FreeCAD CAM Ep. 15 || Creating a custom toolbit || Path Workbench

[@superdau]

I don't know if you thought about it, but in case someone doesn't want to change the model (like removing the fillet) just to fit the bit, which should always be the last resort IMHO. There are several other ways to get around the filleted pocket done: • Create a* pocket operation* for the pocket bottom face, but then set a *negative number for "Pass Extension"* in the operation's properties. With that the tool can be made to cut up to, but not including, half the tool diameter "outside" of the bottom face (i. e. for a 10mm diameter tool, the "Path Extension" can be at most -4.99) • almost the same can be done with a *"Face" operation* . The Parameter is called *"Material Allowance"* instead (or very confusingly "Extra Offset" in property view) and has to be positive instead of negative. Also the "Boundary Shape" has to be set to "Face Region" • Create a *pocket operation* for the pocket bottom face without any special parameters (which will lead to the pocket being too small as in the video). Then add a *profile operation* for the bottom face. It also has an *"Extra Offset"* parameter, which can be set to any value (not limited to half the tool diameter). You set that to the negative of the fillet width. • Select the *vertical* faces of the pocket as the "Base Geometry" for a pocket operation. The pocket will not be deep enough, which can be easily fixed by changing the *"Final Depth"* of the operation. The first two are the fastest, but also most limited. The third one the most versatile, but two operations you have to keep in sync. The last one is the most tedious when it comes to selecting the faces, if the pocket has a complicated shape, but also the "safest" because the necessary offsets are calculated by FreeCAD (even when you change the tool).

[@opensourcecnc]

Great! All those ways are good ways if you don't want to change the model. That's what I love about FreeCAD: for anything there are at least a few ways of doing things in order to get to the same result. I might add that instead of selecting the side faces for the profile, you can select the top perimeter and change the final depth (using the+0.02 mm hack). This way you don't need to add any extra offset, it's a simple profile with just the final depth changed. I'm still waiting for the moment when KZbin allows for adding to a video, there are so many things I would change...

[@attepitkanen7358]

Thanks, this was helpful! I made error on placing property bag on wrong level, but got it fixed in the end.

[@opensourcecnc]

Glad I could help!

[@pimmerd1992]

Hi, thank you very much for all your video's! Stupid question probably, I am a noob. I am trying to engrave some text but don't see a 30 dregree v carve bit in Free Cad with the correct dimensions in the library. Is this video explaining what i should do or is there an easy way? Seems to me that 30 degree is pretty standard for engraving. Would really appreciate your respons :) Kind regards Pim, and keep up the good work!

[@opensourcecnc]

Hi! Thanks for the appreciation. Go to episode 5, create a new predefined shape toolbit, because the v bit is already in the default shapes, you just need different dimensions. There I explain how to add a new toolbit to the library and give new dimensions

[@pimmerd1992]

​@@opensourcecncThank you! I'll check that out :) Really appreciate your channel!