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DIY Prusa I3 Rework from Scratch

Posted by RickK3DNOB 
DIY Prusa I3 Rework from Scratch
February 04, 2016 08:14PM
Hello all,
Thanks to everyone that has posted in this form. I have learned a lot. I am attempting to build my first 3D printer based on the Prusa I3 Rework and have some questions for everyone here. I currently live in Central AB, Canada. In the middle of Edmonton and Calgary so kinda in the center of a black hole when it comes to shipping stuff for cheap. I have decided to source as much as I can locally. Cost is not a major factor right now because I want quality out of my printer. I have spend almost 3 months + doing research on Youtube, forms and such. I do apologize for the randomness and length of this post. I am also planing on using 24v for the heated bed and the extruder hot end. I will also be using Direct drive for my filament. This is how my brain works.

Question 1: I have seen a lot about using P3Steel and but to reduce cost, is using aluminum a bad idea? I have a dedicated workbench that this will sit on that will never move by my hand. I have a local machining shop that I am asking for a quote to have them cut out the I3 rework frame. Do I need to up the thickness of the material to say 8 mm instead of 6 mm? I have also seen some people with the solid frame under the printer made out of metal to help stabilize it, and I have no problem screwing the frame from under the work bench into the ABS printed parts.

Question 2: I would like to use the RAMBo control board as I have some concerns over the RAMPS and other boards out there.
This video was the best review I could find about this board. https://www.youtube.com/watch?v=6PHExxK8lLg
My biggest concern is and consideration for using this board is the fact that there is a REMOVABLE fuse attached on the board. Am I paranoid about not shorting out my board or is this a preferred thing among 3d printer owners?
I have heard bad things about the RAMPS boards and the fuses they use. https://www.youtube.com/watch?v=FYJn6FuWOv4. I would like to use the Marlin firmware because of the amount of users and support that is available. The Smoothieboard interests me but because of the firmware I am shying away from it. The BeagleBone Black and Replicape add more hardware and functionality then I want with this printer. Yes having a Linux OS would be nice, but it is over kill for my needs at this time. Is there another board that I should be looking at? I want to have a standalone controller for controlling my printer without having to purchase a Ardunio Mega. (I want to save that for my robot that gets me a beer out of the fridge, side project, hence the reason why I am building a 3D Printer to print out my parts for it)

Question 3: I would like to use Optical End stops over mechanical because over time I can see the metal end stop switch bend and cause false readings. Is there a manufacture / source that people prefer ? Again I ask if i am paranoid or not.

Question 4: Threaded Rods - following the wiki for the Prusa I3 rework it calls for them to be used but after extensive reading, it looks like I should abandoned them but I am unsure what I should use in their place. This also means that the axis holders and drive line will have to be modified. What has worked for everyone in the past and what are you using currently?

Question 5: Linear bearings - I have priced out from a local supplier the LM8UU's from SKF and they came back with over $500 for 15 of them. I am not happy with the cost but high quality has its price. I have heard that the ones from Ebay will be ok but after a few years, they need to be replaced. I fully understand mechanical wear and tear but I would prefer not having to replace them after a few years. Again am I going off the deep end on this?

Question 6: Bearings in general - I have decided to go with rubber shielded bearings to keep out any contaminants. Good or bad idea?

Question 7: Smooth Rods - I understand that there are precision rods that should be used for this as suggested by multiple people but trying to source these can be slightly costly. 3 supplies in Red Deer told me they could not get metric smooth rods. AES Industrial can get them but it will be more then standard rod size. I could get them from Ebay / Amazon but I have read many reviews about them not being straight and causing issues. This is why I went local on sourcing these. Good or bad idea?

Question 8: Power supply - I would like to re-purpose an ATX PC power supply because of being able to completely shutdown the high power components using the control wire. Other then the amount of power (24V) for the heated bed and the hot end on the extruder (24v heater), is there any other consideration I should have when doing this?

Question 8: GT2 belts - I plan on using these belts in my build with a 2 mm pitch. Is this the best one to use or is the MXL better to use?

Question 9: 20T vs 16T GT2 Timing Belt Aluminum Drive Pulley. I would like to use the 20T drive pulley just because it has more teeth to make contact with the belt and should reduce slippage I believe, or am I way off ? I was thinking about getting these machined at the local CNC shop but the cost online is reasonable.

