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Nophead Mendel90 Instructions Manual

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Mendel90 Kit Instructions
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Summary of Contents for Nophead Mendel90

  • Page 1 Mendel90 Kit Instructions...
  • Page 2 The build is broken down into sub assemblies that can be worked on sequentially by one person, or in parallel if there is more than one person building. For this reason each assembly begins on a new page so the instructions can be separated. All the diagrams can be viewed in OpenSCAD allowing real time zooming, rotating and panning to...

  • Page 3: Table Of Contents

    Table of Contents 1.General Build Tips........................6 Tools Required..........................7 Recommended........................7 Consumables .........................7 2.Frame Assembly...........................8 Vitamins............................8 Printed parts..........................8 Assembly.............................9 3.Bed Fan Assembly........................11 Vitamins............................11 Printed part..........................11 Assembly...........................11 4.X Idler Assembly........................12 Vitamins............................12 Printed............................12 Assembly...........................13 5.X Motor Assembly........................14 Vitamins............................14 Printed parts..........................15 Assembly...........................16 6.Z Motor Assemblies........................21 Vitamins............................21 Printed parts..........................21...
  • Page 4 Assembly...........................38 13.Y Axis Assembly........................39 Vitamins............................39 Printed parts..........................39 Sub-assemblies..........................39 Assembly...........................40 14.X Carriage Fan Assembly......................42 Vitamins............................42 Printed parts..........................42 Assembly ..........................42 15.X Carriage Assembly........................43 Vitamins............................43 Printed parts..........................43 Assembly ..........................44 16.Hot end assembly........................45 Vitamins............................45 Assembly...........................45 17.Extruder connection pcb assembly...................47 Vitamins............................47 Assembly..........................47 18.Extruder Motor Assembly......................48 Vitamins............................48 Printed parts..........................48...
  • Page 5 Arduino IDE..........................68 Pronterface..........................68 25.Testing............................70 Jumpers.............................70 Power up...........................70 Limit switches...........................70 Motors............................70 Heaters............................71 Fan.............................71 26.Calibration..........................72 Levelling..........................72 Extruder Calibration........................73 Z Home Point..........................73 First Print...........................74 Slicing with Skeinforge......................75 Extrusion Limits........................76 27.Operating Instructions.......................77 Heated Bed..........................77 Changing filament........................77 Removal..........................77 Insertion..........................78 Different types of filament ....................78 Cleaning the hobbed bolt......................79 Using Other Software Tools......................80...

  • Page 6: General Build Tips

    1. General Build Tips X is left / right. Y is backwards / forwards. Z is up / down. • Bar lengths: The longest and shortest bars are the Y bars. Of the two pairs left, the longer • ones are the X axis and the shorter two the Z axis. The longer belt is for X and the shorter one is for Y.

  • Page 7: Tools Required

    Tools Required Spanners: 5mm, 5.5mm, 7mm & 13mm. • Allen keys: 1.5mm, 2mm, 2.5mm, 3mm & 6mm. • PZ 1 Pozidriv screw driver. • PH 1 Philips screw driver. • Small flat blade screw driver (for Melzi screw terminals). • Vice (to close IDC D type connector).

  • Page 8: Frame Assembly

    2. Frame Assembly Vitamins 2 MDF sheet 166mm x 586mm x 12mm 1 MDF sheet 485mm x 436mm x 12mm 1 MDF sheet 485mm x 586mm x 12mm 39 No6 pan wood screw x 16mm (4mm shank & 9mm head) 39 Washer M4 x 9mm x 0.8mm 39 Star washer M4 x 0.8mm Printed parts...

  • Page 9: Assembly

    Assembly Note that this view is from the back of the machine. 1. Attach the 6 fixing blocks to the base with a kebab of No6 pan wood screw and M4 Washer and a M4 star washer, the star washer goes on the screw first and the washer last so when screwed in the washer will touch the fixing block first.
  • Page 10 7. Loosely attach the two ribbon clamps. The longer one goes at the back of the base for the bed wires. The shorter one goes at the top of the gantry for the X axis cable. 8. Loosely attach the two AB Cable Clips. One at the front and one at the foot of the gantry 9.

