What am I missing? PW and zero to tool bed...

[harryball]

I have a file that is all cut outs so I thought I'd try zeroing to the bed instead of the material surface. I can't get it to make sense... I have set the model to machine bed.

I'm creating a profile and first tried...
Start Depth .52 (the approx thickness of the material) and Finish Depth .06 (about 1/8" above the bed) when I try to calculate I get an error "Cannot calculate for hte following reasons, Finish Depth must not be below Start Depth."
ummm... wouldn't the finish depth be below the start depth... i.e. cut deeper?

Anyway... trying to think this through I thought maybe the model knows the material thickness and wants a start depth of 0, it'll magically figure out what I mean (doubt it but I'll try it)
Start depth 0
Finish depth .06
Calculate worked but 3D preview shows me a shallow surface cut, not a cut almost to the table.

I don't see the difference here... if I have to set the finish depth to .52 I'm back in the same boat of having to measure material thickness.

It's almost like the software is not changing the zero method.

What am I missing? doing wrong?

Robert

[Brady Watson]

Robert,
Zeroing off the bed is confusing at first when you setup the part in PW/Insignia/Pro. 1st set the model with zero at the bottom of the block. Then toolpath just as you would when you zero at the top of the block. All the numbers are the same. Leave the start depth @ zero. All values start at the top of the block & go down regardless of whether you zero at the top or bottom.

The main value that you will need to change is the safe Z height. If you are using .52" material, and you set a safe Z height of 1", then your real safe Z will be .48" above the .52" thick material. If you had try to set the safe Z at .5", then it would give you an error.

Other than the Safe Z height, there isn't much else you have to mess with. As a side note, area clears/pockets or dados/rabbets are not a good idea using this method if you are working with multiple sheets with varying thicknesses (let's say a variation of .03 between sheet thicknesses) because your depths can be off. If you are using one sheet of consistent thickness, then this is not a problem. Setup your file just like you would a Top of the block file.

Make sense?

-B

[harryball]

Yep, that makes sense, I was trying to reverse things to fit what was physically happening.

I generally use the top of the block but in this case everything is a cut out and the sheets I'm using are not consistent in thickness.

Is there a way to vary the zero method in other programs when creating the tool path?

I PW I know I can create a tool path then change the model and create another tool path for cut outs. I just have to remember to rezero Z to the table etc...

Thanks,
Robert

[paco]

What I do is to zero at the surface of the material when I do surface work; V carvings, pockets, engraving and such. For all cut out, I zero at the surface of the spoilboard and add the thickness in the zeroing process. This is all program in a "spoilboard zeroing" routine. Zeroing at the spoilboard surface help at having control on the spoilboard gouging without bothering with material thickness (though I have to be careful with hard material).

If you don't change tool bit between toolpath, and want to optimize 'em, it's then better to measure the material thickness.

Surface work with material blank thickness that vary can be a pain...