Cube 3D printer community

Hi Folks,


As promised, here is my instructional for the the project I've dubbed FrankenCube.  Basically, Im in the process of ripping out the guts of my Cube 2 (although these hacks will work with any Cube) and turning it into a printing monster with the Merlin Firmware, running on a Mega2560 Arduino with Ramps 1.4.  Im still working on this instructional, so be prepared for changes to be made as I figure stuff out myself.

So why am I doing this?  Basically I got so sick of the predictable average and slow prints the Cube 2 puts out.  One thing I've noticed with the Cube is the lack of options available.  3D Systems seem to have taken a one size fits all approach to 3D printing... so while this works for many objects, it certainly doesnt work for all.  Being able to adjust print speed, retraction to prevent filament hairs, use way different filaments (like wood filament), change the print head, layer height etc is just scratching the surface of the funcationality I plan on getting out of this baby.   If you're after a full feature list, check out Slic3r, the equivalent to cubes propriety software.. Just have a poke around and check out how many different ways you can manipulate the printout.  The feature list is awesome - and thats why im doing this. 

OK so lets get into it.

You will need
1x Mega 2560 Adruino Board, -$10
4x Stepper Drivers A4988 -$12
1x RAMPS 1.4 -$10
1x Pack of 100 Dupont 2.55mm Wire Terminals $5
1x Pack of 4 pin Dupont Termal Housing (You can cut these in half if you need to make 2 pin housings). $5
1x Soldering Iron for some very basic soldering $5-500
1x Multimeter with Resistance and Continuity Beeper $5-$500
1x Roll of lead free Solder  $5
1x No Clean Flux Pen $5
1x Small Brain inc. patience $5
1x Screw Driver
1x Set of Hex Drivers
1x Merlin Hotend (Purchased from eBay)
1x AirTrippers Bowden Extruder (Any version - this is printable and will require a Nema 17 Motor. Make sure you print it BEFORE dismantling your Cube)
1x Nema 17 high current Motor.  There are different types - get one that has high current - this is VERY important.  I got mine from Josh at Cultivate 3d in Australia

www.cultivate3d.com
1x Dupont Crimper (Not necessary, but makes the job much easier).
1x 12v Power Supply (Im using a modified computer power supply) https://www.google.com.au/webhp?sourceid=chrome-instant&rlz=1C1AVSA_enAU453AU453&ion=1&espv=2&ie=UTF-8#q=how%20to%20make%20a%2012v%20power%20supply%20from%20a%20computer%20power%20supply

OK So now we've got our shopping list out of the way, the next thing you will need is an afternoon or two. 

Overview
Half the work is already done for us by 3D Systems as we are only working on the motherboard end of this unit.  We will however have to unscrew all the covers on this thing in order to verify (preferably with a multimeter) which cable leads to what.  What we're going to do is cut off all the cables on the motherboard end of the printer and leave the other ends in place. As we identify and cut the cables, we will tag and name each set of cables to ensure we plug them into the correct place on our RAMPS 1.4 board.  With all that Arduino hardware -- Basically, our A4988 Drivers plug into the RAMPS board in 4 of the 5 driver positions (Danger DONT DO THIS YET!!!), then our RAMPS Plugs into the arduino, we screw exposed wires in to the power connector from our power supply then plug all the bits and pieces we labeled and terminated from our Cube 3D printer earlier.

Sound simple?  Yeah.

• OK SO start by removing all visible screws from the case of your Cube 2, start at the bottom, and remove the motherboard tray from the rest of the cube.
• Unscrew and remove the hotend cover
• Lift the top off the motherboard tray but be careful, the LCD is connected via a ribbon cable.  Disconnect it from the motherboard, then disconnect all other cables from the motherboard
  
• Remove the screws from the back of the cubes Z axis and remove the back cover
• Remove the screws from the back of the X axis and remove the back cover.  When you remove it, disconnect the 3 fans from the wiring lume by pinching the connector.
• Remove the 2 screws from the underside of the Y axis and wiggle the bottom cover plate out of position.   
• Remove all screws holding the motherboard in position and vigorously remove and discard the motherboard (or keep it for parts... those voltage regs may come in handy later if you make a mistake with your wiring).
• Now using a Multimeter to check continuity, you need to identify wiring, cut at the motherboard end, re-terminate using dupont connectors the following of your wires on your Cube.  Be sure when re-terminating these wires that you match the colour sequence on the other end of your device.  THis is particularly important for the 4x  Motors, almost everything else are 2 pin cables. 
• Identify, Cut and Tag wires for the following
  X Motor
  Y Motor
  Z Motor
  Extruder Motor
  X End Stop
  Y Endstop
  Z Endstop
  Thermistor (Purple wires leading into the top of the hotend nozzle)
  Heater wires (thicker white wires leading to the coil around the nozzle)
  All Fan Wires (Mark them according to what they cool ie. Extruder Fan, X Fan, y fan, motherboard fan etc.) - YOU DONT NEED TO TERMINATE THESE WIRES, JUST STRIP THEM
  
