.

[0012] The injection molding tool comprises a mold insert frame for receiving a multiple nozzle head and a plurality of mold inserts, each having a cavity formed therein, which can each be supplied with plastic melt via the multiple nozzle head. The mold insert frame has a central recess extending in an axial direction, in which the multiple nozzle head is received, and a plurality of peripheral recesses arranged around the central recess and extending in the axial direction, in each of which one of the plurality of mold inserts is received. The mold insert frame comprises a central frame part with the central recess and at least one peripheral fixing part removable from the central frame part, wherein the plurality of peripheral recesses are formed by the central frame part and the at least one peripheral fixing part.A separation between the central frame part and the at least one removable peripheral fixing part runs through the plurality of peripheral recesses such that with a removed peripheral fixing part the mold insert is removable from the central frame part in a direction perpendicular to the axial direction of the multiple nozzle head.

[0013] Such a multi-part mold insert frame, which can be accommodated in a mold plate of the injection mold, allows for easy removal of a mold insert from the corresponding nozzle tip of the multiple nozzle head in a radial direction. This enables cold removal. Furthermore, the central frame part ensures that the remaining, unremoved mold inserts are held on the multiple nozzle head in the correct position. For later reinstallation, no laborious alignment of the individual mold inserts to the respective peripheral recesses is necessary, as is the case with conventional one-piece mold insert frames. The system can also be combined with conventional multiple nozzle heads without the need for complex, removable nozzle tips.

[0014] Preferred embodiments of the invention are set out in the dependent claims.

[0015] In some embodiments, the central frame part can form an inner, proximal (i.e. closer to the center or the central recess) circumferential surface of the plurality of peripheral recesses and the at least one peripheral fixing part can form an outer, distal (i.e. further away from the center or the central recess) circumferential surface of the plurality of peripheral recesses. The two circumferential surfaces form the peripheral recess in which the mold insert is positioned and fixed exactly opposite the nozzle tip. The part of the recess in the central frame part and its proximal circumferential surface are already designed such that the mold insert can be precisely positioned and held therein. As a rule, the proximal circumferential surface on the central frame part spans a maximum of 180 degrees of the peripheral recess so that the mold unit can be removed in a (radial) direction perpendicular to the axial direction.In some embodiments, the peripheral fixing part can be formed by a mold plate of the injection molding tool, into which the central frame part can be inserted together with the multiple nozzle head and the multiple mold inserts. During removal, the central frame part, together with the multiple nozzle head and the mold inserts, is lifted axially out of the mold plate or the peripheral fixing part using a suitable tool. The mold insert can then be removed from the central frame part, away from the nozzle tip, in a direction perpendicular to the axial direction.

[0016] In some embodiments, the mold insert frame can comprise a single peripheral fixing part that surrounds the central frame part and can be inserted into a mold plate of the injection mold together with the central frame part, the multiple nozzle head, and the plurality of mold inserts. During removal, the mold insert frame is first pulled out of the mold plate in the axial direction using a suitable tool. Subsequently, the central frame part, together with the multiple nozzle head and the mold inserts, is pulled out of the peripheral fixing part in the axial direction using a suitable tool. The mold insert can then be removed from the central frame part from the nozzle tip in a direction perpendicular to the axial direction.

[0017] In some embodiments, the mold insert frame can comprise a plurality of peripheral fixing parts which, together with the central frame part, the multiple nozzle head, and the plurality of mold inserts, can be inserted into a tool plate of the injection mold. The plurality of peripheral fixing parts can be arranged in corresponding recesses in the central frame part. The plurality of peripheral fixing parts can be individually removable from the central frame part in a direction perpendicular to the axial direction. During removal, the mold insert frame is first pulled out of the tool plate in the axial direction using a suitable tool. Subsequently, one of the plurality of peripheral fixing parts can be removed from the central frame part. The mold insert can then be removed from the central frame part from the nozzle tip in a direction vertical to the axial direction.

[0018] In some embodiments, the plurality of peripheral recesses may be circular with one or more circular cylindrical sections.

[0019] In some embodiments, an outer contour of the mold insert frame is cylindrical, preferably with several circular-cylindrical sections. The mold insert frame can be received in a corresponding recess in the tool plate. In some embodiments, the peripheral recess can have a circumferential shoulder against which the mold insert rests in the installed state and on which the mold insert is guided during installation or removal. The mold insert can have a correspondingly complementary shoulder.

[0020] In some embodiments, the central frame part may have a recess between the central recess and the plurality of peripheral recesses, in each of which a nozzle tip of the multiple nozzle head is arranged.

