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issues with PCB milling - newbie
« on: April 28, 2012, 04:38:31 PM »
Hello,

I have played with Mach3 for a couple of weeks - great! I bought a small milling machine called Panther-210, and I am trying to mill some PCB... so far with very little luck.
I draw my PCB using DipTrace/PCB layout, export the layer as a DFX file, then convert the DXF file with a small utility called ACE. This gives me g-code I can then import in Mach3.

The issues I have are:
1- most traces are not "closed": for example a circular pad would look like a "u" instead of a "o"
2-I tried to drill the PCB (just using an engraving tip with very small Z, just to see where it will be drilled), and the holes are not well centered
See attached picture

basically the PCB is unusable with all the tracks not being disconnected from the rest of the copper plane.

The feed rate I use is 30inches per min.

Where does the issue come from? Is it the accuracy of the mill? How can I improve that? The mill is sold as a small PCB mill, and I have used the settings recommended from the vendor:
e.g. velocity is 1400 mm/min, accel 150 mm/sec/sec...etc

many thanks for your help

Thomas
Re: issues with PCB milling - newbie
« Reply #1 on: April 28, 2012, 04:49:01 PM »
see any instructions for backlash adjustment that came with your mill
Re: issues with PCB milling - newbie
« Reply #2 on: April 28, 2012, 05:10:17 PM »
That is what I feared... it is badly written in Google translate Chinese to English...
Re: issues with PCB milling - newbie
« Reply #3 on: April 28, 2012, 05:48:30 PM »
Thanks for the tip. What is the best way to see the amount of backlash I have? Plot a square 10 times?
The manual says I need to loosen 3 setscrews that hold an auxiliary screw. The I need to turn the auxilairy screen "half a turn" - it does not turn more that 30 degrees. Is anyone familiar with this design?
Will post a scan tomorrow...

many thanks

Thomas
Re: issues with PCB milling - newbie
« Reply #4 on: April 29, 2012, 05:33:04 AM »
close up pictures would help.
also try to determine the type of backlash nuts you have.

 if it has hand wheels turn the wheel one way then revese it and notice how much it turns untill the axis reverses direction. that 'play' is what you need to get rid of.
Re: issues with PCB milling - newbie
« Reply #5 on: April 29, 2012, 10:28:33 AM »
Hi TramAlot,

I posted the manual in another thread:

http://www.machsupport.com/forum/index.php/topic,21446.0.html

many thanks for your help!

Thomas

Offline Jeff_Birt

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Re: issues with PCB milling - newbie
« Reply #6 on: April 29, 2012, 10:46:02 AM »
With the information given there is no way to tell if the problem is relayed to the machine or how the GCode is generated. If you try to mill a simple circle with your new machine does that work out OK?
Happy machining , Jeff Birt
 
Re: issues with PCB milling - newbie
« Reply #7 on: April 29, 2012, 11:21:26 AM »
Hi Jeff,

Unfortunately I have started to look at the nuts to try to remove the backlash... so at the moment the mill does not work at all - the resistance is so great that the motors can't cope. Drives me mad...
What I can say is that when I tried to make a square of 12 by 16 cm, the X axis was accurate (12 cm) while the Y axis gave me 15.8 cm...

any ideas?

many thanks

Thomas
Re: issues with PCB milling - newbie
« Reply #8 on: April 29, 2012, 04:01:59 PM »
If the machine is new check every nut bolts and things like the couplers and motor shaft flats and set screws.

And once you get it running again the first few times you run it make a test program and cut air for an hour or two. And then check your nuts by using a dial indicator and counting steps.
Re: issues with PCB milling - newbie
« Reply #9 on: April 29, 2012, 04:19:51 PM »
Still stalling all the time... really frustrating. Every time I connect the nut to the Z block - more stalling, even if the nut was moving well on its own.
Also there are a couple of "binding" places on the spindle - what is causing that??

cheers

Thomas