request for hint on create additive operation

[filippor]

I want to create an additive operation like 3d printing. What I need to change?
add a new tool type and an operation similar to pocket but in reverse direction. Someone has some hint on how to proceed?
thanks

[chrisb]

Hi filippor, welcome to the forum.
There is already the reverse-to-pocket additive operation in the Part Design workbench. It is the PartDesign Pad. Since this is a very very basic question, may I recommend that you work through some of the excellent tutorials? I can recommend bejant's, others found those of r-frank useful, who wrote a complete series of tutorials as BPRLFE on youtube.

[JoshM]

I want to create an additive operation like 3d printing. What I need to change?
add a new tool type and an operation similar to pocket but in reverse direction. Someone has some hint on how to proceed?
thanks

Assuming you’re asking about processing an additive job, and know how to model it:

Existing Path WB Operations do not currently support this—only subtractive jobs.

I bet you could get it done by modeling your Job, then inverting it along Z-axis, and subtracting it from a Cube to get a negative of your model that’s upside down.

Then define a Tool diameter according to your additive material extrusion diameter.

Define Tool controller(s) with Feed rate(s) corresponding to how fast you want to process your Operation(s).

I think you’d have to change your working plane for your job. So that Path WB will Output current Z axis GCode.

Set the Step down in pocket operations to define the slice height of your additive process.

Pocket operations correspond to solid extrusions with correct step over. If you want a honey comb or similar structure internal to your results, leave solid material in your model where you want negative space in your model.

Profile passes would build shells.

Best,
Josh

[chrisb]

I want to create an additive operation like 3d printing.

fillipor, I have to excuse myself. Reading Josh's answer I realized that you wrote to the Path subforum while I had read it as a general help request.
There where general remarks on 3D printing on the wiki documentation of Path workbench, and they still exist in yorik's FreeCAD book. Perhaps that lead you here.
And, of course, there are similarities. There is the G-Code language describing the paths and there is some movement besides the modeled shells. Instead of stepping down in multiples of mm you could step up tenths of mm...
I am not sure how far libarea, which is used for path creation, supports this.
Perhaps it is better to investigate some slicing software like Cura and see if the algorithms can be applied to FreeCAD objects directly.

[filippor]

thank's for the answer. Yes I would create something like a slicer using the freecad library to support arc and advanced editing like create non planar layer. I'll take a look at libarea