(Video below)
So I just got back into fighting working with my CNC machine. After a few failed attempts at PCBs (I’ll post what I learned there some other time) I thought I’d work on something on the macro scale. Below are notes to myself on the workflow.
Designing a sign in Fusion 360, simple enough. CAM is tough though, especially when using mm.
First I had Jess (Queen of fonts) find a cursive font that connected most of the letters together and had her create a SVG file for me of it. She used photoshop and MakeTheCut (for our Zing vinyl cutter) to generate the SVG.
I used easel to get the settings I would use for feeds and speeds, then converted them to mm. This can likely be fixed by creating my own tools file locally with these values hard-coded as defaults.
Realize that my machines is Left hand rule orthoganal axes.
Z
^ Y
| /
| /
*——> X with Y pointing into the screen.
Set CAM origin to nearest-leftist-top face of project stock (0,0,0)-ish on my machine
Set up a 2D contour and select the bottom of the design to be cut out. Make sure to select all the inner contours as well. Add a tab or so to the inner parts to prevent them flopping around or going ballistic.
Multiple passes, no more than 1/2 bit thickness each with triangular tabs.
I set clearance heights at 5mm, 10mm is safer but slower. (Click pic to make bigger).
In the first 2D contour settings tab, you must select the tool. The menu seems to have changed since I last saw it. Simply use the search bar at the top. I used 1/8″ as my term and easily found something that would work.
Export the CAM using smoothieboard CAM process. Save the file with a .gcode extension. We’ll be using printrun (does anything else work for smoothieboard?) which only looks for .gcode files.
(needed?) Open the file by hand like a cave man and add “G1 Z5” to the code JUST BEFORE the first G0 or G1 command. This will raise the bit to a safe height from the start. I might be able to ignore this if I follow the correct steps below… but do it until I learn better. I might also be able to modify the smoothie post processor to add this in.
I used 2-sided scotch tape to secure the part. It works well for light duty stuff.
Using the step blocks, set the gantry roughly equal on each side to square up the machine. This is a tip from a youtube video I cannot find again (sorry to the guy who made it. Thanks man, you’re the real MVP). I got my step blocks for practically nothing online. Bonus, once you’ve squared you floppy gantry with them, you can use them as they were designed to be used, as actual step blocks with clamps for holding your stock down to the table top as well.
Turn motors on and use printrun to move to Set up the X and Y of the machines to where Fusion360’s workpiece offset was (nearest-leftist-top face of stock).
Raise the bit like 30mm and prep for an air run.
Reset axes, then RESET THE SMOOTHIE. Fully disconnect and reconnect, and I don’t mean in printrun, I mean unplug the USB cable and plug it back in. This is the only way to change the stupid machine offsets which will cause problems. If you don’t, before the machine does the G1 Z5 we added, it’ll immediately move to the place the router was when you powered on the smoothie last. Often times this means moving directly through the stock, especially if the Z was touching the stock or lower when you started running the file. IT WILL ALWAYS GO BACK TO MACHINE 0,0,0 BEFORE GOING TO WORKPIECE 0,0,0 AND STARTING YOUR PROGRAM.
Once you’ve rebooted the smoothie, load the file and run an air cut (at Z 30mm) to verify nothing funky happens.
Once this is all verified, move to the actual start position you want (bit touching the top of the stock)
Adjust the Z by hand to verify starting position.
COMPLETELY REBOOT THE SMOOTHIE ONCE MORE. The whole shebang, unplugging and all.
Turn Speed on router to lowest setting. If I had a superPID it’d be able to go the correct speed but as it stands it is almost always spinning too fast.
Turn on the router, turn on the vacuum, connect to the smoothie, reload the .gcode file in printrun, then Run the file.
Keep an eye out especially at first, always be ready to smack the E-stop.
If you smack the E-stop, be ready to jog the machine back to the workpiece offset (or new area of the workpiece ) and completely reboot the smoothie. The latest printrun (1.6.0)/smoothie firmware (April 4th 2018 firmware) I’m using seems to lag dramatically after E-stop has been reset and could be dangerous.
