Tuesday, 23 May 2006

Automatic Assembly (15/16)

Parts are orientated by tooling, inside or outside of the bowl feeder.  In-bowl tooling tends to be passive and relies on the probability of a correctly orientated part moving along the conveyor track.  Incorrectly orientated parts are detected by the bowl tooling and deflected back to the bowl base.  Correctly orientated parts are accepted by the tooling and presented to the workhead.  Active tooling accepts parts in more than one orientation and re-orientates them correctly for the workhead.  This method of tooling gives a 100% 'first time through' rate and can be used outside the bowl.

It's important to make parts as symmetrical as possible.  Higher feed rates are obtained with parts having greater degrees of symmetry.  This is achieved by duplicating non-productive features.  If it is not feasible to make a part symmetrical then it must be designed to be definitely asymmetrical.  Features which are too small to be detected by bowl tooling must be exaggerated, for them to be detected.  The use of cylinders having a length to diameter ratio of unity and rectangles having slightly dis-similar sides should be re­designed to give greater asymmetry.

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