Re: Which Mini CNC mill #mill


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.



Sent from Mail for Windows 10


From: John Ferguson via Groups.Io
Sent: Monday, February 10, 2020 8:01 PM
Subject: Re: [pcbgcode] Which Mini CNC mill #mill


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.

> Dan Staver

> Tave Tech Corp.

> 3130 Hollycrest Dr.

> Colorado Springs, CO 80920

> +1-719-359-5352 - office

> +1-719-502-1675 - cell

> tavetech - Skype

> dan.staver@...



>> On Feb 10, 2020, at 11:06 AM, John Ferguson via Groups.Io

>> <jferg977@...> wrote:


>> 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.



>> john



>> Attachments:

>> DSC07301.JPG:

>> pcb-etching-fixture&pcb-drill-jig.JPG:










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