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alan hoyle
08-29-2014, 3:15 PM
Hi have found that when try cutting a large circle ' 250' mm

its not cutting it properly
its about 3 mm longer on the y axis.

any help is gratefully apriciated
Alan..


btw its a SH-G350
coreldraw x6
rd works v8

Rich Harman
08-29-2014, 3:24 PM
In the steps per pulse setting (maybe it is pulses per step) you probably have an odd number there. In case you don't know, there is this "feature" where you cut something out, measure it, then feed the numbers into this calculator "feature" and it will update the pulses per step setting automatically for you. The problem is that this is accurate only for that size of piece, and it ignores kerf losses. When they first put together the machine they use this to determine what the value should be.

What I do is use the number of pulses per step that are calculated based upon the physical size of the pulleys and the number of steps required for a full revolution. In my case the correct number was 6.000.

AL Ursich
08-29-2014, 3:27 PM
Someone who knows will chime in with the Calibration Procedure... It's all about matching the rotation of the stepper or servo to a distance moved on the X and Y. You will change a number in memory of the Laser and run a test and keep at it until 3 inches on corel draw is 3 inches on the laser bed....

The helpers in the know will look at your signature block looking for the make and model of your laser. I don't know enough to know what a SH-G350 is...

Also if you can post what Firmware the Laser is running and what programs you are using. I have seen problems when I did not make the table size the correct size in my corel draw causing scaling problems.

Someone will know..... Add more details... you will get a quicker answer.

And I see this is your first post... WELCOME !!!!

Good Luck,

AL

Edit: Rich types faster... :)

Rich Harman
08-29-2014, 3:32 PM
If you need a method to quickly fix the issue, just select the circle in Laserworks and type in a value that is 3mm less for the height (247).

alan hoyle
08-29-2014, 4:39 PM
Hi have found that when try cutting a large circle ' 250' mm

its not cutting it properly
its about 3 mm longer on the y axis.

any help is gratefully apriciated
Alan..


btw its a SH-G350
coreldraw x6
rd works v8
The reason i ask is because have been trying to cut a roll top box and the finger joints are out of line..
but others have used same file with no problems...thats why decide to cut the large dia circle to see if was cutting true to size..
Alan

Rich Harman
08-29-2014, 7:19 PM
247 is 98.8% of 250. You should be able to scale the height of whatever you are cutting by 98.8% and it should be much closer to the proper size. It is something quick and easy to do. If it works, then you know you need to adjust your pulses per step settings.