[0021] In some embodiments, the peripheral recesses can be evenly distributed around the central recess. Typically, they are arranged in a circular pattern. The mold insert frame can have 2 to 8 recesses and, accordingly, 2 to 8 mold inserts, each of which is connected to a central multiple nozzle head.

[0022] In some embodiments, the separation may be substantially circular and divide the peripheral recesses into approximately two equal parts. This is particularly advantageous for a substantially annular peripheral fixing part.

[0023] In some embodiments, the central frame part can have a plurality of elongated, radially outwardly open recesses with substantially parallel side walls, into each of which one of the plurality of peripheral fixing parts can be inserted, thereby forming the peripheral recess. The separation between the central frame part and the peripheral fixing part runs along the substantially parallel side walls of the recess.

[0024] In some embodiments, the plurality of mold inserts may be retained in position in the peripheral recesses of the central frame member even when the peripheral fixing member is removed.

[0025] In some embodiments, the multiple nozzle head may have a primary melt channel, which may extend in an axial direction, and, for each cavity, a secondary melt channel branching off from the primary melt channel, which may extend in a radial direction. The secondary melt channel may be connected to the primary melt channel at a proximal end and to a cavity at a distal end by a nozzle tip attached to the nozzle head.

[0026] In some embodiments, the multiple nozzle head may have multiple nozzle tips for side-injecting the multiple cavities. In some embodiments, the injection molding tool may have a cover plate with which the mold inserts and / or the multiple nozzle head are fixed in the respective recesses.

[0027] In some embodiments, the plurality of mold inserts can have a fastening means for a suitable tool on the side opposite the respective nozzle tip, so that the plurality of mold inserts can be pulled out of the central frame part with the suitable tool in a direction perpendicular to the axial direction. The fastening means can, for example, be a bore with an internal thread into which a suitable tool can be screwed. The fastening means can also have one or more openings into which a suitable tool can engage and clamp.

[0028] The injection molding tool can also have several mold insert frames with multiple nozzle heads and several mold inserts as described above.

[0029] Short explanation of the figures

[0030] The invention will be explained in more detail below using exemplary embodiments in conjunction with the drawing(s). They show:

[0031] Fig. 1 is a perspective view of an injection molding tool with a two-part mold insert frame;

[0032] Fig. 2 is a perspective view of the injection molding tool from Fig. 1 with the mold insert frame removed;

[0033] Fig. 3 is a plan view of the two-part mold insert frame from Fig. 1;

[0034] Fig. 4 is a perspective view of the two-part mold insert frame of Fig. 1 with the central frame part removed;

[0035] Fig. 5 is a perspective view of the central frame part of Fig. 1 with the mold insert removed;

[0036] Fig. 6 is an exploded perspective view of the mold insert frame of Fig. 1 with a multiple nozzle head and a mold insert;

[0037] Fig. 7 is a perspective view of an injection molding tool with the multi-part mold insert frame removed;

[0038] Fig. 8 is a plan view of the multi-part mold insert frame of Fig. 7; Fig. 9 is a perspective view of the multi-part mold insert frame of Fig. 7 with the peripheral fixing part removed;

[0039] Fig. 10 is a perspective view of the multi-part mold insert frame from Fig. 7 with the mold insert removed;

[0040] Fig. 11 is a perspective view of the central frame part of Fig. 7 with the multiple nozzle head removed.

[0041] Ways to implement the invention

[0042] Fig. 1 shows an injection molding tool, or rather a tool plate 1 of an injection molding tool with multiple mold inserts 7. In the embodiment shown, the mold inserts 7 are arranged in a circle around a multiple nozzle head 6, each of which supplies a cavity of the respective mold insert 7 with plastic melt. A prechamber for the plastic melt is formed by a recess in the mold insert 7, into which a nozzle tip 61 of the multiple nozzle head 6 protrudes.

[0043] The multiple nozzle head 6 and the multiple mold inserts 7 must therefore be arranged in a sealing manner relative to one another in the region of the prechamber. This is generally achieved by holding the multiple nozzle head 6 and the multiple mold inserts 7 in a mold insert frame 3 and thus fixing them in the correct position relative to one another. For this purpose, the mold insert frame 3 has a central recess 4 for the multiple nozzle head 6 and several peripheral recesses 5 for the multiple mold inserts 7. These recesses 4, 5 and their arrangement are clearly visible in Fig. 3, among other things. Fig. 3 shows a top view of the two-part mold insert frame 3 from Fig. 1.

[0044] The mold insert frame 3, the multiple nozzle head 6 and the mold inserts 7, which are installed in a tool plate, e.g. in a holder 11 for the mold insert frame 3, can be further provided and fastened with a cover plate 2.

