RPP Mendel 3 maintenance (z-axis drive-couplings & x-axis probe-stop)

Hello all, I've been a reprappers for more than a year now, and have been very pleased with my printer. I am printing on a RepRapPro(RPP) Mendel 3, and have enjoyed it very much for the past year. Thinking back I probably would have gone with the Ormerod 2. The Mendel was a fairly complex printer to build for a beginner, and with some of the large prints i have done I would have liked the extra print space of the Omerod. Sadly RepRapPro is no longer in business, so every small mishap with my Mendel is a bit of a scare sending me looking for a replacement printer each time. The good news is there are plenty of good cheap printers out there to buy; though I'm a little wary of some of these independent sellers on eBay, and I have also become attached to the web-interface for RepRapPro.

I recently had an accident that set me back enough that i did buy a new printer. However in the time waiting for it to arrive in the mail, I figure out a fix for my Mendel 3 and was able to get it printing again. That fix is why I am writing this post. I hope that my story will help other RPP Mendel users keep there Mendel 3 running.

So the Accident..

There are some design difference with the RPP Mendel 3 from the GPL Mendel that I think contributed to my problem. Firstly, and I'm not sure if anyone else has had this problem, but the z-axis sliders tend to bind on the travel, and no amount of adjusting seems to fix it. Oiling mine actually seemed to make the problem worse. On the GPL Mendel these sliders are linear bearings. I don't know if this was changed as a cost savings? but it was giving me trouble on my printer.

The problem wasn't so bad that I couldn't print, but it did require that i put extra downward force(with my hand)on my x-axis-assembly during setup for each print(I still have to do this each print). My accident was preceded by numerous warning signs(mainly creeping print-bed-alignment) until one day my entire x-axis fell off during setup. I tried reattaching and tightening the clamps, but they ended up cracking.

This is when I started looking for a new printer.

Anyway, I got the idea to use screw-on-clamps for plumbing, but the tubing diameter was too small for clamp, so I have instead used zip-ties, and so far they are holding.

During the install I managed to snap off probe-stop for the x-axis. I used a paperclip, a lighter, and some tape for this one, and it also seams to have done the trick. I don't know if this constitutes it a frankenRap.

And it STILL prints! =)


Hope this post was helpful.
Thanks

Good stuff

A few comments, never tighten those u style clamps too much they just need to be nipped up tight enough to hold the rod in place no more.

I use aluminium expanded couplers on the Z axis on my RepRapPro printed mendel they have enough give to avoid introducing issues in the z axis and they are smooth.

I moved to a z max stop and run the printer using mattercontrol with auto bed levelling although mine is an early mendel with no z probe etc.... and it uses ramps for the controller.

Ben

I also see you mentioned issues with the igus bushings not sliding very well, I never liked the fiddly nature of those so I mashed up my own x axis ends to include linear bearings.

Ben

Quote
plexer
I also see you mentioned issues with the igus bushings not sliding very well, I never liked the fiddly nature of those so I mashed up my own x axis ends to include linear bearings.

Ben

I'd love to get my hands on that STL. At this point i might just stick with what i've got, but I think linear bearings would have fixed the whole problem from the start.

mattercontrol sounds interesting, I'm really a fan of the RPP version of Marlin

If you are going to stick with the RRP Mendel, get a couple of the flexible aluminium couplings that someone else mentioned. These things [www.ebay.co.uk]. Also, on mine I made some horseshoe shaped spacers to go around the rods between the clamps, about 4mm thick. Then you can do the clamps up as tight as you like without putting too much strain on the bend. When I upgraded mine to a tri-colour, I found this was necessary for the clamps at the top of the Z rods because the nuts need to be tight to hold the plywood extruder mounts. HTH

Thanks for the tip deckingman!

...and I guess i've been miss abbreviating RepRapPro(RRP)

Edited 1 time(s). Last edit at 11/14/2016 02:50PM by kippbits.