The cost of build is ~$550, prices with taxes and shipping included. Folger Tech is selling a Kossel Mini for $399 which can also be upgraded to Beaglebone / LinuxCNC as shown here for a few dollars more.
BOM is as follows, proceed at your own risk:
- Kit for most of the components: ebay (from here): $175.00.
- Cork motor isolators: ebay (from here): $5.98.
- Sorbothane feet ebay (from here): $8.49. (Installed one centered under each motor.)
- Screws and bolts: BoltDepot.com: $23.29. You can use the screw list here as a starting point, but most screws need length & quantity modification for the $175 kit.
- Direct order the following from Folger Tech: $122.24:
Qty | Item #| Description
6 | #000299 | LM8UU (Optional as the $175 kit can upgrade to this for free on request)
4 | #000276 | NEMA 17 4800g/cm with wires 70 cm
1 | #000357 | 1.75mm All Metal J-Head (Bowden Style)
4 | #000252 | A4988 Driver / Heat Sink (Older, cheaper, & works just fine)
1 | #000231 | 1.75 / PTFE / 2meters
1 | #000351 | Fan
1 | #000355 | 0.5mm Nozzle (Optional as the J-Head comes with ∅0.3mm)
- MK8 Drive Gear (Folger Tech ebay store) (from here): $5.99. (Needed as the MK7 included in the $175 kit needs marginally more torque than the selected motor can provide.)
- Acrylic Frame: MakerFarm: $30.00. This is the Mini frame. Comes with an acrylic J-Head holder, which you will need. If building full size, source elsewhere.
- Beaglebone Cape (CRAMPS): Pico Systems: $87.50.
- Beaglebone Black Rec C: Adafruit: $64.47.
- 6 x ⅛” rubber grommets radially cut in half for silencing the motors and misc. nuts and bolts: local Ace Hardware $10.43.
- 7″ round mirror: ebay (from here): $4.23.
- 7″ round cork board: local Michael’s $1.00.
- Spiral wire guard: local HomeDepot $3.26.
- Power supply: I recycled an old PC power supply, for free. Any $20+ PC power supply should do. Instructions on how to trip it on for use outside of a PC are abundantly available on the internet, generally referred to as a “paper clip test”. I recommend using proper wiring.
- Additional limit switches with easier to remove levers: ebay (from here): $6.45.
- Connectors (saves crimping, but requires cutting and soldering): ebay (from here): $3.89.
- Calipers: ebay (from here): $10.00. Nice to have.
- Micro HDMI cable for Beaglebone: Monoprice: $8.00. Not needed unless you are doing development.
- Initial Setup: CRAMPS BeagleBone cape with MachineKit: here.
- MachineKit Delta configuration + calibration: here.
- Cape & software: here.
- Machinekit google group: here.
- Slicing: here.
Rapid Prototyped Parts Once Running
- Bracket: for extruder.
- Bracket: for Beaglebone.
- Tabs holding mirror: STL file.
Machinekit / LinuxCNC Setup
Custom files: for LinuxCNC Rostock Delta configuration.
To Get The Fan & The LED Working:
In my setup:
- CRAMPS FET5 is the fan
- CRAMPS FET6 is the LED
In file machinekit-dev/M106
halcmd setp hal_pru_generic.pwmgen.00.out.04.value $1
# halcmd sets fan.speed.set $1
In file machinekit-dev/M107
halcmd setp hal_pru_generic.pwmgen.00.out.04.value 0
In file CRAMPS.lineardelta.hal
# FET 5 - Fan / LED
setp hal_pru_generic.pwmgen.00.out.04.pin 52
setp hal_pru_generic.pwmgen.00.out.04.enable 1
setp hal_pru_generic.pwmgen.00.out.04.value 0.0
setp hal_pru_generic.pwmgen.00.out.04.scale 255
# FET 6 - Fan / LED
setp hal_pru_generic.pwmgen.00.out.05.pin 34
setp hal_pru_generic.pwmgen.00.out.05.enable 1
setp hal_pru_generic.pwmgen.00.out.05.value 1.0
I set the last line to default on so that the LED is turned on as soon as the machine is armed to be a visual indicator.
Problems / Issues / Notes:
The $175 kit is for full size Rostock. When you build it as a Mini, the 250mm arms are a bit too long. Not a big deal though. The height is also a bit too tall for the Mini, but I see that as an advantage as the build height can be as tall as 350mm.
The orange colored 40mm fan and the LED are held in place with a paper clip bent to form, and a single screw each. Saves weight. The fan needs to be oriented & aligned as shown. It needs to be running when the heater is on, otherwise this particular J-Head heats up towards its top, and causes the fed material to buckle during extrusion.
The acrylic part holding the J-Head needs to be opened up in size, since it is just a hair too tight to accept the selected J-Head. I used a Dremmel tool. I epoxied the J-Head in place on the acrylic piece using high temperature epoxy (J•B Weld).
MK8 drives the ∅1.75mm material successfully. MK7 is marginally on the weak side. This particular setup probably would not feed a ∅3.0mm material successfully.
Also, I did not include a heated bed, but the Kossel version from Folger Tech does include one.
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Rostock Mini with Beaglebone Black Rev. C & LinuxCNC,