What should be noted in IML mold design?
Release time:
2022-08-25
Source:
1. When designing the layout of IML molds, multi-cavity products must be placed in the same direction (cannot be rotated, only translated), which is beneficial for the placement of sheets during injection molding.
2. To facilitate the insertion of sheets, the mold must be installed in a direction that can be freely rotated, and the mold base must have lifting holes processed on all four sides.
3. Most products made by our company have a through-insert structure, with the insertion height between 1.0 and 4.0 mm. The insertion positions should be as consistent as possible, with a perimeter greater than 60% (the longest non-insertion length should not exceed 25 mm). The front mold position at the insertion point must have a rounded corner.
4. The insertion angle of the IML mold is between 2 and 3 degrees, which should align with the demolding angle at the product edge (generally, for larger products like door locks, the demolding angle should be above 3 degrees). When the product has a large curvature and beneficial edges or sharp corners, if alignment is not possible, a 0.1 mm flat reduction can be made, followed by a 2-3 degree slope.
5. Due to the sheet sleeve in IML products, the shrinkage rate is relatively small, generally between 1.002 and 1.003 depending on the product, and should not be based on the shrinkage rate provided by the raw materials.
6. If the IML product has transparent areas and high appearance requirements, the steel material should be made of very good polishing material, preferably using mechanical polishing. Hand polishing surfaces may have a sense of unevenness, especially noticeable in black glossy products.
7. IML molds generally use submerged gates for injection, including: horn gates, submerged pin gates, submerged bone position gates, or inverted molds injecting at the back of the product. Large gates are only used in special cases.
8. Due to the requirements of the IML process, it is not recommended to use hot runners to inject directly onto the product; various types of injection can be achieved using heated nozzles.
9. The FIT mold at the insertion point of the IML should not be too tight, with a gap of 0.05-0.01 mm (at the insertion point).
10. High-polish IML molds must be polished before the FIT mold, and polished again after the FIT mold is completed.
11. All positions where the film material can contact the front mold must not have sharp edges (sharp edges of the steel), to avoid scratching the film material. This is also one of the main reasons why our IML process molds must have a through-insert structure.
12. IML molds have high requirements for venting; in addition to venting on the parting surface, the rear mold should have as many inserts as possible to facilitate venting.
13. Due to high pressure and fast injection speed in IML molds, it is easy to make the overall glue position of the product thick during injection, so the depth of the front mold cavity should be appropriately reduced based on the product structure.
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