So I am running 2 pocket toolpaths with the same bit. I duplicated the first toolpath and the only setting I changed was the stepover from 30% to 5% for the final pass (on the second toolpath).
Issue is that the machine does not follow the exact same path as with the first toolpath. It goes slightly wider for some reason. Am I missing something?
it’s frustrating…
Any possibility the material moved during machining? BTW, is that a cumaru wood? very hard if it is…
By chance did you change your start depth? If so that is why this happened. basically vcarve doesnt think your cutting as deep as you are and the “shape” of your bit allows for it to move closer to the vector because of the curve of the bit.
i have had the same thing happen to me and it is frustrating! Based on Troy’s comment, I wonder if you could set a second pocket pass with starting depth of 0 and finish depth of slightly more than the first pocket, then modify the depth of cut so that it cut in one pass?
you absolutely can - just change your tools “PASS DEPTH” to the full cut depth. make sure you dont save that change to your tool database only the tool path or later down the road you will have a big accident.
Thanks, that was the approach I was thinking about. I’ve been frustrated by this but your comment explained why it was carving outside the previous carve!
What is the corner radius of your bowl bit? If your first toolpath hasn’t cut down to the depth that matches the corner radius, it will still be away from your vector on its final pass. Once you get to the depth of the corner radius, you’ll be cutting at the full bit diameter and should be on your vector line. As you cut deeper, you’ll still be on the line and start having a vertical wall.
Thanks for the heads up. I believe it is 3/16” but I’ll double check it to be sure. It is the bowl bit from Cadence (Cody). I also have the 3/4” from Whiteside and it appears to be around 1/4” radius. Most of the trays I do will be deeper than either of these.
Thanks Ken! I do have a profile pass selected as Last, but what I dont understand is why would it be wider than the actual vector? Also, it is the same toolpath as the first, just duplicated, and the depth is 0.8mm (about 0.028”) lower than the previous toolpath. Nothing moved, same bowl and tray bit, just selected the second toolpath when the first finished and hit run…
No it was secure. I only selected the second toolpath right after the first finished and hit run. Same toolpath, just duplicated and set 0.8mm (about 0.028” lower) to smooth out the bottom at 5% stepover VS 30% to save some time.
It might have. See below
In the pocketing toolpath you can select any number of tools you wish to use to perform your pocketing. When multiple tools are chosen then the first tool removes as much material as it can, all subsequent tools in the list will remove as much material as it can from any previously unmachined areas. If multiple tools are selected then the order of the tools in the list should match the order they will run on the machine.
Note
An allowance will always be left on for the final tool to remove.
Clicking the Select button opens the Tool Database from which the required clearance tool can be selected and added to the list.
Clicking the Remove button will remove the selected tool from the list.
Clicking the Edit button opens the Edit Tool form which allows the cutting parameters for the selected tool to be modified, without changing the master information in the database.
Clicking the up and down arrow buttons will move the selected tool up and down the list respectively.
This option is used to leave material on the inside of the pocket for the Profile Pass to clean-up. This is often very useful for ensuring the cutter does not mark the edge surface of the pocket when roughing out.
Its possible to have the wrong tool parameters set for the final pass
With no offsets, the center of the bit will be half its diameter (bit radius) away from the vector. You mentioned that you went 0.8mm deeper on the second toolpath. On your first toolpath, if you did not go deep enough to reach the maximum width of your bit, you will still be away from your vector. As you go deeper, the pocket will continue to get wider until you get to the bit radius.
