Author Topic: wrong sized holes  (Read 277 times)

Offline Chip Owner

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wrong sized holes
« on: June 26, 2020, 11:46:55 am »
Odd one today.

Initially on loading the gcode it zoomed through to about a 3rd of the way through, then didn't actually do anything clicking cycle start. Reloading or clicking on the first line did nothing either.

This was based on a part that cut yesterday.

So I broke down the part into different operations, the first being a series of 4mm holes. It began at the beginning in Mach3 but instead of 4mm holes, it's simulating cutting 4" holes.

The default template is the MM version I'm using.

Baffled!

Offline kvom

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Re: wrong sized holes
« Reply #1 on: June 26, 2020, 12:37:45 pm »
Check g-code for G20 or G21 at the start, then work backwards to the post you're using and/or inch/mm setting.

Offline Chip Owner

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Re: wrong sized holes
« Reply #2 on: June 26, 2020, 18:02:27 pm »
Non the wiser what was happening, rebooted PC's, (inc cnc Mach3), nothing, finally loaded a small file with a couple of moves that previously worked into Mach3 and it corrected.

Crazy day!

Offline Bob La Londe

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Re: wrong sized holes
« Reply #3 on: June 26, 2020, 18:48:21 pm »
as somebody else said check near the beginning of your code for a G20 or a g21. Those tell mach3 whether it is in inch mode or millimeter mode. 
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Offline Chip Owner

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Re: wrong sized holes
« Reply #4 on: June 26, 2020, 19:17:20 pm »
Yes, all checked and fine.
This was def an error on the cnc pc running mach3, cleared as soon as I loaded the previous test file.

Infuriating, I'm putting it down to Friday.

I think the previous stammer, Mach3 jumping to part way through was down to me creating a new MOP and moving it to the top of the tree, before creating toolpaths, after having deleted the previous first MOP, thinking I'd got the settings wrong.  All part of my attempts to work out what went wrong.



 

Offline Dragonfly

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Re: wrong sized holes
« Reply #5 on: June 27, 2020, 07:27:59 am »
Are you running a demo version of Mach3?  There is a limitation of the number of lines of code it will execute.

Offline Chip Owner

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Re: wrong sized holes
« Reply #6 on: June 30, 2020, 11:33:43 am »
Are you running a demo version of Mach3?  There is a limitation of the number of lines of code it will execute.
No full version.

Seems to do it every time I boot up.

I now quickly run a file I know works seems to reset the machine then.

Odd behaviour.  I should add PC & Mach 3 came with the CNC machine, I can't speak for the quality of PC or installation of M3.  At the moment, now I know how to solve it, it's trivial, I can live with it for now. In future upgrades I may look at the whole process.

Offline Bob La Londe

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Re: wrong sized holes
« Reply #7 on: June 30, 2020, 15:49:45 pm »
Possibly a G20 in the initialization string on the general config page of Mach 3. 

Listen to what people are telling you. 

The G-Code G20 sets the machine operation to inch units. 

The G-Code G21 sets the machine operation to millimeter units. 

This can be changed on the fly, although generally its set one time at the beginning of a program with several other setup codes to set operational modes. 

You could add a G21 to the initialization string on the config page of Mach3, you could go to the MDI page of Mach 3 and enter G21 on the command line, or you could make sure all your programs have a G21 near the beginning of the program with the other setup codes. 

You do not need to run a program.  The program no doubt works though because it has a G21 near the beginning of the program. 

DO NOT CHANGE THE NATIVE UNITS.  The native units is part of and related to the electromechanical configuration of the machine.  It should never change. 
« Last Edit: June 30, 2020, 15:55:34 pm by Bob La Londe »
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Offline driedeker

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Re: wrong sized holes
« Reply #8 on: June 30, 2020, 19:06:02 pm »
All ways helps if you upload the .cb file so we can take a look. as Bob says your gcode should include a G21 for metric.
i use metric and my mach3 is set for metric as my machine is also using metric lead screws.
Believe if I use a g20 mach3 will convert to imperial but never tried it
« Last Edit: June 30, 2020, 19:29:44 pm by driedeker »
Made in England in 53

Offline Bob La Londe

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Re: wrong sized holes
« Reply #9 on: June 30, 2020, 21:27:13 pm »
Yes it will shift on the fly. You could run an imperial program and insert metric G-Code somewhere in the middle of it and as long as you had the appropriate G20 and g21 in the right location they would both work and they would both cut accurately.
Getting started on CNC?  In or passing through my area?
If I have the time I'll be glad to show you a little in my shop. 

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Offline Chip Owner

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Re: wrong sized holes
« Reply #10 on: July 03, 2020, 19:01:59 pm »
Possibly a G20 in the initialization string on the general config page of Mach 3. 

Listen to what people are telling you. 

The G-Code G20 sets the machine operation to inch units. 

The G-Code G21 sets the machine operation to millimeter units. 

This can be changed on the fly, although generally its set one time at the beginning of a program with several other setup codes to set operational modes. 

You could add a G21 to the initialization string on the config page of Mach3, you could go to the MDI page of Mach 3 and enter G21 on the command line, or you could make sure all your programs have a G21 near the beginning of the program with the other setup codes. 

You do not need to run a program.  The program no doubt works though because it has a G21 near the beginning of the program. 

DO NOT CHANGE THE NATIVE UNITS.  The native units is part of and related to the electromechanical configuration of the machine.  It should never change.

I repeat this is a glitch in my system.

The gcode is fine!!!!!!!!

Offline Bob La Londe

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Re: wrong sized holes
« Reply #11 on: July 04, 2020, 23:46:51 pm »
Did you read the whole message and check everything or just see the word g-code and decided there was nothing there. 

Getting started on CNC?  In or passing through my area?
If I have the time I'll be glad to show you a little in my shop. 

Some Stuff I Make with CamBam
http://www.CNCMOLDS.com