Prusa i3 MK2 Scratch Build

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jasonrp7743
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Prusa i3 MK2 Scratch Build

Post by jasonrp7743 »

Well- this is sorta related to the IBM PCjr, because, once it is ready, I plan to print a new side cover! :-)

I've played around with 3D printing for a while- but my existing 3D printer, a kit (Printrbot 1405 Simple) is indeed very simple. On the negative side, It has a laser cut wood frame (which actually looks amazingly cool!), a small 100mm x 100mm x 100mm build volume, and no heated bed. On the plus side, it has a bed levelling sensor, a very reliable extruder, and I've got it pretty well dialed in. I can make good (but small!) prints, in PLA only. Within these limits, it has served me well (and it was cheap, and I got to assemble it)..

Now I want to move into a more capable printer. I've daydreamed about the Prusa i3 for a LONG time. Now I'm finally going to build one. I don't want to order the kit though; In true RepRap fashion, I plan to build my own, using the Printrbot to print as many of the parts as I can, and also using wood for the frame plate (the Prusa design actually uses metal rods held together with printed pieces and nuts.) Its wood frame is really just a stiffener for the X-axis, for which it is 100% equivalent to an aluminum plate for the forces it would generate. However, >200mm in all directions build platform, I've ordered a mk42 heated bed, and a genuine E3Dv6 hot end. I'll use a mk8 extruder as well, and a meanwell power supply. I also got a genuine "minuRambo" for the CPU. SO: It is economizing where I can, but I've spent the money on the parts that count. I'm still around $100 less than a Prusa kit costs.

Anyone else 3D print here? If so, what are you using?
Jason
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chuckphd53
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Re: Prusa i3 MK2 Scratch Build

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I have 4 prusa i3 MK2, 1 prusa i3 MK3, and a Makerbot Rep2 I use for ABS.. these are our work machines....

but for all the machines the typical bearings used are junk, ball bearings ugh...
I spent a little more money to upgrade when I built all the prusa's and use a PBC Linear bearing
"FJC08" Bearing.. from www.pbclinear.com
they are smooth as butter...and help with the layer transition lines you sometimes see on the flat sides when
making square items like boxes etc....
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Re: Prusa i3 MK2 Scratch Build

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Those special sliders look nice!

I've got a huge pile of parts that I'm collecting to build this thing. Even the stock prusa with cheesy linear ball bearings will be exponentially better than my current printer: Image

:lol: Funny thing is, it actually produces quite nice prints! But- can only do PLA, and build volume is small.
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Re: Prusa i3 MK2 Scratch Build

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I love the Print bot, had wanted to buy one years back, just never did.
but always thought it was a great little printer.
Super Picture, great laser cut parts....
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Re: Prusa i3 MK2 Scratch Build

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The old Printrbot is actually a fantastic printer for what it is... It so far has produced outstanding parts for my Prusa build. Some say that PLA is no good for mechanical parts- but I've used them on other contraptions without an issue.. I've got a friend with a Prusa that will 3D print the extruder parts for me, but otherwise I'll use the PLA parts I've printed on this printrbot to build the Prusa. I figure, at the very least, they'll work long enough to use the newly built Prusa to print new parts in PETG..

Obscure question: Do you happen to have and Prusa frames lying around where you can take a picture of that yellow caution sticker (on the front of the Z-axis frame, on the right side- 3 warning pictures on a yellow sticker)? I'm trying to find a pic of this sticker from a straight on perspective, but cannot find one. I'd like to print this sticker to put on my homebrew- make it look more authentic! :-) (Yes, I am a nerd!)
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Re: Prusa i3 MK2 Scratch Build

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sure can do will send it monday when I get to work
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3d printing

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I need to do a special purpose "small box" for a project. I'm not afraid of the printer but scared to death of the software (ironic as I'm a software guy primarily). Whats the down-low on how to get where I need to go? I need a small box that will contain a particle photon with a reset switch and hole for the USB connector. https://store.particle.io/products/photon. Any help much appreciated!
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Re: Prusa i3 MK2 Scratch Build

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jasonrp7743 wrote: Sat Mar 28, 2020 11:19 am The old Printrbot is actually a fantastic printer for what it is... It so far has produced outstanding parts for my Prusa build. Some say that PLA is no good for mechanical parts- but I've used them on other contraptions without an issue.. I've got a friend with a Prusa that will 3D print the extruder parts for me, but otherwise I'll use the PLA parts I've printed on this printrbot to build the Prusa. I figure, at the very least, they'll work long enough to use the newly built Prusa to print new parts in PETG..

