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Geeetech MK8 Extruder Tips & Tricks :: 3D Printers


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18 minutes ago, mitch25 said:

I'm sorry but I edited my question. the one you replied to was the non-edited one. I know its a 100k ntc thermistor but when i'm building firmware, I need to select what kind of thermistor it is, like the specifications. which option do I select?

I'm sorry, but I can't help on this case, but I suggest to contact geeetech at technical@geeetech.com, they normally give a feedback in 24 hours. Could you please share the reply you'll get here? Thank you.

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1 hour ago, mitch25 said:

Also when I'm building firmware, I need to know specifications for the gear attached to the stepper. Can someone tell me how many teeth it has and what the pitch is also?

 

If you mean the extruder stepper, you have to just follow this guide http://reprap.org/wiki/Calibration#Extruder_steps the gear specs doesn't matter.

in general you have to modify this line in configuration.h:

#define DEFAULT_AXIS_STEPS_PER_UNIT   {80,80,2560,XX}  

If you have the i3 pro B, just change the XX with the value you get following the guide, the rest must remain the same

if you mean the axis stepper, I suggest to use the Geeetech firmware here: http://www.geeetech.com/forum/viewtopic.php?f=20&t=17046&sid=fc66f364b549e7aa6b240835d36c0c9e

Edited by Gericho
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The standard Geetech TEMP_SENSOR_0 and TEMP_SENSOR_BED thermistor values are set to 1 (EPCOS 100k with 4.7k pullup). These two defines are in the configuration.h file. But this choice may be different if you are not using a typical Geetech controller board.

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  • 2 weeks later...

Wow! Very informative. Thanks a lot.  Much appreciated.

I've just put my Geeetech Prusa Acrylic I3 Pro B together with the MK8 nozzle and it works like an absolute charm !

No problems whatsoever ... so far !

Once I had adjusted the MK8 draw tension it works every time.

And most probably in a number of ways due to your excellent discussion.

From what I can tell the key to obtaining excellent prints in Knowledge.  I spent a lot of time reading and studying before pressing buttons.  I made sure I understood exactly what I was doing before doing it.  I implemented the square sponge filter to stop 'gunk' getting into the nozzle assembly and I think most importantly I have bought excellent PLA and ABS from an Australian supplier 3Dprintingsuppliers.com.au or 3DPS for short.  Along with the supplies they recommend exact temperatures for the nozzle and platform (nozzle 210/240 and platform 60/110 for PLA/ABS).  I've only used PLA so far with Repetier and Slicr3D.

By trial an error I've found layer thickness of .2 perfect.

A few problems I had to overcome initially...

1. Using Repetier Manual functions, I found the X motor moved in the wrong direction.  I had do research into the problem, which lies in the Marlin Arduino code, brush off my Aduino education and relearn the IDE, find and load the appropriate Marlin code, change the X motor direction, compile and load into the Prusa I3.  Thank God it worked !

2. Could not get the Y axis to home, until I discovered one of the wires had dropped off the Y minimum switch !  Putting the wire back fixed the problem.

3. Had a clear 'wobble' in the initial builds.  I could see the right hand z axis threaded screw wobbling and found out it was because the motor/rod connector was installed skew.

It's important when fitting this connector to tighten the diametric clamping screws that tighten the connector around the motor shaft / threaded screw shaft first, before the grub screw that fixes directly into the shafts.  Not discussed to my knowledge in the instructions off of Geeetech.

4. Only one of the screws fits when mounting the power supply.  So mine is just hanging from one screw (instead of 4) until I drill the appropriate holes in the Acrylic.

5  Ardiuno cooling fan has to be mounted 'backwards' in order to blow over the Ardiuno electronics.

I'd recommend when you start up, play with the Slicr3D parameters finding the best settings for you.  Use small objects that don't take long to print or use up excessive PLA/ABS.

I'm using Blender (blender.org) for drawing my objects.  Very happy with it.  It natively exports SLA files.

While Blender does have 3D checking addons, I'm using https://netfabb.azurewebsites.net/index.php to check my models before printing with Repetier.

Always check your home position and slide the nozzle across the platform with a piece of paper between the nozzle and the four extremities of the platform before print runs to check horizontal and correctly positions.

Good luck and have fun.

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I love your design for the Sanguinololu board fan duct, but the links are no longer working.

The STL's link is working for me, so please try again. If it still does not work then provide more details to the error.

 

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  • 4 weeks later...

Hi there.

I´m having a similar problem with my Geeetech I3 pro b, I have printed other projects before the problem ( Pokeball, base for 3D scanner for PS eye and a 26 cm/10 inches  figure ), the problem started when the filament broke before entering ( 10 cm/4 inches aprox ), so no problem, easy change, but after that, the filament don´t flow like before, sometimes it stop flowing at the middle of the proyect, sometimes when finishing the raft or before, if I feed manually it flows fine, I checked the gear, the filment is entering fine, bed level is ok, speed ok, feed speed is ok, temp is ok, any advise or i´m missing something?

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Your issues are what I had to deal with too. My recommendation is to do a "tuneup" by following ALL the advice that was provided earlier. Also, during the Teflon Throat inspection I suggest you do a thorough brass nozzle cleaning to remove any debris that may be hidden in the extrusion path.

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  • 2 weeks later...
On Thursday, June 23, 2016 at 5:50 PM, Mr.RC-Cam said:

Here is the STL file for the hot end fan: fan_duct_set.stl

TProvidenks fine for me. I have a toggle switch on it that as me to select always-on or GCode control. You might want to add a simple on/off switch so you can turn the fan off when it is not needed.

I could not find the invoice to the 12V fan I bought. It came from one of the many online China sellers. I found this one on eBay and the photo looks the same as what I have:
http://www.ebay.com/itm/75mm-x-30mm-DC-12V-0-36A-2Pin-Computer-PC-Blower-Cooling-Fan-TP-/171916843021?hash=item28070ad80d:g:SFsAAOSw0JpV5mpz

Hi Thomas! First oft all, thank you for your elaborate guide! My extruder seems to work fine, allthough I am not getting reliable print quality yet. Still at the beginning, a lot oft trial and error, so many parameters to fiddle with. Anyways, layer cooling seems to be important for certain print jobs. I am curious about your toggle switch. Not sure, how that works with a 2-wire fan. Could you provide a wiring diagram? I would really appreciate it!

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I am curious about your toggle switch. Not sure, how that works with a 2-wire fan. Could you provide a wiring diagram?

My Geeetech controller board and firmware has been modified to allow G-Code control of the hot end cooling fan. All details are explained here:
http://www.rc-cam.com/forum/index.php?/topic/4049-custom-features-for-the-geeetech-i3-pro-3d-printer/

But skip considering it as the type of solution that will solve your problem. I've found that a layer dependent cooling feature is not necessary; Good prints are possible without it.

If you do not get reliable print quality now then go back over EVERYTHING. As I have learned, with the MK8 hot end **any** little issue is all it takes to ruin success.

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Hi Thomas, thanks for your quick answer! I'll follow your advice and work my way through your guide. Your i/o extension project is way beyond my electronics skills. My printer came with the gt2560 board which provides two extra fan ports. Not sure wether they are separately controllable, but I'll skip the layer cooling thing for now.

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