Hey all.
I want to build a small CNC with the main purpose of carving 3D reliefs / sculptures from wood.
Is the MPCNC good for this kind of work?
And more importantly, how does one create the gcode for something like that?
I have a lot of experience with 3D printers but know very little about CNC software. Is there anything free or reasonably priced that can do this?
Where to start ?
Thanks!
I don’t know how to do them…but fancy things can be done…
When 3D printing, a slicer is used to generate g-code from a model. For CNC work, the tool is called CAM. CAM solutions take 2D and sometimes 3D files and allow you to define toolpaths for your job, and then generate g-code based on those toolpaths.
EstlCAM is the most popular tool for CAM on this forum. A distant second is Fusion 360 (which is a CAD/CAM solution). Both have free versions. Both versions will take STL files as input and allow you to do relief carvings.
Hobby level CNC machines (including the MPCNC) cannot be run as fast as commercial machines. I don’t know your specific uses, but, due to the need to run slower, relief carving on hobby machines can be time intensive. I’ve done some small pieces on my Primo, and they took over five hours to carve. I tended to use a smaller stepover (kind of like resolution) to avoid sanding, so some kinds of relief carving could be done much faster.
Note it is highly recommended you remain near your CNC while it is carving. Things can go bad quickly, and there is a risk of fire when they do. I wouldn’t leave my Primo running overnight like I do with my 3D printer, so when I was doing the relief carvings, I needed to be in the shop most of the day.
Some of CAM solutions take monochrome images as input for relief carving where the darker the pixel, the deeper the cut. You can convert between monochrome (height map) files and STL files, though in my limited experience, significant detail is lost.
Hello and welcome,
Most people with MPCNC’s mostly do 2.5D work with very little full 3d carving.
As Robert stated above the time to carve issue does stop a lot of folks from doing full 3D carves.
I do some 3d carving, and I am setting up a dedicated 4th axis lathe using the MPCNC as a base.
With that said there are very few free cad/cam packages that generate tool paths for 3d work.
Fusion 360 can do it, and there are post processors for the MPCNC/Lowrider.
In the low cost bracket, Carveco maker can do 3d/2.5D, and is a monthly fee at $15US. This version is somewhat limited in its manipulation of 3d reliefs, but can import 3d models, Bitmaps to reliefs, and do vector designs. I have a post processor for Marlin, I posted it somewhere, either here or the FB group.
For the 4th axis sculpture work, Deskproto seems to be in a class by itself. I can import STL’s directly, orient them automatically, and generate the tool paths. It is strictly CAM, being designed originally for the rapid prototype/medical prosthetics feilds. A bonus feature is it can run the machine as a sender as well. I have modified a machine profile/post processor that puts out usable gcode and am in the testing phase on it. Bonuses are that it can do regular CAM 2.5D work, and import vectors and bitmaps for carving. Price is $247US for the Multi-Axis hobby license
Also there is CamBam,it can design the CAD and do the tool path CAM, using the LinuxCNC post processor. It has the options of a lot of plug-ins that are free, and can expand the usability of the program. Too many features to list here. Priced at $149US
Thanks John. Reading more about this, I realized that I actually want 2.5D and not full 3D.
But my main concern is the time it takes. Is running a small hobby CNC like MPCNC for 5 to 10 hours feasible? Considering it will be running in my garage, while I’m at home (but not sitting in the garage).
Is that crazy unsafe?
“Most” of the time"…maybe not
But it only takes a split second for that “most of the time” to become the “one” time that something goes wrong and it’s all up in flames.
To be fair, it did stop by itself. 
Welp, there goes my dream of CNC’ing at home
Does anyone know of a service that can CNC 2.5d stuff for me?
Just start with other stuff, take your laptop over to work, rearrange the shop, tell your wife you are at a whole day meeting… So many options.
Well like me he may like the wife. LOL
Most jobs take considerably less time. I do 1/4 sheets several times a week with 12 parts on them and it takes an hour and twenty minutes.
What do you think you might run for 5+ hours?
2.5D sculptures.
How big??
Small ones only take a few minutes.
between 10x10cm and 30x30 cm
Unless you used a very tiny tapered carving bit that should not take all that long. If you did something super crazy detailed you can do a roughing pass. Stop. And do the detailed pass next time. 5 hours would be as long as I could ever see that taking for something extremely detailed. Most regular carving at that detail will be about half that.
If you are not doing a 3d carve just a v bit (30 min) or a 2.5D sign that is like an hour.
Maybe have a look through the gallery, click on something along the lines of what you are thinking, click on the picture and ask the person about how long it took.
I agree with Ryan.
Only over-achievers use .25mm tapered ball nose engraving bits…I am guilty
I’m the one who (mis?)lead about the 5 hours in my post above. My only serious attempt at relief carving was a series of mountains. Each was small at only 4" x 4" but had 1 3/8" of relief. My best results took around 5 hours. This is with one adaptive clearing pass, and one finishing pass with a small stepover. I tried running faster and/or with larger stepovers, but I either had issues with the carving or significant hand finishing work at the end of the carve. I was using a 1/8" ball nose bit. Since then, I’ve done a number of relief carvings in foam (decorations, cosplay, props), but haven’t done anything significant in wood.
It does depend, I just can’t be sure what sort of stuff we are going for here. When I see 2.5D I think 1 hour would be something super fancy for a 300x300 carving.
3D with a 0.25mm ball taper will take a long time but will be a stunning piece of work. We had a couple examples at the Colorado show. So it wasn’t misleading, I am just not sure that is what is being asked about.
Do you have a sample of what you want to carve?