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[[Category:PrusaMendel]]
[[Category:PrusaMendel]]
[[Category:RepRap]]
This is the page on how to use the newly built Prusa Mendel (iteration 2). A PC has been dedicated to run it, below you will find the toolchain used to run it and other details that you may find useful. [[File:PrusaMendel.jpg|thumb|right]]
=Current Machine Status=
'''Operational'''


More detailed documentation on the newly built Prusa Mendel (iteration 2). A PC has been dedicated to run it, below you will find the toolchain used to run it and other details that you may find useful.


=Workflow=
=Workflow=


CAD/Thingiverse -> Netfabb -> STL -> Slic3r -> Pronterface -> PRINT!
CAD/Thingiverse -> Netfabb -> STL -> Slic3r -> Pronterface -> PRINT!
See operation section for a tutorial.


;CAD
;CAD
: Any modelling software that can output the file format STL.  
: FreeCAD (free, open source) and SolidWorks (expensive, some extra features) offer intuitive sketch and constraint based modeling.
: Some programs of interest might be the following: Google Sketchup, OpenSCAD, TinkerCAD, Solid Works, AutoCAD, Rhino.
: OpenSCAD uses programming code to describe 3D models.
: And in case you don't want to model anything and simply want to print stuff, go to [http://www.thingiverse.com Thingiverse].
: And in case you don't want to model anything and simply want to print stuff, go to [http://www.thingiverse.com Thingiverse].


Line 41: Line 37:


=Materials=
=Materials=
* PLA
Switching from PLA to ABS, or vice versa, will require purging extruder at with at least one meter of filament at >225C.
 
Generally, PLA is stronger, better for the environment, and easier to print with. Please use ABS only if there is a specific need for it.
 
* PLA - Polylactic Acid
: '''Extremely ecologically friendly''', made from corn starch, smells like waffles/syrup while printing.
: Harder than ABS at room temperature.
: Needs a fan for parts with overhang/bridging.
: Recommended solvent for gluing or vapor polishing is tetrahydrofuran. Slightly more hazardous, much more expensive, and less effective.
: Low operating temperature (160C-200C).
 
* ABS
* ABS
: '''Much less environmentally friendly.'''
: Weaker than PLA at room temperature.
: Poorer adhesion to bed while printing, may need polycarbonate bed, paper tape, kapton tape, etc.
: Degrades nozzle, forcing more frequent cleaning by an experienced person with blowtorch and acetone.
: High operating temperature (225C-240C).
: Recommended solvent for gluing or vapor polishing is acetone. Low risk, low cost, highly effective.
: Suitable for moderately high-temperature applications like coffee mugs, outdoor fixtures, and certain 3D printer components.


;PLA
=Extra Maintenance=
: Polylactic Acid
==Malfunction==
: made from corn starch, smells like waffles/syrup while printing
*Only grease with PTFE SuperLube, kept at HacDC next to printer.
: extremely ecologically friendly
*Grease smooth rods and Z-Axis threaded rod if axes show signs of binding.
: less prone to warping
*Tighten timing belts if not taunt.
: more brittle compared to ABS
*Floss the hobbed bolt in the extruder.
: needs a fan, it remains much more molten after being extruded
*Replace linear bearings if they are grinding, slipping laterally, or otherwise ruined.
: lower operating temperatures (160C-200C)
: Preferred plastic of choice
 
;ABS
: UNSUPPORTED, WILL DAMAGE PRINTER
: burns when heated too long
: same plastic in which LEGOs are made of
: flexible
: higher operating temps (220C-240C)
: smells like death, releases small quantities of hydrogen cyanide
: requires a heated bed (110C) or warping occurs
: requires kapton/PET tape on heated print surface for best adhesion. Possibly a light sanding of the surface and slurry of dissolved ABS in acetone for further warp prevention.


