CTC DIY Printer improvements

This blog to document what I have done with the printer to try and improve it.

The current state is that I have been printing face masks and they are not very good because the sides are rippled.

I tried to adjust the baseplate height but on one side the adjustment screws were completely tight and on the other side almost completely undone. At this point I measured the height of the horizontal guide bar (X-axis) and discovered that it was 6mm higher at one end than at the other, so I adusted that by turning one z-axis screw until both sides were the same height from the base. I then adjusted the z-axis  position of the nozzle so that it was with the plate about half-way done up on the adjustment screws. A business card  worked well to get the nozzle-baseplate seperation correct.

One of the problems that I have not been able to resolve is that the threaded z-axis rods are not straight but have a bow in them. Each level of deposition of the print is 1/8th of a turn of this screw.  I have removed and tried to straighten this rod, but have not been successful. The results are obvious in the picture below as you can see on the white knight . The black knight  was the very first thing printed on the printer.

What can be noticed is that the ripple up the sides of the white knight is very close to the pitch of the thread of the rod. One implication could be that as the rod turns  it moves the nozzle head from it's perfect position and  gives a bit of an offset to each layer.

In the next picture you will see that at the top of the threaded rod where is is held by the top board I have added a bushing to hold the top of the z-rod more firmly. This means that the bowing of the rod will push against the other vertical guide rod and force the print head mechanism out of position.   If I remove this bushing that I have added, then the bowed rod would have room for play in the top mounting, and hopefully will not affect the print.








Picture one - Closeup of Knights.

Picture 2 = Left hand frame showing guide rod and threaded z-rod (bowed) with blue bushing.

Removing the bushing sort of goes against good engineering practice, but if it allows the z-rod to flop around and not affect the print nozzle, it may have to be that way. There is also a bushing on the rod on the right side of the machine, but we will see if this sorts the problem to some degree.