405 Design Considerations
In Process Gaging---
An "in process gage" checks the presence and accuracy of the previous operation. To be effective in an automated operation, the gage requires the ability to communicate to the machine it is associated with that the previous operation is correct. This can be done with proximity sensors or video cameras as required. The advantage of in process gaging is that problems caused by broken tooling or a machine that needs adjustment only create one bad part and then the system stops - greatly reducing scrap.
Vendors ---
An excellent rule to go by when considering a tube fabricating work cell is this; "KEEP THE NUMBER OF VENDORS TO A MINIMUM". Only one vendor is preferable. The reason for this is to reduce problems after installation should things go poorly. The situation to avoid is having one problem and two suppliers, each holding the other responsible for the problem and neither doing anything to solve it.
Machine Reliability ---
When machines are put into a work cell, if one needs adjustment or breaks down it stops the whole group. So, the quality of each machine selected for a work cell is critical since it can be the weak link in the chain. To do a job in a work cell, the machines need to be very reliable, both in that they don't break down, and that they need very little adjustment in process.
After set up is completed, the machines should be able to function without attention. This can happen only if the manufacturer has provided the machine with a chassis or base which is sturdy enough to maintain dimensional integrity between the tooling and the work piece. Maybe this sounds like too much of a generalization. However, no amount of control accuracy can accommodate variation between where the tooling is supposed to be, relative to the work piece, and where it is. This is controlled strictly by the mechanical strength of the machine chassis.
A machine that hasn't a strong enough chassis will require constant attention while operating. Most people find that the additional cost for quality equipment is money well spent, especially after years of losing time to adjustment.
Part Reliability ---
The quality of the parts being processed is critical. The computer term "GIGO" (Garbage In = Garbage Out) is an appropriate description of the materials situation. Tube fed in must be straight, dent free, accurately cut to length, and the hardness must be consistent from foot to foot as well as from part to part. Again, the extra money spent on quality material will be made up in more and better production.
Better Productivity ---
A well coordinated work cell is capable of more parts per hour and, most importantly, more through-put than any other method of fabricating groups of tubular parts commonly used today.
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