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Author Topic: Unwanted Gcode Line  (Read 5145 times)

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Offline kolias

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Unwanted Gcode Line
« on: October 01, 2012, 09:15:38 AM »
Trying to cut a simple 10”x10” square, the origin is at the top right then with the tool raised she goes with line N30 to –X10 and then she goes down and starts the cut.

Any ideas why the line N30 is generated? (see attached code)

Also why I get the message on the status line “PWM Bumped to minimum Setting”
Nicolas

Offline ger21

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Re: Unwanted Gcode Line
« Reply #1 on: October 01, 2012, 06:26:10 PM »
Quote
Any ideas why the line N30 is generated? (see attached code)

That's where you have it set to start in your CAM program.

Quote
Also why I get the message on the status line “PWM Bumped to minimum Setting”

Your g-code has no spindle speed, and you have a minimum rpm setting in the pulley setup I think. So when you start the spindle with M3, Mach has to bump it up to the minimum that you have set.
« Last Edit: October 01, 2012, 06:27:56 PM by ger21 »
Gerry

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Offline RICH

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Re: Unwanted Gcode Line
« Reply #2 on: October 01, 2012, 07:23:38 PM »
Quote
Any ideas why the line N30 is generated?
LC does what it does if you don't define it. I touched on how to change / set  where the cutting can start in one of your other threads.
Have a look in the manual, the section on lead-ins / outs.
Sorry to always say go look in the manual, but, everything I know about LC is in there and you won't find it anywhere else.

RICH

Offline kolias

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Re: Unwanted Gcode Line
« Reply #3 on: October 02, 2012, 12:50:31 AM »
I don’t understand what you mean Gerry by “That's where you have it set to start in your CAM program” because I draw my square and set the origin at the top right of the square and expect it to start the cutting at that point. Mach starts at that point but travels with the bit raised to –X10 and then lowers the bit and starts the cutting from –X10 to X10 and continues on the rest..

I just don’t understand why Mach travels from the origin (0,0) to –X10 with the bit raised and then starts the cutting.

Thanks for the tip on PWM Gerry, I will correct it. I just put a value on the spindle RPM to try various options in case they have an affect on the problem described above. I control the spindle manually right now because it’s a new machine and I feel safer this way. I will set Mach later on to control the spindle. (one step at the time lol)

RICH I did read the Manual and tried what I understood with no success but eventually I will get it right

Thank you both
Nicolas

Offline RICH

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Re: Unwanted Gcode Line
« Reply #4 on: October 02, 2012, 06:38:40 AM »
Quote
I just don’t understand why Mach travels from the origin (0,0) to –X10 with the bit raised and then starts the cutting.

I think, guessing...... that LC selects a location for the start of cutting based on having a lead-in and as such it provides for a first move to a location which will allow it. One can set the type of lead in used on import or apply it afterwards. Note that LC  is an importer of a drawing, does some things automaticaly, should not be used as a CAD program, it's up to the user to define or change each machining step and how they want to accomplish it.  See Tutorial #7 (all of it) and always read the comments. No one knows the logic applied to LC  as no documentation exists, thus, the only way is to hack at the program and see what it does.
 
RICH
« Last Edit: October 02, 2012, 06:43:26 AM by RICH »

Offline ger21

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Re: Unwanted Gcode Line
« Reply #5 on: October 02, 2012, 10:41:37 AM »
I don't use LazyCAM, but a lot of simple CAM programs like it will start the cutting where the start of the line is in thew .dxf file.
Yes, your origin (0,0) is the upper right, but most likely, the square in the .dxf is draw starting at the lower left corner. Better CAM programs will allow you to set the start point. Or you can try to make sure when you draw it in your CAM program, you draw it exactly the way you want it to cut.
Gerry

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Offline kolias

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Re: Unwanted Gcode Line
« Reply #6 on: October 02, 2012, 12:08:42 PM »
I don’t use lead-in RICH, this is a cut of only 0.0625 depth on a 10”x10” MDF square. But I noticed as per attached pic that on the Extends Tab when the origin is at the BOT LEFT the extends show the Min values as 0,0, and when I move the origin at TOP RIGHT the extends show the Min values as -10 and this field is not editable. Anyway I can live with it but I was just curious why on my other cnc I never had a similar problem and now I do. Perhaps its related on how I have set my Homing / Limits values on Mach? I remember these values were different.

Gerry I made the square in MastercamX5 with the origin at the top right. I can draw nicely in Mastercam but setting the tool path is a daunting task for my right now and the NC code it produced is much longer and don’t trust it because I don’t understand what all these lines mean. That’s why I prefer to use LC which is so easy for me to use and the gcode much smaller.
Nicolas

Offline ger21

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Re: Unwanted Gcode Line
« Reply #7 on: October 02, 2012, 12:49:17 PM »

Everything left and down from the 0,0 point is negative, and everything right and up is positive. So, when you set the origin tio the upper right, the lower left corner becomes -10,-10. WHat you're seeing is correct.
Gerry

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Offline kolias

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Re: Unwanted Gcode Line
« Reply #8 on: October 02, 2012, 01:35:52 PM »
You are right Gerry that all I see is correct. My question as per my 1st post is why line N30 is generated on the gcode. I mean since the origin is at top right when the cutting starts there is no reason for the tool to go raised to -X10 and then to lower and start the cutting, its waste of time.

On my previous cnc this did not happened. I used to set the tool manually close to the top right of the table, then zero the DRO's and when I started the cutting the tool will lower and start the cutting right away. Now when I do the same setup, the tool will go raised to -X10 and then it will start the cut.

As I mentioned, I can live with it but I'm just curious why this extra line appears on the gcode
Nicolas

Offline ger21

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Re: Unwanted Gcode Line
« Reply #9 on: October 02, 2012, 02:57:35 PM »
Quote
My question as per my 1st post is why line N30 is generated on the gcode. I mean since the origin is at top right when the cutting starts there is no reason for the tool to go raised to -X10 and then to lower and start the cutting, its waste of time.

I already ansered this. The origin is the 0,0. position, and has nothing to do with where the cutting starts. As I said before, it's most likely starting there because that's the starting point in the .dxf file.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
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