John's Alu Profile build

[Evengravy]

So,

New ballscrews have arrived, TBI motion ground 2005 with double nuts. These ballscrews have BK15 mounts at both ends rather than a floating end and each BK15 holder, four in total, has a pair of Japanese 7002 angular contact bearings. These parts were bought lightly used from the same seller that I bought a lot of the other parts from in South Korea, but are clearly much better than the Chinese ones that I'm going to pull off the Y axis. One of these screws will be on each side of the Y axis as before so it should improve the smoothness of motion and the extra thickness of the screw (going from 16mm to 20mm) should enable me to increase the speed of the rapid movements a little without encountering whipping.



The only downside of the change so far is that I've lost a bit of travel on the Y axis, down from just over 1100mm to just over 1000mm. I'd rather have the piece of mind of these motion parts than the extra cutting envelope so I'm okay with it.

As a result I've needed to redesign a few parts though. As per Jazz suggestion I've added a new bracing for the gantry which will tie in to the Y axis linear bearing plates. This part only braces towards the back side of the gantry, as the new ball-screw connection will be made to the front side via a plate as shown below. I might figure out something for the front too at a later date.



I've designed some new shoes for the ballscrews to fix to to mate them with the Y axis profiles.



I've also rethought the design for connecting the ballscrew to the Gantry. I was never too happy with the previous welded solution, they were a mess.



Lastly, since I've moved up to a larger screw my motor mounts have to change too. These attach to the end of the Y profile on each side and carry the Y motors.



Since I can't buy materials at the minute I've decided to try to get all of these laser cut in the UK and shipped over. The company are running but with minimal staff so it might take a while to organise.

Gantry to ballscrew mating part will be made of 15mm mild steel laser cut and I'll paint that later. The rest will be laser cut from 10mm stainless steel. That's the plan at the moment, it's hard to get companies to do much at the moment so we'll have to see.