scaling

[mike hide]

This thing is about to drive me crazy. I did a drawing in turbocad basically a name plate in some relatively fancy script. Turbocad accepts this script, and I exported the dxf drawing to sheetcam.

I made the script almost exactly 12" long.I did all the leaps,bounds and summersalts in sheetcam sent it through the mincer [postprocessor] and managed to produce a reasonably decent G code so mach 3 accepted it and in fact will run my machine using it.

The problem it does great job BUT it is always about one third size . to correct is size I increasd the scaling factor next to the DRO window by a factor of 3 and reran it same result, one third size. so then I went back to the motor setup and increasd the revs per one inch travel from 2000 to 6000 and re ran the machine, with exactly the same result . So I have done all I know [not that much I am afraid] to do in Mach3 so I was wondering if there could be a solution in sheetcam ....any help appreciated ....mike hide

[locost_cam]

First of all, is the drawing the correct size in SheetCam? Use the measure tool or simply use the mouse position display at the bottom of the screen.

In Mach, make sure the scaling is set to 1 then manually make a 1" move. Does the machine move exactly 1"? If not, you need to change your steps/unit.

[mike hide]

Well partial success. I went back and checked the motor settings ,they had dropped back to 2000,they should have been at 4000 .Further more I had not set the X,Y and Z axis individually and pressed both buttons save settings and the ok button for each axis.

I did as you instucted and all motor settings are now at 8000.Prior to this I have checked the drawing ,printed the drawing and it was the correct size 12". I also checked the size in sheetcam with the measuring tool it registered 12" also.

I then ran the machine and every thing worked except for two things .

The length of the finished nameplate ended up at 8" [should have been 12"]

Secondly the name was backward i.e. MICHAEL ended up as LEAHCIM that seems somewhat a mystery........Thanks for the help

[locost_cam]

If the text came out backwards in the X direction then the X axis is working the wrong way round. Reverse the X axis motor direction. Depending on the machine type the X jog buttons may now seem the wrong way round. Imagine you are stood on the table with your shoulders parallel to the X axis. When you jog right the cutter should move right relative to you. If this is a moving table machine it means that the table will move left - remember you are stood on the table so the cutter will be moving right relative to you. This takes a bit of getting used to but it will make sense in the end.

The scaling issue is probably still the steps/unit. Try 12000 steps/unit instead of 8000. You really need to check this is right. If you have a digital vernier, gently clamp it on the machine bed, parallel to the X axis and in such a way that the spindle can move one of the vernier jaws. Start with the verniers right open then use the machine to close them a little. Now zero the verniers and zero the X axis DRO. Jog the machine to close the jaws. If you have your scaling correct the vernier reading and X axis DRO should agree with each other. Repeat for Y and Z.

[mike hide]

Well I had not thought about that .I have been wondering why the machine was not starting from the lower left corner.I like to stand with the X axis infront of me and moving to my right and the text going from left to right .So now the text is not only reading right to left but id also upside down. So it would appear that bothj X and Y axis motors are rotating in the wrong direction .

Next question , how do I reverse motor direction? Thanks for the help

[mike hide]

Should have included this in my last post .The steps per inch figure had reverted to the previous setting 2000 ihd forgotten to do all axes and had not aplied the changes and the ok button.

I will give 12000 tomorrow and see how that works regards mjh

[locost_cam]

I normally reverse the motors in ports and pins. Simply reverse the direction output. If it was hi active, set it low active or vice-versa.

[mike hide]

Thank you for your help ,followed the instructions and found the direction in the Y axis was incorrect .In addition, I ramped up the revs /unit movement by one third and the machine is now making movements as per instuctions .

Thanks again for the help.....regards mjh

[escowizard]

Originally Posted by locost_cam If the text came out backwards in the X direction then the X axis is working the wrong way round. Reverse the X axis motor direction. Depending on the machine type the X jog buttons may now seem the wrong way round. Imagine you are stood on the table with your shoulders parallel to the X axis. When you jog right the cutter should move right relative to you. If this is a moving table machine it means that the table will move left - remember you are stood on the table so the cutter will be moving right relative to you. This takes a bit of getting used to but it will make sense in the end. The scaling issue is probably still the steps/unit. Try 12000 steps/unit instead of 8000. You really need to check this is right. If you have a digital vernier, gently clamp it on the machine bed, parallel to the X axis and in such a way that the spindle can move one of the vernier jaws. Start with the verniers right open then use the machine to close them a little. Now zero the verniers and zero the X axis DRO. Jog the machine to close the jaws. If you have your scaling correct the vernier reading and X axis DRO should agree with each other. Repeat for Y and Z.

Nice job! Nice explaination