Dealing with CNC Off-Fall

      CNCs can rapidly create a huge pile of odd-shaped scrap. Here's how shop owners manage the mess. August 19, 2008

Question
Now that we have almost fully implemented our CNC and Cabinet Vision, I have found that our off-fall has become harder than ever to manage. The sizing and the shapes of the parts after CNC have left my shop looking like a hockey stick manufacturer with a delivery fleet on strike. Obviously, the more jobs we can batch together through the router, the less off-fall we produce, but this creates its own problems by increasing work in progress (another discussion for many other threads). Also, the router cuts pieces so efficiently it just does not make sense to spend the labor in the office, by inputting off-fall back into the CV part library, or hunting in the shop to find the right sizes manually. Finally, it makes me want to cry just cutting this stuff up and having to pay to have it dumped. Any brilliant ideas out there?

Forum Responses
(Business and Management Forum)
From contributor S:
Labor + your floor space cost = $$$$.
Off-fall = trash.

Get a grinder and sell the chips to mulch makers, or get a large trash. Don't waste time and labor.



From contributor P:
Nest the stuff as best you can, then put cuts into the nested sheets so that your cutoffs wind up as square or rectangular cutoffs, not stuff that looks like the remainders of stamping out Christmas cookies. Have your operator trash stuff that looks like junk right away. Don't keep 6x96 pieces or other dumb little stuff. We've also got a cordless DeWalt saw next to the CNC to make chopping up the junk a simple process.

From contributor T:
In CabinetVision, go to:
NC Center
Optimizer Parameters
Offcuts
square off nest

That will square off the offcuts for you. The stuff we cut is $1 to $3+ per sqft. It doesn't take that much time to salvage it. We put it right back on top of the unit it came from - if they have to move it anyway, they will use it up. If they have to look for it, they won't.



From contributor J:
This is just an idea, certainly not from direct experience, but I thought I'd throw it out there anyway. If it's possible to program the CNC to trim offcuts to square or rectangular sizes anyway, could you take it a step farther and have it cut into a small number of pre-determined sizes? For example, you could have, let's say, 3 size categories of 12" x 12", 24" x 24", 36" x 36", and anything that could fit into the requirement would be cut to size. This way you could have an inventory of specific sizes that would be useful to your specific operation ready to go when needed instead of a stack of various sized parts too labor intensive to go through.


From the original questioner:
Thanks. Contributor S, you are right and that is why I am asking the question. There almost always is a better mouse trap eventually. Contributor P, I like the cordless trimmer idea. I'll go buy one next week and give it a try. Contributor T, many thanks to you. We made the change for our next job and we'll see how much of a difference it makes in a day or so. Contributor J, I may be wrong, but I don't think I can do that in CV. Then again, I'm no expert... yet.


From contributor D:
What about burning the scrap for heat, or selling it to people who have fireplaces?

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