  • Page 11: Bed Fan Assembly

    3. Bed Fan Assembly The bed fan speeds up the cool down period when the parts are finished. Vitamins 4 Nyloc nut M4 4 M4 cap screw x 25mm 4 Washer M4 x 9mm x 0.8mm 1 Fan 80mm x 38mm Printed part 1 fan_guard.stl Assembly...

  • Page 12: Idler Assembly

    4. X Idler Assembly Vitamins 1 Nyloc nut M4 2 Ball bearing 624 4mm x 13mm x 5mm 8 Washer M3 x 7mm x 0.5mm 8 M3 cap screw x 20mm 2 Washer M4 x 9mm x 0.8mm 1 M4 cap screw x 45mm 2 Washer M5 x 20mm x 1.4mm 2 LM8UU linear bearing 8 Nyloc nut M3...

  • Page 13: Assembly

    Assembly 1. Insert the two linear bearings by pushing the end which is towards the outside in first. Then slide it up against the shelf at the end before pushing in the other end. The bearings should be a snug fit. If for some reason they are loose wind a layer or tape around them. 2.

  • Page 14: Motor Assembly

    5. X Motor Assembly Vitamins 6 M3 cap screw x 16mm 1 Polypropylene strip 677mm x 25mm x 0.5mm 10 M3 cap screw x 20mm 2 M3 pan screw x 8mm 2 M3 cap screw x 45mm 4 No2 pan wood screw x 13mm (2mm shank - 5mm head) 1 15 way D IDC socket 1 Ribbon cable 20 way 1455mm...

  • Page 15: Printed Parts

    Printed parts 1 d_shell.stl 1 d_shell_lid.stl 1 ribbon_clamp_14_33.stl 1 ribbon_clamp_14_33NB.stl 1 ribbon_clamp_20_33.stl 1 x_motor_bracket.stl 1 pulley.stl 1 x_motor_ribbon_bracket.stl 2 x_end_clamp.stl...

  • Page 16: Assembly

    Assembly 1. Cut the two polypropylene strips to the lengths shown in the vitamins list. 2. Insert the linear bearings and bar clamp screws as described above for the X idler assembly. 3. Insert the two M3 nyloc nuts for the ribbon clamp, two in the ribbon_clamp_14_33NB and the remaining two in the x_motor_ribbon_bracket.
  • Page 17 and a washer. 9. Fit the motor with the ribbon bracket at the top and secure it to the front of the motor bracket with two M3 x 8mm pan screws, star washers and plain washers. 10. Motors have a ± 1mm tolerance on their length so the bracket at the back will have rome for a washer between 0 and 2mm clearance.
  • Page 18 11. The next task is attaching the 20 way ribbon cable. Peel back the first two wires at the red edge and the last four wires at the opposite edge. Insert the remaining fourteen wires into the first fourteen pins of the D type socket. i.e. pin 3 of the cable mates with pin 1 of the socket.
  • Page 19 M2.5 washers. 16. Clamp down the cable with the thinner polypropylene strip under it (against the D shell) using the ribbon_clamp_14_33NB, M3 x 16mm cap screws and M3 washers (from the underside). 17. Complete the D connector by adding M3 x 20mm retaining screws and washers and then secure them in place with the rubber O rings.

  • Page 21: Z Motor Assemblies

    6. Z Motor Assemblies Vitamins 8 M3 cap screw x 20mm 2 M4 cap screw x 20mm 2 NEMA17 x 47mm stepper motor 8 Nyloc nut M3 2 Nyloc nut M4 8 M3 pan screw x 8mm 2 Neoprene tubing OD 8mm ID 5mm x 16mm 18 Washer M3 x 7mm x 0.5mm 6 Washer M4 x 9mm x 0.8mm 8 Star washer M3 x 0.5mm...

