Fail: When it’s not strong enough

27th November 2019 0 By Neil Stevenson

Ok, we’ve 3D printed a new chassis, made various attachments, updated the wheels and motors, switched to the Redboard+ controller and written lots of software. What could go wrong when we tried an impromptu obstacle course…

FAIL: after bumping into a few walls at high speed, the new bumper/PiNoon attachment broke in two. A few more bumps and more pieces fell off… only lasted 3 hours from print to destruction…

So the problem appears to be that PLA is quite brittle, especially thin areas. Not good a choice for a bumper. Solution is to try another material, such as flexible TPU which should be more impact-resistant. We’ll see.

FAIL: The impromptu ramp had no safety walls, so Dangle fell sideways, and again, and again. The new laser-cut 3D wheels just didn’t stand a chance… Cracks appeared around the wheel hub…

Fractures on wheel spokes

So, 5mm acrylic may seem quite tough, but it’s still quite brittle, especially at stress points. Solutions include removing those stress points by adding curves around the cutouts, or by doubling up the wheels to make wider. Also, the tyres didn’t have much grip, but that’s another story…

FAIL: Zgun and jaw mounts both also failed to survive the onslaught…

Gun and jaw mount fail

OVERALL RESULT: Obstacle Course 3 : Dangle 1.

Great to identify and iron out these weaknesses early on. We don’t want breakages on the day. We’ll also come equipped with lots of spares…