Any item to be anodised requires reliable jigging, firstly to stop it falling to the bottom of the anodising tank and secondly so that the electrical current can safely pass from the jig to the workpiece. Anodising Jigs are usually made from aluminium or titanium. Aluminium jigs get anodised of course and have to be chemically stripped, the constant anodising and stripping results in a short life and hence the use of titanium which does not require stripping after the anodising process.
EXAMPLES OF JIGS IN USE
Titanium is far less conductive than aluminium so that jig design, always very important, is critical. Contact points and therefore jig marks need to be larger than with aluminium jigs to avoid contact burns during processing.
Many jigs rely on small sprung fingers gripping the workpiece in some way; with hard anodising the favoured way with large pieces especially is to use titanium screws to get a positive reliable contact. It should be remembered that holding work in the process will result in small un-anodised areas and it is unrealistic to expect 100% coating. Jigging can usually be arranged to avoid sensitive areas. This should be borne in mind when designing for corrosion resistance and wear resistance inparticular.
EXAMPLES OF JIGS IN USE
Usually a technique can be found that suits both parties, but it is advisable to discuss this at the design stage to reduce potential jigging cost at the outset.