[0045] In the embodiment of Fig. 1, a two-part mold insert frame 3 is shown. This has a central frame part 31 and an annular peripheral fixing part 32. The central recess 4 is formed in the center of the central frame part 32 (cf. Fig. 3). The plurality of peripheral recesses 5 are arranged in a circle around the central recess 5 and are formed by both an outer contour of the central frame part 31 and an inner contour of the peripheral fixing part 32 (cf. Fig. 3), so that a separation T between the two frame parts 31, 32 runs through the peripheral recesses 5. The central frame part 31 forms a proximal circumferential surface 51 of the peripheral recess 5, which spans a maximum of 180 degrees of the peripheral recess 5. The peripheral fixing part 32 forms a distal circumferential surface 52 of the peripheral recess 5, which spans a maximum of 180 degrees of the peripheral recess 5.These circumferential surfaces 51, 52 are clearly visible in Figures 3 to 6.

[0046] Fig. 2 shows a situation in which the mold insert frame 3, comprising the inner and peripheral fixing parts 31, 32, together with the multiple nozzle head 6 accommodated therein and the plurality of mold inserts 7, has been removed. For this purpose, the mold insert frame 3 is lifted out of the receptacle 11 of the tool plate in the axial direction A using a suitable tool.

[0047] In Fig. 4, the mold insert frame 3 is shown in a situation in which the central frame part 31, together with the multiple nozzle head 6 accommodated therein and the plurality of mold inserts 7, has been removed. For this purpose, the central frame part 31 with the plurality of mold inserts 7 is lifted out of the outer annular frame part 32 in the axial direction A using a suitable tool. The peripheral recesses are generally circular-cylindrical, with sections having different diameters so that a circumferential shoulder 53 is formed. The mold insert 7, which is also circular-cylindrical, has a complementary shoulder 72, with which it can rest on the circumferential shoulder 53 of the peripheral recess 5 in the installed state and can be guided during installation and removal.

[0048] Fig. 5 shows the central frame part 31 with the multiple nozzle head 6 and the plurality of mold inserts 7. Two of the plurality of mold inserts have been removed by being pulled out of the corresponding peripheral recess 5 in the radial direction R, i.e. perpendicular to the axial direction A. Fig. 5 shows a nozzle tip 61 of the multiple nozzle head 6 and a pre-chamber 71 of a mold insert 7. The design of the central frame part 31 and the peripheral recesses 5 allows the mold insert 7 to be removed from the nozzle tip 61 without having to remove it. The protruding nozzle tip 71 is received in a recess 54 of the central frame part 31, which forms an opening between the central recess 4 and the respective peripheral recesses 5.

[0049] Fig. 6 finally shows the mold insert frame 3 on Fig. 1 with the multiple nozzle head

[0050] 6 and a mold insert 7 in an exploded view.

[0051] In contrast to the embodiment of Fig. 1, Fig. 7 shows an embodiment of the injection molding tool with the multi-part mold insert frame 3 removed, which comprises a central frame part 3T and several peripheral fixing parts 32'. Each peripheral fixing part 32' holds one of the several mold inserts 7 in the corresponding peripheral recess 7, which are also arranged around the central recess 4. These recesses 4, 5 and their arrangement are clearly visible in Fig. 8, among others. Fig. 8 shows a plan view of the multi-part mold insert frame 3 from Fig. 7.

[0052] The central frame part 3T has a plurality of elongated, radially outwardly open recesses 33' with substantially parallel side walls 34' (cf. Fig. 10), into each of which one of the plurality of peripheral fixing parts 32' can be inserted, thereby forming one of the plurality of peripheral recesses 5.

[0053] The peripheral recess 5 is formed, as in the embodiment of Fig. 1, by the central frame part 3T and the peripheral fixing part 32' and also has a proximal peripheral surface 51 formed by the central frame part 3T and a distal peripheral surface 52 formed by the peripheral fixing part 32'.

[0054] In contrast to the embodiment in Fig. 1, when removing a mold insert 7, the inner frame part is not lifted axially out of the peripheral fixing part, but a peripheral fixing part 3T is removed in the radial direction R perpendicular to the axial direction A from the recess 33' of the central frame part 3T. This releases the mold insert 7 and can also be removed in the radial direction R. Fig. 9 shows a multi-part mold insert frame 3 with the peripheral fixing part 32' removed. Fig. 10 shows a multi-part mold insert frame 3 with the mold insert 7 removed.

[0055] Fig. 11 finally shows an empty central frame part 3T with the multiple nozzle head 6 removed.