=Machine Setup/Specs=
==Replacing filament/changing spools==
#Turn on the printer, open pronterface, and connect to the printer.
#If there is filament sticking out of the top of the extruder, you'll need to remove it.
#Set the hotend temperature (175-185 degrees Celsius for PLA)
#When extruder is warmed up, raise the extruder (+z axis) so it's not touching the bed.
#Click the reverse button while gently pulling upwards on the filament you wish to remove.
#Continue gently pulling and pressing reverse until the remaining filament is drawn out from the top of the extruder housing.
#Once the filament has been removed, replace the spool.
#Feed the new filament into the appropriate hole in the extruder housing.
#Gently press down on the filament while clicking "extrude" in pronterface. The extruder should grab the filament as you feed it.
#Repeat the previous step until you see the new material being extruded from the tip.
#Sometimes it may be necessary to loosen the spring loaded screws on the extruder, and manually unload/load the extruder.


This Prusa is fitted with the following:
=Tips=
*'''Always swing fans in during a print. They engage automatically as appropriate.'''
*Time estimate in pronterface's bottom bar is wildly inaccurate. The console printout when a gcode file is loaded will be about 75% accurate.
*Some problems may be ambient temperature related. When the room is 52F (11C), plastic curling, extruder jams, and Z-axis endstop malfunction are more likely. Placing a space heater on medium heat (~750W) at least four feet from the RepRap helps. Usual concerns about space heaters apply, be safe.
*Bare glass bed is best for quality, tightly grips plastic when hot, releases when cold. Paper tape on glass is generally more tolerant to misalignment. Bare polycarbonate provides extremely strong adhesion, too strong above 45C.
*When printing long parts (eg. 150mm*50mm), it it is better to rotate the part, and align its length to the X-axis. The bed is slightly more level along the X-axis than the Y-axis due to a minor design flaw.


* Melzi - loaded with the latest Marlin firmware (as of 9/1/2012)
=Slic3r Settings=
* 12V 30A PSU
* Makergear 0.35mm for 3mm filament hot end
* LM8UUs
* GT2 (2mm) belting and pulleys (5mm bore, 20 tooth)
* 100K Thermistors (extruder an heated bed)


For FW reference on steps per axis: (80, 80, 2560, 666.67) {X, Y, Z, E}, this is also assuming 1/16th microstepping.
==Print Settings==
===Cheap===
High speed, low plastic consumption, lightweight part. Also most appropriate for model aircraft parts, as the strength-to-weight ratio is likely approaching that of carbon fiber.


=Maintenance=
===Quality===
==Safety - ALWAYS CHECK==
Maximizes quality, strength, and accuracy. Used for Prusa Mendel Replication.
*Power Supply. NEVER leave ATX power supply on after a print job, it gets hot.
*Loose wires. Short circuits can cause severe damage.
*X/Y endstops. Manually push X/Y axes to test the switches.
*Z-axis endstop. Visually check that it will trigger before severe crash into print bed.


==Malfunction==
===Precision===
*Grease smooth rods and Z-Axis threaded rod if axes show signs of binding.
75micron layer height, for parts with smaller features.
*Only grease with PTFE SuperLube, kept at HacDC next to RepRap.
*Floss the hobbed bolt in the extruder.


==Bed Cleaning==
==FilamentSettings==
*Polycarbonate bed should be kept flat, without excessive protrusions. Scrape excess plastic off, and trim deep cuts.
===HacDC===
*Glass bed must be clean, but not too clean. Best practice seems to be wiping with a paper towel, and then gently brushing dry fingers across the glass.
Optimized for bare glass bed, solid parts, and fast printing. Decrease bed temperature to 45C for bare polycarbonate bed. Decreasing extrusion temperature to 167C may improve bridging but requires slowing down print speed, reduces quality, weakens printout, and may significantly increase extruder wear.
*Use paper/kapton tape on the polycarbonate bed, not the glass bed.


