projects:group_projects:mhv_delta_printer

MHV Delta Printer

Group project to prototype a delta printer. Changed for now into a group buy of a Rostock delta printer, probably still want to try making our own at some stage.

For how to use the printer see: Using the Rostock

This page is a history of updating the printer - most recent at the bottom of the page.

Rostock Delta 3D Printer Rostock from below Rostock from above

Today (18/3/2014) MHV was offered a Rostock 3D Delta printer http://reprap.org/wiki/Rostock for $300. It needs some calibration, belt tightening and firmware updates (hasn't been used for at least 6 months). Brenda bought and is asking for $20 contributions towards it becoming MHV's. Contact her or add your name below if you can contribute. It is already 2/3 MHV's (10 contributors).

There are quite a few extra parts with the printer including a LCD screen that can be fitted and a lot of bearings.

Cameron & Jamie tried it out tonight without doing any tuning or firmware updates and everything seems to be working except the plastic extruder sheath isn't attached so the feeder is just making a longer loop of plastic instead of feeding it to the hot end. Printing movement seemed to be correct, just almost no plastic coming out of the head.

They also found a problem where if you ask it to move in the x-y direction when it is too high there is an overflow error and the head moves rapidly down - need to cut power to stop it crashing into the heated bed. Maybe a more recent firmware would avoid this, or perhaps we need to add a hardware fix so it can't go that low. Until we work it out, make sure you are ready to turn it off when testing it!

Bua, Jamie & Brenda made some more progress. Bua & Jamie moved the extruder to inside the box and reattached the plastic extruder sheath. Bua added a piece of perspex as a 'washer' to the sprung latch for the extruder and removed the cable tie. It is now possible to open the rollers to manually feed plastic or shut the latch so the the rollers feed the plastic. Extruder feed still didn't seem to be working well, only a small amount of plastic extruded.

Brenda & Jamie worked on the Rostock printer today with some advice from Ian and Cameron. They updated the firmware to the Marlin fork by J Crocholl available at https://github.com/jcrocholl/Marlin/ The most recent version wouldn't compile for us, so we went back a couple of weeks to before the latest updates to the auto levelling code and used: https://github.com/jcrocholl/Marlin/tree/d485988becdc5e70e2913f3f629cc9dd825a7f28 (click 'Download Zip' on the right of the page to get the code).

After copying the Configuration.h and Configuration_adv.h from the Marlin/example_configurations/delta/ directory overwriting the ones in the Marlin directory, we changed the following settings to match this printer:

Configuration.h changes

#define DELTA_DIAGONAL_ROD 285.0 // mm
#define DELTA_SMOOTH_ROD_OFFSET 177.0 // mm
#define DELTA_CARRIAGE_OFFSET 23.5 // mm

#define TEMP_SENSOR_0 5
#define TEMP_SENSOR_1 0
#define TEMP_SENSOR_BED 1

// changed endstops, so now need this commented out
// #define ENDSTOPPULLUPS // Comment this out (using // at the start of the line) to disable the endstop pullup resistors

#define MANUAL_Z_HOME_POS 303.7 // 250 For delta: Distance between nozzle and print surface after homing.
#define DEFAULT_AXIS_STEPS_PER_UNIT   {80, 80, 80, 760*1.1}  // default steps per unit for Kossel (GT2, 20 tooth)

#define G3D_PANEL // when LCD panel is attached

Installing firmware on the Rostock printer

You need to have to Arduino software installed from here http://arduino.cc/en/Main/Software (we were using 1.05).

Plug the USB cable from the printer into your computer and open the Arduino software (Arduino.app on Mac). Set the board in the tools menu to an Arduino Mega 2560 or Mega ADK, and the serial board to whatever is correct for your USB port (usb.tty on Mac).

Then open the Marlin.ino file in the Marlin directory where you edited the config file. Verify that it compiles, and if it does, upload it to the printer.

Software for printing

We've downloaded the Cura software from here: http://software.ultimaker.com

During the configuration wizard, create a 'machine' called Rostock by selecting machine kind “Other”, pressing 'next' and then selecting 'custom' on the Other Machine Information panel. Press 'next' again and you will see a screen asking for details of the printer. Fill it with these values:

Machine name:  Rostock
Machine width: 200
Machine depth: 200
Machine height: 400
Nozzle size: 0.4
Heated bed:  tick
Bed centre is 0,0,0: tick

Select the same port as you did for the Arduino, and set the baud rate to 250000.

G1 Z100 - Go to 100mm on the Z axis.

G1 F1000 - Set movement rate to 1000mm/minute

M114 - Get current position of print head

M104 S220 - Set hotend temperature to 220C

Set hotend temperature manually: M104 S220

Report hotend position: M114

Changed attachment of guide tube between extruder and hot end at extruder to use the M4 screw as designed instead of being upside down and using hot glue. This has also made it easier to release the tensioning screws for feeding new plastic. The entry to the plastic tube is now smaller and has a small rim, so you need to rotate the feed plastic gently until it feeds into the tube.

