Slider/Lifter Design in Injection Mold


Due to the special requirements of the product, the stripping direction of a certain part is inconsistent with the mold opening direction of the injection machine, and the side parting and the core drawing are required to smoothly eject the product. There are two types of side splitting and core pulling mechanism: row position and inclined top.

 

I Slider

1. Slider calculation (example below):

In order to ensure the smooth release of the product, the distance of the movement of the row must be sufficient. Generally, the minimum distance from which the product can be demolded is 2~3mm.

 

2. The structure of the back die is in the form of press block + oblique pin + slingshot as shown in the figure (sometimes when the row width exceeds 100, and it is not convenient to use this structure, the T block structure can be considered), but when the row position Located in the direction of the heavens and the earth, when it is limited by the position of the return needle and the size of the mold, it can be used as the original body without the briquetting.

 

3. The relationship between the bottom surface of the row position, the top surface and the bottom and bottom of the mold, see the figure:

 

4. Regardless of whether there is sealant on the side of the row, the slope should be inclined on both sides. The general value is 3~5° on one side, but the angle is 45° when the two rows are perpendicular to each other. If the product has a row of four sides, the design should consider extending one of the rows to an ear to ensure accurate positioning.

 

5. The ratio of the height of the row to the thickness is at most 1. Otherwise, the movement of the row will be affected by the turning moment, resulting in motion failure. Generally, L1.5H is required.

 

6. The angle of the oblique position of the row is generally 15 ° ~ 25 °, the maximum can not exceed 25 °, the angle of the oblique pin is 2 ° smaller than the row position, generally try not to use a small oblique pin to ensure smooth movement of the position.

 

7. The oblique pin hole is 1/64" larger than the single side of the skew pin, about 0.4. When the skew pin passes through the row position, it needs to leave enough space for the space on the template.

 

8. The position of the oblique pin in the row position: the oblique pin is placed in the middle position of the row position as much as possible. The specific size requirements are as follows:

 

9. The matching surface of the shovel chicken and the row position is required to exceed 2/3 of the height of the row, and the screws used for shovel the chicken should be as large as possible. The following figure shows the shovel chicken of two different structures. Try to avoid the structure of Figure b.

 

10. The length of the slingshot in the position should be determined to ensure that the slingshot space is sufficient to prevent the slingshot from failing.

Set the travel of the line position to M, the total length of the slingshot is L, and set the spring to compress 40%. After the position is completely exited, the slingshot is still preloaded by 10%.

(40%-10%) L=M

L=(10/3)M

Slingshot space is 0.6L


However, when L is too small, in order to prevent the slingshot from failing, it is often necessary to increase the length of the slingshot.

 

11. When the row position completely wraps the side of the product, in order to prevent the rubber component from being scratched during the movement of the row, a side top device is required on the row position, and its structural form is as shown in the figure: in the design, it should be selected according to whether the mold space is sufficient. For a suitable structure, the structure of Figure a is recommended.

 

12. In order to make the movement of the position smooth, there should be no sharp corners that hinder the movement, etc. Generally, the corners of R3~R5 should be inverted.

 

13. When installing the slingshot under the row position, the size requirements are as shown in the figure. To prevent the screw from being caught by the slingshot, refer to the table when selecting the slingshot and the screw.

 

14. Large rows should be cooled separately, and wear blocks should be placed on the rows or shovel. At this time, the row and the shovel are avoided by 0.5, as shown.

 

15. When the limit slot is to be set on the front die position, the structure is as shown in the figure, h is determined according to the line travel (with the limit block size). The limit block is fastened with at least M3/8" screws.

 

Sometimes, when the current die position is too small, the T block guide is not used, and the limit block is used for directing and positioning.

 

16. In the front die position, the T block and the T slot are emptied by 0.3~0.5 on one side, and only one side is the mating surface. as the picture shows:

 

17. Calculation of the length of the front die position slingshot.

 

Set the travel position M, the total length of the slingshot L, 40% compression, 10% preload after the row is completely exited, the row angle α, the total height H of the row, then:

 

(40%-10%) Lsina=M

L=10M/3sina

At the same time should be checked: 0.3Lcosa < 1/2H, otherwise the angle should be increased, but the maximum should not exceed 25 °, sometimes to prevent failure, often to increase the L size.

 

18. The front row position must be checked by the row position.

 

19. The front die position is changed to the T block to be in the row position, and the T slot is opened on the shovel chicken.

 

20. The front mold position generally requires the wear block to be set, as shown in the figure. At this time, the mating surface of the front mold and the row position avoid 0.5 mm.

 

21. The front mold position must not exceed 1/2 of the total length of the line as shown in the figure.

 

22. In the front mold, the product is required to set the front mold position, as shown in the figure. At this time, in order to avoid the problem of excessive A-plate avoidance, the T-block is often placed in the row position, and the T-slot is opened on the shovel chicken.

 

23. When the “V” type oil tank is opened in the row position, the direction of the row position should be inclined. The “O” shaped oil tank should be interlocked with the ring, the oil tank depth is 0.5-1.00mm, and the oil tank side is not made to prevent oil leakage. .

 

24. Parts with mutual movement on the line are quenched. For example, limit blocks, beading, and the like.

 

II Lifter

The use of lifter is often a very effective method when there is an undercut on the inner surface of the side wall of the article or the inner surface of the top end of the article. The working principle is as follows: while the product is ejected, it is restricted by the inclined surface and simultaneously moved laterally to disengage the product.

 

1. The angle of the sloping roof is generally 5°. The size depends on the stroke and the ejection space. Sometimes the C plate is raised to ensure the ejection.

 

2. The minimum thickness of the inclined roof is 8.00. In most cases, it can be appropriately increased to 10~15mm. At the same time, the inclined top should be equipped with wear blocks to ensure accurate positioning.

 

3. When the product arc is required to set the inclined top, the processing method is shown in the figure:

 

4. The inclined top is fixed by T seat and screw, and the minimum screw is M3/16".

 

5. When the size of the slanting top and the height of the ejector are limited by the surrounding bone position, the boss, or the distance between the two slanting tops, the solution is to set the limit ejector and communicate with the design department to change the product.

 

6. The limit ejector mechanism, the basic form of the limit ejector mechanism is shown in the figure, generally two. H is set according to the limit ejector height.


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