Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: cuecaps on February 15, 2010, 10:45:49 PM
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Howzit Guys...
Please help... ???
I'm engraving with Mach3 Mill and my fonts seem move or lose the X0Y0 position.
There is no z axis feed in the g code, meaning always G1 Z0.000 and I manually feed down .002" and repeat thesame simple font G-code cycle again.
The first few times is O.K., but, soon after, it engraves the fonts as if from another reference point.
I engraved others and never had this problem before.
The piece is secure..
Thanks for viewing..
(Click on the image for enlargement)
Alton - Cue Caps
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I'd first check the machine mechanically.
X or Y axis slides and screws have not gotten tight, dry, dirty, sticking or dragging.
Couplings, shafts and pulleys are all tight and secure with no slippage.
Do multiple rapid moves to a dial indicator or accurate reference point to check closely for any missed steps.
As machines get used, their characteristics can change due to the above factors and sometimes require a clean-up/lube job or a re-tune of the motors.
If missed steps are suspected, reduce the max speed and acceleration by 50% and try it to verify, then tune up for best results.
If it worked well before, and you changed nothing, my guess would be mechanical.
Good luck,
Russ
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All looks good until you get to the letter O and then that throws things off.
Do you have any problems when you try to do the O by its self? I am wondering if its a rapid move and you are skipping.
RICH
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Thanks Russ and Rich!!
Appreciate your fast replies to help me..
I will do both your suggestions.
I did recently have to re-configure my Mach 3 to Gecko 540 and the Motor tuning was haed to set,
being that I don't know what is ideal..
I will also do the check on the font letter "O".. as a control to be sure it's not isolated to that particular font.
I will post tomorrow after I do what you guys told me.
Thanks, good night.
Alton
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Alton,
Get the code just for the letter O, but include any G0 or G01 before it.
You may want to try exact stop and constant velocity modes.
Like Russ, said reduce 50% as that should allow you headroom, but start there after
the retuning and work you way up still leaving a safety margin of say 30%.
May run slower, but at least you avoid possible problems. If you are using backlash compensation
reduce that also. Do as you wish since, i work on the conservative side on speed for the sake of movement reliability.
BTW, went to your site some very nice work there.
RICH
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Hi,
I did the travel test and seems to be O.K.
I re did the top and it moved .005" on the 5th time I ran the program.
I stopped it and did the upper fonts.
I'm getting a hard time taking a photo to show the defects, 'cause that abalone material
gives off reflective lighting making photo taking frustrating.
The Fonts are in a .750" disc.. Following the curve.
On the 2nd cut, the fonts cut it to a smaller radius.
The Motor tuning is at 10.42 Velocity and 3.75 Acc. for X & Y Axis.
The fonts are about 1/8 " tall. Diameter of round piece is .750" or 3/4"
The cutter size is .0079" Depth of cut is .002"
Spindle speed is approx. 18,000 and feed rate I'm using is .8 units/min.
Could there be a "Virus" in the program that Norton Security Scans can't detect?
Or something wrong with my computer's micro chip?
Thanks for your comps on my site Rich...
Alton
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Could there be a "Virus" in the program that Norton Security Scans can't detect?
Or something wrong with my computer's micro chip?
Thanks for your comps on my site Rich...
Alton
The PC running Mach should only be running Mach not anti virus software
Phil
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I re did the top and it moved .005" on the 5th time I ran the program.
I stopped it and did the upper fonts.
Can't really tell from the picture because of the reflections and how the pic was taken ( not perpendicaular to the piece).
Looks like the center is different due to machine moves. I am thinking it is a mechanical problem.
I would, for example, do four circles of say .020" diameter / four equaly spaced about the center. If your machine along with setup etc. is
really good you can engrave those four circles say 5 times and see how well they all engrave. You can measure any
differences.Not bragging, but i probably couldn't see much differences under a microscope with mine other than spindle run out.
link to example pic below:
http://www.machsupport.com/forum/index.php/topic,13762.msg90926.html#msg90926
I don't think it is a Mach problem.
