by cnczane » Thu Jul 27, 2017 11:44 pm
Hi, Mitch,
In fact, I learned MeshCAM by doing things I wanted to do. I was itching to get started. I'd been waiting YEARS to get a machine, and in fact had MeshCAM before a machine... (However, I got a CNC simulator too first, to verify that the result was going to be what I thought. I use linuxcnc and execute MeshCAM's output without turning on the machine when I'm unsure about behavior.)
I didn't have formal CNC machining training, but when I did have a chance to get some years afterward, I was surprised by what I considered to be unnecessary busy-work steps. For example, I don't use an edge-finder: I work off of pencil marks in the middle. I don't define stock: I just make sure I load a piece that's thick enough. And so on.
The point is, I use MeshCAM like any other tool in my box--in the way I want to use it, and not necessarily the way machinists use it.
The most important thing is to get experience. The more you can see how it behaves, the more confident you'll be to predict how it will behave.
Off the top of my head, I think the steps are:
- load the digital model
- specify either X or Y, and Z sizes
- smooth it if you want (not for machined parts)
- tell MeshCAM what point on the stock you're going to use for your origin when you cut it out later
- here's where I use top-center, and others use top-lower-left, etc.
- define stock, if you want
- generate toolpath
- have to define tools before you can use them, and I think this is a major MeshCAM weakness in having to do it interactively
- define whether you want both roughing and, various, finishing passes, or just roughing, or just finishing
- pick the tool for each of the passes you've checked off
- set the parameters for each
- save the toolpath settings to a file so you can reload them later when you have a similar part
- generate the path(s)
- look at the result, variously hiding the model, and different passes, so you can look at one pass at a time
- does it do what you want? is it what you expect?
- load it up into your CNC controller and "cut air" with it (raise your cutter safely high enough off the table and tell your controller
this is the origin; this is the place you told MeshCAM to use--all of the movements MeshCAM will command are computed
with respect to this point)
- if nothing exciting happened during the air-cut
- load up a piece of stock
- move the tip of your cutter to the position you told MeshCAM you wanted to be your zero, and tell your CNC controller this is
the zero
- raise the cutter so it's not in contact with the surface when you hit "start" and hit start
It occurs to me that there are things to learn here that newcomers might not realize are separate. "Learning MeshCAM to create G-code files" and "Learning G-code" and "Learning how to operate a CNC machine" are not the same thing. There are good websites out there for the last one, and I recommend LinuxCNC.org for learning what the various G-code commands mean--you will want to learn them sometime if you're going to become comfortable with CNC machining or routing.
Until then, ALL the Best!
--
David, the CNC zane
If you have not received a reply from me in over a year, I am not ignoing you: more likely I am fallen asleep under a tree. Again. Please poke me if you think it worth your trouble.