60 Photos - Jan 9, 2013
Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Finally found the problem - the spool on one axis was slipping on the motor shaft and thus slowing drifting.

This picture was taken after a couple of minutes printing and then manually 'homing' the print head. The other two carriages are on their endstops whilst this one is ~5mm away.

Unfortunately the fix is more complicated than just tightening the grub screws on the spools. The motors don't have flats; fixable with a dremel but involves dismantling / re-threading all 3 columns.

Another problem is that the carriages can 'twist' slightly around the columns. Solution for this is to sand down the faces of the carriages so we can increasing the clamping force between the bearings and the OpenBeam.Photo: Kossel carriage detail; using IGUS 623ZZ equivalent bearings on OpenBeam extrusions. It'll be interesting to see how these wear with use.Photo: I'm making a note here, huge success!

Well, mostly. The observant among you will notice the slight non-vertical component of the print. Mostly likely due to a firmware issue after a dodgy git merge. I'll try again tomorrow with the latest version from +Johann Rocholl's Marlin fork.Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Not had much time over the last couple of weeks to work on the new printer. However here's a new motor bracket with support  for an endstop microswitch.

The plan is to use the motor brackets (9 standard, 3 with endstops) for both the top and bottom of the frame, and mount a bearing (608ZZ or similar) at the top to support a GT2 belt. Since I need new uprights I'll length them to 750mm or so for extra build height.

And yes, I've seen (and printed) +Johann Rocholl's new 4-in-1 bracket. But I'd already printed this one ... :(Photo: Photo: Photo: Photo: Better springs for the Kossel 3D printer, holding the carriage halves together.

These are 4.7mm OD, 3.1mm ID, 15mm long. Unfortunately the Ebay seller screwed up, and sent only 10 of the 30 springs I orderd. Sigh; time to "contact seller".

Bolts are M3 x 60mm stainless steel from A2Stainless (www.a2stainless.co.uk).Photo: The start of an Airtripper V3 extruder; just add a motor, bearings, drive gear, bolts, bowden tube, ...

Note to self: Westfield Fasteners (http://www.westfieldfasteners.co.uk) sell the 6mm M3 Low Head Cap bolt needed for the top-right motor mount.Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Photo: Video: Photo: Photo: Photo: Photo: Photo: Photo: Photo: