dthc dragging on small circles

[Skinnedrabbit]

Hello ,
I have a candcnc mp30002 dthc and hypertherm 45 .when im cutting small circles the t45 torch head seams to be dragging on the surface of the material .Its fine when cutting in longer sections as you can see it adjusting to the preset 1.5mm .Thanks in advance . Rob

[weldguy]

I am not familiar with the CandCNC stuff but it sounds like your controller is not turning off the height control on the small circles. Typically a controller will reduce the cut speed on small circles to produce a nicer hole, this in turn changes the voltage across the arc since it is now removing more material and reading a higher arc voltage. With the higher voltage the height control wants to lower the torch to obtain the proper voltage which is why most controllers will turn the height controll off for small circles to eliminate the problem that you are seeing.

[jimcolt]

weldguy is 100% correct...your machine slows for corners.....which results in highjer arc voltage....and the DTHC lowers the torch in an attempt to correct. You can increase corner speed and acceleration...or you can have your software disable arc voltage control on all corners under a certain diameter (I would suggest holes under 1")....consult with CandCNC on the proper settings to eliminate diving in corners and holes and fine features.

jim Colt Hypertherm

[Skinnedrabbit]

Thanks for the quick replies guys

[sodfarmer]

I put my holes less than 1" on a separate layer and program them and run them first. I automatically turn off the DTHC in Mach 3. After I run the holes then I run the rest of the parts.

[Skinnedrabbit]

Hi guys,
i thinki have a 0 setting in the sheetcam post processor so ive zero'd z and then raised up until i can slide a iece of paper betwen the torch and material .ive then put this reading into the post processor in sheetcam as a + figure .