I have a 40 watt laser (Glowforge) that can’t touch carbon fiber or aluminum but supposedly cuts Delrin panels like a boss. Delrin is an Acetal engineering plastic with high strength, stiffness & wear properties.
Wondering if anyone has experience with this material here? I might fabricate an arm section and load it up to test the strength. How much force must it be able to take in order to safely support the thrust from the props? 40 - 50 lbs perhaps?
Each motor can create up to around 37lb thrust plus it creates torque which your design needs to withstand. I would probably recommend a safety factor of 2 but that’s up to you. The biggest thing is to have the design capable of handling the motor torque and gyroscopic effects that come from turning and maneuvers.
I used parallel Delrin plates connected with standoffs on a UAV project a while back. The setup was similar to the OpenPPG motor arms. I was not impressed; they pretty quickly ended up permanently warped and were not very stiff in torsion.
not very strong strong stuff compared to aluminum or carbon fiber.
might be able to mark aluminum with the laser to use as a guide to cut it…I found a fine tooth carbide blade on even a cheap plastic table saw cuts aluminum very well. There are aluminum cutting blades that work better.
Don’t do it!! You need to imagine the ~15 Kg load each arm has to bear without deforming. I have worked previously with 10 mm thick delrin plates (150x150mm), and could easily bend them several mm just by hand.
The carbon fibers in CFRP hugely improve the material stiffness, compared to aluminum and even steel (in the direction parallel to the fibres).