Plastic Injection Mold Components- Ejector
The best plastic injection mold in the world will fail if something as simple as an ejector pin
fails! That is why choosing the right pin for the job is important. Saving money on poor quality mold components
just does not make sense in the long run.
Types of ejector pins
Basically, there are only three types of ejector pins commonly used in plastic injection molding
Thru-hard pins. As the name implies, these pins are heat-treated to be
thouroughly hardened. Obviously, you won't be drilling and tapping any holes in these pins! They are
great all purpose pins with a hardness of 58-62 RC. They are made of either M-2 or H-13 tool steel.
They can be used for most molds, up to 400°F, or 200°C
Case hardened pins. These pins are nitrited to 65-72 RC and are also great for
general use. They perform well at temperatures above 400°F, thus are often used in die-casting. Because
they are so hard, they also tend to chip much easier than thru-hard pins. It is possible to drill and
tap the larger pins because the core is 40-45 RC. Most of the time, anyway! Nitride pins are made of
Black ejector pins are not so common, and were developed for high temperature
applications. They are specially coated for this purpose, and are also self lubricating. Their higher
cost makes them somewhat of a specialty pin.
Mold components suppliers
There are numerous high quality suppliers, and many specialty suppliers. Here is a partial
Standard mold component suppliers for ejector pins
Specialty suppliers of mold components