Question 10: Heated Bed using a heater mat - I am planing on using a heated mat (24v) with 3M sticking it to a plate of aluminum with a thermister wired to the control board. The reason for this is based off the video listed here. I want an even heat distribution and do not want sag in the middle of my print bed. Am I way off on my thinking?

Question 11: E3D v6 Print head - I have heard good things and my only question is I want to print PLA and NingaFlex in the same print without having to switch in and out without stopping eg. Printing a rubberized cellphone case in NingaFlex, then print abs for the back cover. I see the Cyclops does this but Has anyone used or are using it? for now I will go with the single E3D v6 print head.

Question 12: What do you do with your failed prints? I have found a series of videos that has me excited to take on this next project. I believe that all my failed prints and over-shots should be able to be recycled into reusable filament.

Question 13: Motors - Nema 17 motors are what I am seeing people use but how do you tell the correct stepping they use?

Thank you again for taking the time to read this.
Re: DIY Prusa I3 Rework from Scratch
February 05, 2016 12:11AM
If your looking for a much easier way out than finding all that stuff look at the Afinibot A3 from Robot Shop in Quebec as the kit comes with ALL bearings smooth rods lead screws steppers LCD belts gears everything in a nice packaged box an ok MK8 extruder all for about $450 free shipping to you. All software on SD card uses Repetier and Slic3r in kit form and I have found it to be a good printer to start with. Only thing its all acrylic so if you wanted in Aluminum or steel take all those parts and have them laser cut but personally I only plan to change the Y axis bearing plate to aluminum as the rest is solid as is once you have it running then you can change to an E3D if you want it comes with heated bed only lacks a glass plate which I added (optional) When I read some of the posts here about peoples problems I am happy I got this one and accuracy is good. If you choose your route rubber shield on bearings xxxx rs not zz, E3D make sure you choose the one for filament you use i.e 1.75 or 3 1.75 most common any nozzle size. I get my filament from Filaments.ca in Toronto but you have Spool3D near you. The Nema stepper is a fairly good stepper as opposed to the clones. If you want optical stops make sure its compatible with the board i.e has its own dry contacts. While I am familiar with Arduino I haven't looked at Ramps schematics to know them the drivers should have heat sinks. The number of gear teeth only affects steps/mm which you need to set anyhow. As far as recycling you would need somebody local to recycle or box and pay for shipping to someone who does unless you purchase or make a filament maker and recycle yourself. If you haven't used a printer before I suggest the kit above then design your own with features you want. There are so many other software settings like temperature, feedrates, infills, supports to mess with and different filaments PLA ABS NINJA NYLON POLYthis POLYthat TGLASS etc. Then if you want to design parts you need to learn CAD and how to orient parts for best print. I use AUTODESK123 which is free for personal use with commercial version available or you can pay for MAGICS. Final warning 3D printing is addictive. I started an Afinibot group on 3D printer chat from Google+......good luck

Re: DIY Prusa I3 Rework from Scratch
February 05, 2016 12:32AM
First question - Flames or Oilers?

It's nice to see someone wanting to build a quality i3 from scratch rather than from the cheapest kit they can find.
I have built 3 i3's from scratch, the first being a "vanilla" i3 the next two being reworks.

1. Use an aluminum frame and bed frame, better than plywood. 6mm is fine. For the build we did for my local Hackspace we used aluminum. A member CNC'd one for us. I wouldn't even consider acrylic.

2. The aliexpress RAMPs can have their issues. I've found you usually have to replace the heatbed MOSFET. For my personal printer I use this one:

3. I've only used mechanical and had no issues

4. For Z threaded I use stainless m5 threaded. I could never find straight mild steel m5 threaded rods

5. ebay LM8UU's have been OK for me. I have a link somewhere for supposed better quality ones from the US. I can dig it up if you like

6. I have used both. The rubber sealed 608's seem better. For the 624 and 623 I use ebay suppliers

7. I have bought M8 smooth rods from a 3d printer supplier which were good quality, but they screwed up my order so bad I vowed to never recommend them. I have also used an ebay supplier
from memory it was this store - [stores.ebay.ca]

8 & 9 Use GT2 20 tooth. I've used aliexpress/ebay suppliers and they were fine

10. I have used both PCB and alloy 12V heated beds. The alloy one is way better. I bought it from Dan Royer from Marginally Clever in Vancouver. He is also a member at the Vancouver Hackspace were I go to. He has an online store with lots of 3D printer parts. [www.marginallyclever.com]
[www.marginallyclever.com] - it's a 12V bed. Doesn't flex like the cheap aliexpres pcb ones.
I haven't used a 24V bed

11. never used a E3D. I have used a J-head from Makerfarm and a Hexagon from Marginally Clever. Currently use 3mm nozzle but have bought a 1.75 as it seems to be the standard now.