Obscure question: Do you happen to have and Prusa frames lying around where you can take a picture of that yellow caution sticker (on the front of the Z-axis frame, on the right side- 3 warning pictures on a yellow sticker)? I'm trying to find a pic of this sticker from a straight on perspective, but cannot find one. I'd like to print this sticker to put on my homebrew- make it look more authentic! :-) (Yes, I am a nerd!)

Jason..

I was going to take a picture but the Guide rails in in the way and the only way to take a straight on picture is to disassemble the unit ugh...
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Re: 3d printing

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toddvernon wrote: Mon Mar 30, 2020 8:59 pm I need to do a special purpose "small box" for a project. I'm not afraid of the printer but scared to death of the software (ironic as I'm a software guy primarily). Whats the down-low on how to get where I need to go? I need a small box that will contain a particle photon with a reset switch and hole for the USB connector. https://store.particle.io/products/photon. Any help much appreciated!

Todd....I use Sketchup as my design for 3D printing....it is very intuitive...so easy to use...after a few hoops learn to jump thru...
but you can get very proficient quickly..

if you give me dimensions I can make a box for ya.....
I tried to make a video on how to make a box but the cursor did not show in the video.. (first time to use)
but here is the link, just keep an eye on the lower LEFT Box it has dimensions for making squares and circles, offsets etc...
sorry bout the quality again first time user..
if you want have aphone call I can explain what the heck is going on in real time :)

https://www.pcjribm.com/pcjrfiles/MakeBox.mp4
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Re: Prusa i3 MK2 Scratch Build

Post by jasonrp7743 »

chuckphd53 wrote: Tue Mar 31, 2020 9:39 am I was going to take a picture but the Guide rails in in the way and the only way to take a straight on picture is to disassemble the unit ugh...
No worries, Chuck- I managed to grab the image from Prusa! Please don't take apart your printer! :-)
I could use the x/y dimensions in mm if you have a chance.. If that requires disassembly, no worries- I'll wing it!

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Re: Prusa i3 MK2 Scratch Build

Post by chuckphd53 »

54mm x 78mm
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Re: Prusa i3 MK2 Scratch Build

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Just figured I'd post an update. Here's the Prusa i3 mk2 clone, as of last night- I'm finally done with the mechanical assembly. Now I just need to do wire routing, mount the power supply, rambo board, and heated bed, and then plug in all the connectors, and it's ready to work on it's first print! (well, ready to calibrate first, then do it's first print!) It came out looking pretty cool if I do say so myself (note the joke warning sticker! I don't have a color printer, but printing yellow on a B&W laser came out matching the frame color!) :lol:

Image
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Re: Prusa i3 MK2 Scratch Build

Post by chuckphd53 »

Looks really good, what material is the main frame, I like the marbled look...
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Re: Prusa i3 MK2 Scratch Build

Post by jasonrp7743 »

Frame material is OSB, sanded and painted. Plywood would probably look better, but I think OSB might be more rigid? At 3/4" thickness, I think it is plenty strong. I put the heated bed on it, and got it to run and pass it's XYZ calibration- it got the top score- with measured 1% skew, it considered X/Y as perpendicular. I was pleasantly surprised!

I got to say, there is a LOT to these printers.. A lot of parts, a lot of things to get working just right..
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Re: Prusa i3 MK2 Scratch Build

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A comment for the wiring... the Prusa kit gives you the plastic wrap for the wires. this tends to be stiff when the motors are moving..
I use the mesh net on a couple of my Prusa's and it is a little more forgiving and puts less tension on, say , the extruder as moves left and right...

it's obvious, but just be sure the wiring has large loops that allow all the movements to be free.

the fact that you have the X/Y correct is a HUGE accomplishment.. good job.... I built 5 Prusa's and this is always the weak link, getting the
frame square and having smooth movement...

Soon you will be melting filament :)
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Re: Prusa i3 MK2 Scratch Build

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Chuck- you were so right about the plastic wrap- I plan to switch to the textile wiring sheath as soon as I can get some in hand. But- it is up and running! Here's a still picture of how it sits now- printing parts for itself (I just need to switch over to the "rambo board" box I printed, and had to do some tinkercad to mod the Prusa power supply holder to fit my power supply. I'm currently printing the LCD cover as I type this.
Image

I simply cannot believe how well this design prints! I mean- parts are straight, and look fantastic! I've not even really dialed the thing in yet beyond the standard start up tests, and first layer config. I might not even need to dial it in beyond that.. Here are the rambo box parts:
Image

Here's a vid I put on YouTube- I've loosely been posting updates on the build as I go:
https://www.youtube.com/watch?v=9z5fdw8dnyA&t=29s

This has been a super fun project!
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Re: Prusa i3 MK2 Scratch Build

