CNC machining is a technology that combines various techniques such as computer control, machining, measurement technology and finite element analysis to achieve high precision machining of mechanical parts. Today we will talk specifically about CNC, and hope that this article can answer questions for CNC beginners and reduce d fear of CNC machines.
Basic workflow of a CNC machine
We generally speak of 3-axis CNC machines with 3 axes: x-axis,y-axis,z-axis.
Step 1: Come up with a very clever design on the computer, here using Computer Aided Design CAD.
Three type of cutting strategies
2D File: Inkscape,Adobe Illustrator
In between are the programs created for hobby CNC machines: CAMLab,Carbide Create,Easel
3D File: Solidworks, Autodesk Fusion360
Most CNC projects use one of three different cutting strategies
Firstly we have two-dimensional cutting (2d cut), which is when we simply have the machine track an object and cut it out of letters and basic shapes and things like that.
Secondly we have 3D cutting, where the machine uses all three axes at the same time, which is used for more complex projects.
We also have 2.5D, which is when we just follow a simple shape (like a regular 2d cut), but we tell the machine to cut deeper in a certain area. This is not true 3d cutting because the z-axis never moves at the same time as the y-axis or x-axis.
Step 2 :CAM (Computer-Aided Manufacturing): takes the design and creates a description of how to engrave it.
1.Select the material:MDF, PLYWOOD, HARDWOODS
2. Select the cutting tool : the point is that our cutting tool must be smaller than the size of the object we want, and we need to tell the software which tool we are using to ensure that it is suitable for our shape.
3.Toolpath:The spatial path followed by the cutting tool
Step 3 :Passing instructions to the machine(CNC)
Derive these good instructions in a language that the machine can understand and most machines will read the G-code.
How do I transfer the code to the machine?
GRBL, an open source CNC controller, is generally used.
1.Hold the material in place, you can use clamps to secure the material to the workbench. Make sure that clamps and screws and such are not in the path of the tool
2. Fit the machine with a suitable drill bit
3. Place the machine in a central position and set the depth for the surface of the work before you start.
Advise for newbies for CNC machine
1.Your tool length offset may be off by the thickness of the paper, this may be important when manufacturing more precise parts. You can correct this by selecting your length offset in the tool offset menu and typing (for example) -0.002 or whatever the thickness of your paper is.
2.You can press the “cancel” button on the program menu to then be able to switch between the machine files and the usb device without scrolling all the way to the top.
3.You can search for a program by typing in the program’s number or file name and pressing the down arrow, or the up arrow if you believe you have already scrolled past it. Keep in mind this will take you to the nearest file that matches what you typed, so you may have to hit the up or down arrow again to continue searching if files have similar names or you didn’t type in the full name/ if there are more iterations.
4. You can can clear all work and tool offsets faster in the work/tool offset page by pressing “Origin” and selecting one of the options that appears. This only works for the offset menu you have currently highlighted. You should only do this if you are certain that you will not lose anything important like probe tool offsets when doing so. The old machines may have used “F1” then “edit” or in the reverse order at some point
5:lazy way to clean a machine is to turn the coolant on and have it wash the bed as you hand jog.