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Author Topic: Help this newbie (engraving)  (Read 1767 times)

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Help this newbie (engraving)
« on: July 21, 2015, 12:49:17 PM »
Hello everyone!

First of all I want to thank all of you who share your information to the newbies like me.
I wanted to show you guys my first pcb board which I made to test my CNC 2030T using mach3. Everything looks great until the engraving part as you can see in the image attached (ignore the drills, it was just an engraving test) did not engrave successfully.

Is the board bend? If so, or not, how can I fix this in future boards?

Thank you and sorry for my English, is not my native language

Offline Tweakie.CNC

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Re: Help this newbie (engraving)
« Reply #1 on: July 23, 2015, 08:03:50 AM »
Hi Carlos,

Your board may be bent but this problem is usually associated with the machine's table not being flat and true with the machine's motion.

It is usual to fit a 'spoil-board' to the machine table then 'surface' this board (with a reasonably large diameter cutter) to make it flat and true with the machine's motion. Thereafter your PCB's will have equal depth of engrave over the whole surface.

Re: Help this newbie (engraving)
« Reply #2 on: July 28, 2015, 04:22:01 AM »
Hi Carlos,
I had the same problem when I first built my machine. As Tweaky has said it is the table not quite being flat with respect to the vertical
axis. As it turns out it wasn't that bad, about .2mm variation over the extent of the board. Problem is that .2mm (20 micron) is nearly
two thirds of the thickness of the copper.
In my case as the bed of the mill is 25mm steel I took it off and had it ground in a surface grinder ($40.00) and now it is flat to 8 micron
over the entire table and within 3 micron over the extent of the board of 160mm by 100mm. That's close enough for me to produce good
If I wish to do better then I will do as Tweaky suggests and use a spoil board that I can machine flat in place. I wanted to use some sort of
plastic like polycarbonate so  I could cut a 160 by 100 pocket and use vacuum to hold the board down. Keep on getting overtaken by more
pressing jobs...
Looks to me like you are on the right track, keep it up and you will make some excellent boards. Extremely satisfying.

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