==Print Depth==
==Printer Settings==
*First-layer depth. For polycarbonate beds, this must be <0.4mm below the bed surface. For glass bed, exactly 0.2mm above the bed surface is required.
Leave at "HacDC" unless you feel they need debugging.


*Z-axis height. Z-axis endstop position sets depth for entire bed.
=Advanced=
*Z-axis level. The dual threaded rods must be kept aligned.
Entire software load used on dedicated laptop available at [https://github.com/HacDC/PrusaMendel github]. With these files, one can use their own computer to control the reprap.
*Bed leveling. Place Z-axis just above bed, then move X/Y axes. Place thin paper strips under bed until level.


=Operation=
WARNING: Slic3r configuration changes made on the dedicated laptop will be reset at reboot. Export your changes from slic3r to save them elsewhere. Alternatively, fork our github repository, make modifications there, and issue a pull request. Failing these options, email blabber.
#Go through the maintenance list as necessary, especially the safety section.
#Check which bed you are using. Polycarbonate (lexan) bed is strongly recommended.
#Turn on power strip. Switch on the ATX PSU behind the machine. Large fans should start spinning.


#Load an STL model onto the dedicated laptop for printing. If you haven't made one, download one from [http://www.thingiverse.com/ Thingiverse]
=Credits=
#Open Slic3r. Drag your STL file from a file manager onto the "Drag your objects here" box in Slic3r.
{| class="wikitable"
#"Print settings: Cheap" "Filament: Solid" "Printer: HacDC" Use these settings to print fast, with minimal plastic, high strength, and reasonable droop on short bridges.
|-
#Export G-Code in Slic3r. This can take a while, so proceed to the next steps without waiting.
|digifab
|Constructed and donated working PrusaMendel Reprap.
|-
|juri
|Consultation on maintenance and multiple emergency repairs. Many emergency replacement parts.
|-
|nully
|Consultation on maintenance and multiple emergency repairs.
|}
*Several HacDC members for initial capital.
*HacDC members for all [http://wiki.hacdc.org/index.php/Category:Project_Awesome Project Awesome] funds.
*Others.


#Open pronterface.
=Technical Specs=
#Connect to the printer. Make sure the baudrate is set to the 250000 and the correct port is selected, should read "...USB0". You will know when it is connected when it spits out some basic stats of the firmware loaded. Check the box that read "Monitor Printer," this will spit out current temp readings, make sure they are reasonable (~20C at room temp).
#Set heated bed to 45C.


#Wait for Slic3r to finish. Click "Load" and load the G-Code file you have created. A preview of the first layer should appear in the middle of Pronterface. You can click on the preview and walk through the layers by holding shift and scrolling on the trackpad. In the console, a time estimate for the print should also appear.
This Prusa is fitted with the following:


#Set extrusion heater to 185C.
* Melzi - loaded with the latest Marlin firmware (as of 9/1/2012)
#Extrusion rate in pronterface should be 50mm/min or less. Faster speeds while priming can grind filament.
* 12V 30A PSU
#Wait for it to hit temp and prime it. You can do this by either manually turning the large extruder gear or pressing the "Extrude" button. Do so until there is a nice and steady flow.
* Makergear 0.35mm for 3mm filament hot end
* LM8UUs
* GT2 (2mm) belting and pulleys (5mm bore, 20 tooth)
* 100K Thermistors (extruder an heated bed)


#Once all temps are hit and stable, file is loaded and extruder is primed...you can now hit print!
For FW reference on steps per axis: (80, 80, 2560, 855) {X, Y, Z, E}, this is also assuming 1/16th microstepping and 9/47 gears. Old extruder used 666.67steps/mm.
#Sit back and watch as the printer homes itself and sprints off to print your file!


