Othermill was kind of enough to let me swing by and try some experimentation on their fantastically small and powerful desktop CNC machine. Traditionally, this machine has trouble cutting rubber. As described in house, "cutting rubber on a small CNC machine is like slicing really soft cheese with a blunt knife". Mental images aside. It seems as though Flexible Magnetic sheeting (ferrous metal suspended in rubber as it sets) is just firm enough to CNC. So why do this? Knitting is one of the oldest forms of additive manufacturing, especially in the garment industry. While CNCing is subtractive, it seemed like using a CNC to create pieces for a knit textile provides and interesting way to explore mixing manufacturing methods to encourage modularity. This "knit textile" can be molded into shapes using magnets, or change dimensions by linking together the individual pieces in different ways. I would image that with enough pieces, one could make a modular bag or case that can form to different objects, sizes and shapes.
To make this swatch, you'll need just a few things:
1.) Othermill CNC Machine
2.) 1 Roll of Flexible Magnetic Sheeting cut into 4"x5" sheets
3) 1 4" x 5" piece of copper. Something used for etching PCBs is perfect
4) Neodymium magnets to test out your final creation
5.) 1/32 inch bit for your Othermill
Let's get started!
Step 1: Prepare Your File
To effectively make this swatch, you'll need to either render your own .SVG file, or use mine. I'm inspired to the point of obsession with modular clothing, so was excited to try and replicate a knit structure for flexibility and modularity, using the flexible and magnetic rubber. As you can see above, there's quite a bit of room to experiment with interlocking structure shapes and sorts!
Step 2: Upload to OtherPlan
Once your .SVG is ready to go, upload it to OtherPlan where you can properly size it to the cutting board. We found that the following settings were most effective:
- Set on engrave to the depth of the magnetic rubber
- 1/32" bit
- 3 passes
- .12 inch depth progression each pass
With these settings, the Othermill cuts through the rubber, but not through the adhesive backing that comes on the magnetic rubber.This allows you to remove the adhesive backing from the individual pieces. It's a bit tedious, but with care, the links can come out quite nice!
Step 3: Mount Magnetic Rubber on a PCB Board & Print
Mount your magnetic rubber piece onto a pre-cut PCB board and put this onto the cutting bed using double stick tape. You want a firm and flat connection with the cutting bed for a quality cut. Once that's set, let the machine calibrate and press print!
Things get rather, well, fuzzy, as the rubber tends to shred a bit. With a bit of dusting, this can be cleaned up pretty nicely.
Step 4: Clean and Remove
Remove your board from the machine and give it a good dusting so you can clearly see the engraved lines.
Step 5: Separate Links, Chain Together and Explore!
Remove the magnetic sheet from the copper plate and take care to remove the individual pieces from the adhesive backing that's part of the magnetic sheet. With care and patience, the resulting individual pieces and "knit" up into a small swatch of a somewhat flexible and magnetic textile. With enough prints, it seems possible to make something more substantial in terms of form and utility!