PURPOSE
Allow gases to escape during the combined process of billet upset, and burp decompression, reducing blisters
Maintain a minimal uniform skin of aluminum on the liner inner diameter reducing profile inclusions
FUNCTION
The function of the dummy block is the extension of the ram or stem, which pushes the softened alloy through the die. Key functions include:
To repeatedly transmit the force of the ram, at high temperature, to the alloy
To expand to pre-determined size under load and maintain a secure seal with the container wall
To cause no gas entrapment that can result in blistering, or damage the face of the container and/or dummy block
BENEFITS
Reduce scrap, due to back end blisters and surface defects
Increase container liner life