I added some epoxy tubing to reinforce the the delta arms on my Tiko. The tubes are approximately 200mm long and have an inside diameter of 0.219 inches (5.56mm). You can get them from Tap Plastics, but you will need to cut them yourself (one 32.5″ rod can be cut down to 4 – 201mm rods for the Tiko, you’ll need 6).
The rods don’t fit perfectly, there’s about half a mm gap between the rod the and delta arm. The arms are just under 5mm in diameter, so rods with a 5mm inner diameter might fit, but the connecting ends (at least the one near the hotend) are about 5.3mm wide and I’m not sure how much they compress enough to fit. I plan to wrap some tape around the delta arms under the epoxy tube to fill the gap, but haven’t done that yet.
So do they improve print quality? I didn’t see any improvement in the one controlled test I tried. I probably won’t try many more controlled tests as I’m not sure I can keep disassembling the delta arms without eventually breaking one. But I’ve left them on for now since they definitely make the arms stiffer. I also like the way they look.
One downside of the stiffer arms is the printer occasionally gets stuck going to the home position if the main bowden cable gets in the way. With the original arms, the arms would bend, allowing the printer to still reach the home position.
I tried putting tape around the delta arm before attaching the epoxy tubes, some thin masking tape worked well to give it a snug fit. Unfortunately running with stiff delta arms seems to just generate more layer shifting, it seems to require more torque than the motors have available. So for now, I’ve removed the tubs and will experiment with them more later.