12. failed prints?? I bin them :-)

13. NEMA 17's I use these - [www.aliexpress.com]
There are jumpers you place under the stepper drivers to make them 1/16 step. I think the NEMA with 1.8 degree step angle combined with the 1/16th step is what is needed

I did an Instructable on our first build - see the link on my sig

Hope this helps


Edited 2 time(s). Last edit at 02/05/2016 12:35AM by SteveRoy.

My updated Instructable on our Prusa i3 Build
Re: DIY Prusa I3 Rework from Scratch
February 05, 2016 12:12PM
Thanks for the reply gents. All of the links and additional information is greatly appreciated.

Steve - it was your post that got me geared to this whole DIY thing. I will have to say that when you mentioned in your post about laser cut parts, you were spot on. I routed 6mm plywood on the original I3 frame to find it was out of square by .02 inch. So I bite the bullet and get it CNC'd. As far as the Hockey Team goes. GO Jets.thumbs up Manitoba born and raised. Just like I still support the pathetic Blue Bombers. drinking smiley. There good to bet against because the outcome is predictable. Do you have an LCD attached to your current printer? if so what type? I like the board you suggested. Have you used the ATX board listed on their site? Could I please the link that you have for your LM8UU's? Have you put a Proximity sensor on your Z axis ?

Roger - Thanks for the advice on Robot Shop. As the wife has said, "It has everything and you can modify it from there." Thanks again for the Spool3D advice for Filament. I know what you mean by this 3D World is addictive, I posted my questions last night and here I am again doing research. I almost feel like a crack addict. LOL. What Control board and LCD came with your printer? Did you find that there were any dry solder joints or anything you need to "Fix"?
Re: DIY Prusa I3 Rework from Scratch
February 05, 2016 04:44PM
I have a geeetech LCD12864
I haven't used any of the other products from Staticboard, but I'm very happy with the quality of their RAMPs board

I also haven't needed a proximity sensor for the i3's I've built, I just use a simple setup like in this post:

Re: DIY Prusa I3 Rework from Scratch
February 05, 2016 04:52PM
Hmm very good point..... One more thing to consider when doing the design phase. Thanks for the link.
Re: DIY Prusa I3 Rework from Scratch
February 19, 2016 12:13AM
Hello everyone, I was able to get an aluminum frame made by jigsaw and files. Is there a reason why the heat bed carriage or squished frog only has 1 LM8UU bearing on one side and not 2 like on the other side?
Re: DIY Prusa I3 Rework from Scratch
February 21, 2016 09:12PM
My printer came with a Melzi resembling version 2 and an MK8 extruder which I have torn apart a few times for general cleaning but the printer has worked as expected when I see others nightmare posts on here it makes me appreciate mine. While far from great with acrylic not its best aspect all the motors worked no overheat but don't expect support from China frankly you don't need them. This is my first printer but it won't be my next the thing is I can use all the motors, electronics,power supply,extruder to offset the cost of my next build and this one taught me alot about printing and designing, how you CAD a part to be stronger etc. I would say use aluminum for the frame and bed supports, while steel is cheaper and stronger it is also heavier putting more stress on steppers to move. X carriage up and down and Y you get my point.As far as electronics you can use Arduino but need a Mega 2560 or equivalent to start and that won't drive anything without stepper drives which can be built using Mosfets and now your making PC boards and have become an electronic engineer as the PLA waits to be printed. As far as endstops they have only two purposes one to tell the stepper to shut off when you trigger it keeping stepper from ramming the carriage off the printer or burning itself out and the second is to tell the controller where HOME is which then with the aid of printer settings for travel distance now creates software end stops for maximum travel the opposite way. Optical end stops use an LED and phototransistor, to detect a break in a beam of light requires appropriate input to controller whereas most just need an open close microswitch which is fine if the wires don't come off or wired right.Then one morning you say do I want to be a builder or a printer or both. I am hoping to do away with all my rods and lead screws and bearings with linear slides in the design stage. As far as extruder try for Bowden type to get the extruder off the X carriage less weight pushing on the Z axis = better prints. Do a web search for IGUS and see what you find it may simplify your build and feel free to contact me at 3D Printer Chat website or join in.

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