CNC Production Cycle Time Decession

[Designer99]

My company CNC manufactures about 30 different 2-dimensional 'widgets' in lot sizes of about 1000 parts. We have about 20 different products and the jobs typically take 3-12 days to complete depending on the cycle time and setup. As new products come about, I am constantly faced with the decision to design tooling to machine multiple parts at one time(long cycle), or to machine single parts (short cycle). Pros and Cons are somewhat obvious: long cycle--(Pros) more parts are milled per tool change, operator is free to work on other tasks, less waste (Cons)more parts at risk, longer setup, more expensive tooling, longer tool design and build time, more parts at risk if a tool breaks or wears...
Does anyone have some advice or know of some good research articles or case studies that address this issue? Thanks

 

[griffengm]

Designer99,
For a problem like this I use economic order quantity techniques and simply use time instead of money.
Basicly, you add up the cost of each step for each option and the lower cost gets the nod. This implies that you have some idea of the likelihood of the tool crashing and assumes that the labor rate for all steps is equal. If it is not equal you will need to apply costs to the steps.
Not sure of web sources but a basic text on engineering economics will address you issue.

Griffy

 

[tygerdawg]

In addition to the standard quantitative methods, you may also consider using simulation to give you insight from the timing/resources/scheduling point of view. I haven't used it, but I saw a reasonably priced simulator called SIMUL8 for ~US$1500. My guess is that it would be found on

http://www.simul8.com

?

TygerDawg