  • Page 22: Assembly

    Assembly 1. Fit all the nyloc nuts into their nut traps. 2. Fit the M4 x 20mm cap screws to the bar clamps with plain washers. 3. Attach the motor with the wires exiting towards the back using four M3 x 8mm pan screws, star washers and plain washers.
  • Page 23 using an electric drill. Tie a knot in the far end and put it in the chuck. The reason they are twisted is to minimise the radio frequency emissions. 9. Attach the motor assemblies to the gantry using No6 16mm pan wood screws and washers and star washers.

  • Page 24: Z Axis Assembly

    7. Z Axis Assembly Vitamins 2 M4 cap screw x 20mm 2 Smooth rod 10mm x 545mm 2 Brass nut M8 1 Microswitch 2 Nyloc nut M4 2 Threaded rod M8 x 505mm 2 No2 pan wood screw x 13mm 2 Washer M2.5 x 5.9mm x 0.5mm 4 No6 pan wood screw x 16mm 6 Washer M4 x 9mm x 0.8mm...

  • Page 25: Assembly

    Assembly 1. Note that the Z bar clamps are the two longer ones. 2. Insert the M4 nyloc nuts into the nut traps inside the bar clamps 3. Fit M4 x 20mm cap screws and washers to the bar clamps. 4.
  • Page 26 9. Thread the M8 brass nuts onto the bottom of the lead screws (threaded rod) about 100mm of the way up. These eventually seat in the nut traps in the top of the X ends. They need to be a snug fit.

  • Page 27: Y Idler Assembly

    8. Y idler assembly Vitamins 2 Ball bearing 624 4mm x 13mm x 5mm 1 No6 pan wood screw x 16mm 1 M4 cap screw x 30mm 5 Washer M4 x 9mm x 0.8mm 1 Nyloc nut M4 2 Washer M5 x 20mm x 1.4mm 1 Star washer M4 x 0.8mm Printed parts 1 y_idler_bracket.stl...
  • Page 28 screw the screw in one or 2 turns as it will have to come out later.

  • Page 29: Y Motor Assembly

    9. Y motor assembly Vitamins 1 M3 grub screw x 6mm 4 Star washer M3 x 0.5mm 1 NEMA17 x 47mm stepper motor 4 Star washer M4 x 0.8mm 4 M3 pan screw x 8mm 1 Nut M3 4 Washer M3 x 7mm x 0.5mm 4 No6 pan wood screw x 16mm 4 Washer M4 x 9mm x 0.8mm Printed parts...

  • Page 30: Assembly

    Assembly Put the M3 nut in its nut trap in the pulley, then assemble as shown above with the motor shaft protruding 3mm from the pulley. The wires should be twisted in pairs (as described for the Z motors) and routed along the base though the 2 clips and then thorugh the mouse hole in the right stay.

  • Page 31: Y Carriage Assembly

    10. Y Carriage Assembly Vitamins 8 M3 cap screw x 16mm 8 Nyloc nut M3 6 M4 cap screw x 16mm 8 Nyloc nut M4 2 M4 cap screw x 20mm 8 Washer M3 x 7mm x 0.5mm 1 Dibond sheet 426mm x 426mm x 12mm 14 Washer M4 x 9mm x 0.8mm 3 LM10UU linear bearing 3 Ziptie 105mm min length...

  • Page 32: Assembly

    Assembly This view is from the bottom of the bed which is the matt side of the DiBond. Except for the cable clamps, the nuts go on the bottom and the screw heads and washers on top . The cable clamps have the heads on the bottom to avoid a clash with the Y idler.

  • Page 33: Y Heatshield Assembly

    11. Y Heatshield Assembly The heatshield insulates the bottom surface of the heated bed to allow it to get hot enough for ABS. It isn't needed for printing PLA . If you want to print ABS it can be added later as it just slides under the bed.

