# Specific 3D Printers, Scanners, & Hardware > RepRap Format Printer Forum >  Kossel Mini Build (750/360)

## MK-X

Hey guys, starting my build log for my Kossel Mini. 750mm tall with 360 mm horizontal extrusions.

What I do need left are:
8x8 glass for my heated bed or 9" roundWheelsPower supplyHobbed Pulley

IMG_20140501_223206.jpg

I am trying out Prime line rollers instead of rails and Steve Graber's Wheels as of right now.

Power supply, I am still deciding between a LED PSU 12V 30A or a ATX/ITX/MicroATX PSU 

Currently having trouble with the m4 screws into the carbon fiber rods. I need to purchase a m4 tap drill.

This will be the first iteration, all in preparation for the *MK-X* ​build.

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## Maggie

Awesome, I look forward to following your thread.  Please keep us all posted your your progress!  I was talking to someone only a couple weeks ago who just built their own Kossel printer. He loved it!

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## f.larsen

You happen to be running this machine with a heated bed?

Your amperage choice might be a little high, not sure what board your using though make sure you check the specs first so that you know it can handle that much. More than adequate cooling would be needed as well.

At the moment I am able to run my Delta nicely off of a Xbox 360 (NOT SLIM) PSU, which is 12A - no heated bed.

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## MK-X

Im using ramps with a mk2A heated bed. Do you have any other recommendations?

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## f.larsen

A MK2A heated bed is a great go to bed. There are rubber mats that I have seen people starting to use, but I haven't heard anything that proves that are a solid route to take.

I also use RAMPS and a MK2A heated bed, not my Delta though.

I'm getting off track.

RAMPS, 4 Motors, 12V 12A PSU(or higher, no more then 12V 20A is needed) and you are good.

Best of luck with the build.

For awhile my hotend kept on getting driven into the build plate. 

Oh oh, and as an aside, I am using a nicely polished piece of granite I picked up from Rona as the build plate. Little bit of tape, or glue stick and it works great.

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## MK-X

This is good to hear as I can find a Micro-ATX psu or a mini-itx psu to control my octopi and still fit it within the bed. Is 16A okay for RAMPS and a heated bed?



> A MK2A heated bed is a great go to bed. There are rubber mats that I have seen people starting to use, but I haven't heard anything that proves that are a solid route to take.
> 
> I also use RAMPS and a MK2A heated bed, not my Delta though.
> 
> I'm getting off track.
> 
> RAMPS, 4 Motors, 12V 12A PSU(or higher, no more then 12V 20A is needed) and you are good.
> 
> Best of luck with the build.
> ...

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## f.larsen

For a Delta..... I believe it should be yes. Anybody else who is a little smarter in this area, it would be great if you chimmed in with your experiences.

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## MK-X

I got a tap drill from home depot : Tap Drill and finally assembled the diagonal rods which took up significants amount of time because I was afraid they would split, one did, but just barely.I didn't have an allen wrench long enough, so I used a bamboo skewere I had lying around, it worked perfectly.
Once attached to the effector
Then I assembled the frame (except for connecting the top piece, still waiting for my motors and vertical carriages:
Getting the nuts perfectly aligned nearly made me nuts! 
My MK2A board is a too small to fit, so I need to get some larger cork insulation board.

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## f.larsen

Great Progress!

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## nka

> Your amperage choice might be a little high, not sure what board your using though make sure you check the specs first so that you know it can handle that much. More than adequate cooling would be needed as well.


There's no "max" for amperage. I mean, if the device require 500mAh, he will take only 500mAh from the 30A.

 The only problem with too much amp, is if you short something or if there's a design flaw, diode might not be able to "catch" the power and will blow.

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## MK-X

Any suggestions on how I should cover up the bare extrusions on my delta? I want it to have a clean-sleek look. MDF? Metal Panels? thanks.

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## nka

Metal plate if you're able to powder paint it. Else, I would do MDF with glossy paint!  :Smile:

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## MK-X

Any idea on how to attach it to the extrusions? I am thinking about just using M3 screws, but I hear MDF doesn't take well to screws.

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## nka

if you use MDF, make sure the MDF hold my the head of the screw, it should work like this!

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## paradiddle65

> Any suggestions on how I should cover up the bare extrusions on my delta? I want it to have a clean-sleek look. MDF? Metal Panels? thanks.


