El Beast - Initial design phase, comments and critique welcomed!

[Zeeflyboy]

Hah thanks, very kind. Yes I did specifically go with the red seal bearings because OCD lol....

I tried out driving the Z-axis and while it works beautifully (there appears to be no lost motion and no backlash I can measure using my 0.01mm DTI), if I try to ramp up the acceleration higher I get a fault on the motor drive, which was surprising given it's unloaded but suggests that it's failing to follow the steps asked (closed loop drive).

I thought back to a comment about rotational mass and had another look at my pulleys, which were solid steel. The main one was seriously heavy.... so why not an experiment!

Bought some AT5 pulleys and belt, same ratio as before but this time the belt is steel reinforced and more importantly the pulleys are aluminium.

Of course we can't be dealing with stock... so modification time. I wanted to anodise the aluminium to increase wear resistance but of course that required me to remove the steel belt retainers. To make putting the belt on easier I decided to have the new ones be removable.

So first to the lathe for some slimming down of the necks





Next to the router for some drill holes and weight loss cut outs






Bubble bubble




Cut out some belt retainers from some spare stock




Fitted them to the pulley to apply a 60 degree chamfer and do some smoothing:




Anodised and laser etched




Comparison - Old steel 28T HTD pulley, unmodified 28T AT5 pulley, and the modified 28T AT5 pulley.




So moving to the alu pulley was a weight reduction of around 60%, then modifications to the alu pulley dropped that down by about 22% - not bad. Totally not worth the effort from stock pulley I'm sure but it's so preeeeettty...


Proof is in the pudding as they say, and acceleration is happily ramped up with no motor stall :)

Lesson learned - watch your rotational mass, especially if it's placed on a fairly large diameter like a pulley!