Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: sevenbor on May 06, 2010, 02:05:30 PM
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Everyone in a while, when i start a code the router drives the bit all the way through the piece and into the bed of the machine to the lowest limits of the gantry. It does this in less than a second and I don't often have time to hit the e-stop before it bottoms out. When I look at the screen It then shows that the Z is WAAAAAAY off. I have had this problem a few times and i have no idea why it happens sometimes and not others. I am wondering if I am doing something wrong. I have been recording my actions with the hopes that someone might be able to spot my problem. Here is what I did today
I started Mach 3
I tried to move the gantry with the key board so I could fasten a board, but the estop was pressed in
I pulled it out,
I fastened the board
I hit return to zero it did not move
i manually moved it to a central location
I set new zero locations and zeroed out the screens
I loaded the g code
I started the run
It ruined the board
Any ideas?
I
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I should also add that I use vectric procarve 5.5 to create the txt files.
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What is the code like?
Hood
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I am not sure I understand what you mean by that. what is "the code" and how can I tell you what that is? the file I load is txt file. I am assuming that is Gcode. The fellow that gave the 30 minute how to called it g code. Is that what you are talking about? is there somewhere on the mach 3 scree that displays what you are asking?
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I guess I should have stated that i know nothing about cnc machines, I am sorry. I bought a little table top machine (romaxx hs1) about 3 months ago to help me make toys and games for kids. I am an artist who likes to use wood as a medium an make custom toys and scale models.
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Yes its the G Code, you can attach the file by using the additional options button on the reply page.
Hood
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this was a poket for a marble tile inlay, but it has happened on many other files. The crazy thing is, once it happens one. If I run the exact same file immediately afterwards, it runs fine.
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Do you have any height offsets set in the Tool Table?
Hood
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It would be awesome if I knew what that meant, so i am assuming that since I don't that means no. is that something I do in Mach 3 or in vectrc?
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I have one code that I have carved at least a dozen times and it has done it twice. each time it is the first time I try to carve it once I turn on the computer and turn on mach 3 and set the zeros
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Look at the Config menu then ToolTable and see if you have a height offset for Tool 1
It could be that you are starting off and zeroing the axis with Tool 0 loaded and when your code calls Tool 1 the height offset is applied.
Hood
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Thank you for you kind donation of your experience. and offering your suggestion, I will try that... I know this is a dumb question, but those are all on Mach 3 right?
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Yes, config menu in Mach and then tooltable, see screenshot. Also when you first start Mach see what tool number is showing, again see screenshot.
Hood
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A few questions -
Is there a g41 or G42 ahead of the line where this happens? I have had a couple times where I got strange results because of something not quite right when I used Cutter Left/Right. Not lately, not sure whether the problem is gone, or I am just writing better gcode...
Have you tried going to the toolpath screen and hitting Simul;ate Run - I have had a few times where this cleaned up the display and made things run better.
Is this on the first run of the day? If the machine was not in a good position when you started you might want to move it to a good area in the middle of travel and then exit and restart Mach3.
Can you post the code so we can see what it looks like?
Does the Z display show agree that the cutter is way below zero or is it at some bizarre position? Could be you are starting with bad values in one of the g54 through g59 settings. Check the offsets page and make sure there are no odd numbers there before you start. ( a set of MDI lines with G90 for the first one, and then G92 X0 Y0 Z0 can clean them up, just resets the current position to 0,0,0)
The reason I ask a bunch of questions is not that I am a Mach3 Guru, but because the biggest problem with diagnosing a problem is a lack of details so everyone makes a bunch of guesses and they may or may not provide any benefit.
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My guess is that it's being caused by G43. The Standard Vectic Mach3 posts insert a G43, and I've seen this happen due to that. I use a modified post with no G43.
As for G41/G42, I use them for everything, and have never seen them cause an unwanted Z axis move in years of use.
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Thanks for all the great questions.
********Is there a g41 or G42 ahead of the line where this happens?
It always happens the same time. When I start Mach 3, I start the code, it runs a few lines, then stops, then I hit start again and then it drives through the material.
*******Have you tried going to the toolpath screen and hitting Simul;ate Run
No I have not, I didn't know this was something that I could do, so I will try it.
*******Is this on the first run of the day?
Now that you mention it, It is almost alway on the first run of the day. can you tell me more about that process in a step by step please,I am not sure i completely understand.
******************Can you post the code so we can see what it looks like?
It has happened on all kinds of code, but I will attach the last inlay I was doing. I don't think it was the code, because after doing it, I used the same code to cut the perfect inlay.
***********Does the Z display show agree that the cutter is way below zero or is it at some bizarre position? When I start it says 0, but when it bores, it says that it is +60 sometimes.
The reason I ask a bunch of questions is not that I am a Mach3 Guru, but because the biggest problem with diagnosing a problem is a lack of details so everyone makes a bunch of guesses and they may or may not provide any benefit.