3D CAM work arounds? rotating the part

[PeskyNgon]

hello. i would like to make 3D parts, rather than 2.5D (from what ive seen, 2.5D is all freeCAD can do). this "3D surface" thing looks promising, but im afraid i don't understand if this is the same thing as a 3D part. https://wiki.freecadweb.org/Path_3DSurface

so if that doesn't work, and freeCAD has no other way of making a 3D part... would this work?:

from what i understand, a normal cut is a movement on two axis at once. with this, you can get smooth turns around corners and such on a 2D surface, but not 3D. the axis that move at the same time are always X and Y, not Z. and this is why you get stepping. the way i see 3D parts being done, is to first do the normal 2.5D cutting. then fix an axis like X, rather than Z. then move Y and Z together across the part to get the same type of smooth cut, but in a different direction. then, Y gets locked and X and Z move together to get a smooth cut in the other direction.

so, if freeCAD cant do this axis stuff... could i just rotate my part to match the axis i need locked? for example, if i rotated it onto the left side, then did a cut, one side of the part would be done. then id need to flip it onto the right side to do the other half. with the right settings that should have the same result as changing the locked axis from Z to X. then if i rotated it onto the top, and did more cuts. then the bottom, and did more, that would be like changing from X to Y. and that would be the completed 3D part. i imagine this would be very tricky to line up each time, but i don't see why it couldn't work.

i am very new to CAM, so i would be very grateful for your input. even if its just to crush my dreams and tell me my idea is terrible

[chrisb]

Hi and welcome to the forum!

Moved to Path forum.

FreeCAD can move all axes at once, this is done e.g. in the helix dressup, but basically you are right with 2.5D.

Inside of the job, there is a clone which can be turned to your desire, without the need to turn the original object. Turning the stock object can be necessary on each type of machine, e.g. when you want to mill the bottom which is placed on the table.

[PeskyNgon]

Hi and welcome to the forum!

Moved to Path forum.

FreeCAD can move all axes at once, this is done e.g. in the helix dressup, but basically you are right with 2.5D.

Inside of the job, there is a clone which can be turned to your desire, without the need to turn the original object. Turning the stock object can be necessary on each type of machine, e.g. when you want to mill the bottom which is placed on the table.

thank you for the reply

im afraid i don't understand what you mean by a clone, or how turning it would help. from looking online it looks like a way to duplicate an object?

i was able to find this video that mentions a name for the kind of cut i want:
https://www.youtube.com/watch?v=iqnvzxuXFTQ
at 6:00 she says "parallel passes". going first from left to right, then a second pass from top to bottom. this is exactly what im looking to do. is there a way to do this in freeCAD?

[chrisb]

So you don't move the part itself at all. Then you don't need to move the clone.
FreeCAD's Path workbench can do such things with 3D surface. I'm not sure what tools are currently supported though. You should use 0.19 for that.

[PeskyNgon]

awesome, thank you for your help dude. i will look into that more and see if i can get it to work.

[Steveco]

FreeCAD can do 3D, at least enough to cut the curving smiley face shown in that video. To create the two sets of passes I would use the 3D surface operation - once with Drop Cutter Direction = X and a second time with Drop Cutter Direction = Y.

Here is a simple file I created a while back which can serve as an example:

RadusSandingBlock9.5_2.FCStd

(148.06 KiB) Downloaded 36 times

Note: there are two separate jobs in this file. That's just because I wasn't sure if I would want to wait for the second set of passes, so I wanted the GCode in a separate file.

Code: Select all

OS: Ubuntu 16.04.7 LTS (Trinity/trinity)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.22960 (Git) AppImage
Build type: Release
Branch: master
Hash: c5a4b01d2e4218bcc0eb6650337650a6c65ef0e4
Python version: 3.8.6
Qt version: 5.12.5
Coin version: 4.0.0
OCC version: 7.4.0
Locale: English/United States (en_US)

[PeskyNgon]

thank you very much for the explanation and example. that looks perfect for what I'm trying to do

[janc.linders]

Hi, you can have a look at the example provided in Google Drive.

https://drive.google.com/file/d/1G3VsLZ ... sp=sharing

It shows the surface 3D capabilities of the FC 019-pre version I'm currently working with.
Just finished this model on my DIY Desktop CNC.

1st step is Roughing
2nd step is Finishing.

Have fun

[janc.linders]

Here is the result of the first try.. Not to bad at all I think..
Material i started with is a high density soft material that won't break my bits.
Picture is not that good in low light

[PeskyNgon]

Thank you for the example, it looks great for what I'm doing. I won't be able to try it right away because I'm still building the CNC.