Think3DPrint3D Kossel Mini Kit: Unboxing, Review & Upgrade

A few months ago we got the amazing news that our project 3D Printed DNA Lamp was one of the winners of the instructables 3D printing contest! As a reward we received the Kossel Mini Kit 3D printer, so here’s the unboxing, review and … upgrade? (I’ll explain later :P)


So this is what we received:


The small package is the instructables prize pack, which contains the robot t-shirt, some stickers and a patch:

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Now the big box is the Kossel Mini Kit:


If you’re wondering, the box size for the Mini Kossel kit is 70cm x 24cm x 18cm and it weights just over 7kg.

This is everything it brings inside:


First thing I noticed is that everything is very well organized and identified so it shouldn’t be hard to find something when you’re looking for it. Also each package brings a detailed list of materials and quantities which is quite useful:


This is basically the electronics box and also some heated bed related stuff:


Here you can see everything that is inside:


After the printer was shipped Think3dPrint3d contacted me and warned me that the heated bed M3x10 screws inside the kit were incorrect and that had already shipped me the new ones. By the way, all the communication I had with them was great, and they were pretty ready to help me with anything I needed. They even let me choose the colour for the 3D printed parts 🙂 This is the letter I received with the correct screws:


This is the heated bed package:


An aluminium  base with the heater and thermistor already pre-assembled:


It works quite well actually, it heats up to 135ºC relatively fast!

And also the glass:


This is the mechanics box:


It brings the motors, the belts, the screws, nuts and washers, some tools and other accessories:


These are all the screws:


These are the 3 long aluminium profiles:


And the nine shorter ones:

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The carbon fibre diagonal arms:


The power supply:


A bit of filament, PTFE tubing and spiral cord for tidying everything up:


This are the components to mount the spool holder:


After assembled, this spool holder works very well, it unwinds the filament super smoothly.

This is the E3D V6 Hot End box:


And here is what comes inside:

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This hotend is awesome! Since it’s all metal, it reaches very high temperatures, so it’s max temperature is only limited by the thermistor inside.

And last but not least, the 3D printed parts, green as I asked for:

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Now for the assembly. I’m not going into details because they already have a nice assembly guide. Be sure to follow the right one though, because so far they have 3 releases for the Kossel Mini, so the assembly guides are a bit different. This one I received is the second release, which can be found here at the documentation tab.

So I’ll just show a bit of the different steps. First coupling the motors to the base’s 3D printed parts:

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And putting the base all together with the aluminium profiles:


Then the same for the top:


Building the spider:


The tower carriages:


The endstops:


This is the Z probe:


Which I have to say it’s kind of tricky to assemble, calibrate and get it working. Fortunately their 3rd release has a new contactless Infrared probe which is way way better!

Now for the hod end parts:

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It’s a nice all metal E3D V6, 1.75mm with a 0.4mm nozzle.

The 1.75mm extruder block:

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I quite like this block. It’s simple, small and works great!

Then getting the frame all together:

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Connecting all the electronics:

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This 2nd release uses a Arduino Mega + RAMPS 1.4 board while the new version uses a Duet V0.8.5 board.

And after a few calibration procedures I was printing my first objects! The first one was a bit weird, I supposed I didn’t get the filament parameters right 😛


But I got better:


Until I got the hang of it:

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The ultimate test was to print the LCD case, which was a success by the way! I forgot to take a picture when it was printing, but here it is already assembled in place:


I was very happy with it. It’s always kind of hypnotizing to see a delta 3D printer working. It took me a bit to calibrate everything but soon enough it was working fine and with great results. A new and awesome 3D printer!

And this should be the end of this post. However I screwed up…

I wanted to change the nozzle of the hotend but I didn’t follow the right procedure of heating it up first. So I broke the hot end :/

Even though I was sad that I just broke my new prize, this gave me the opportunity to change something. Our printers all use 3mm so far, which means we already have a few spools with a 3mm diameter. Having this printer with 1.75mm would force us to buy different spools which is a bit “uncomfortable”. So I thought I could change things up a little to transform the Kossel Mini into a 3mm printer.

Therefore I designed a new extruder block, based on the normal wade extruder:


Also changed the PTFE tube:


And exchanged the broken E3D hotend by a normal 3mm all metal J-head hotend:


After a while it was printing again!

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Great success! Our Kossel Mini is now a 3mm 3D printer, it is not exactly better but is at least more convenient. I also changed the spiral cord for a green PET expandable sleeving.

Now we can use our old filaments:

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Even though it’s useful that it now prints with 3mm filament, I think it’s important to say that that “upgrade” only happened because of the accident when I broke the 1.75mm hotend, because you won’t feel any need to upgrade the printer as it is, it works great! This change sure is something that I wanted to try but like I said earlier is not necessarily better than it was before. I say this because the 3mm filament creates a bit too much friction on the PTFE tube and it’s harder to “manoeuvrer”, this sometimes generates small defects on the prints and has made retractions a bit of a headache. Other than that it’s still awesome.

So I have to say, the Kossel Mini Kit, as it was when I received it, was great, the assembly is relatively simple, the documentation is well explained, everything is well organized. The printer itself has an amazing quality, when you finally get the parameters right, you’ll be surprised with the quality you’ll achieve and even at high speeds! I gotta say I’ve never seen a 3D printer print so fast and still keep this much quality. I guess that’s one of the advantages of a delta 3D printer. Only thing I disliked was the Z-probe, it was a hard to get it working properly and even then it sometimes fails. Thankfully this problem was fixed with the contactless Z probe of the new revision.

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