  • Page 34: Print Bed Assembly

    12. Print bed assembly Vitamins 4 19mm bulldog clip 2 Heatshrink sleeving ID 1.6mm x 15mm 1 PCB bed 428mm x 428mm 2 Heatshrink sleeving ID 2.4mm x 15mm 4 M3 cap screw x 10mm 2 Heatshrink sleeving ID 6.4mm x 30mm 1 Glass sheet 428mm x 416mm x 2mm 1 Epcos B57861S104F40 100K 1% thermistor (pre-fitted)

  • Page 35: Bed Wiring

    Bed Wiring The thermistor comes pre-glued to the bed with J-B Weld, which is a high temperature thermally conductive epoxy. 1. Separate all the 26 ways of the ribbon cable and strip about 10mm of insulation. 2. Twist the first 12 wires together, leave two for the thermistor and then twist the last 12 together.
  • Page 36 6. Separate, strip and bunch the other end of the cable in the same way and solder the red and black 32/0.2 wires as shown below and then sleeve with the 6.4mm heat shrink. 7. Use red and black wires trimmed from the X motor for the thermistor wiring. Twist them before soldering and sleeve with the 2.4mm sleeving.

  • Page 37: Assembly

    Assembly 1. Screw the pillars into the Y carriage. Note that the rear two pillars have a washer under them. The front two are initially spaced the same distance by using a washer as a temporary shim. They can then be adjusted up or down slightly to level the bed relative to the nozzle. 2.

  • Page 38: Y Axis Assembly

    13. Y Axis Assembly Vitamins 1 Belt T5 x 6mm x 1320mm 1 Smooth rod 10mm x 504mm 4 M4 cap screw x 20mm 1 Smooth rod 10mm x 855mm 4 Nyloc nut M4 1 Microswitch 2 No2 pan wood screw x 13mm 2 Washer M2.5 x 5.9mm x 0.5mm 8 No6 pan wood screw x 16mm 12 Washer M4 x 9mm x 0.8mm...

  • Page 39: Assembly

    Assembly 1. Insert the captive nyloc M4 nuts and M4 x 20mm cap screws and washers in each of the Y bar clamps. 2. Loosely fit the two left hand Y bar clamps to the base with No6 pan wood screws washers and star washers.
  • Page 40 7. Clamp the Y belt (the shorter of the two) in the front belt anchor with the teeth facing away from the carriage. The end of the belt should project enough to have four complete teeth showing. 8. Put a half twist in the belt and the thread it through the Y idler assembly with the smooth side against the bearings and then clamp it in the rear clamp with the teeth facing the carriage.

  • Page 41: Carriage Fan Assembly

    14. X Carriage Fan Assembly Vitamins 4 M4 cap screw x 30mm 4 Nyloc nut M4 1 Fan 60mm x 15mm 4 Washer M4 x 9mm x 0.8mm Printed parts 1 x_carriage_fan_bracket.stl 1 x_carriage_fan_duct.stl Assembly 1. Assemble as shown below with the fan label downwards and the wires exiting nearest the leftmost screw in the picture.

  • Page 42: Carriage Assembly

    15. X Carriage Assembly Vitamins 2 M3 cap screw x 10mm 4 Nyloc nut M3 1 M3 cap screw x 20mm 4 Washer M3 x 7mm x 0.5mm 2 M3 cap screw x 25mm 3 Ziptie 105mm min length 3 LM10UU linear bearing 1 Belt T5 x 6mm x 860mm 1 Nut M3 Printed parts...

  • Page 43: Assembly

    Assembly 1. Insert the linear bearings and secure each one with a zip tie. 2. Put M3 nyloc nuts in the four nut traps. 3. Add the two M3 x 10mm screws and washers for the fan mount but leave loose. 4.

  • Page 44: Hot End Assembly

    16. Hot end assembly Vitamins 1 JHead MK5 hot end 2 PTFE sleeving OD 2.6mm ID 2mm x 45mm 1 110mm x 25mm self fusing silicone tape 1 Heatshrink sleeving ID 6.4mm x 60mm 1 UB5C 5R6F 5R6 3W vitreous enamel resistor 2 Red PTFE wire 16/0.2 length 170mm 1 Epcos B57560G104F 100K 1% thermistor 2 Green wire 7/0.2 length 140mm...