3D printed parts would be perfect for this. Proves that having two printers is very helpful  :Smile:

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## MK-X

Finally got my NEMA 17 motors. Will be finishing up assembly in the coming days.

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## MK-X

Finally soldered 3 motors and temporarily set up an atx power supply to run with it. However, I am running into issues. When I decrease the Z-axis control on Repetier, the Z-motor does not rotate, however when I increase the z-value, it does rotate. Any ideas?

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## nka

Is the motor moving both way if you using RAMP test ? 

If yes...  I dont know... it's software related, but I dont really know the software yet. You're using a "delta" configuration right?
If no... 
- Did you ajust the "power" screw ?
- Make sure all the cabling is good. Maybe you didnt connect "Enable A/B" or power is not working.

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## MK-X

Actually I figured it out, I had autoprobe in the firmware on, but had no endstop in the autoprobe pins, so when I checked M119, it showed Z_min as always high and thus Z would never decrease in value. It is fixed now though Thanks. 

However, I am having issue wiring up my Geared Stepper Motor from Kysan. I purchased it from Tridprinting. The schematic is located here: http://www.tridprinting.com/Electron...perMotor-1.pdf

The plug I received are reversed though. I am unsure on how to wire it to my RAMPS board.

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## nka

red, green, yellow, blue.

To me, the wiring seems okay, just need to "flip it" so the red wire is on first PIN. First PIN is the first on the left if you look at the board with the power input/output to the left.

edit: http://reprap.org/wiki/RAMPS_1.4#Wiring

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## JohnA136

I build a Kossel Mini about a month ago and I am using a 20A Power Supply.  Round Borosilicate Glass with Kapton heated build plate.  Working pretty good so far.

photo (58).jpg

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## MK-X

So I plugged the extruder into one of the XYZ motors wiring it up and it worked fine. I just can't get it to extrude without attempting to warm up the hotend in repetier host.

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## JohnA136

I think there is a setting in Repetier to not allow the extruder to turn until it is 170 degrees.  I use by LCD panel to turn the extruder motor on my Kossel Mini.

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## MK-X

Yeah I was able to get it to work by turning the minimum extrusion temp as well as the minimal defect temp below -10 degrees. I didn't have my hot end thermistor plugged in so the defect temp showed -58C. Now I am trying to wire up 615rakabMOL._SL1500_.jpg to my dedicated power supply. Any ideas?

Mechanically its up and running, but the belts aren't too tight.

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## MK-X

Figured out the wiring of the switch and tightened up the belts enough, I am current working on getting the glass bed situated. I do have a heat bed, but I think ill just play around with plain glass first, until everything else works for sure.

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## MK-X

Man oh man is calibration rough and tedious. On to Extruder calibration!

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## JohnA136

One thing we learned a long time ago is that you have to be very patient when building a 3D Printer. You seem to be doing a great job!

My first Cupcake build took me 14 hours. I think I spent about an hour just getting the Kossel calibrated.  It is indeed tedious but once it is done, it seems to print very well.  We built this one with mostly "left over" parts from other builds and the Stepper motors are a little small (the shorter the motor, the lower the torque?).  The axis work fine but I just got a larger one for the extruder, which seems a little too weak for the direct bowden extruder.  I was going to go to a geared extruder like on my Prusa i3 builds but will try a larger stepper first.

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## MK-X

I finally got it printing after some extruder problems! Will post pictures soon, will have to recalibrate my printer for sure.

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## MK-X

So I built my Kossel Mini to 760/360 extrusions. Inadvertently, I am using the Tridprinting 12" strong wall rod and traxxas rod kit for a diagonl rod length of (340mm). Using Jay's visual calc, it calculated that my Delta radius would be 173.84mm. Directly measuring my Zmax I got 311mm approximately. However, I can't get the printer to level out. It remains ever so slightly convex(~1mm) but I can get X/Y/Z to calibrate to Z=0. Since my rods are shorter than expected (348mm), I'm not sure how much its affecting my calibration. Thanks guys.

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## nka

I just "finished" mine.



Need calibration and I also need to fix the arms (they are not equal, I did pay attention the the ball milling and magnet...)

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## MK-X

Printer is up and running, but wiring is quite messy still haha. IMG_20140802_190415.jpg

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