Process for Obtaining Flashless Forging

Forging industry is undergoing competitive pressures. With raw material price increasing and the conversion costs going down, saving of every gram has become crucial.

Dr Vasant Khisty, CEO, Sammy Consulting

Traditional forging have used draftangles and flash by default as traditional forging hammers did not have the scope of ejection. With forging presses becoming more popular it is now practical to manufacture forgings with minimal draftangle and without flash. Flash is the excess material that is kept to ensure complete filling of die. In order for the flash to exit land and gutter was provided. Normally depending on the profile flash percentage as large as 40% to 10% for round forgings was provided. This flash is then trimmed and sold as scrap at a much lesser price.

The advantage of flashless forging is saving in material consumption and saving in trimming operation, also since the parts are not trimmed there is no bend and subsequent coining can be avoided

Several experiments are being carried out globally to manufacture flashless forging. Great amount of success has been achieved in manufacturing round jobs on presses without flash. On hammers it is not yet practical. Several experiments have been carried out on flashless forgings of crankshaft, connecting rod, universal crosses, bevel gears etc.

The principal behind flashless forging is to choke up the flow of extra material by using exact volume of material required in the impression of die. The challenge for flashless forging is the control of raw material weight as excess raw material has no escape route and it creates immense pressure on the die impression which results into breakage of dies. The other issue with flashless forging is if the volume of raw material is less it creates under filling defect in the forging hence the weight has to be accurate .

Factors that affect the successful development of flashless forging are