20 January 2017

Chemical Machining

Chemical machining is stock removal process for the production of desired shapes and dimensions through selective or overall removal of material by a controlled chemical attack with acids or alkalis.

The metal is gradually transformed into metallic salt by chemical reaction and is ultimately removed in this form.

The process can be suitably applied to different types of operation such as milling on a milling machine, blanking, and engraving. The chemical machining process can be classified as :
  • Chemical milling
  • Chemical blanking 
  • Chemical engraving

Chemical Machining
Chemical milling :

Chemical milling sometimes called chilling or contour or etching is used mainly to produce shapes by selective or overall removal of metal parts from the relatively large surface area.
The main purpose is to achieve shallow but complex profiles, reduction in weight by removing unwanted material from the surface as in the skin of an aircraft.

Chemical milling complete in four steps :
  1. Cleaning
  2. Masking
  3. Etching
  4. De-masking
Application of CHM :
  • Chemical machining has been applied successfully in a great number of usages where the depth of material removal is critical to a few microns and tolerance are closed.
  • The surface finish obtained in the process is in the range of 0.5 to 2 microns.
  • One of the major application of CHM is in the manufacture if burr-free, intricate stampings.