RepRapPro Mendel X-Carriage Problem

Oh no, my reprap just broke 2 hours into a 3 hour print. The bottom linear bearing slid out of the x-carriage. Looking at the design I can't really see what holds it in place and stops it from sliding out.

Has anyone else had this problem? Maybe someone can suggest an improvement on this part to stop the bearing from coming out.

Any advice appreciated.

Hi There,

I've being using my RRP mendel for a few months now. You're right the bottom x carridge bearing is held in just by pressure from the top bearings. If your main X carridge block is a bit loose it can slide out (as you are painfully aware!)

A simple fix would be to take both extruder mounting plates off and drill two small holes into the x carrige block just above the grooves in the linear bearing. Then you could clamp the bearing on with two pieces of light 0.5mm solid wire looped through the holes and twisted together under the bearing. You may be able to use nylon cable ties for this, but given the temperature around this part, wire is probably safer.

It would only take a minor re-design to stop this from happening. Two lips either end of the linear bearing would hold it in place safely, although you may need to change the build order to assemble the x axis with this new part.

If I can find a copy of solid works I may have a go at doing this for you.

Hope this helps.

Pete

Providing files in a closed, proprietary backward incompatible format for an open source design is an oxymoron. Seriously, WTF! It completely defeats the whole purpose of openness.

The least they could do is provide the files in STEP format, which is an open (and ISO standard) file exchange format that any worthwhile CAD program can open. There won't be any history/feature tree but at least you'll be able to open them and edit them.

You should request STEP files from RepRapPro. That way you wouldn't have to pirate SolidWorks, a $4000 (basic version) program.

I was able to open the x-carriage.SLDPRT file from the github repo in Solid Edge V19 (a 7 year old version from my workplace) and export it to STEP. It can be opened in most CAD programs. There are a few free choices out there if you're on Windows. Personally I use FreeCAD which may not be as polished or complete than the commercial offerings but it is open source and available on Linux.

Edited 2 time(s). Last edit at 08/22/2013 12:26AM by NormandC.

@srayner02: The simple fix is to wrap a couple of layers of Kapton tape on the linear bearing to make the friction fit more positive. As PLA is quite slippery, it can slide on the metal of the bearing. Make sure the linear bearing is moving smoothly on the rod; refer to the instructions on cleaning and lubricating them during construction:

"Check that the linear bearings slide smoothly on each of the smooth rods. The linear bearings may need a little extra oil, and the smooth rod may need cleaning, for smooth running. The quick way to clean the smooth rod is to put it in an electric drill, then use wire wool or a kitchen scourer on it while the drill turns the rod. Be careful though! "

From [reprappro.com]

The part is designed this way as no clamp can extend around the bearing due to the proximity of the hot ends; during extensive testing when we built this, any thin captive part ended up warping. A couple of lugs that fit into the grooves of the linear bearing would help, though.

Yes, we use SolidWorks 2013 at RepRapPro. We are in the process of converting all the files to STEP files; they should be in the github repository later today.

Ian
RepRapPro tech support