Hi all,

I'm having some problems with my CNC machine.

I have attatched a picture of some engraving work.

You can see in the circles that sometimes there is a wierd space between some of the letters.
It seems to be always to the X- direction,  but the sapce is not always the same.   Looks like missing steps to me, but the strange thing about it is that the name he does next is in the place it should be, and with no spaces ....

the Gcode seems to be fine when i generate it in Aspire 8.5  and also when i load it into mach 4


Anny idea's on this ?

Thanks,
Bart

I have absolutely no idea what is causing this but what is really weird is the C and y transposed (in the centre circled example). Obviously, that could not be caused by 'missed steps' so something is going on with Mach4. Are you using the M62/M63 commands for switching your laser ?

Tweakie.

Looking again at your pic. in more detail I see you have more instances of transposed letters and I am inclined to suspect the Gcode.
If you attach your problem Gcode I will run it here and see if I can replicate the result.

Hi,  thanks for you reply!

I used missing steps in my discription, because i don't know how else to call it ....

But like you say,  looks more like a software bug maybe ... I have checked the preview window in mach 4 and there everyting is like it should be.

No i have mapped a second motor to the Z axis, and use the direction pin to fire the laser...

I have attached the gcode file,  it is a lage file of 21Mb and it runs for about 3 hours....

Did a test in the air this morning (no engraving just the movements) and my origin is exactly the same in the end of this program.

will do an other test tis evening with the laser on...

I only ran a small portion of your Gcode and it is not good.

Your Gcode consists of too many short segment moves and missed letters (which are returned to later in the Gcode for completion of the word). If you did, for any reason, miss a step or two this could explain the transposed letters.

I think that if you improved your Gcode compilation you would not be having this problem.

You may also want to look at using the M62/M63 commands for switching the laser Output# rather than the Z axis direction pin. If it's any help to you my Vectric / Mach4 / Laser post processor is here; https://www.machsupport.com/forum/index.php/topic,36640.0.html

Tweakie.

Thanksfor the fast usefull reply

I ineed had a problem in this engraving with missed steps,  now it al makes sense   thanks.

I have already seen this in the Gcode file (the missing letters), and other Gcode files with text in them,  why does aspire calculates it in this way, or is it the postprocessor ...?

I don't think i can do annything about this ....? (exept for the postprocessor...?)


I will look into you postprocessor   why is the M62 M63 an advantage ? 

thanks,
Bart

I have already seen this in the Gcode file (the missing letters), and other Gcode files with text in them,  why does aspire calculates it in this way, or is it the postprocessor ...?

Who knows, the way in which Aspire creates it's toolpath is a mystery to me.

why is the M62 M63 an advantage ? 

Those commands have been specially created for laser use, taking effect at the instant of axis movement, and performing a better job with Mach4 than an axis direction pin.

I will look into you postprocessor

My post processor was just for inserting the M62/M63 commands it will not create a different toolpath or workflow.

Tweakie.

Do you know how the setup mach4 to use these commands ...?

The 'P' defines the Output# so M62P1 would turn on Output#1 and M63P1 would turn off Output #1 but only at the instant of following axis (any axis) movement.

At the moment you have the Z axis direction pin set as your laser trigger, change your setup so that Output#1 is your laser trigger then the M62P1 / M63P1 commands will switch your laser.

Tweakie.

I have tried this and mapped an output of my pokeys to output 1  but it just stays high.  can see this in de machine diag.


any sugestions..

i have added the G-code file