Re: "Lites out" machining--what's amenable, what's not?

Proctologically Violated©® wrote:
Awl--

So ahm doin my li'l *** prototypes, 10-15 fadal tools, and I fantasize about the day I'm finally bustin out production.

But as I look at the various accumulating chips, esp. those spiralling around drill bits, occasionally end mills, taps, etc., I wonder how I can walk away from the machine for even 5 minutes, never mind all nite.

Is "lites out" machining a very specialized set of operations, or can all operations be finagled, so as to be suitable for lites out?
For example, what does one do about the spiral (alum) ribbons around drill bits? Zillions of pecks??

I know molds can be done overnite, cuz of the lite cuts, some screw machine stuff, but how bout general VMC work?

Some things that will be very helpful.

Positioning multiple parts is important for chip flushing, allow no way for chips to build up and create problems for your tools.
Clear out any build up of chips.
Flood the coolant.
Make sure the coolant is topped off before you lock the leave.

In milling, run the feedrate back to about 85%. If you push too hard once and break a tool, the tool following the one that breaks may all be broken when you return. Remember the object is to stay running at a steady pace vs stopping. 85% feedrate "over an entire weekend" will get you quite a long way down the road.

Running over night is easy, to run across entire weekends will require someone to drop in for an hour to refill coolant, clean out chips, do a quick check in case the dnc link may have been broken or any of a long list of things that happen over many hours of running. In that "usually 1 hour" drop in check, anything needing doing can be done.
I say one hour because most companies have to pay for an hour with overtime/holiday pay even if you are there only 15 minutes. 15 minutes is about what it takes to check everything out and be done.
On holidays and weekends we routinely run the entire time on long mold jobs and multiple parts "fixture offsets type" jobs.

Trust your programmer, if he stands at the cnc doing manual edits on anything other than setup positioning, that guy is probably NOT a lights out programming candidate.

Programming musts:
Clear z retracts: .050 clearance works for day shift and to impress girls, at night .500 is smarter.

85% of normal feed rate.

Only long, long weekend and holiday runs you can always program a second set of "fresh" tools or only a second "finisher".

With only day shift "living people" presence, we have run 24-7 when needed since about 1992 with great success.
If you trust your work, you will sleep well at night.

Michael



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Michael Gailey
Artistic CNC Mill, Router and Engraver Programming
3D modeling for Product Design and Development
http://www.microsystemsgeorgia.com/toc.htm
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