Screw tips for Injection Molding
Published by Complete Plastics on 2010-06-28 14:22:59
Screw tips for Injection Molding
Screw tips assemblies and front end components are designed for the specific application. From the
material it is made from to the number of pieces it is made of. Screw tips are designed to be a check
valve in the process to allow an injection molding machine the ability to hold material forward of the screw
and for the plastic into the mold.
With many designs come many benefits of each design.
There are several styles of Screw tips on the market.
4 piece Locking screw tip Style
4 piece Rotating Ring
3 piece Locking Style
3 piece Rotating Ring
Ball Check
The most widely used is a 3 piece non-locking screw tip style free flow style. This style offers the most flexibility of
any other styles. The 3 Piece screw tips allow processors the best of all worlds. It gives the capability to
run 90 of all material.
The locking style of either the three piece or the four piece screw barel screw tip give a benefit of having a positive shot off
because the ring is always seating off in the same place. It also has a tighter fit with the retainer which
can give a molder a more stable process.
4-Piece none locking check ring style gives a molder the option to replace the front and rear seat
instead of the retainer. From a cost effective stand point this tip allows for molders with ware
issues to stock a few components for quick and cost effective replacement.
When picking a screw tip for your application it is very important to make sure you pick the proper base
material for the Tip and that works well with the plastics material you’re running. There are materials that
are most commonly used for injection molding that have proven themselves as excellent for
molding.
H13 - General Purpose
H13 Nitrided – General Purpose with longer life
CPM9V - For Glass filled material up to 30%
CPM9V - For Glass filled material above 30%
CPM440V - Wide Range of uses.
Pick a Screw Tip for your application that will give the longest life with the best productivity for
your process your run.
