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- If you are building this machine using SAE (imperial) fasteners, see also SAE Prusa Mendel.
Prusa Mendel is the Ford Model T of 3D printers.
Like the Model T, the Prusa Mendel improves on a previous design by being more streamlined for manufacture. The Prusa Mendel is a simpler remix of the original Mendel. By default, it uses printed bushings instead of regular bearings, though options to substitute inexpensive lm8uu linear bearings or other types of bearings or bushings are available. The current version uses three 608 bearings in total, one for the X axis and two for the Y axis. The 624 bearings are gone altogether.
Prusa's main goal is to be the purest and simplest 3D printer you can build.
- It's much simpler to build it.
- It's much simpler to modify it.
- It's much simpler to print it for your friends.
- It's much simpler to repair it.
Because of its complexity, the Prusa Mendel can be a living thing. I update it all the time. It's a unique feature but it should be standard. We are living in feature, we don't care if it's a bit different every time; our printer will print it in same time ;-)
The development of the Prusa Mendel is hosted on github: http://github.com/prusajr/PrusaMendel.
You can follow the changes on Changelog.
You can sign up for github for free and fork the project to begin working on it.
Bill of Materials
|4||frame-vertex with foot||RP|
|12||pla-bushing||RP-PLA||check your build file, the file makes either 4 or 12|
Non-Printed Parts ("vitamins")
Note that additional parts are required for the extruder, although some extruder parts are included in the table below.
|83||M8 nut||Fastener||Buy a 100-pack to be on the safe side.|
|93||M8 washer||Fastener||Buy a 100-pack to be on the safe side. (Grade 2 works fine.)|
|6||M8×30 mudguard / fender washer||Fastener||These are also known as penny washers, they have a much larger outer diameter than regular washers.|
|2||M4×20 bolt||Fastener||To mount the extruder|
|2||M4 nut||Fastener||To mount the extruder|
|2||M4 washer||Fastener||To mount the extruder|
|16||M3×25 bolt||Fastener||Or eight M3×25 bolt plus eight M3x20 bolts. The M3x25 bolts are too long for the recent Prusa z-motor-holder and rod-clamp, and also for the Z motor couplings. See Section 8, steps 4 and 13 for details.|
|40||M3 nut||Fastener||8 optionally locknut / stop nut / nyloc|
|2||M3 grub screw / set screw||Fastener||M3x8 seems about ideal but anything 6mm or longer should do. If these are hard to get, additional M3×10 bolts will do the job instead.|
|3||608 roller skate / inline skate / skateboard bearing||Bearings||You don't need to ask for a "608 bearing" at a skate shop, just ask for wheel bearings.|
|4||ballpoint pen springs||Spring||To fit over M3 bolts. Ballpoint pens are a common, cheap source of suitable springs. They are about 25mm long and compress to about 10mm.|
|6||M8×370mm||Threaded rod|| 3 per side |
Note: The threaded rods can be cut from larger 6x1m pieces (see Threaded Rod Cut Order below).
|4||M8×294mm||Threaded rod||front / rear|
|3||M8×440mm||Threaded rod||top / bottom|
|1||M8×50mm||Threaded rod||or M8x30 or longer bolt for X idler. Take care: if the bolt is too long, it may not be threaded along a sufficient length|
|2||8mm×420mm||Smooth rod|| X-bar |
Note: 304 Stainless Steel, A2 Tool Steel, or O1 Tool Steel are recommended for smooth rods as it can help to prevent friction from rust and manufacturing (straightness) standards are higher. Rust issues can be prevented on the normal steel rods by maintaining a coat of oil. The smooth rods can also be cut from larger 3x1m pieces (see Smooth Rod Cut Order below).