If the tensioning wheel is too tight it will stop the feed, if it is too loose you can hear the feed motor running without load. Seems like the plastic is extruding well now.

Accidentally broke the fan tube off the hot end. Need to print a new one - see if we can make the attachment section stronger.

Worked out an approach to calibration, but one of the end switches broke before we finished. There are different end switches, that look more accurate, amongst the spares. Will need to get different mountings for them.

End switches have all been replaced using brackets printed on Ian's printer. Bed has been levelled by *removing* the bulldog clips and just taping the glass to stop it moving but let it sit flat instead of being bent.

Printed a series of calibration blocks with different settings.

Cura settings that worked (still room for improvement):

First interesting print. The messy layer is where the filament tangled and stopped feeding. Looks worse on the back.

End Stops

These are the endstops we have Mechanical Endstop v1.2

Installing LCD panel

Warning: see next entry - problems with LCD board

This is the LCD kit that we have: |RAMPS GADGETS3D LCD and SHIELD v1.0 (FULL SET)

The information about how to install it is on the RepRap wiki: RAMPS 1.3/1.4 GADGETS3D Shield with Panel

Configuration is easy: 'In Configuration.h file search

//#define G3D_PANEL

and uncomment to

#define G3D_PANEL

The default text is “Mendel Ready”. Fix that by uncommenting CUSTOM_MENDEL_NAME:

#define CUSTOM_MENDEL_NAME "MHV Rostock"

We might need to use the info here if the X,Y,Z numbers on the screen don't make sense: https://github.com/ErikZalm/Marlin/issues/662

There are some problems with the LCD board, I think we probably need to make some changes in firmware to get it working properly. One problem is that when it is powered only from RAMPS not from USB it only get 3.3 V across pin 1 & 2 on AUX2 and this isn't enough to power the screen properly. The other is that when printing we are getting MAX temp error and stopping printing. So looks like we need to find some more configuration settings for the board. Some instructions seem to suggest setting it to have two extruders, but I didn't want to do that without understanding why: http://blog.protoneer.co.nz/configure-marlin-with-ramps-lcd-sd/

So for now the LCD has been taken off again.

Yesterday Cameron fitted new glass on raised heat bed and started the calibration. Reset MANUAL_Z_HOME_POS to 394.5. Today Brenda got the calibration closer to accurate. I think perhaps the height parameter needs to be adjusted - would like to try 394.6 or so (also not sure if it listens to decimal points on this parameter). Updated details further up the page.

#define MANUAL_Z_HOME_POS 294.5 // 250 For delta: Distance between nozzle and print surface after homing.

Bed temperature sensor needs to be fixed to bottom of bed - until it is need to use lower bed temperature and check that thermometer is touching the bed.

Interested in adding auto bed levelling… This looks useful: https://groups.google.com/forum/#!topic/deltabot/SrmxHMxdgBE%5B1-25-false%5D

The 'lacy' prints on Tuesday were caused by the extractor grinding instead of feeding the plastic. It had been overtightened. Got it working again and prints were better. There is still something not quite right with the fill - it is still not getting quite enough plastic, but completed a successful print even with that. Changed the height again to 294.2 as it seemed to be pressing the glass too much for the first layers.

Updated the endstops to use screws for fine adjustment. Works much better.

Cleaned the extruder. It was way too tight. It should be just a turn or two past finger tight. Make sure the roller wheel is over the feed plastic, it is possible to have it beside the plastic which doesn't work. If it is over tightened it grinds the feed plastic.

To get good prints today I had to set the feed to 115% (up from 110%), seems like the plastic feed rate might need recalibrating.

Because the endstops had moved, had to do the height and individual endstop calibration again. The new height is:

#define MANUAL_Z_HOME_POS 286.8

A Note on the adjustment screws: The screws are M4 so have a thread-pitch of 0.7mm. This means for every full turn of a screw, it will be raised/lowed by 0.7mm.

To move the head's zero closer to the bed, you need to screw out (counter-clockwise). Likewise, to move the heads zero further away from the bed, screw in (clockwise).

This group buy requires 15 people to put in $20 each for the printer to become MakeHackVoid's. Note that all contributions toward this purchase are considered donations, anyone may use the printer and everyone must pay the material costs associated with use.

Name Paid
Brenda Yes
Jamie Yes
Tony Yes
Cameron Yes
Bob Yes
Patrick Yes
Lachlan Not yet
Paul G Yes
Michael Yes
Owen C Yes
Andrew Yes
Jack Yes
Andreas Yes
Steve not yet
?? you?
  • projects/group_projects/mhv_delta_printer.txt
  • Last modified: 2014/09/12 09:45
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