TOM's i3 Dolly Prusa MK2 scad

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jlambier
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Joined: Wed Aug 09, 2017 6:08 am

Re: TOM's i3 Dolly Prusa MK2 scad

Post by jlambier » Wed Aug 09, 2017 6:19 am

I'm also looking for SCAD models for Tom's modified parts, but have had no luck.
I understand that Tom never created SCAD models, however I'm hoping that someone else has.
I need to make a slight modification to the x-end-motor and I'd like to avoid having to figure out how to add the end-stops to the original Prusa SCAD files.

Aziraphale
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Location: Wiltshire, UK

Re: TOM's i3 Dolly Prusa MK2 scad

Post by Aziraphale » Mon Aug 21, 2017 10:46 pm

Is this what you're looking for? https://github.com/ardenpm/Original-Prusa-i3

I used the STLs that were the result of that github repo for my Dolly build and they worked great. I now need to make a few changes for when I reprint all of my parts, so I need to either learn OpenSCAD or I need to modify the STLs themselves - I'm not sure which would be easier at this point :)

jlambier
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Joined: Wed Aug 09, 2017 6:08 am

Re: TOM's i3 Dolly Prusa MK2 scad

Post by jlambier » Mon Aug 21, 2017 11:46 pm

Aziraphale,
Thanks for the github link. The SCAD version of Tom's files is what I've been searching for. I wanted to make some minor changes, but had no idea how to do this with Tom's STL files.

arden
Posts: 8
Joined: Mon May 22, 2017 11:15 am

Re: TOM's i3 Dolly Prusa MK2 scad

Post by arden » Sun Oct 15, 2017 1:46 am

Just to note when I recreated the SCAD from Tom's STL files I did make a few changes (mentioned in the readme of the repo). Mainly that I based them in the MK2S parts rather than the MK2 ones. Also rather than drill out the hole for the extruder stepper to shift the extruder housing over to correct the filament path I realigned the path in the extruder itself.

Great to hear it worked for someone else since I had all of one test point before :-)

Modifying the OpenSCAD isn't hard once you get into a groove. However if you do it you will find very quickly you need to comment out large chunks of the geometry to work feasibly on the rest because it is *painfully* slow if you just go at the whole thing (at least for the extruder).

Monkeh
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Joined: Fri Sep 29, 2017 11:56 pm

Re: TOM's i3 Dolly Prusa MK2 scad

Post by Monkeh » Mon Oct 16, 2017 11:26 pm

arden wrote:
Sun Oct 15, 2017 1:46 am
However if you do it you will find very quickly you need to comment out large chunks of the geometry to work feasibly on the rest because it is *painfully* slow if you just go at the whole thing (at least for the extruder).
You can work around much of this by prerendering sections you're not working on - wrap them in render().

There's a whole hell of a lot of mess in the Mk2 sources, I was about to go on a serious cleanup and then the Mk3 was announced.

Aziraphale
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Joined: Mon Aug 21, 2017 11:21 am
Location: Wiltshire, UK

Re: TOM's i3 Dolly Prusa MK2 scad

Post by Aziraphale » Mon Oct 23, 2017 10:22 am

arden wrote:
Sun Oct 15, 2017 1:46 am
Great to hear it worked for someone else since I had all of one test point before :-)
I used your extruder model for my printer and that worked great :)

I'm in the process of re-printing everything now, and ideally I need a mount for my BLTouch clone instead of the inductive probe, so that the BLTouch has a secure fixing rather than just being wedged and hot-glued in place! I've found a model on Thingiverse that modifies the original Mk2 model, so I'll probably try and merge that mesh with your modified mesh rather than try to figure out how to do it in SCAD :P

arden
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Joined: Mon May 22, 2017 11:15 am

Re: TOM's i3 Dolly Prusa MK2 scad

Post by arden » Mon Oct 23, 2017 12:13 pm

Just a note, I updated the x-axis stuff yesterday since I noticed the reinforcement parts added to the MK2S clash with the endstop. You can get away with it but it bends the PCB a bit so I reduced the size of one of them.

I also added a version of the x-axis for use with the smaller size leadscrew nuts you typically get with leadscrews from Aliexpress etc. It switches the internal nut trap to use a square nut which I found offered more clearance as those smaller leadscrew nuts are almost right on the hole. Just finished upgrading to leadscrews yesterday.

Since my inductive probe triggers very low I was thinking of moving to BLTouch as well (I have one sitting around). However I am moving to a 6.35mm milled aluminium bed which I think will trigger a bit higher.

Are you already using the BLTouch? How have you found it and are you using it with Marlin 1.1.x UBL yet? Mounting looks a bit tricky to get right and sounds like it needs to be pretty precise.

