The knowledge of mold

- Sep 08, 2017-

The knowledge of mold

1、The basic structure of the mold

  (3) insert (insert) (4) line position (slider), (5) rear mold (male mold) (3) insert (insert) ) Slanting (6) thimble (7) gate (inlet)

2、 The effect of the shape of the mold on the article

  Wall thickness, geometry, will affect the forming shrinkage, stripping slope size

3、The influence of the inlet on the shrinkage of the product

      The size of the inlet is large, the shrinkage rate is small, the size is small, the shrinkage rate is large, the flow direction parallel to the shrinkage rate is large, the vertical direction is shrinking small

4、 Die wall thickness is too large, too thick wall thickness

       Wall thickness is too large: (1) increase the cost (2) to extend the forming time, reduce production efficiency (3) difficult to control quality, prone to bubbles, shrinkage, depression, etc.

       Wall thickness is too small: (1) plastic in the mold flow resistance. If the shape is more complex, forming will be difficult (2) the intensity is poor.

   If the plastic parts of the wall thickness is not uniform, then the forming process will shrink uneven, not only caused by bubbles, depression, deformation, there will be a large internal stress. Wall thickness and wall at the junction to avoid an acute angle, excessive ribbon and thickness should be along the direction of plastic flow gradually reduced.

5、 Fillet (R bit)

       Set the fillet (R bit) to increase the strength so that the plastic parts do not deform or crack


     (1) In order to ensure the strength and rigidity of the product, and not to make the plastic wall thickness, the appropriate parts in the plastic parts to set the ribs to prevent deformation, in some cases, can also improve the plastic flow in the formation of the problem.

     (2) the thickness of the ribs can not exceed 50% of plastic parts, usually about 20%

     (3) stiffeners should be lower than the plane of the plastic parts (