I decided that the upper pulley provided too much friction, as well as some misalignment. As observed here. The belt touches the sides of the washers. This gives the belt friction as well as slack.
This is how it’s put together.
I decided to print a new grooved pulley that would fit in the roller skate bearings I had. I rather like those bearings, they don't have much play in them as well as they are sealed and don't have much friction.
This is the solution. 100% infill.
Another shot from the back. There is a 1mm lip there that keeps it from wondering. I also used ABS/Acetone mix to lube up before press fitting the bearing in.
Here it is in place. Not a bad fit. I am using the small washers for the proper fit so it does not rub on the holder; however I took the liberty of adding some grease behind it just in case it wonders. I doubt it will wonder as I pressed the bearings in when the part was still hot and used acetone/ABS mix to glue it in place. However I would hate for it to wonder and kill my print due to a jam.
Well I have a baseline tune on the firmware. Its not bad, however its not as good as I would have hoped. It is still uneven across the full motion of the head. This is bothersome as at this point it is showing that my mounting of the bed is nowhere near close as I would have hoped, there is some .3mm variation from the front two towers and the back tower. I think I may remove 1 layer of cork from the heat bed itself and allow the glass to sit lower. I may have miscalculated when I built this part. I also have to mention my end stop adjusters are not exactly easy to use. I may investigate a new way to do the job at some point. A small screw changing the height of the end stops may prove beneficial. Also the hot bed may get a screw type of adjustment instead of the shim type.
A few things to NOTE:
- The hot bed certainly needs a form of adjustment.
- Tuning should be done when the bed is fully warm as well as the head to operating temp.
- There is a slippery slope to printing when doing large prints.
- Reducing friction comes way before reducing weight.
However I can't help but feel pleased so far. I have not put up a new video on the YouTube channel this time. I may do a tuning video at some point.