Aziraphale
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Location: Wiltshire, UK

Re: TOM's i3 Dolly Prusa MK2 scad

Post by Aziraphale » Wed Oct 25, 2017 12:30 pm

Ah, cool :) I noticed when building my printer that the brass leadscrew nuts didn't match up with the holes in the printed parts at all so I ended up bodging it with zip ties, more drilled holes, and glue... Fixing the holes that align with the leadscrew nuts was something I needed to do before I could rebuild my printer. The diffs of your STLs don't seem to show the holes being moved at all, though, so I'm not sure what you did there. (This Thing is probably the size of leadscrew nut that I have, though I've not tested that yet.)

I originally switched to the BL Touch clone because the inductive sensor wasn't triggering sensibly on my aluminium bed. I've now moved to a Mk42 bed, so using an inductive probe would be even trickier because I'd have to figure out how to tell Smoothieware exactly where to probe to hit those probe points on the bed. I've had one issue with my BL Touch clone in that it enters its "alarm" state (red LED flashing) after about 15 minutes of printing ABS in my enclosed chamber - it's like it overheats or something. I've not found anyone else complaining about that via Google, though, so maybe mine's just faulty? Or maybe it's something that the clones do that the real things don't? Hard to say. Either way, I just have to let the enclosure cool down a bit before each print, move the hotend & probe away from the heated bed, then reset the alarm, deploy and retract the probe, and then the red LED lights solidly and it's all ready to go again. A bit of a pain in the arse, but still better than what I was getting with the inductive probe!

So yes, I'm not using Marlin I'm afraid, so I can't comment on that. Mounting it isn't super hard: I used a hot knife attachment on my Dremel gas torch thing to remove some of the plastic between the inductive probe mount and the nut that holds the part cooling fan in place, then wedged the probe in that gap and hot glued it in place (once I'd got the height set). That worked fine until just today (i.e. it worked for months) when it entirely detached and just started dragging around the half-finished part, so now I'm going to have to reposition it and glue it down better. I definitely need a proper mount for it, though!

This Thing looks like a good starting point for a BL Touch mount, but I'll need to merge your changes to that part with this model.

Edit: Oops, I forgot to mention that you have a reasonable amount of flexibility when mounting the BL Touch probes. There's a good maybe 2mm of vertical play available - you just need to get it so that the probe extends past the nozzle by 2-3+mm when down, and retracts back up above the nozzle when up, but the probe tip moves quite a distance which makes this easier than it sounds. You just have the fact that the nozzle can vary in the amount that it protrudes past the heater block, and that would affect where any mounting point would need to be. I think I'd be inclined to have the mounting point ever so slightly too high up and then make up the difference with some washers between the mount and the probe body - that way you have a reasonable amount of flexibility to it all.

arden
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Joined: Mon May 22, 2017 11:15 am

Re: TOM's i3 Dolly Prusa MK2 scad

Post by arden » Fri Oct 27, 2017 1:34 am

You wouldn't have noticed in a diff since I made a new part with a '-small-nut' suffix for that version. I didn't want to overwrite the original file since it is still useful to be able to use Tom's M5 nut version (though I guess I could change that to have the same hole layout as well.

Have to say I am happy with the switch to proper (though not integrated) leadscrews so far, it's definitely quieter for one thing, though would probably be more so with Drylin leadscrew nuts instead of the metal ones.

Thanks for the BLTouch notes, will come in handy if I decide to give it a go. Are you using Smoothieware on a ReARM or Smoothieboard? I have a ReARM sitting on the shelf I keep meaning to try, just to learn about another firmware.

Aziraphale
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Location: Wiltshire, UK

Re: TOM's i3 Dolly Prusa MK2 scad

Post by Aziraphale » Fri Oct 27, 2017 7:56 pm

Ah, oops, how did I miss that? :)

I never tried using threaded rods for the Z axis, so I've no idea how leadscrews compare - I just preferred the idea of using leadscrews from the outset. I may or may not switch to integrated leadscrews at some point; I'm not sure there'd be a lot of benefit in doing so.

I'm using a MKS SBASE board, which is electrically the same, really, but without actually contributing to Smoothie development :p I plan to drop a decent chunk of change at Smoothie's donate button when I'm feeling a little less poor, and I'll be all over Smoothieboard v2 once that's out. Smoothieware is definitely very nice to use, though. I love being able to update the config just by modifying a .txt on its SD card (which is accessible over USB, and I've then mounted the SD on my Octoprint Pi so I can access my printer's config via SFTP/SCP on my laptop wirelessly - just remember to mount the SD card with the "sync" mount option to force the OS to write the file changes to the SD immediately, or you'll find that nothing changes on the SD card when you hit the reset button - that confused me for ages :))

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