3D Printer decisions

We are starting a project to build and maintain a 3D printer. At the moment we are discussing which model we will focus on. Here are some options:

RepRap

RepRap Prusa Mendel (Taken from Wikimedia user Julianh72)

Model: Mendel

Version: Prusa

The RepRap seems to be a promising, affordable and flexible, adaptable candidate. Especially the RepRap Prusa Mendel seems to be well suited for a Hackerspace. It costs between 450€ and 800€ as a ready set and probably less than 200€ if we get the parts locally.

The parts needed for the Prusa Mendel are almost entirely standard parts that can be found in almost any hardware store. These are mostly M8 thread rods, M8 screws and nuts, standard skateboard bearings, the common NEMA 17 stepper motor.

Here's a list of the parts needed (taken from the RepRap Wiki)

Printed Parts

Quantity	Description	Type	Comments	Printed
2	coupling	RP	stl[[1]]	none
3	endstop-holder	RP	stl[[2]]	none
1	x-carriage	RP	stl[[3]]	none
1	x-end-idler	RP	stl[[4]]	none
1	x-end-motor	RP	stl[[5]]	none
1	y-motor-bracket	RP		none
2	z-motor-mount	RP	stl[[6]]	none
4	belt-clamp	RP	stl[[7]]	none
8	bar-clamp	RP		none
2	rod-clamp	RP		none
2	pulley	RP		none
4	frame-vertex with foot	RP		none
2	frame-vertex	RP		none
12	pla-bushing	RP-PLA	check your build file, the file makes either 4 or 12	none

Non-printed parts:

Quantity	Description	Type	Comments	Available?
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
2	M3x8 screw	Fastener	Anything 6mm or longer should do. Even M3×10 bolts will do the job.
22	M3×10 bolt	Fastener
8	M3×20 bolt	Fastener	The M3x25 bolts are too long for the recent Prusa z-motor-holder, rod-clamp, and couplings.
8	M3×25 bolt	Fastener
4	M3×40 bolt	Fastener
70	M3 washer	Fastener
40	M3 nut	Fastener	8 optionally locknut / stop nut / nyloc
3	608 (roller/inline skateboard)	Bearings	Standard wheel bearings.
4	ballpoint pen springs	Spring	To fit over M3 bolts. About 25mm long and compress to about 10mm.
6	M8×370mm	Threaded rod	3 per side - 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
2	M8×210mm	Threaded rod	Z-leadscrew
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 - 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).
2	8mm×406mm	Smooth rod	Y-bar
2	8mm×350mm	Smooth rod	Z-bar
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	At least 20mm of shaft length. One should have a torque of > 40Ncm.
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, Generation 6 Electronics, Generation 7 Electronics, Generation 3 Electronics, or any other Mendel compatible electronics. End-stops are either optical switches or micro-switches (Recommended), and you need three, one for each of the X, Y, Z axes.

Extruder (Print-head)

[TODO]

Electronics

[TODO]