  • Page 46: Extruder Connection Pcb Assembly

    17. Extruder connection pcb assembly Vitamins 1 15 way D PCB mount plug 1 2 way Molex KK header 1 3 way Molex KK header 1 Extruder connection PCB 2 4 way terminal block Assembly Solder the connectors to the PCB as shown. Start with the shortest parts first and solder one pin in the middle then check it is flat and aligned (better than mine!) before soldering the remaining pins.

  • Page 47: Extruder Motor Assembly

    18. Extruder Motor Assembly Vitamins 2 M3 cap screw x 45mm 2 No2 pan wood screw x 13mm 1 M3 grub screw x 6mm 2 Washer M2.5 x 5.9mm x 0.5mm 1 NEMA17 x 47mm stepper motor 2 Washer M3 x 7mm x 0.5mm 3 Nut M3 Printed parts 1 d_motor_bracket.stl...

  • Page 48: Assembly

    Assembly Note that the wires exit the motor on the bottom edge (left edge in the picture). 1. Remove two of the motor's screws and replace them with the longer M3 x 45mm screws and washers that fasten the d_motor_bracket to the motor. The motor screws are Philips head screws, not Posidriv.
  • Page 49 Terminal PCB Label Motor Wire Black Green Blue...

  • Page 50: Extruder Assembly

    19. Extruder Assembly Vitamins 3 Ball bearing 608 8mm x 22mm x 7mm 2 Nut M8 3 M3 cap screw x 16mm 1 Smooth rod 8mm x 22mm 3 M3 hex screw x 10mm 2 Spring 7mm OD, 1mm gauge x 10mm long 2 M4 hex screw x 20mm 3 Washer M3 x 7mm x 0.5mm 2 M4 hex screw x 50mm...

  • Page 51: Assembly

    Assembly 1. Press fit the bearings into the extruder with a vice or pull them in using the M8 bolt and a nut. They are a tight fit to ensure there is no movement during reversals which would wear away the plastic. 2.
  • Page 52 3. Insert the two M4 nuts into the slots in the bearing block, one from above and one from below (not visible in the picture). 4. Push the idler axle through the bearing and snap it into the idler block. 5.
  • Page 53 to pull it in. Some force on the filament is needed initially to open the idler but once you see it open the filament can be fed by just turning the gear. 12. This is the way the extruder is loaded. Normally one would wind it in by hand until it hits some resistance, then heat the extruder and feed it with the motor.

  • Page 54: Axis Assembly

    20. X Axis Assembly Vitamins 2 Smooth rod 8mm x 381mm 2 Wingnut M4 Sub-assemblies 1 extruder_assembly 1 x_carriage_assembly 1 x_carriage_fan_assembly...

  • Page 55: Assembly

    Assembly 1. Put the X ends at the bottom of the Z axis. 2. Make sure the X bars are completely free of grease or the clamps won't grip. 3. Remove the idler's axle bolt. 4. Slide the X bars through the idler bracket and the X carriage. Sliding them through the bearings will make them oily so degrease the ends that pass through again.
  • Page 56 9. Tension the belt enough to play a low note when plucked. 10. Run the carriage up and down a few times and check that the belt does not rub on the idler washers. If it does then shim one side of the penny washer where it rests against the plastic with a few layers of paper (or an off-cut from the cable strips) until it runs true.

  • Page 57: Spool Holder Assembly

    21. Spool holder assembly The spool holder will hold a 300 x 85mm spool commonly used by filament suppliers for 2.3kg reels. The spool is not included in the kit. Vitamins 4 Ball bearing 608 8mm x 22mm x 7mm 2 No6 pan wood screw x 16mm 2 M4 cap screw x 16mm 1 PTFE tubing OD 4.6mm ID 3.84mm x 750mm...

  • Page 58: Assembly

    Assembly The male and female halves of the brackets press fit together. 1. Insert the two M4 nyloc nuts into the nut traps in the male brackets. 2. Screw the bearings to the brackets using the sequence of washers shown above. 3.

