If you're just getting started with the Othermill, you may need to download the Otherplan software from Othermachine's website. You'll need to learn how to switch out tools and probe the bed. I won't cover the basics in this guide, there's some beginner friendly lesson plans on Othermachine's website to get you up and going. From here, I'm expecting you know the basics of Otherplan.
We'll use a generic material profile to start with and adjust the settings as we need. Enter the dimensions of your stock in the size drop down. Under placement, leave the alignment to spoilboard set to the left. We should zero out the X and Y axis but add an offset to the Z. Since we're using NITTO tape to secure the stock to the spoilboard, we need to tell Otherplan our stock is slightly elevated from the spoilboard. I tend to use 0.20mm as the offset since that is the thickness of a piece of NITTO tape. Once that's setup, we can move onto adding our gcode files.
Under the plans section, we can hit the Open Files... button to add our gcode. Navigate to the directory where we saved out our gcode files and choose the facing operation and click open. Then, select the 1/8" flat end mill from the Milling Tools T1 dropdown menu. Repeat this process for each gcode file, making sure to select the correct tool.
We'll run our facing operation first. In the configure section, under the Tool select "change" and follow the tool changing process. We'll use the 1/8" flat end mill for the face and adaptive clearing operation. The Othermill should be connected to the computer via USB. The toolhead will automatically run the homing sequence so it knows where it is. When you change the tools, Otherplan will automatically ask you if the spoilboard is cleared and safe to probe the bed. Probing the tool is how the Othermill knows what offset to use so it doesn't mill into the spoilboard. So make sure you have adequate area on the spoilboard for probing. If your stock is takes up the entire bed, you need to probe your tools before securing material down to the spoilboard. If you're following this guide linearly, we actually haven't done that yet.
Now it's time to secure our stock material to the spoilboard. I used a few strips of NITTO tape to secure my wood stock to the bed. It's pretty strong stuff, also works well with metals like aluminum and brass. With strips now stick on one side of the stock, you'll want to carefully lay the stock on the spoilboard with the corners lined up square with the lower left side. If you're a little off or over, it's OK. This is why we set a 4mm offset in Fusion 360, so our stock doesn't have to be perfectly 100% lined up with the bed. Firmly press down on the stock to ensure we have good adhesion to the bed.
OK, now it's time to run our first operation, so let's go forth and Face! Click on the Start Milling button below the face operation. Once the spindle ramps up, I suggest carefully watching the toolhead and watch out for any unexpected movements. It's noisy, so be sure you're milling in an area that is OK with lots of noise. The machining time depends on a few factors such as cutting feedrate. The thicker our stock, the more time it takes to face. If it's really thick, it'll take maybe an hour. I believe mine took about 20 minutes to a half an hour. Either way, it's good idea to periodically check on it and make sure our tool isn't broken or milling too deep. If you do find something is wrong or weird, you can either pause the operation or stop it completely. For really nasty situations, there's a built-in kill switch on the side of the Othermill, it's a nice and big red button. Push it in to immediately kill the operation. If we did everything correctly, we won't ever have to use it :-)
Once our face operation is complete, we can remove the acrylic cover and clean up the swarf using a vacuum cleaner. Swarf is the fine chips of material produced by the machining operations. And there's lots of it. The Othermill can run decently with a lot of swarf in the chamber, as long as it doesn't obstruct the toolhead and motors. I tend to clean it after every operation, but it's up to you how much of a neat freak you want to be. With our first operation complete, we can move onto the next. From here on out, we'll repeat the same process.
Once we've completed all of the files that use the 1/8" flat end mill, we can change the tool out for the 1/16" and run our first pocket. For the second pocket, we'll use the 1/32" bit because it's small enough to make our mounting holes. The Othermill automatically probes the bed for each tool change, so the toolhead is calibrated before we start a new process.