What is a manufacturing cycle time?

Question

i want to define a formula that will get a manufacturing time, with Burn-in tests(10-30slots for example) and with a Yield or efficiency factor.

Has anyone did this before?

Thanks

Answer 1

There are lots of different definitions. You should use definitions consistent with other models developed in-house. Cycle time is how long it takes. Thus, for an 8hr burn-in, cycle time is 8hr. I also include the load/unload time, but not all do.

Now, the uph (units per hour) is the rate. So take units/slot * slots/oven * number of ovens divided by cycle time to get uph.

So, say 10 slots, 100 units per slot, 10 ovens total, for 24 hr burn-in. Cylce time is 24hr (possibly plus load/unload time), and rate (units in) is 10*100*10/24 = 416 2/3 uph. Multiply this times yield to get units out (though we used to yield them at test, not here, as you don't know which ones are good.

I usually model man-hours at the same time, as this is an important input.

I've done enough modeling where I don't worry too much about book defintions, however, I suggest you get a book on industrial engineering, possibly including an overview of MTM (method-time-motion) studies. It's easier to justify your numbers where the calculation methods follows standard principles.

If you standardize your boards and make an extra set, you can be unloading/loading while all the ovens are full. We used standard busses and fixturing.