RICH
Post your code if you wish and "maybe" i will run it.
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Thanks Phil,
Should I remove the AVA Anti-Virus program from my computer?
I use another computer strickly for the CNC/Mach 3. No internet connected to it.
So, I don't need any virus protection since I'm not connected?
I am wiling to do this.
Now, I'm on a new HP desktop for e-mails and other media, and my turbo-CAD.
Below is a photo of the tool Path.
And, the other shows how the top fonts curve is smaller than the required radius.
Rich,
What is that "exact stop and constant velocity modes" ?
Yes, I will be running in circles today... ;D
..test it as suggested..
Thanks,
Alton
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Explaination of exact stop vrs constant velocity, here is the link:
ftp://ftp.machsupport.com/Docs/Mach3_CVSettings_v2.pdf
RICH
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I am guessing you are missing a step when it is done with the letter R and then going to the letter C.
Don't know if it is in the rapid move .....
Additionaly you see the little .008" out of wack engraved portion in #2. It is very small and at first i thought it may be the fine point of the tool deflecting sum, but , don't think so.
Are your motors getting rather hot?
I would try still try slowing down the velcocity and acceleration. Heck, try it at crawl speed.
The rest of the lettering looks good so i don't think it's mechanical ( backlash, etc ).
I always use constant velocity for my engraving work. My engraving machine also runs very slow and is extremely reliable. So even though it can run at around 10 inches per min i use it at 3 or 4.
RICH
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Alton,
Got to go and will check back later tonight on what you think.
RICH
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A good check to see if you are missing steps is to run the VERIFY routine.
If you have limits of course.
This function verifies the positions of all axes by performing a home operation on all axes simultaneously,
then moving all axes to position 0.0000 of the current fixture. If Safe_Z is enabled, a move to Safe_Z will
be performed first. If the Silent argument is True, then upon completion, a message is displayed on the
status line showing the offset errors of all axes from their home position. This function I used to ensure
that no position loss has occurred, and/or to correct any position loss that may have occurred since the
previous home or verify operation.
Russ
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So... I figured I put this VERIFY button on my lathe screen and use it instead of the way I previously checked for missed steps.
Looks like it won't work if the home switches are in series to one pin as all axis's home simultaneously and the first axis to reach its switch is the only one verified.
The other axis acts as though it hit its switch then reverses as well showing a discrepancy.
You can work around it by jogging one axis closer to its switch than the other axis, verify that axis, then jog the other axis closer to its switch to assure it homing first, then verify that axis.
So, back to the other way.
Home the machine as normal with Auto Zero checked.
Run the code several times.
UNcheck Auto Zero and re home the machine.
Machine coords dros will show any steps missed.
You can use this also to check consistency/repeatability of the switch itself. Mine fluctuate around .0002"
Heck, you probably don't even have home switches do ya.
Russ
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Russ,
Good post.Never used the VERIFY and documentation is about nill in the manuals.
Nope don't have any of those switches yet......someday...... i guess. I need about 20 of them. ;)
RICH
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I've been trying 2 other g code engravings.
They both work O.K.
I re-did the faulty "Abalone" program in LazyCAM and re-posted to Mach 3.
It did the same thing on the 5th cycle of the g-code.
I am going to re d0 it in LazyCAM and try once more.
Also, I notice , when I re-uploaded Mach3 and LazyCAM, I don't have all the fonts I had originally.
Why would LazyCAM have missing Font styles?
How can I get them Back, Like Mono Corsiva?
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I re-did the whole Layout in LazyCAM and made 3 seperate g-code .tap files.
One for the HERCERK, one for the 1st and one for the ABALONE.
Then, ran it all seperatly .
And, I didn't go that deep (Z axis).
Finally it didn't "Jump"..
But, It's little off-center.
Or, that, as the machine engraves, the fonts get bigger as they move to the right end fonts.
The font is slightly larger, thereby, increasing the space between the top of the Font and the border.
It happen before.
I have another Cap completed, with the engraving that shows that "Effect".
Thanks for your time Guys..
I don't know if the problem will occur again.
Alton