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that is fantastic..... and yes the Prusa design is super, I use mine at least2-3 times a month for work and play...
and in the video I see that great PCJR disk drive box in the back.. :) I heard of that elusive animal but never seen one in the real life :)

The prusa build is not that bad once you get the X/Y axis square.... and I guarantee you will be printing stuff you never thought you would
before and it will become indispensable.... great job......
here are a few youtubers I like to watch..
Makers Muse
3D Printing Nerd
Thomas Sanladerer
Simplify 3D

keep us updated on the final build....
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Re: Prusa i3 MK2 Scratch Build

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Almost there! So far, I've for 35 hours printing with this printer.. It's printed the Rambo box (mounts and houses the system board for the printer), the LCD cover, and a couple of power supply mount prototypes. I had a weird failure, where it suddenly stopped extruding- and would only click the extruder hobbed gear. After a little bit of switcheroo to troubleshoot, I found that the stepper harness had a broken wire in it- perhaps I was a bit too zealous in my tightening of one of the zip ties- it's all fixed now. I'm printing a benchy (well known print of a small tugboat model as a benchmark) to see if it improves the result- because I suspect a wee bit of inconsistency I've been getting is from that wire not making 100% contact before it failed entirely.

Here's where the printer sits right now- still waiting on the power supply mount, but, it's almost ready (just need one more test fit, to see if the last set of adjustments to the file are good)... Oh! And I need to implement a better filament guide than my cheesy lego tempo solution! :lol:

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Re: Prusa i3 MK2 Scratch Build

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...and, I'm done! Here's some glamour shots! :-)

Image
Image
Image

What a fun project! So, the grand totals:
  • Parts printed by the old, PrinterBot 1405 Simple Maker's Kit: 15 (PLA, basically the whole Y-Axis, the LCD mounts and knob, and the heated bed wire cover.
  • Parts printed by a friend, because he has a printer with a heated bed: 12 (11 PETG- the extruder, X-Axis, Z-Axis; and 1 ABS- the parts fan shroud)
  • Parts printed by me, for this printer, by this printer (because it has a big-enough bed): 7 (PLA, the LCD Cover, Rambo Box parts, and the Power Supply holder and spacer)
Ultimately, this printer is a Prusa i3 MK2S, not a MK2 (because, I liked the Rambo Box on the 2S better- it holds the wires much better than the 2)

LOTS of lessons learned.. If I were to do this again, I'd not have even bothered with the cheap chinese clone PINDA probes, nor the hobbed gears (ordered 2 from Amazon but Chinese vendors- and they are still not here after 2 months!) For known quality, from the same supplier as Prusa uses, just buy these parts from PrintedSolid.com: MK42 heated bed, V1 PINDA probe, miniRambo v1.3 (comes with micro swiches, wires, etc.) and E3D Hobb-Goblin hobbed gear. I ended up using the parts I just listed, but only after buying the knock-off bed-level probes and hobbed gears from Amazon first, and realizing I needed the real deal. I also used a genuine E3DV6 hot end, and I think I avoided a lot of frustration because of this.

Net result? I have a really good 3D printer; a VERY close replica (running the real firmware even!) of a genuine Prusa i3 MK2s that was new perhaps late 2017? This printer comes out SLIGHTLY cheaper than if you were to buy the current model year Prusa i3 MK3s kit. All-told, and not including my labor, or parts I already had, I paid just under $700- around $680 bucks. A new Prusa (kit version) costs $749, plus $50 shipping? My printer took perhaps 2 months to research, order parts, fabricate stuff, tinkercad stuff, print stuff, and build. A genuine Prusa has about a 1 month lead time currently.

Would I do it again? Absolutely! Would I rather have a real Prusa? That's a tough call. They are really cool printers, and Prusa seems to be a wonderful company to deal with. Plus that orange looks AMAZING in person! And, the MK3s's removable bed with the powder-coated, textured PEI makes insanely good looking prints, that just pop off the bed. BUT, my version is really close (to a MK2S anyways), and every single part of the build sort of tells it's own story: How I fabricated this, why I had to mount these parts like this, learning about the PTFE tube in the hot end, designing the power supply holder, and having to print it a total of 4 times until it was right (and each print takes 5.5 hours!), etc. etc. etc.

Overall, a very fun and rewarding project. Glad I took this on. Ok, no more bringing us off topic from me, now I'm able to print some of these cool PC-jr parts Chuck has designed! :-)

PS: Here's the link to my power supply cover/holder design on thingiverse: https://www.thingiverse.com/thing:4289906
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Re: Prusa i3 MK2 Scratch Build

Post by chuckphd53 »

This was excellent work, Kudos :)

Don't ya just love machines that make clones of themselves, hmmmmm
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