Configuring the CNC

I have some questions regarding the CNC module, in specific the SnapmakerJS software.

  1. Where do I define the material height?
  2. Why do I need to upload a vector (SVG) while it displays it in the preview as a low-res bitmap?
  3. What is a carving step?
  4. What is the use of the jog height? Why does it matter that the difference between the tool and the material is when it is not carving?
  5. Same question as at 4, why does the height between the tool and material matters when the carving is done (stop height). Why doesn’t it simply go fully back up.
  6. What are tabs?
  7. What is the difference between carving along the side of an image & along the contour of an image?
  8. How should I read the coordinate system? When I select “align center to origin”, does this mean it starts carving from the center?
  9. Why does the “Generate G Code” button not work without throwing an error?

The image I am using is attached: test


  1. You do not define the size of the piece
  2. I do not know why you need to upload an svg. But here is a awesome free converter that converts images to svg.
  3. A carving step is how far down the bit goes on each layer so it does not over work itself.
  4. The difference matter because it it does not go up before moving it could try and go through the wood and possibly break something.
  5. Same answer as 4.
  6. Tabs are what keep your design in place in case you are cutting through the whole material.(Piture of tabs below)
  7. Outline - Carves along the contour of an image On the Path - the shape of am image.
  8. No the coordinate system does not determine where it starts. It just shows where it is going to be when you start the carve (Example- If you do clip to axes you would set your work origin in the corner of where you want it to be carved. If you do align center to origin then you would set work origin in the center of your piece)
  9. I can not answer that without knowing what the error was.
    If you have any further questions just ask.
1 Like

Complementing/rephrasing Johnny’s answer:

  1. Although you don’t define the “stock” size, it is up to you to define the coordinate system (x,y,z origin point) and the total depth cut (multiple pass will be done using the ‘carving step’ - your question 3)
  2. When using svg, the CNC will use the shapes (curves) define in svg. The bitmap is displayed just as a preview of the uploaded file (for example, a filled shape will not be fully carved, but usually only its “edge”)
  3. Nothing to add
  4. One important thing is that if you are holding the piece using some type of clamps, you should increase the jog height to avoid any accidental hit on these
  5. same I guess
  6. The picture explains it all
  7. outline - the resulting carved object will have the dimension as defined in the svg (the CNC will offset the carving to count for the bit size). On the path - CNC will follow the paths as is. You should design considering the bit sizes
    8 . you should define the bit position origin (e.g.: bottom left corner) as you prefer. The “Align center to origin” is used to make the “gcode” origin to consider the middle of the design (in this case, you should also move your bit to the center of your piece and set it as origin!)
  8. I’ve notice some quirks here and there, but usually reloading a file (preferably with a different name) fixes it.
  1. SVG is Scalable Vector Graphics. The router works by carving a series of lines or curves (vectors), not by drilling a series of holes in the material. So an SVG input is a better match to the task. It’s actually quite a bit of work to convert a bitmap back to an SVG, and usually produces a very messy set of vectors that only look correct at the original scaling. It’s much better to do the design work in SVG if possible. Obviously that doesn’t work with photographs.

An SVG-from-the-start scales better too. You could print an always-a-SVG on a 3"x3" piece, or a 4’x8’ piece just fine. If you tried that with a bitmap-to-SVG, it’s not going to look very good on the larger piece. I don’t think that really applies to most of us snapmaker users, but it does apply to the professional CNC community.

Flat panels are bitmap devices, so you can’t display an SVG on them. It must be converted to a bitmap to be displayed. I won’t go into the whole history of vector display outputs, but they’re pretty rare these days.

I checked the CNC tutorial video and everything start to make sense now. Where the 3D print module can be run fully with the Snapmaker. The CNC requires a computer to run. Still don’t understand how a 2D SVG file can result in a 3D shape. But that is something to experiment further on and might be asked in a seperate topic. The fact that fullfilling a CNC task is a 2 step process is something I was not aware of. Now I think of it, it does is logical. I mean, the 3D printing module works the same. First generate GCODE, then run the GCODE.