Welcome! Log In Create A New Profile

Advanced

Scaled down result

Posted by Anonymous User 
Anonymous User
Scaled down result
August 07, 2014 08:44AM
I purchased Zen tools 7x7" kit as frame and put it together.

I use grbl as controlling software.

I installed pcbgcode into my eagle software and created the gcode files.

I did a test run for a pcb design I already have (made by a pcb fab). I realize that the result is smaller than the original design (around %25).

I tried several different machine settings in pcbgcode but the result was same.

Any suggestion?

Thanks
Attachments:
open | download - photo (2).JPG (214.9 KB)
Re: Scaled down result
August 07, 2014 09:04AM
My first thought looking at the photo would be. Have you properly calibrated the router to move the expected distances (eg mm or in)?
Also, are you mixing metric vs imperial between eagle and your router control software?

My quick thoughts.
Anonymous User
Re: Scaled down result
August 07, 2014 10:16AM
The firmware I use lets me set 'steps/mm' value for each axis. (currently 250)

is there a specific value for pcbgcode or should I try various values until I find the correct one?

Thanks
Re: Scaled down result
August 07, 2014 11:10AM
Steps/mm is determined by your machine, not by pcb-gcode.

It would be best to figure out what the proper value is, rather than picking numbers until something works.

You would need to know things like how many steps per revolution for your stepper motors. Do your drivers support micro stepping? Do you use drive screws? If so, how many threads per mm? If you use belts and pulleys, how far does one revolution move the carriage?

When you have gathered these data, you (or we) can do the calculations and find how many steps/mm for each axis.

Regards,
JJ
Anonymous User
Re: Scaled down result
August 07, 2014 12:12PM
Thanks for pointing to right direction, I found Steps per millimeter - leadscrew driven systems calculator and put my values in.

The result was 320 and the value I had as default in my controller was 250 (%22 less)

I re-run the same test pcb after setting the values and the result was perfect.

Thanks.
Re: Scaled down result
August 07, 2014 12:32PM
Cool. Glad you got it working.

Regards,
JJ
Sorry, only registered users may post in this forum.

Click here to login