=To Do=
=To Do=
* Tune trimpots on motor drivers
* Tune trimpots on motor drivers
* Binder clips for glass surface
* Print spare parts.
* Kapton tape for 2nd glass plate (for ABS)
* Experiment with higher supply voltages.
* Acetone/Cotton balls (for cleaning Kapton surface)
 
* Spool System (mount printed Sky Hooks)
=Known Bugs=
* Cable Management (Spiral wrap loose wires and ziptie down)
* Model holes will print the wrong size. The proper way to manage this is by keeping about 0.25mm per wall or 0.5mm diameter clearance in CAD models.
 
=Additional Resources=
* "Slic3r is Nicer - Part 1 - Settings and Extruder Calibration" http://richrap.blogspot.co.uk/2012/01/slic3r-is-nicer-part-1-settings-and.html
* A guide to calibrating and using slic3r: https://github.com/alexrj/Slic3r/wiki/Calibration

Latest revision as of 11:34, 16 February 2014


More detailed documentation on the newly built Prusa Mendel (iteration 2). A PC has been dedicated to run it, below you will find the toolchain used to run it and other details that you may find useful.

Workflow

CAD/Thingiverse -> Netfabb -> STL -> Slic3r -> Pronterface -> PRINT!

See operation section for a tutorial.

CAD
FreeCAD (free, open source) and SolidWorks (expensive, some extra features) offer intuitive sketch and constraint based modeling.
OpenSCAD uses programming code to describe 3D models.
And in case you don't want to model anything and simply want to print stuff, go to Thingiverse.
Netfabb
software for checking the "3D printability" of the model you created. Go to Netfabb and download the Studio Basic option. You can also simply use their cloud offering and have a repaired model emailed back to you.
if your model has issues, run the repair function with default settings and see if that remedies the issues. The repair function can be used by clicking the "first aid" symbol found at the far right on the tool bar.
STL
current format for 3D printing (AMF is coming around the corner).
at this point, your file should be patched up and ready to print.
Slic3r
software for creating 3d printing toolpaths
precompiled binaries can be had from Slic3r.org or be built built from github.
use the profiles already generated for best results.
Pronterface
GUI for controlling the Prusa.
where you will connect to the printer, home, warm up and send print jobs from.
can be built from github or download precompiled binaries for Windows/Mac here.
preview G-Code generated by Slic3r.
Print
File is good to go, toolpaths are generated, time to let the robot do what it does best, PRINT!

Materials

Switching from PLA to ABS, or vice versa, will require purging extruder at with at least one meter of filament at >225C.

Generally, PLA is stronger, better for the environment, and easier to print with. Please use ABS only if there is a specific need for it.

  • PLA - Polylactic Acid
Extremely ecologically friendly, made from corn starch, smells like waffles/syrup while printing.
Harder than ABS at room temperature.
Needs a fan for parts with overhang/bridging.
Recommended solvent for gluing or vapor polishing is tetrahydrofuran. Slightly more hazardous, much more expensive, and less effective.
Low operating temperature (160C-200C).
  • ABS
Much less environmentally friendly.
Weaker than PLA at room temperature.
Poorer adhesion to bed while printing, may need polycarbonate bed, paper tape, kapton tape, etc.
Degrades nozzle, forcing more frequent cleaning by an experienced person with blowtorch and acetone.
High operating temperature (225C-240C).
Recommended solvent for gluing or vapor polishing is acetone. Low risk, low cost, highly effective.
Suitable for moderately high-temperature applications like coffee mugs, outdoor fixtures, and certain 3D printer components.

Extra Maintenance

Malfunction

  • Only grease with PTFE SuperLube, kept at HacDC next to printer.
  • Grease smooth rods and Z-Axis threaded rod if axes show signs of binding.
  • Tighten timing belts if not taunt.
  • Floss the hobbed bolt in the extruder.
  • Replace linear bearings if they are grinding, slipping laterally, or otherwise ruined.