[0056] List of designations

[0057] 1 tool plate

[0058] 11 Holder for mold insert frame

[0059] 2 cover plate

[0060] 3 mold insert frames

[0061] 31 , 3T central frame part

[0062] 32, 32' peripheral fixation part

[0063] 33' recess

[0064] 34' side wall 4 central recess

[0065] 5 peripheral recess

[0066] 51 proximal circumferential surface

[0067] 52 distal circumferential surface 53 shoulder

[0068] 54 recess

[0069] 6 multiple nozzle head

[0070] 61 nozzle tip

[0071] 7 Mold insert 71 Prechamber

[0072] 72 shoulder

[0073] A axial direction

[0074] R radial direction T separation

Claims

Patent claims 1. Injection mold comprising a mold insert frame (3) for receiving a multi-nozzle head (6) and several mold inserts (7), each with a cavity formed therein, which can each be supplied with molten plastic via the multi-nozzle head (6); wherein the mold insert frame (3) has a central recess (4) extending in an axial direction (A), in which the multi-nozzle head (6) is received, and several peripheral recesses (5) arranged around the central recess (4) and extending in the axial direction (A), in which each of the several mold inserts (7) is received; characterized in that the mold insert frame (3) comprises a central frame part (31, 3T) with the central recess (4) and at least one peripheral fixing part (32, 32') removable from the central frame part (31, 3T);wherein the multiple peripheral recesses (5) are formed by the central frame part (31, 3T) and the at least one peripheral fixing part (32, 32'); wherein a separation (T) between the central frame part (31, 3T) and the at least one removable peripheral fixing part (32, 32') extends through the respective peripheral recess (5) such that, with a peripheral fixing part (32, 32') removed, the mold insert (7) can be removed from the multi-nozzle head (3) in a direction (R) perpendicular to the axial direction (A) from the central frame part (31, 3T).

2. Injection mold according to claim 1, characterized in that the central frame part (31, 3T) forms an inner, proximal circumferential surface (51, 5T) of the multiple peripheral recesses (5) and the at least one peripheral fixing part (32, 32') forms an outer, distal circumferential surface (52, 52') of the multiple peripheral recesses (5).

3. Injection mold according to one of the preceding claims, characterized in that the peripheral fixing part is formed by a tool plate of the injection mold into which the central frame part (31 , 3T) can be used together with the multi-nozzle head (6) and the multiple mold inserts (7).

4. Injection mold according to one of claims 1 to 2, characterized in that the mold insert frame (3) comprises a single peripheral fixing part (32) surrounding the central frame part (31), which together with the central frame part (31), the multi-nozzle head (6) and the multiple mold inserts (7) can be inserted into a tool plate (1) of the injection mold.

5. Injection mold according to one of claims 1 to 2, characterized in that the mold insert frame (3) comprises several peripheral fixing parts (32') which together with the central frame part (3T), the multi-nozzle head (6) and the multiple mold inserts (7) can be inserted into a tool plate (1) of the injection mold.

6. Injection mold according to claim 5, characterized in that the multiple peripheral fixing parts (32') can be individually removed from the central frame part (3T) in a direction (R) perpendicular to the axial direction (A).

7. Injection mold according to one of the preceding claims, characterized in that the multiple peripheral recesses (5) are formed circularly with one or more circular cylindrical sections.

8. Injection mold according to one of the preceding claims, characterized in that the peripheral recess (5) has a circumferential shoulder (53) against which the mold insert (7) rests in the installed state and on which the mold insert (7) is guided during installation or removal.

9. Injection mold according to one of the preceding claims, characterized in that the central frame part (31 , 3T) has a recess (54) between the central recess (4) and the several peripheral recesses (5), in which a nozzle tip (61) of the multi-nozzle head (6) is arranged.

10. Injection mold according to one of the preceding claims, characterized in that the peripheral recesses (5) are arranged evenly distributed around the central recess (4). Injection mold according to any one of the preceding claims, characterized in that the parting line (T) is substantially circular and divides the peripheral recesses (5) into approximately two equal parts. Injection mold according to any one of claims 5 to 10, characterized in that the central frame part (3T) has several elongated, radially outwardly open recesses (33') with substantially parallel side walls (34'), into each of which one of the several peripheral fixing parts (32') can be inserted, thereby forming one of the several peripheral recesses (5). Injection mold according to any one of the preceding claims, characterized in that the several mold inserts (7) are held in position in the peripheral recesses (5) of the central frame part (31, 3T) even when the peripheral fixing part (32, 32') has been removed.Injection mold according to one of the preceding claims, characterized in that the multi-nozzle head (6) has several nozzle tips (61) for laterally injection molding the multiple cavities. Injection mold according to one of the preceding claims, characterized in that the multiple mold inserts (7) each have a fastening means for a suitable tool on the side opposite the respective nozzle tip (61), so that the multiple mold inserts (7) can be pulled out of the central frame part (3T) with the suitable tool in direction (R) perpendicular to the axial direction (A).

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