  • Page 59: Psu Assembly

    22. PSU assembly Vitamins 1 THS15 Aluminium clad resistor 10R 1 Heatshrink sleeving ID 10mm x 15mm 1 THS15 Aluminium clad resistor 4R7 3 Heatshrink sleeving ID 2.4mm x 15mm 1 PSU e.g. ALPINE500 5 Heatshrink sleeving ID 3.2mm x 15mm 1 IEC mains lead 2 Heatshrink sleeving ID 6.4mm x 15mm 2 6-32 pan screw x 9.5...

  • Page 60: Wiring

    Wiring 1. Cut one of the black wires to a length of 240mm and one of the red wires to 280mm, strip them, add 15mm of 3.2mm heatshrink and solder to the 10R (gold in the kit) dummy load resistor. 2.

  • Page 61: Summary

    cut off the point and sleeve with 15mm of 6.4mm heatshrink leaving enough wire protruding to fit the terminal block on the Melzi terminal. 8. Cut the 12 remaining black wires to a length of 210mm, strip 15mm, twist and solder them together, cut off the point and sleeve with 15mm of 10mm heatshrink, leaving just enough wire protruding to fit the terminal block on the Melzi.

  • Page 62: Assembly

    Assembly 1. Put four M4 nyloc nuts in the nut traps of the two brackets. 2. Screw the brackets to the frame with M4 x 16mm cap screws and washers. 3. Run the wires from the right Z motor, the Y motor and the bed up the corner between the gantry and the right stay before fitting the PSU between the brackets.

  • Page 63: Electronics Assembly

    Please double check before connecting the power. It is supplied loaded with Marlin firmware configured for the Mendel90, has the stepper motor current pots pre-set to 0.5V, which gives 1.2A and has had a full functional test on a jig with motors, limit switches and dummy loads for the heaters and fans.
  • Page 64 Melzi Connector Wire Signal D connector pin ETEMP GND Ribbon 4 Extruder thermistor GND Pin 9 ETEMP SIGNAL Ribbon 3 Extruder thermistor signal Pin 1 BTEMP GND Black Bed thermistor GND BTEMP SIGNAL Bed thermistor signal ZSTOP GND Blue Z limit switch GND ZSTOP SIGNAL Blue Z limit switch signal...
  • Page 65 The Z motors are wired in series, so connect red and green of the first motor and blue and black of the second motor to the Melzi, connect blue on the first motor to red on the second motor and sleeve the joint with 2.4mm x 15mm heatshrink.

  • Page 67: Software

    The following softwares are included: Marlin Firmware This is the source code for the firmware that is pre-loaded on the Melzi. It is Nophead's fork and is also available on GitHub https://github.com/nophead/Marlin. The pre-installed version is sufficient to test the machine but calibration involves tweaking the Z axis home position and the hobbed bolt diameter.

  • Page 69: Testing

    Open pronterface, set the baud rate and serial port and press “Connect”. After a few seconds the following should be displayed. Connecting... start Printer is now online. echo:Marlin: 1.0.0 RC2 echo: Last Updated: 2012-07-27 | Author: nophead echo: Free Memory: 12982 PlannerBufferBytes: 1232 echo:Using Default settings: echo:SD card ok Limit switches Check that the limit switches are working with M119.

  • Page 70: Heaters

    Note that both the X and Y axes are backwards by normal conventions when viewed from the front of the machine. Because the Z limit switch is at the top the +Z button should move the Z axis upwards towards its limit switch and -Z should move it back downwards. When all the axes have been homed successfully enter G1 X0 Y0 Z100 F30000 to centre them.

  • Page 71: Calibration

    26. Calibration Bed Levelling The best way to level the bed relative to the nozzle is to use a dial gauge mounted in place of the extruder using this clamp. If you don't have a dial gauge you can roll a spare piece of smooth rod or slide some paper or film under the nozzle and feel when it is just touching.

  • Page 72: Extruder Calibration

    Extruder Calibration The E steps per mm should be adjusted so that when commanded to extrude 100mm it actually feeds 100mm. This is done by placing a mark (a piece of tape for instance) on the filament 120mm above the extruder and telling it to feed 100mm at say 60mm/min. Then measure the distance to the mark to work out how much it actually extruded.

