Quick Release Idler
I had a horrible jam with PETG that required a rebuild of most parts near the hot-end. One of the things I found frustrating was access to the hot end parts and loading of filament. So, since they will need to be printed again and MK2.5 is a month away, I designed a quick-release idler clamp and modified the heat-sink capture collar to allow slip out ease.
The design revolves around a custom U-bolt made from end threaded 120mm M3 rod and 10cm thumb nuts. A couple bends on a rod bender should be simple enough.
Once my printer repair parts arrive (broke heat-brake and thermistor wire), I will share real-world usability then post once input and corrections are applied.
Window was retained but not really necessary anymore.
Here, the extruder-body's collar is reduced since the extruder-cover provides most of the clamping location. The older design doesn't allow easy removal of hot-end due to being partially trapped by PTFE guide tube. Not impossible but needlessly difficult. The new design retains upward force however as crash forces can be extreme in some cases.
MK2S kit owner since 8/15/2017
Re: Quick Release Idler
I like the idea with the reduced collar. I also had a serious jam (because of a nonsense prusa edition slic3r profile - seriously eroding my confidence in prusa optimization) with my mk2s and needed to disassemble basically the complete printhead. Becaused of a botched screw (I bought the assembled printer) I had to saw things apart... quite messy (consequently I ordered the MK3 as kit, so at least I'll know what's messed up with assembly). Being able to take out the hotend without disassembling the entire Z block will certainly help.
BTW, do you have a good idea where to get models for non-printable parts from? As soon as the MK3 printable parts are published, I'd like to start with the design of the MK3 volcano head.
BTW2 nice render images. Can you also generate 3D PDFs?
- Martin
- Martin
Re: Quick Release Idler
Update on my replacement (upgraded) parts for distroyed extuder body post PETG jam.
The prototype print took 11 hrs and had many failures where auto-supports were used. As I used the manual support method in Cura 4 which is clumsy but sort of works the print was salvaged for testing. Not worth sharing as most will just get MK2.5 or MK3 so it will likely never to cleaned up for posting.
The print was done with a damaged and bandaged togther original extruder-body part so there is a lot of hotend wiggle error but good enough as a structural part.
But might as well show you guys my design installed.
Yes, that is a Capricorn PTFE low friction tube. And, the "see-through" filament guide is temporarily colorFabb XT Clear, Plexiglass machined version is planned that will actually be clear.
Also, along with the slip out hotend mods to extruder-body collar, I switched all detachable parts to MOLEX connectors based on AWG.
The photo shows my temporary solution with zipties and unoptimized wire lengths. A more perminent flat ribbon slip hold wire guide printed in TPU is being designed.
Hope you guys like.
MK2S kit owner since 8/15/2017
Re: Quick Release Idler
...
Also, along with the slip out hotend mods to extruder-body collar, I switched all detachable parts to MOLEX connectors based on AWG.
The photo shows my temporary solution with zipties and unoptimized wire lengths. A more perminent flat ribbon slip hold wire guide printed in TPU is being designed.
Hope you guys like.
This kind of reminds me of the Quick Change Extruder I was working on awhile back. I do plan on retooling this for the MK3 eventually.
and an 8 inch (200mm) or greater caliper is recommended.
Re: Quick Release Idler
This kind of reminds me of the Quick Change Extruder I was working on awhile back. I do plan on retooling this for the MK3 eventually.
Interresting design, go ahead !
Thomas
Re: Quick Release Idler
I am seeing this as a MK3S upgrade ... haha 😀
nice work
Re: Quick Release Idler
Nice connector work! I thought about using D-Sub connectors, but maybe separate connectors are easier. Which connector types did you use? I spent today looking for interesting wire-to-wire connectors, which is about as fun as learning the ZBrush transpose tool (just discovered the secret ALT function). There's this nice writeup on crimp connectors: http://tech.mattmillman.com/info/crimpconnectors/ . Mini-fit Jr. would be a candidate - one could even combine all signals in one single housing. Might be a bit on the large side though.