Replacing filament/changing spools

  1. Turn on the printer, open pronterface, and connect to the printer.
  2. If there is filament sticking out of the top of the extruder, you'll need to remove it.
  3. Set the hotend temperature (175-185 degrees Celsius for PLA)
  4. When extruder is warmed up, raise the extruder (+z axis) so it's not touching the bed.
  5. Click the reverse button while gently pulling upwards on the filament you wish to remove.
  6. Continue gently pulling and pressing reverse until the remaining filament is drawn out from the top of the extruder housing.
  7. Once the filament has been removed, replace the spool.
  8. Feed the new filament into the appropriate hole in the extruder housing.
  9. Gently press down on the filament while clicking "extrude" in pronterface. The extruder should grab the filament as you feed it.
  10. Repeat the previous step until you see the new material being extruded from the tip.
  11. Sometimes it may be necessary to loosen the spring loaded screws on the extruder, and manually unload/load the extruder.

Tips

  • Always swing fans in during a print. They engage automatically as appropriate.
  • Time estimate in pronterface's bottom bar is wildly inaccurate. The console printout when a gcode file is loaded will be about 75% accurate.
  • Some problems may be ambient temperature related. When the room is 52F (11C), plastic curling, extruder jams, and Z-axis endstop malfunction are more likely. Placing a space heater on medium heat (~750W) at least four feet from the RepRap helps. Usual concerns about space heaters apply, be safe.
  • Bare glass bed is best for quality, tightly grips plastic when hot, releases when cold. Paper tape on glass is generally more tolerant to misalignment. Bare polycarbonate provides extremely strong adhesion, too strong above 45C.
  • When printing long parts (eg. 150mm*50mm), it it is better to rotate the part, and align its length to the X-axis. The bed is slightly more level along the X-axis than the Y-axis due to a minor design flaw.

Slic3r Settings

Print Settings

Cheap

High speed, low plastic consumption, lightweight part. Also most appropriate for model aircraft parts, as the strength-to-weight ratio is likely approaching that of carbon fiber.

Quality

Maximizes quality, strength, and accuracy. Used for Prusa Mendel Replication.

Precision

75micron layer height, for parts with smaller features.

FilamentSettings

HacDC

Optimized for bare glass bed, solid parts, and fast printing. Decrease bed temperature to 45C for bare polycarbonate bed. Decreasing extrusion temperature to 167C may improve bridging but requires slowing down print speed, reduces quality, weakens printout, and may significantly increase extruder wear.

Printer Settings

Leave at "HacDC" unless you feel they need debugging.

Advanced

Entire software load used on dedicated laptop available at github. With these files, one can use their own computer to control the reprap.

WARNING: Slic3r configuration changes made on the dedicated laptop will be reset at reboot. Export your changes from slic3r to save them elsewhere. Alternatively, fork our github repository, make modifications there, and issue a pull request. Failing these options, email blabber.

Credits

digifab Constructed and donated working PrusaMendel Reprap.
juri Consultation on maintenance and multiple emergency repairs. Many emergency replacement parts.
nully Consultation on maintenance and multiple emergency repairs.
  • Several HacDC members for initial capital.
  • HacDC members for all Project Awesome funds.
  • Others.

Technical Specs

This Prusa is fitted with the following:

  • Melzi - loaded with the latest Marlin firmware (as of 9/1/2012)
  • 12V 30A PSU
  • Makergear 0.35mm for 3mm filament hot end
  • LM8UUs
  • GT2 (2mm) belting and pulleys (5mm bore, 20 tooth)
  • 100K Thermistors (extruder an heated bed)

For FW reference on steps per axis: (80, 80, 2560, 855) {X, Y, Z, E}, this is also assuming 1/16th microstepping and 9/47 gears. Old extruder used 666.67steps/mm.

To Do

  • Tune trimpots on motor drivers
  • Print spare parts.
  • Experiment with higher supply voltages.

Known Bugs

  • Model holes will print the wrong size. The proper way to manage this is by keeping about 0.25mm per wall or 0.5mm diameter clearance in CAD models.

Additional Resources