  • Page 73: First Print

    First Print 1. Clean the glass bed to remove any finger marks. 2. The SD card also contained a G code file: android_export.gcode. This should print well assuming your filament is close to the 2.86mm that it was sliced for. Open it with the File / Open menu option of Pronterface and then press the SD button and select SD Upload.

  • Page 74: Slicing With Skeinforge

    Slicing with Skeinforge The android sample was sliced with Skeinforge (downloaded from http://fabmetheus.crsndoo.com/), which was also on the SD card in the Skienforge50 folder and the settings used to slice it are in the Settings\.skeinforge folder. 1. Running Skeinforge requires Python 2.7 to be installed and then run skeinforge\skeinforge_application\skeinforge.py.

  • Page 75: Extrusion Limits

    Perimeter Flow Rate Multiplier (set from the formula below to get accurate outlines) Note that the temperatures are set in .skeinforge\alterations\start_PLA.gcode, rather than using the Temperature module because start.gcode contains the warm up code for ooze free start. Extrusion Limits The kit comes with a 0.4mm nozzle, which sets the maximum layer height you can use and the minimum line width.

  • Page 76: Operating Instructions

    27. Operating Instructions Heated Bed The purpose of the heated bed is twofold: to reduce warping and to make the first layer stick. In general molten plastics don't stick well to cold smooth surfaces but they will stick to some hot surfaces.

  • Page 77: Insertion

    transition temperature but below its melting point). As it is therefore not a liquid but a rubbery solid, it will pull out in one piece leaving very little behind. It does stretch a lot though, so you need to rewind about 150mm to get it all out. The same trick can by done with ABS at 150˚C. Do not leave the extruder hot without filament as the plastic residue inside will oxidise and become baked on to the inside of the melt chamber.

  • Page 78: Cleaning The Hobbed Bolt

    Cleaning the hobbed bolt In normal use the hobbed bolt does not need cleaning. If the filament starts slipping for any reason, such as not enough spring tension, or the nozzle is blocked then its teeth can become clogged with plastic.

  • Page 79: Using Other Software Tools

    Other slicers and hosts can be used but note that they usually assume the origin of the machine is at the front left corner of the bed by default, whereas Mendel90 has it in the centre. The slicer needs to be configured to slice the object at (0,0) and the host needs to be configured to display gcode with (0,0) in the middle of the simulated bed.
  • Page 80 In Slic3r the centre of the bed is defined in the Printer Settings dialogue box.
  • Page 81 In Pronterface the centre of the bed is defined in the Settings / Options build_dimensions field by setting it to 200x200x200-100-100+0. In Repetier Host it is set in the Config / Printer Settings / Printer Shape dialogue. Another important setting is to select relative extruder motion. The firmware expects the E codes to be relative by default.

  • Page 82: Notes For Printers

    28. Note for printers X idler bracket and X motor bracket has nut traps in the that dont come up if sliced with slic3r. Use skeinforge for this instead. Most parts are small, so it might be usefull to keep the extruder fan running all the time. Since these small parts have a high risk of wapring at corners close to the fan, its best to print them as singles, even thou you have to print the same object several times in a row.
  • Page 83 Randomize starting points: No External perimeters first: No Infill Infill Fill density: “look in table above” Fill pattern: Honeycomb Top/buttom fill pattern: Rectilinear Reducing print time Combine infill every: 1 Layers Only infill where needed: No Advanced Solid infill every: 0 Layers Fill angle: 45º...
  • Page 84 Loops: 1 Distance from objects: 6 mm Skirt height: 1 layers Minimum extrusion lenght: 5 mm Brim Brim width: 0 mm Support material Support material Generate support material: No Overhang threshold: 0º Enforce support for the first: 0 layers Raft Raft layers: 1 layers Raft Raft layers: 1 layers...
  • Page 85 Ooze prevention Enable: No Temperature variation: -5 ∆ºC Advanced Extrusion width Default extrusion width: 0 First layer: 0 Perimeters: 0 Infill: 0 Solid infill: 0 Top solid infill: 0 Support material: Flow Bridge flow ratio: 1 Other Threads: 2 Resolution: 0 mm...

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