THE ALLSTEEL AIR DISHED HEAD PROCESS
• This process requires heads to be dished only with a female die.
• The head material may be pre-polished and paper protected before air dishing and the dished area of the head does not need to be re-polished.
• Air dished heads do not have internal stresses like spun heads.
• These heads do not have distortion problems when holes are cut in them.
• Many different sizes of heads can be made from the same female die.
• The dished head is trimmed to the required size needed to form the knuckle and straight flange. (using a flanging machine)
THE BUMP PRESS PROCESS
- Bumped heads are formed using male and female radius dies.
- This process forms a small dished area into the head at a time.
- Many passes are required over the entire area until a dish is formed to the specified radius.
- This process is generally used to form thicker heads.
- This process is not recommended to form thin materials because the dies leave forming marks (“fish scales”) in the head material.
- After the dishing process the heads must be flanged (using a flanging machine).