MicroCube

thingiverse

It is recommended to use the CoreXY version with Nema17 stepper motors instead of the H-Bot as the speed and quality is significantly better. Link to MicroCube CXY:https://www.thingiverse.com/thing:3222004 The MicroCube is a small, inexpensive 3D printer, designed around the cheap 28BYJ-48 stepper motors (files for Nema17 included except Z axis). The structure of the printer is based on an exoskeleton, which also serves as the smooth rods for the y-axis. The printer type is an H-bot style printer using a fishing line. In order to provide enough torque for the extruder, two steppers are used in series (or single Nema17 version). Due to the limitations of the 28BYJ-48 steppers, the precision is limited as well as the print speed (2-3 times slower than a standard printer). Video of print: https://youtu.be/JlPdN9ktdqY Features: Low cost ~100€ Easy to build Printable Area of 120mm x 115mm x 95mm Small footprint 220mm x 220mm Low noise during print (with 28BYJ-48 steppers ~50dB, with Nema17 ~60dB) Upgradeable with Nema17 motors for higher speed and precision History 2016/12/03 Version 1.0 Initial Version 2016/12/07 Video added 2016/12/18 Added Nema17 extruder and X/Y axis components incl. diagonal stabilizer 2016/12/27 Added assembly guide to the files 2016/12/28 Added part cooling fan, increased print quality 2017/04/02 Edited corner Nema17 mounts to also hold Nema14 motors 2017/05/14 Added spool compartment and spool holder 2017/06/05 Added PSU holder for Laptop supply 2018/11/17 Upload of CoreXY version Print Settings Printer Brand: Robo 3D Printer: R1 ABS + PLA Model Rafts: Doesn't Matter Supports: Doesn't Matter Resolution: 0.2 Infill: 30% Custom Section Instructions Partlist Printed parts: 4 x Corner parts bottom (Corner_bottom.STL) 1 x RAMPS holder (Ramps_holder.STL) 1 x LCD controller bracket, bottom (optional) (LCD_holder_bottom.STL) 2 x LCD controller bracket, side (optional) (LCD_holder_side.STL) 1 x z-axis bottom (z_axis_motor_mount_rod.STL) 1 x z-axis top (z_axis_bearing_mount_rod.STL) 2 x z-axis motor coupler (z_motorshaft_shaft_coupler.STL) 1 x z-axis bed platform (Z_axis_platform_mount.STL) 2 x z-axis bed holder (Bed_Lever.STL) 2 x End switch holder (Limit_switch.STL) 1 x Corner part front left (Corner_l.STL) 1 x Corner part front right (Corner_r.STL) 2 x Corner part motor (Motor_corner.STL) 1 x Motor mount left (Motor_mount_l.STL) 1 x Motor mount right (Motor_mount_r.STL) 2 x Motor pulley (Pulley_15mm.STL) 2 x y-axis carriage (y_carriage.STL) 1 x y-axis end stop trigger (y_carriage_endstop_trigger.STL) 1 x x-axis carriage (x-carriage.STL) 1 x x-axis wire holder (Wire_holder.STL) 1 x x-axis fan holder (Fan_holder.STL) 1 x x-axis carriage tensioner (x-carriage_tensioner.STL) 1 x hotend fan duct (Hotend_duct.STL) 1 x Extruder base (Extruder.STL) 1 x Extruder lever (Extruder_Lever.STL) Cable clips small/big as required (Cable_Clip.STL/Cable_Clip_big.STL) Nema17 upgrade: 1 x Extruder_Nem17_axis.STL 1 x Extruder_Nem17_Mount.STL or Extruder_Nem17_Mount_strip.STL 1 x Extruder_Nema17.STL 1 x Extruder_Nema17_Lever.STL 4 x Corner_stabilizer.STL Spool holder upgrade: 2 x Corner_stabilizer.STL 4 x Corner_middle_motor.STL 2 x Spool_holder.STL 1 x 135mm x 8mm axis (aluminum tube from the frame) Electronics: 5 x Stepper motor 28BYJ-48 5V (bipolar hack required) 3 x Nema17 motors (optional) 1 x 12V / 80W or more power supply (Laptop charger or for LED stripes ) 1 x Arduino Mega 1 x RAMPs 1.4 Board 1 x LCD Controller (optional) 3 x SS-5GL microswitches 1 x 30mm fan 12V 1 x E3D V6 hotend or China clone 1 x USB cable 1 x Power supply power cord Ribbon cable to extend motor wires Metal parts: 2 x Direct drive gear 11mm 6 x Smooth rod 8mm x 200mm 10 x Aluminium tubes 8mm (imperial 5/16 should also work) x 200mm (or other material) 8 x LM8UU linear bearings 2 x Springs for extruder (7mm x 30mm, strong) 4 x Springs for bed