- Martin
Re: Quick Release Idler
Nice connector work! I thought about using D-Sub connectors, but maybe separate connectors are easier. Which connector types did you use? I spent today looking for interesting wire-to-wire connectors, which is about as fun as learning the ZBrush transpose tool (just discovered the secret ALT function). There's this nice writeup on crimp connectors: http://tech.mattmillman.com/info/crimpconnectors/ . Mini-fit Jr. would be a candidate - one could even combine all signals in one single housing. Might be a bit on the large side though.
The Bill of Materials is linked from within that document. Check it out.
and an 8 inch (200mm) or greater caliper is recommended.
Re: Quick Release Idler
Aaron's build is full swap while mine is maintenance centric. I also went down that rabbit hole but thought MK2 series was too fragile for any kind of machining head, MK3 is another story. This build was a limp-home setup to tide me over until 2.5 and 3 became widely available next year.
I posted this info somewhere else but my full swap head was based on D-Sub 680S17W2103L201 and 680M17W2203L201.
But that project is on hold to see what MK3 SCAD files look like. As for the thing in the photos...
HotEnd
2 pin power connector also known as Tamiya battery inline connector
Molex Mini-Fit Jr. (4.2mm pitch) 18-24 awg
Thermistor
2 pin inline connector
Molex Micro-Fit (3.0mm pitch) 20-24 awg
Fan connectors will depend on your build, I have FLX (Noctua) fans so I use Molex KK 2.54mm pitch 1 row straight 3 way connectors. Would prefer PWM but maybe Prusa chose VR instead due to signal noise and PINDA probe? Not sure. Also worth noting, Molex never specified an inline male connector as these were designed for PCB mounts but non-standard inline styles can be sourced from Chinese makers easily. A note of caution, KK series never being designed for use inline is a terrible choice on a moving assembly. You must secure them together in some way as they will slip off. I used zipties, cuz Prusa.
MK2S kit owner since 8/15/2017
Re: Quick Release Idler
Aaron's build is full swap while mine is maintenance centric. I also went down that rabbit hole but thought MK2 series was too fragile for any kind of machining head, MK3 is another story. This build was a limp-home setup to tide me over until 2.5 and 3 became widely available next year.
I posted this info somewhere else but my full swap head was based on D-Sub 680S17W2103L201 and 680M17W2203L201.
But that project is on hold to see what MK3 SCAD files look like. As for the thing in the photos...
The MK3 SCAD files have been released. I'm still sorting through them. As for the connector you show here, I looked at something similar. A $30 space age connector that I considered too pricey to use. I went with the connector that could fit the best on the rear of the X-carriage (width wise) and still not cause problems with lots of current. I had the help of an electrical engineer on this project.
and an 8 inch (200mm) or greater caliper is recommended.
Re: Quick Release Idler
@Aaron
It may be time to link your thread, I'd like to keep this thread about "Quick Release Idler".
Oh, and thanks for the tip on SCAD files, I wasn't going hunting for them until I got the announcement. Might have been lost in my junk box.
MK2S kit owner since 8/15/2017
Re: Quick Release Idler
Jonathan made a Solidworks assembly, you can load that directly (GrabCAD). See here:
https://shop.prusa3d.com/forum/original-prusa-i3-mk3-f30/cad-models-for-mk3-parts-t6875-s40.html
I'd say little changes with regards to stiffness - except for replacing the threaded rods for the Y carriage. But hardly usable for machining - unlesss you think of a 200k rpm 0.5 mm engraving tool.
- Martin
Re: Quick Release Idler
Off topic, but downloaded Jonathan's about 5 minutes after reading Aaron's post. Found incomplete work but much appreciated. 80% of conversion is much better than waiting for OpenSCAD > FreeCAD > STEP. I also tend to find lots of junk surfaces as well as droop compensation imbedded in Prusa files. This could be SolidWorks or OpenSCAD junk or intentional but I tend to prefer "ideal" geometries prior to modding.
Still frustrated with slicer tech though. Droop compensation and conflict wizards should have been built in by now. I'm looking at you Simplify3D!
Yeah, agreed. After having a closer look via Johathan's work, MK3 is no better for useful structural machining. Small part of me dies inside.
MK2S kit owner since 8/15/2017