Pocket Inside of Pocket "Max depth must be greater than start depth" message

I am trying to create a pocket inside another pocket. For instance I have a box pocketed out that is .4" deep. Then I create a circle pocket .2" inside of that pocket. I would think that for my circle, I would START the cut at .4". and cut a depth of .2".

But I get “Max depth must be greater than start depth” message.

Yes I know that I can calculate this and make the circle pocket .6, but what is the sense for the “Start Depth” then?

The start depth allows a toolpath to start at the bottom of a previous feature for more efficient toolpathing.

If you wish to use relative values you can use the T variable for Stock Thickness and set up math equations using that.


All measurements are relative to the top of the stock. That is not to be confused with the origin using bottom of the stock for the Z. So in the job setup you tell CC the material is 1.0". You want a pocket to be .4" so the tool path would start at the top and finish at the bottom at .4". Then you want to add an additional pocket starting at .4" (bottom of first pocket) and end at .6". CC is not smart enough to handle a relative second pocket to the first. It can only work with the exact measurements you want for both pockets. CC is a smart program in some respects but it cannot read the mind of the user and just responds to exact measurements you input.

@WillAdams mentioned about using the “t”. The “t” has been around since v6 CC and a handy thing if you change the stock measurement. When you use the “t” instead of in this case above 1.0" after you get the 1.0" stock mounted and you measure it and it is really 1.1" then you just change the job setup and save the file and all tool paths are updated. If you had put the 1.0" measurement in and changed the stock size the tool path calculations are not updated and the tool path would still think the stock thickness was 1.0 and not 1.1". You would have to individually edit all tool paths to get the new stock dimension into the tool paths.

Using the “t” you can also express it as a formula. In the case of a 1.0" material and you made a .4" pocket and then a .2" pocket you could use the absolute figures from the above example or for the second pocket use t+.4" and the bottom of the second pocket would be a total of .6" deep and if you changed the stock size it would still be .4" above the bottom of the stock making the second pocket .3" deep and not .2" as when you entered the absolute numbers.

You can use the “t” in a lot of formulas but the “t” is always relative to the stock thickness set up in the job setup.


This topic was automatically closed after 30 days. New replies are no longer allowed.