  
• Note - there are 3 wires we are NOT going to use in this project which come from the movement sensor on the extruder... THey tell the Cube when you have a Filament Flow Fail. (Unnecessary) - Identify these wires and tag them, but at least in this version of the FrankenCube, we wont be using them. 
• Once this is done, Terminate all the wires with your Dupont Connectors.  Basically, if the set consists of 4 wires, make sure you match the colour pattern / sequence  eg Blue red black green ->Blue red black green
• Now, time to put together your new motherboard.  Plug each of the 4 Stepper drivers into the appropriate location on your ramps 1.4 board.  MAKE SURE the little pots on the steppers are  furthest away from the power connectors (green / blue)  connectors.  If you plug them in backwards, expect them to burn and need replacing.
  
  
• IF your Ramps 1.4 comes with a separate small resistor, wire it between R5 and R19 with the band on the resistor closest to the power connectors (it passes power from the arduino to the ramps). IF your ramps doesnt come with this resistor, dont worry, its likely already in place (see in between the connectors for the X Motor?)
• Now connect up the end stops as pictured.  Then the motors as pictured.  Now connect the heater wires and connect the thermistor ... as pictured, then connect your power supply wires as shown.  Wire your heater wires (dont worry about polarity) to D10 on the RAMPS 1.4 board and the Hot End Fan to D9 on the RAMPS board.  With the Fan, if your polarity is incorrect, the fan will blow in the wrong direction, just reverse the polarity on D9 if that's the case.  As for all the end stops, polarity wont matter (not for the endstops in my cube anyway).
  
  

[/list]
OK.. Thats about as much as I've got tonight.  Tomorrow : Merlin Firmware.   Any questions?
_____________________________

Edit.  You may have noticed in the pictures I posted, Im no longer using the Cube direct drive extruder so I decided to post some notes on the subject. 

Basically the old Cube 2 runs on a 24v system.  This is fine for the coil based hotend the Cube 2 comes supplied with, but fails miserably when converted to 12v.  It just doesnt get hot enough to melt plastic running on 12v.  Another advantage to changing the hotend and extruder is that I was able to lighten the load on the X axis thus reducing backlash and I could pick and chose my hotend.  AS I really only want to do this once, I went for the Merlin Hotend.  It's a 12v cartridge heater hotend which has interchangeable nozzles.  THis means if I really do require finer prints, I can always change the nozzle.  The heater cartridge supplied with the Mrlin hotend heats to 230C in about 2 mins - on 12v the Cube Hotend/Extruder would get passed 205C - after 10mins. 

I recommend you download, print and assemble the Airtrippers Bowden extruder prior to dismantling the Cube, as its the only printed part I ended up requiring for this project.  Fortunately for me, I was able to rip one off a Rostock printer I'd made previously, otherwise, I'd have been up **** creek. 

THe extruder I mounted to the side of the printer (see pics) with some button head wood screws.  This seems to hold it quite well.  I used PFTE Pushfit connectors in the top of my Extruder and another in the top of my Merlin Hotend.  THe Merlin hotend does not come with a screw in connection in the top.  I had to drill a 3/8" hole in mine and use a 3/8" die to cut the thread.  Easilly done by hand with a $15 Tap from your local hardware store.  To each of the push fit connectors, I inserted about 50cm of PFTE tube to suite 1.75mm filament.  The PFTE Push fit connectors will grab permanently once you push in your tube so make sure it's cut to size first as once it goes in, it aint coming out.

To attach the hotend, I removed most of the metal parts from the X axis, grinded a slot in the end of the remaining metal bit that sticks out the bottom - big enough to "house" the PEEK part of the Merlin hotend, then used cable ties around the top and bottom of the PEEK (important - to avoid melting cable ties) and secured to whatever I could on the remaining metal part of the X axis.  Complicated sounding, but I really did fudge this - works a treat though.  Just remember, it really doesnt matter how high, low, left or right you mount your hotend - or what flavor of hotend you use - as long as it is fairly straight and doesnt move - it will be just fine.  One thing worth noting though - mout your hotend as high as possible to ensure your max print dimensions are retained as much as possible. (I lost about 10mm off my Z direction, for me, I've never pushed the limit of my Z with the Cube so I dont really care).

