Two things I’m trying to figure out using Carbide Create. Both seemingly related. I’m running Carbide Motion on the 5 Pro.
It seems like on every run I make, the router will do a final pass around every shape without actually cutting any material. For every run I’ve done, I use 3/4" ply with a 0.15" depth per pass. This divides evenly across the thickness for 5 passes (see crude text diagram below). 0.75 / 5 = 0.15. What’s actually happening is that Pass 4 is cutting through the material completely (when it should actually be cutting to 0.60"), and Pass 5 is doing nothing. Why is this happening? If anything, I should have just barely cut through the stock or not at all depending on any odd variation in thickness.
NOTE: upon measuring the actual stock thickness, it’s about 0.72". The issue above would still be valid.
My process for zeroing the Z-axis is: Take scrap magazine page, place on X/Y location, jog down until a 0.025mm increment results in not being able to move the paper anymore. Zero Z-axis set.
All material is secured with 6 Shapeoko Essential Clamps. Largest stock size held down was 24" x 48".
This is how it should be cutting, right?
___ Stock top
.15|___ Pass 1
.15|___ Pass 2
.15|___ Pass 3
.15|___ Pass 4
.15|___ Pass 5 - Bottom of 0.75" Stock
Your reasoning is sound. Double check the tool for the depth of pass to make sure it is .15. I typically use the bottom of the stock as my reference instead of the top. This does two things. One is it saves my spoilboard. Secondly if I have miss measured the material the first pass with either be air or a little deeper than it should.
I have found very little plywood that is actually .75". Usually it is really metric (19MM) or slightly under the .75" even for US made plywood. Are you sure your plywood is actually .75". If you set the material to .75 and then zero on the top and your material was just under .75 you would likely cut through the bottom and into the spoilboard.
One more thing to consider is calibration of your Z axis. You want to make sure that if you cut .5" deep pocket it is actually cutting .5" and more or less. You can fine tune the steps per MM in the settings if your machine is not calibrated properly. Most machines use the default settings just fine but once in a while you need to adjust the settings.
If the last pass is actually less than .15" then something else is going on. If the material is set at .75 and it is .15 then each pass should be the same. The last pass should be cutting through the bottom and into the spoilboard if the material is less than .75. If the material was more than .75 then there would be an onion skin on the bottom to remove.
You don’t mention measuring pass 1. Is it actually 0.150 deep?
I’ve developed the following process after several mishaps…
Initialize
Insert the first tool I will use
Let it measure the tool
Set my zeroes
Start the job
When CM asks me to insert the tool (It’s already there), I look at the Z value. Usually 4.[something] if I’m cutting a 3/4" part.
After measuring the tool, compare the Z value. It should be the same. If it’s not, stop the program & double check Z zero.