Machining at an absolute height above the table

[erik_f]

Using partworks it gives the option to zero at the bottom or the top of the material. It would seem however when trying to machine at an absolute height when using the table as the zero, the top of the specified material is still zero. This does not make sense to me. Maybe I am looking at or doing it wrong. What I would like to do is machine the edges of pieces to a certain thickness so they will be a more perfect fit for the dados. Doing it this way I don't have to adjust the file for the thickness of the material every time a new sheet is loaded onto the machine. I would think when using the table as zero, you should be able to tell partworks to machine at .75" and it would position the tool path at .75" above the table, but instead .75" is at the bottom of the piece where it should be zero. What it seems like is if I want to machine at .75" above the table height, I have to specify the material thickness as .75" zero from the table and then machine at a height of 0". Am I wrong?

[jerry_stanek]

You can zero to the table and then tell part works the material is say .78 and you want to cut to .75. Your machine then will drop to .75 above the table and run.

[erik_f]

thanks I will try it

[erik_f]

If I zero to the table and tell the machine to cut at .75" it then proceeds to cut at z-zero for if I have specified the material thickness as .75". If I specify the thickness as .78 and tell it to cut at .75" then it proceeds to draw a tool pass to .03" above the table. I suppose all will work out fine if I specify my material as what I want it to be and then run the tool path at zero...which will actually be at .75" above the table.

[sawdust535]

When you preview the toolpath in PartWorks, I noticed that the cut depth appears to be the same whether you zero to the top or bottom of the material. Anyway, I usually set the z-zero in partworks to the top of the material. I think you are correct in your last post, as long as you run the z-zero routine (C2), using the zeroing plate, to the table top, and specify your depth of cut in PartWorks (as a positive value) to the actual thickess you desire, regardless as to what material thickness you set in PartWorks. For example, in PartWorks, set the depth of cut to .75", run the C2 routine to the top of your table, and the total depth of cut should be .75" above your table.

[sawdust535]

Also, if you are zeroing to your table surface, make sure you set your home position for "Z" (in Material Set-up) to safely clear the top of your material.

[erik_f]

It doesn't seem to work they way you would think. Unless I'm missing a key step here. I have been using PW for a while now, but this is the first time I've wanted to use the table as zero. It seems it is workable I just don't like they way it seems to go from the top of the material down as to from the bottom of the table and up.

[tmerrill]

Erik,

This was recently discussed on the Vectric forum. Here is Mark's (Vectric Staff) answer:

"What I imagine that you are doing, is entering in the amount of material that you wish to be left with, into the “Cut Depth” box. The software does not work this way, I am afraid. The “Cut Depth” is always measured from the material surface, regardless of where the machine has its origin. The position of the origin, does not alter the function of the Cut Depth."

Here is my work around. Say you are working with a nominal material thickness of 0.75" and you want to leave a 0.25" thick piece. Set your material thickness for 0.75" in Partworks and create a toolpath that has a 0.5" cut depth. Now, when you go to cut it, first zero to the table top then raise the Z to 0.75" and use the ZZ command to zero Z at this point. Now your 0.5" cut depth should leave you 0.25 inches.

Tim

[erik_f]

Thanks Tim...
Somewhat of a frustration...I like your work around...most likely I will just do the math or go back to VisualMill for things like this. VisualMill is powerful but no super user friendly.

[beacon14]

I'm not sure why you feel you need a workaround. Erik you described the answer in your first post.

If you tell PartWorks that you are zeroing from the table, and you zero from the table, all you have to do is enter the cut depth that gives you the results you are looking for. If you set your material to .75" thick and the cut depth to 0, the toolpath will be at .75" above the table, regardless of the actual material thickness.

[sawdust535]

Erik,
Please disregard my suggestion on this post. I worded it incorrectly and it will not work as stated.