Photo Chemical Milling

Photo chemical milling machine

Thin stainless steel part cut by photo chemical milling

Sensor device etched and cut by photo chemical milling

Photo chemical milling is a process that produces 2D part shapes by creating a chemical resist mask on the surface of sheet metal and chemically dissolving material from unmasked areas.  The photo chemical milling process follows these steps:

• A photo resistant coating is applied to make the sheet metal sensitive to light.
  
• A photo mask is placed over the sensitized sheet metal.
  
• The sheet is exposed to ultraviolet light.
• The photo resist is developed into the masked pattern.
• The sheet is etched to remove exposed metal areas leaving the final part.
• The part is then cleaned.

Photo chemical milling offers high precision and detailed shapes in thin metal sheets, free of burrs. The process is particularly competitive for complex shapes.

Photo chemical milling can make almost any 2D shape in relatively thin gauge sheet metal, typically 0.001" to 0.050" thick. Applications of photo chemical milling include gaskets, electrical shields, works of art, optical interrupters, shims, eraser shields, etc. The process can also be used for etching which is similar to engraving. Tooling consists of a film transparency. Cost reduction options include minimizing thickness and part area.

Photochemical Milling Design Considerations

• Try to provide a distance between holes at least the greater of .005" and 0.9 of material thickness.
  
• Edges will have a single or double arc profile due to the chemical erosion process (more noticeable on thicker materials).