leveling (7mm x 20mm) 1 x Ball bearing 605 (14mm outer, 5mm hole, 5mm thick) 8 x U grooved ball bearing 604uu (13mm outer, 11mm inner, 4mm hole, 4mm thick for 1.75mm filament) 1 x M5 threaded rod ca. 160mm + M5 nut 6 x M2 x 12mm 1 x push fit tube mount M5 M3 and M4 screws and nuts Nema17 upgrade: 2 x 8mm aluminium tube 230mm Spool holder upgrade: 4 x Aluminium tubes 8mm x 200mm (or other material) 4 x Aluminium tubes 8mm x 120mm (or other material) 1 x Aluminium tube 8mm x ~130mm (or other material) Miscellaneous: Zip ties 200mm x 3.6mm or comparable shrinking tube wires, pinheads Print bed 4mm polycarbonat 150mm x 150mm Pneumatic pushfit M5 Pneumatic tube ca. 400mm ~1.5m fishing line Electronics For the use of the 28BYJ-48, the bipolar hack is required. A description how this can be done is available at http://www.electronicsmayhem.com/?p=13 , all 5 motors must be prepared as described. The wires of the motors are quite short and need to be extended, at this point, the connector could also be set in the correct sequence to match the RAMPs connector: 2B = yellow * (pin1) 2A = blue 1A = pink 1B = orange At the RAMPs board, the current limit needs to be set before powering it the first time, following values could be used as Vref, fine tuning will be required due to production tolerances of the motors. During testing, X/Y/Z steppers didn’t lose any step, but they heated up slightly. X/Y/Z driver = 75mV E driver = 150mV Mechanics The printer is designed as an H bot, due to the small size, a fishing line is used along with ball bearings which are usually used in the extruder to guide the fishing line. The extruder with two motors instead of one is used in order to provide enough torque for a direct drive bowden setup, the tension of the spring must be balanced not to harm the motors or gears but also to provide enough force for extrusion. Software Firmware used for the MicroCube is Marlin 1.1.0 RC7, the configuration.h is provided along the files as a starting point to get the printer setup quickly. Here are some informations about the set values for the MicroCube: Since Arduino Mega with RAMPs is used, Motherboard must be set to: ifndef MOTHERBOARD define MOTHERBOARD BOARD_RAMPS_14_EFB endif Mechanical settings sections holds the information about the kinematics, in case of the MicroCube setup following line must be set: define COREXY To match the mechanical setup with 200mm rods, the print area is set to: define X_MIN_POS 0 define Y_MIN_POS 0 define Z_MIN_POS 0 define X_MAX_POS 120 define Y_MAX_POS 115 define Z_MAX_POS 95 Motor speed settings (28BYJ-48): define DEFAULT_AXIS_STEPS_PER_UNIT {685,685,40758,1000} define DEFAULT_MAX_FEEDRATE {30, 30, 0.25, 5} define DEFAULT_MAX_ACCELERATION {300,300,1,10} define DEFAULT_ACCELERATION 250 define DEFAULT_RETRACT_ACCELERATION 150 define DEFAULT_TRAVEL_ACCELERATION 300 define DEFAULT_XYJERK 5.0 // (mm/sec) define DEFAULT_ZJERK 0.01 // (mm/sec) define DEFAULT_EJERK 1.0 // (mm/sec) Motor speed settings (Nema17 version): define DEFAULT_AXIS_STEPS_PER_UNIT {66.5,66.5,40758,96.1} define DEFAULT_MAX_FEEDRATE {120, 120, 0.2, 10} define DEFAULT_MAX_ACCELERATION {300,300,1,20} define DEFAULT_ACCELERATION 250 define DEFAULT_RETRACT_ACCELERATION 150 define DEFAULT_TRAVEL_ACCELERATION 300 define DEFAULT_XYJERK 5.0 // (mm/sec) define DEFAULT_ZJERK 0.01 // (mm/sec) define DEFAULT_EJERK 1.0 // (mm/sec) Assembly Assembly guide added as PDF to the files (MicroCube assembly guide.pdf) Sample prints After setting up the printer and basic adjustment of the axis, 3DBenchy was printed as reliability test for the printer. The result was surprisingly good, picture of the first print along the picture section. Todo Nema17 holders (including additional frame parts for more stiffness) DONE Improved extruder DONE Include power supply (enough space available besides RAMPS) DONE Setup guide DONE Part cooling fan DONE Endurance test