3d printer

This page is about SkullSpace's 3D printer, a MendelMax 2.0. More info at:

http://www.makerstoolworks.com/support-and-docs/

MendelMax 2.0 Specs

• Print Area Dimensions: 245 mm x 315 mm x 225 mm
• Print Area: 17,364.8 cm3
• Printer Dimensions: 450 mm x 340 mm x 460 mm
• Usable Maximum Print Speed: 250mm/sec or more depending on the part, print material, and extruder
• Usable Maximum Movement Speed: 500+ mm/sec
• Layer Height: .1-.4mm, user selectable. Lower layer heights are also possible.
• X & Y Axis Resolution: .0125mm
• Frame: All aluminum
• Movement: linear rail (X and Y axis), precision shafting and bushing (Z axis)
• Heated Bed: 24V 200W Heated Bed included
• Power Requirements: 110-220 VAC
• Hotend: J-Head Mk V-BV 0.4 mm / 3.0 mm

How to print

Currently it is still being built/calibrated/tuned and cannot be used to print anything yet.

Choosing the right temperature

For ABS, 210c was working good for us. What you should do it heat the hotend up to 230 or so and try extruding 10mm and watch it carefully. If it smokes, bring the temp down to 220 and try again, you want it just under where it smokes.

ABS on bare glass

OhmEye says he prints ABS on bare glass:

(13:59) ( OhmEye) xorrbit: I use 135-140C for the glass temp and first layer speed of 30mm/s with ultimachine ABS and can print most things with only minor lifting issues if I don't have any breeze in the room.

Todo

• Tuning (see below)
• Flash Arduino Mega 2560 *bootloader* using ISP so we can update firmware from linux
• Install heatsinks on pololus (Andrew has ordered these)
• Install/mount fans on heatsinks on pololus (Andrew has ordered these)
• Install Z end stop hall effect sensor (needs 3d printed part)
• Install X/Y end stops (needs 3d printed parts)
• Swap out car pads with tighter tolerance ones
• Install power switch
• Cover up 120v exposures
  • Cover for power supply terminals
  • Grounded box for ac plug
• Replace some temp plastic clips with zip ties
• Print/acquire cable chain for carriage wiring and X motor wiring
• Set up dedicated Raspberry Pi with pronterface and VNC for printing and toss it on the network
• Nice big "don't touch you will get burned" / etc sing should be printed and displayed
• UPS of some kind for long print jobs
• Webcam for monitoring print status

Tuning

• Extruder hotend and bed thermistors were both verified to be working properly
• Z axis was raised to prevent grinding and leveled
• Extruder
  • Discovered high print speed causes abs to accumulate in the gear threads which causes slippage
  • 300 mm/min seems to be a bit too fast
  • 220c & 100mm/min seems to be working best for abs so far
  • Remember to set diameter of filament in pronterface
• Bed needs to be leveled

Things we need to print

• STL Archives:
  • https://www.dropbox.com/sh/3uyotd400xp2ef5/AvakF1Vw25/STLs
  • http://ohmeye.com/download/mendelmax/
• Fan duct and mount
  • https://www.dropbox.com/sh/6615t9t9bzuu1y3/pjrQtghBRT
  • Print the mount first and mount your fan to provide at least some cooling needed to print the shroud.
• Z end stop hall effect sensor mount
  • http://ohmeye.com/download/mendelmax/ohmeye_mm2_endstop_z_cheapo_beta2.stl
• X end stop mount
  • http://ohmeye.com/download/mendelmax/ohmeye_mm2_endstop_x_flat.stl
• Y end stop mount
  • http://ohmeye.com/download/mendelmax/ohmeye_mm2_endstop_y.stl
• cable chains
  • As per https://dl.dropboxusercontent.com/u/95642557/XCableChain1.jpg and https://dl.dropboxusercontent.com/u/95642557/XCableChain2.jpg
  • http://www.thingiverse.com/thing:40124
  • ScottGreen on #makerstoolworks has some cable chain end STLS he should be posting soon

Flashing new firmware

http://www.makerstoolworks.com/support-and-docs/download-center/

Currently we have the MendelMax 2.0 no end stop firmware running on it. It uses an Arduino clone called the Taurino that is similar to a Arduino Mega 2560.

The flashing procedure is to load up the Arduino software and configure it as for an Arduino Mega 2560, compile and flash. It did not work on linux but worked worked fine on Windows with the Taurino drivers installed.

Okay so apparently the default taurino *bootloader* does not work with mac/linux so we need to flash the normal Arduino Mega 2560 bootloader onto it. This has to be done using an ISP programmer or another arduino actiing as ISP. After this is done we should be able to flash new firmware via mac/linux.

Post-flash verification steps

After flashing a new firmware a few things should be sanity checked:

NOTE: NEVER unplug a motor while the MendelMax is powered (even via usb!), these motors idle charged and unplugging them while powered will blow a pololu motor driver (and this costs $15 per driver!)

• extruder are not running reversed
• x, y, z motors are not running reversed

Software

Printer control

We have tested it with Pronterface, and it seems to work well. It should be set to 250000 baud rate. 250k baud doesn't seem to work with linux very well so we may switch it to 115200 or soemthing lower:

https://github.com/ErikZalm/Marlin/issues/205

The stock MendelMax firmware has the extruder running backwards so the plug shoud be flipped (ie blue wire away from the power connector).

Eventually we would like to set up a Raspberry Pi running pronterface that is on the network and can be VNC'd into to control the printer or set up print jobs. Some good links that show how to do this are here:

https://github.com/gklyne/things/wiki/Setting-up-a-Raspberry-Pi-as-RepRap-host-controller

http://entropyprojects.blogspot.ca/2012/07/reprap-printing-from-raspberry-pi.html

http://entropyprojects.blogspot.ca/2012/08/slic3r-on-raspberry-pi.html

Modelling

FreeCAD is the recommended modeling tool, but anything that can produce STLS should work:

http://www.freecadweb.org/