PHOTOCHEMICAL MACHINING PROCESS

Photo Tooling Preparation
Photo tools are made by redrawing the customer’s designs in a CAD system. These are then “arrayed” on a large sheet and laser plotted to generate working tools containing many parts.

Metal Cleaning and Coating
While the tool is being prepared, the metal surfaces are “sensitized” by cleaning, normally in sheet form, and then drying and coating them with a photo resist. Most of the parts presently being produced at Grace use dry film photo resist which is laminated to flat metal. For high volume, relatively loose tolerance parts, Grace uses a screen printing process which combines the application of resist and imaging into one step.

This is followed by a developing step. The metal surfaces now have photo resist stencils on them equal in shape to the parts being produced.

Etching
The etching process consists of corrosive solution being sprayed onto the metal surfaces under pressure. It can attack the metal everywhere there is no photo resist. Since the resist stencils are in the shape of the desired parts, those parts are formed as the surrounding metal is removed.

Stripping
When the parts have been etched into tolerance, they are either soaked in a stripping bath, or run through a conveyorized stripping machine. The photo resist is quickly removed and the finished parts remain.

Inspect & Ship
Although parts are inspected throughout the production process, a final inspection step further assures the Parts have been produced to the proper dimensions, tolerances and other special specifications. The finished product is then properly packaged and shipped.