|1||225mm×225mm print top plate||Thick Sheet|
|1||140mm×225mm print bottom plate||Thick Sheet||Note: The Prusa Iteration 2 design does not use a print bottom plate.|
|1||840mm×5mm T5 pitch timing belt||Belt||Y axis|
|1||900mm×5mm T5 pitch timing belt||Belt||X axis|
|5||NEMA 17 bipolar stepper motor||Stepper||Be sure to get ones with at least 20mm of shaft length. Shorter shafts require modifications to the X pulley assembly and Z motor couplers. One of the five motors, for use with the extruder, should be capable of creating a holding torque of at least 40Ncm, at the very least.|
|50||small cable binder / ziptie||Misc|
|1||Wade's Geared Extruder||for 1.75mm filament RepRap Universal Mini Extruder; or any other compatible extruder for either|
|1||Electronics + endstops||This can be RAMPS, Sanguinololu, Gen6, Gen7, Gen3, or any other Mendel compatible electronics. Endstops are either optical switches or microswitches (Recommended), and you need three, one for each of the X, Y, Z axes.|
|3||30mm×10mm Optoflags||Thin Sheet||if using opto endstops|
|2||8mm ID spring||Spring||to eliminate backlash in the z axis|
|1||object with precisely 290mm length||for frame alignment|
|1||object with precisely 234mm length||for frame alignment|
Note: You can combine the latter two by having a piece of thick sheet with dimensions 290mm×234mm. Make sure to mark which side is which.
Threaded Rod Cut Order (when cutting from 1m lengths):
Required: 6x1m Long 8mm Threaded Rods (or 5x1m pieces + 1x50cm piece) Rod 1: 370mm, 370mm, 210mm, ~50mm (The last piece will end up somewhat shorter than 50mm. ) Rod 2: 370mm, 370mm, 210mm, ~50mm ( Use it for your idler. Alternatively, an M8x30 or ) Rod 3: 370mm, 294mm, 294mm, ~42mm ( longer bolt can be used. ) Rod 4: 370mm, 294mm, 294mm, ~42mm (Also, a piece of M8x20 threaded rod can be used ) Rod 5: 440mm, 440mm, ~120mm ( for the wade's/greg's extruder idler. ) Rod 6: 440mm
Smooth Rod Cut Order (when cutting from 1m lengths):
Required: 3x1m Long 8mm Smooth Stainless Steel Rod Rod 1: 420mm, 420mm Rod 2: 406mm, 406mm Rod 3: 350mm, 350mm
The Prusa Mendel uses the 4 drivers in the standard Mendel electronics package to drive 5 motors by using two steppers wired in parallel to one driver .
Where To Purchase
See the Mendel Buyers Guide for information on where to purchase all of the parts needed.
See the Prusa Buyers Guide for information on where to purchase all of the parts needed.
Printing the Parts
Printing a Prusa on a Mendel
There are now four plates, sized to fit within a 200 x 200 x 140mm build platform.
(The Printing Time Estimates provided are based on 30mm/sec print speeds, and 25% infill. Your times will likely differ.)
(Help me out here: Are Bushings/bearings another print?)
Printing a Prusa on something else
Last but not least, if you have a machine won't print the above plates, or if you're in need of spare parts, all the .stl files necessary to print a Prusa Mendel are available on the PrusaMendel Github where you can download them and print them individually.
Buy the printed parts
- Two printers simultaneously - Prusa and shaper cube working side by side.
- Prusa homing using endstops
- Prusa development overview
- Prusa Y axis stress test
- Prusa Z axis stress test
- Early preview of the Prusa Mendel redesign
- Fumon's Prusa build session 1 - D1plo1d building Fumon's Prusa Mendel at Hacklab.to. Should give a hint as to how the Prusa Mendel parts go together.
- Rob's Auto-centering shaft coupler - designed to reduce shaft/motor vibrations (print 2/replaces 2x coupler). May require widening the openings on the z motor mounts to allow the rotation of the zip tie. Use a zip tie gun to get maximum compression on the coupling.
- Machined Pulleys and GT2 Belts
- Prusa's Blog
- Prusa Builder Blog Feed
- Assembly photo gallery
- Prusa Mendel Visual Instructions - A nicely formatted version of the assembly process in PDF.
- Paperback version the Prusa Mendel Visual Instructions, also available in color.
- Prusa Mendel Assembly Video Tutorial This video, the first of a series, provides an overview.
- RichRap Blog - Prusa Mendel Bling - Pimp my Mendel - How to build up a LM8UU Linear Bearing Prusa
- Latest Aleph Objects/LulzBot Bill of Materials
- ABS Prusa LM8UU based Prusa with build instructions.