Injection Molding 101: Machine Clamp Tonnage

 

This is the second of two videos about the basics of Injection Molding.  This video reviews the Machine Clamping mechanism.

 

Our equipment list shows the various injection molding machines at Hi-Tech and they are generally refered to as a 100 ton press or a 500 ton press.  This refers to the clamping pressure that the press can deliver.

 

An injection molding machines clamping mechanism is made up of two platens, a stationary platen and a moving platen.  Often times from the operator side of the press (side w/ the control panel), the moving platen is on the left and the stationary platen is on the right.  When a mold is mounted into a press, the locating ring of the mold goes into a ring on the stationary platen.  After the mold is installed, the injection unit nozzle tip can come forward and touch off on the sprue of the mold thru the stationary platen.

 

The two most common types of clamping mechanisms in an injection molding machine are a Hydraulic Clamp or an Electric Toggle Clamp.  A Hydraulic Clamp uses hydraulic fluid to apply the tonnage and the Electric Toggle locks an elbow type clamping mechanism in place.

 

The common rule of thumb to calculate the necessary tonnage to keep a mold from blowing open is that you’ll need 2 to 4 tons per square inch of projected area.  Smaller parts need less tonnage to keep the mold closed and larger parts require more tonnage to keep the mold closed.

 

Please comment if you have any questions.  Thanks for watching.