Loose core for ejecting undercut at injection mold

Picture above shows the loose core, or often also called slope ejectors or inclined pin, loose cores is one method to overcome the undercut on the product, particularly undercut the core position facing into the bottom (towards the sprue bush-center of mold) that undercut it can not be made simply by using slider method, part of the loose core complete with mold base include:

1. Top clamping Plate
2. stripper plate
3. cavity plate
4. core plate
6. support plate
7. top ejector plate
8. bottom ejector plate
9. bottom clamping plate
10. loose core rod
11. loose slide unit
12. bushing

for more details look at the picture below, which shows the current position of loose cores prior to the occurrence of loose core ejecting position after ejecting process, shortly after the mold is closed and the injection process, loose cores in the closed position (note the closed mold), after the injection process is complete done, at the push of ejector rod, ejector plate both upper and lower parts helped push out through the ejector, while the loose-core because it has a certain slope (generally 8-15) when driven will move slowly into center with the aid of friction on inclined leader pin bushings, so the position Loose cores are separated from the undercut product (mold opened)

 

Slide the unit mounted on the ejector plate is always on the top or at the bottom, and the main mover of the loose core are ejector rod simultaneously with the process of ejecting, points to consider in designing the loose core is strokes and angles used, too little angle of it can reduce the occurrence of abrasion (wear) but required a long stroke.

If angle is too large can cause the inclined pin (loose core) broken because of the occurrence of high abrasion, but required a shorter stroke. The angle that is used is usually between 8-15 0, while the stroke must be exceeded 5 mm or more to keep the loose core is certain regardless of the undercut in the product.