Messages

11

General Mach Discussion / Re: issues with PCB milling - newbie

« on: May 06, 2012, 03:37:13 AM »

Really nice board!

On my thread on backlash ("   Re: newbie - help with solving backlash issues") I posted this - do you think I could solve some of my backlash using the Mach3 Backlash correction? I am concerned of tried to reduce it by tightening the nuts won't improve things (I am a lousy mechanic) ... thanks

Hello,

Now looking at the backlash on the Y axis. I ran the G-cpde below (also attached) on my small mill. Basically it mills from x=0 to x= 10 mm line in MDF, goes up 150mm, mill a parellel line... comes back and does a line at x=10 to x=20... etc.
Issues are: at Y=0 the three lines are not completely aligned, there is a bit of "ladder" effect. Same with the lines at Y=150 mm
The distance between the lines at Y=0 and the lines at Y=150 is not truly 150mm - more like 148.5
these problems looked even worse when I tried to mill then drill a PCB

Shall I fix this by trying to removed the backlash "mechanically", or should I try to use Backlash correction in Mach3 (as suggested by Hood)?

-to check reliability, is the program attached/below the right way to go? I made a couple of circles as well - but I don't have high precision instruments to measure the distances accurately (electronic vernier calipers is all I have)

many thanks

Thomas


F100
G21
G01 Z2
G01 Z-0.5
G01 X10
G01 Z2
G01 X0
G0 Y150
G01 z-0.5
G01 X10
G01 Z3
G0 Y0


G01 Z-0.5
G01 X20
G01 Z2
G0 Y150
G0 X10
G01 z-0.5
G01 X20
G01 Z3
G0 Y0


G01 Z-0.5
G01 X30
G01 Z2
G0 Y150
G0 X20
G01 z-0.5
G01 X30
G01 Z3
G0 Y0

12

General Mach Discussion / Re: issues with PCB milling - newbie

« on: May 05, 2012, 06:07:06 PM »

Tweakie -
very pretty board, what is it used for? Do you place the components in the hollowed-out places? Very elegant

thomas

13

General Mach Discussion / Re: newbie - help with solving backlash issues

« on: May 05, 2012, 11:30:47 AM »

Hello,

Now looking at the backlash on the Y axis. I ran the G-cpde below (also attached) on my small mill. Basically it mills from x=0 to x= 10 mm line in MDF, goes up 150mm, mill a parellel line... comes back and does a line at x=10 to x=20... etc.
Issues are: at Y=0 the three lines are not completely aligned, there is a bit of "ladder" effect. Same with the lines at Y=150 mm
The distance between the lines at Y=0 and the lines at Y=150 is not truly 150mm - more like 148.5
these problems looked even worse when I tried to mill then drill a PCB

Shall I fix this by trying to removed the backlash "mechanically", or should I try to use Backlash correction in Mach3 (as suggested by Hood)?

-to check reliability, is the program attached/below the right way to go? I made a couple of circles as well - but I don't have high precision instruments to measure the distances accurately (electronic vernier calipers is all I have)

many thanks

Thomas


F100
G21
G01 Z2
G01 Z-0.5
G01 X10
G01 Z2
G01 X0
G0 Y150
G01 z-0.5
G01 X10
G01 Z3
G0 Y0


G01 Z-0.5
G01 X20
G01 Z2
G0 Y150
G0 X10
G01 z-0.5
G01 X20
G01 Z3
G0 Y0


G01 Z-0.5
G01 X30
G01 Z2
G0 Y150
G0 X20
G01 z-0.5
G01 X30
G01 Z3
G0 Y0

14

General Mach Discussion / Re: newbie - help with solving backlash issues

« on: April 30, 2012, 03:58:16 PM »

Rich -

You were right, I got it working now! THANK YOU!

I need to try to get the Y axis working better now, it is very unprecise. I made a Square on a PCB - it is more like 63 vs 62 mm. Also I milled a PCB with a double path, and the paths don't overlap well - the deltaY is really perceptible. Will try to have a look tomorrow...

Thanks for our help!

Thomas

15

General Mach Discussion / Re: issues with PCB milling - newbie

« on: April 30, 2012, 03:54:57 PM »

You're right - I need a mechanic! I live in Denmark, now moving to France in a couple of weeks

I managed to get the machine running again, but it is not perfect - I milled a square on a PCB and it is not true; 62mm vs 63 mm... The Y axis is really not precise, when milling a PCB using a double path, the second path does not exactly match the first  really crappy precision

On the "backlash" thread, Rich gave me the advice to fasten the nut to the Z-block when the Z-block is at the end of its run on X - it works now.

TramAlot - what is a gib? I googled "Gib milling" and got lots of pictures, none of which said what the gib is. Also I realised that what I called a "spindle" is actually a screw... a spindle being entirely different. The issues of never having learned technical english...
And how do you check the thrust bushing/bearing preload?

Thanks a lot for your help folks - will come back with more questions tomorrow!

Thomas

16

General Mach Discussion / Re: issues with PCB milling - newbie

« 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

17

General Mach Discussion / Re: newbie - help with solving backlash issues

« on: April 29, 2012, 02:54:13 PM »

Okay - it looks like I have some binding (I am assuming it is some suddent increase in friction between the nut and the spindle - right) on some segments of the spindle... how could I fix this?

getting crazy here - just got from a mill that was not accurate to something that does not move at all!

cheers

Thomas

18

General Mach Discussion / Re: newbie - help with solving backlash issues

« on: April 29, 2012, 11:33:42 AM »

Now that I have started trying to adjust the backlash on the Y axis... I can't manage to get it right at all. Everything I do lead to the motor stalling... £$%%£
I get the nut to move easily and smoothly on the screw, then when I connect the nut to the Z-block, resistance increases a lot and stalling appears. The tighter the screws connecting the nut to the Z-block, the easier is the stalling...

any ideas?

many thanks

Thomas

19

General Mach Discussion / Re: issues with PCB milling - newbie

« 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

20

General Mach Discussion / Re: newbie - help with solving backlash issues

« on: April 29, 2012, 10:43:39 AM »

Thanks Rich,

Will try... what is "binding"?

many thanks

Thomas