Check the pictures in the OneDrive Link below this post and feel free to ask questions.

After getting the mother of all Filament flow failures, I was forced to dismantle the printhead to remove the filament from the unit.  After removing the fan and letting it hang while running a few load cycles to try to free the jammed PLA, i noticed the printhead fan had stopped spinning.  After invetisgating further, I was very suprised to find the hotend had also stopped heating.  Further after restarting the system (as suggested by various others) I resorted to dismantling the rest of the system to identify the fault.  Turns out these units have a "no resetting" thermal cuttooff just above the hotend.  You'll find it attached with a cable tie. with a thick white wire coming from one end, the other wrapping around the hotend and eventually coiling around the nozzel.  Basically by removing the fan, I had caused the 77 degree thermal cutoff to blow.  Replacing this fixed my problem. 

I ended up removing this thermal cuttoff all together and just shorting the wires which led from either side.  The reason is that Im not confident I wont need to manually remove jammed filament again, and can see no easier way than removing the fan while doing so.  - Perhaps no a smart idea - I could potentially damage something or start a fire if the main fan fails while im out - but ill take that risk.  I may attach an easier to access resettable thermal cuttoff in the future just in case.

FYI - Before I figured this out, I contacted 3D systems for help with a detailed description of the problem and my diagnosis and test results with a Multimeter.  The response was basically "Oh no.  So sad.  please buy a new Printhead for $250USD".   Thanks heaps for all the (lack of) support 3D Systems   . 

While researching the Cube 3D printer, I became aware that 3D systems prevent users from using generic PLA filament by inserting a chip into their cartridges which allows the printer's internal computer to roughly gauge how much filament is left in the cartridge (preventing you from starting a print which there's not enough filament to print) . This hack however : http://hackaday.com/2013/04/26/cube-3d-printer-hack-lets-you-use-bulk-filament/ is "supposed" to be the answer.   In actual fact, all it does is waste time and filament, with zero net benefit... Here's why :

A little background.
The cube printer has an inbuilt chip in every single filament cartridge.  It, like many 2D printers provides feedback to the printer's interal computer to allow it know how much "ink" (filament in this case) is left in the cartridge.  It also prevents the user from using an empty cartridge, or reloading the cartridge with more filament once it becomes empty.  3D systems would like you to purchase more expensive filament instead of reloading your old cartridge. They even scare the user by issuing statements to the effect of "only use cube filament in your printer, using 3rd party filament may damage your printer and void your warranty".   

The hackaday article, provides reference to a seemingly useful part which you can print which allows the user to trick the system into using 3rd party filament, all one had to do is accept the Cube printers warning that it is running out of filament, and apparent problem solved.  Wrong.  Problem is, that even if you do use 3rd party filament with this technique, the printer will continue to reduce the "available filament" variable in the filament cartridge's chip.  When this figure reaches zero, the printer will prevent you from using even your third party filament as you are no longer given a warning of which you can accept or deny... You're simply prevented from printing all together. 

The solution. 
I argued with myself as to whether to make this public, as I'm pretty sure 3D systems will do an applesque fix for this in future firmware, but realized I have copys of firmware on my machine which I will make available should 3D systems patch their firmware to prevent this from working. 

Firstly, forget about printing the part in the hackaday article.  It's a waste of filament and electricity.  (Ill explain why in future articles).  Find and print a suitable spool holder for your generic PLA filament.  Make sure you continue to use the cube tube with your new spool holder though as this is actually a novel and useful idea which prevents your filament from malforming before it enters the Cube's extruder.

 To make things simpler, I keep the instructions in note form.  This also assumes you've figured out how to load generic filament into the extruder.

1) make sure you insert a cartridge which contains available filament into the cartridge slot.  This is to trick the printer into allowing you to select a file to print. 
2) start the print as normal.  If there "dummy" cartridge you used was nearly empty, you may be warned about insufficient remaining filament.  If so confirm your intention to proceed by selecting the "tick" icon. 
3) the cube will begin to old the file and heat the extruder.  At ANY TIME during this process, select the "stop" button.
4) you will be asked to confirm if you want to abort the print... DON'T select anything.
5) Now remove the "dummy" cartridge from the printer.
6) the cube printer will continue print the object despite the cartridge being removed and importantly, won't reduce the available filament variable on your dummy cartridge's chip while it is printing.  If you try and do this without pressing the stop button, the sneaky software will force you to replace the cartridge within 30 seconds before aborting the print.

A little messy, but this "hack" actually will allow you to print using bulk filament and provide you with a real net benefit ; cheaper printing. 

Any questions, feel free to ask.
Dan