Cut from buttom of a project: how to?

Software Carbide Create
1

I need to flatten some pieces to a certain thickness. How to set up the project to use the same thickness from the bottom of the pieces? Means all are 25.x mm thick (all little different, baltic birch plywood…, for my purposes I assume 25.5) and should be 24.7mm thick.
So I found the stock thickness in settings to be set as the stock I have, and the zero height set at bottom under the stock thickness settings, right?

Then with setting the max depth in toolpaths to 0.8mm will give me the desired thickness of the stock of 24.7mm, right?

2

Not sure what you’re asking?

Why is this any different than measuring the stock and cutting to desired thickness?

Is all the stock then same starting thickness and completely flat? If this is the case then just use a surfacing tool path and remove the amount needed to get the desired final thickness.

3

I zero off the top of material most of the time. Your final height will be 24.7mm, measure the stock and get the initial thickness. Say the thickness is 25.5mm as you said above, set your start depth at 25.5mm and final depth at 24.7mm. Your removal of .8mm is correct for your numbers provided. There is several ways to do this and get the same results.

4

the stock is not always the same thickness before, so I always had to Z-zero before every cut what I try to avoid.

5

You can always assume a slightly higher stock thickness and use that as you start point. Worst case it takes longer to get to 24.7mm as the starting point will be higher than the actual stock and will cut “air” at the beginning.

6
  • Use a Z Zero of bottom of stock (i.e., the bed)
  • Set a thickness in the project to be the thickest stock you have.
  • Set the depth of the pocket to be t-24.7.

By using the expression for the depth, if you decide to change the thickness in the project, the pocket will automatically compensate for that, always leaving 24.7mm of thickness remaining.

If some of you stock isn’t as thick as the others, then you may get some air-cutting at the beginning, but that is harmless and the ‘wasted time’ is I think balanced by not having to fiddle with the project for each piece.

2 Likes
7

Tim,
after your comments I realized that I also do not know any more what my question was: it does not matter for that purpose from where I define my Z height. As long as I define it from where ever I just let the machine run that level. TY!

8

mhotchin describes a good way to do this. Glad you got the help you needed.