I agree that height mapping would be a good thing, but I don't have it. I hadn't thought of indicating my fixture after I install it but before I fly-cut level it. I can't get to this for a week or two, because I'm building another shop setup, but when that's done, I'll show you what i have.
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On 2/11/20 9:19 PM, CJD wrote:
I keep seeing this post about getting your bed flat.
I don’t even worry about it.
I get great results using the height mapping routine in candle.
You cannot trust within .05mm a flat bed.
When I height map there is almost always .5mm difference across a 10mm X 20mm piece of PCB.
It gets even worse when the pcb piece is bigger.
I don’t know how anyone can do this without height mapping.
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how did you get your bed flat?
On 2/10/20 6:03 PM, Dan.Staver wrote:
I get good results using very thin double-sided sticky carpet tape to
hold the PCBs down for milling.
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On Feb 10, 2020, at 11:06 AM, John Ferguson via Groups.Io
Maybe there should be a subject change. Have a look at the two
fixtures whose photos I've attached.
I make printed circuits which are about 2 inch by 3 inch. I found
that I couldn't get reliable trace widths unless the board was
absolutely level to the machine. So I started with an MDF fixture
bolted to the milling table and drilled and tapped in four places so
I could use nylon screws to hold the pcb down. Every time I do a new
setup, I mill the surface of the fixture with a fly-cutter to level
it. This works 100% of the time. I've had no bad experience with
PCB's not being of constant thickness.
I had such good luck with the MDF board that I made a better one for
HDPE. I also made a jig to drill the holes in the pcb so they would
be sure to align with the ones in the fixture.
Frankly, I don't see how you could ever get reliable cuts without
leveling the surface the pcb is secured to while etching.