Engineering Properties
Surface Finishing
Because of this large range of objectives, surface finishing costs vary from an almost negligible fraction of the overall cost to a very large proportion.
Included amongst low cost finishes are mostly processes where the components are handled en masse such as vibratory finishing and barrel passivation.
Intermediate cost processes are usually those that require either fairly quick manual handling or robot operations, these include such things as loading and unloading racking prior to powder coating, electroplating or passivating and press trimming.
The most expensive finishes are those that require a significant amount of manual work such as bobbing and polishing prior to electroplating. The costs of such finishes will be substantially reduced if the design is adapted to allow automated processes to be used.
Where the finishing costs are high in comparison to the casting costs it is usually more important to concentrate efforts on maximising the castings suitability for the subsequent finishing operation, rather than striving to save the last fraction on the price of the casting. It will often be found that the reduction in the cost of the finishing operation and the increase in its quality will far outweigh any increase in the cost of the casting or the tooling. Even a low cost finish, if defective for any reason, can be the cause of the rejection of a complete batch of components. It is important therefore that the caster and the finisher should work as a team.