Bertho's Extruder Drive Upgrade

[bertho 6]

I finally got got my upgrade ready and posted it on Thingiverse.

The detailed info is available here:

http://www.vinland.com/UM_Extruder_Bearing.html

Please let me know if there are any questions or suggestions.

The ball bearing is 12mm OD, 8mm ID & 3.5mm thick.

Bertho

[joergen 2]

I finally got got my upgrade ready and posted it on Thingiverse.

The detailed info is available here:

http://www.vinland.com/UM_Extruder_Bearing.html

Please let me know if there are any questions or suggestions.

The ball bearing is 12mm OD, 8mm ID & 3.5mm thick.

Bertho

I kinda really like the idea! I will mod it for a 10x6x3mm bearing (I ordered it because Taylor pointed it out on amazon, and the thingi it was supposed to go in, didn't work). any good sources for the spring?

any direct link for the thingiverse parts?

also, wouldn't it be possible, and actually easier, to simply use standard rollerskate bearings, and optionally groove them?

[thedudevt 0]

Also interested in trying this design, downloading the files now.

I recently tried this one

http://www.thingiverse.com/thing:25490

and put too much force on it and broke the pin thru the bearing. Even at 100% fill pla is too brittle to make a bearing spindle especially when in shear along the layers.

Thus far, other than the original design which works when you sacrifice a goat and/or get lucky tweaking the adjuster, I've had pretty good luck with tlalexander's wade's type. This one

http://www.thingiverse.com/thing:20850

uses a mk6 extruder gear which I have never had to clean out and retracts very well. I think I've tried everything else with no luck.

The ultimaker would be a lot more useful to me if I could do 12+ hour prints, but so far I just can't get the MTBF on the extruder past 6-7 hours.

Thank you for sharing.

[edit]

[bertho 6]

Joergen:

A smaller OD bearing will move the shaft very close to the plywood body of the drive.

If I remember correctly, the roller blade bearings are too wide to fit in-between the plywood sides which is why I chose the 3.5mm wide bearing.

I intended to put an external grooved sleeve on it but that would be a machined part so I left it off for this Thingiverse version.

The bearing can be found here for $7.41:

http://www.mcmaster.com/#standard-ball- ... gs/=i853dw

It is a Dynaroll SMR128ZZ A5

The spring OD is 7.72mm, has 8 turns of 1.14mm wire, and a free length of 20.9mm. Sorry, no part number since it came from my big junk box...

[alaris2 1]

this looks great Bertho - look forward to seeing the files to make it.

thedudevt > I think your second thingi link was wrong (it's the same as the first..)

[rewolff 0]

I have loads of larger bearings. I'll see if I can adapt it for my bearings....

[bertho 6]

Since I needed to measure the spring used for the Ultimaker Upgrade, I documented the steps both for a high accuracy measurement procedure and a simplified one.

http://www.vinland.com/Spring-Testing.html

Note, the spring for the upgrade is not critical. There is a tremendous adjustment range.

Bertho

[alaris2 1]

very nice work Bertho - really impressed with both pages! am building your extruder right now actually..

[bertho 6]

Thanks Alaris2. Please let me know how it turns out for you.

[rewolff 0]

OK. The bearings I have are 8 mm wide. This would require cutting away part of the plywood that you've left "in place".

I'll wait for the smaller bearings to arrive.

[alaris2 1]

so I've built this. some observations on its performance so far would be:

1) makes a huge difference to build quality. first layer is going down much better than ever before

2) but there seems to be a lot of variability unless I completely compress the spring. my spring is not as long as yours Bertho, but should be as stiff. once it's wound all the way in, the spring becomes irrelevant of course and the marks on the filament come back too. however extrusion is then awesomely good.

(there are still less marks than before - no longer a shoelace effect, but still some patterning. if not tight enough, I see smooth filament with occasional vertical scratch marks on it instead)

3) when wound fully in I can print at 120mm/s with no degradation of perimeter as is the case with the default mechanism. what speeds have you tried Bertho?

4) I have retraction off for now during testing, but I see threads are no longer 'blobby' and spider-like as they are with the default mechanism. they're almost solid. this suggests 150mm/s is almost possible???!

I really like the analysis and theory behind this upgrade Bertho - well done. if you don't mind some constructive criticism however,

1) the long screw is a pain to find. I replaced it with an electrical screw instead and used a soldering iron to melt it into the plastic.

2) the tolerances are really close. the bushing was only 0.05mm wider than the bearing when printed. i spent a long time filing other bits to make everything fit and operate smoothly.

3) the bearing was a bit of a pain too. shame it wasn't something easier to obtain..

4) note to others - make sure you copy Bertho's photos when constructing. you need to put the screws facing the right way and the blocks too, otherwise it won't fit.

7/10 for a really awesome upgrade - by far the best of the 20 or so I've tried so far and very recommended to anyone else - but be prepared to put some effort and workmanship into building it.

[bertho 6]

Thanks for the nice words.

It is good news that it works well for you.

Look for a stiffer spring though so you can obtain the needed force while still having a range of compression. That way it will also be insensitive to filament thickness. I have not had time to do any further testing, as usual business is interfering with my hobbies.

Tolerances:

I wish here was more space but the gear wheel is very close on one side.

I have calibrated my printer and by using the independent X_Y_Z scaling option in Netfabb, the size comes out very accurate. I do not like to adjust the Solid model, just the printing process. The major problem I have with Cura is undersized holes so I have to open them up.

[joergen 2]

I wish here was more space but the gear wheel is very close on one side.

I have calibrated my printer and by using the independent X_Y_Z scaling option in Netfabb, the size comes out very accurate. I do not like to adjust the Solid model, just the printing process. The major problem I have with Cura is undersized holes so I have to open them up.

I just used flat-head phillips screws, instead of the 2mm hex... with a little bit of countersinking, there was plenty of room between the gear wheel and the new part.

[rewolff 0]

I can't find the STL files for the parts... Am I missing something? I'm still waiting for the bearings but I like to have things ready for when they do arrive.

[bertho 6]

All the files are in the zip file, including the STL files.

Good luck!

[rewolff 0]

Yeah! I had expected a "I uploaded it to thingiverse:

http://www.thingiverse.com/thing:26094

" note from you here. Either I missed it (*), or it isn't here. I found that note on google groups just now and then a simple search on thingiverse came up with the proper thing.

(*) Sometimes I look with my nose as they say in Dutch. :-)

[bertho 6]

It was my first uploading to Thingivers and also posting on the forum so I guess I overlook that.

Happy Printing!