Introduction: The K'Nex 3D Printer

Picture of The K'Nex 3D Printer

Hello everyone, I'm going to be working on creating an instructable for the K'Nex 3D Printer. It's a 3D printer that I designed with a frame entirely made out of K'Nex and it prints almost as well as a commercial 3D printer (please check out the improved print quality in the second embedded video). It cost about $250 CAD (roughly $200 USD) to make, excluding the K'Nex. I apologize that this instructable will take me a while to complete as there is so much to document. My goal is to break up the instructions into 3 parts, the build frame, electronics, and software. I'll try to update as much as I can in my spare time.

Step 1: Sourcing Parts

The part list below is what I used to make this printer. Feel free to modify or upgrade anything you can. Try to get all your cables with female/male pins already on them so you won't have to solder or crimp anything on and you'll save a lot of time. I've linked some of the parts with sources I've gotten them from. I cant guarantee that the links will stay the same over time, some sellers may increase the price or slightly change their product. I would recommend searching other sellers with similar products before buying anything, you might end up finding something better and cheaper.

Part List:
AC 110V-220V TO DC 12V Power Supply

Arduino Mega 2560 with USB Cable
Ramps 1.4 Board
Motor Driver (5x)

NEMA 17 Stepper Motor (4x)

End Stop Switches (3x)

GT2 20 Tooth Timing Pulleys and GT2 Belt (make sure you get 4 pulleys and 4 meters of GT2 Belt)

GeeeTeck MK8 Extruder (1.75 mm filament 0.4 mm nozzle)

6X6" Fleks3D Print Bed

Zip Ties (get a pack of 100 or more these tend to break easily)

PLA 1.75mm Filament 0.5Kg Spool

2 Binder Clips

and of course, lots of K'Nex

Note: If you are going to mount the spool onto the K'Nex printer make sure it weighs a maximum of 0.5Kg. The standard 1Kg spool is too heavy to properly mount it in that position. Also, the extruder is the heart of the printer so don't cut costs by buying a really cheap one. Cheap extruders tend to clug up more, function poorly, and just cause major headaches.

Step 2: The Build Frame

Picture of The Build Frame

Blue connector 22
Grey/purple connector 10
White connector 2
White rod 8
Grey rod 10
Red rod 8
Yellow rod 2
Green rod 4

Step 3:

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Grey/purple connector 8
White connector 2
Yellow connector 2
White rod 11
Green rod 8
Blue rod 2

Step 4:

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Blue rods 4
White rods 5
Green connector 2
Yellow connector 1

Step 5:

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Red connector 2
Yellow rod 1
Beige connector 4
Grey spacer 2 (or every grey spacer = 3 blue spacers)
Blue spacer 8
White rod 2
Grey connector 2

Step 6:

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Attach the parts from Step 3,4 & 5 onto the part from Step 3

Step 7:

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Attach the part from Step 6 onto the part from Step 2

Step 8:

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Grey/purple connector 6
Yellow connector 1
Blue connectors 4
White rod 10
Blue rod 5

Step 9:

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Attach the part from Step 8 onto the part from Step 7

Step 10:

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Blue connector 3
Grey/purple connector 1
Yellow connector 1
White rod 2
Green rod 4
Red rod 1

Step 11:

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Attach the part from Step 10 onto the part from Step 9

Step 12:

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Grey/purple connector 4
Yellow connector 2
Grey 45° connector 1
Red 90° connector 1
White rod 12
Green rod 6

Step 13:

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Attach the part from Step 12 onto the part from Step 11

Step 14:

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Make 2 copies of this piece, so in total you will need:
Straight grey connector 4
White rod 2

Step 15:

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Attach the parts from Step 14 onto the part from Step 13

Step 16:

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Add 4 white rods to each side of the base of the 3D printer as seen in the image
(8 white rods required in total)

Step 17:

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Make the following two pieces which will support the Z axis motors:

Grey/purple connector 8
Blue connector 4
Yellow connector 4
Red 90° connector 4
Straight grey connector 2
White rod 14
Green rod 18
Blue rod 2

Step 18:

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Attach the two parts from Step 17 onto the left and right sides of the base of the 3D printer

Step 19:

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Make these 4 parts which will help the Y - axis printer bed move around,

Grey/purple connector 8
Red 90° connector 8
Grey 45° connector 12
Orange connector 8
Black connection 4
White rod 16
Green rod 4
Blue rod 12

Step 20:

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Attach the 4 parts from Step 19 onto the final part from Step 18

Step 21:

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Yellow connector 8
White connector 3
Blue rod 10
Green rod 6
Yellow rod 4
White rod 4

Step 22:

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Yellow connector 4
Red 90° connector 6
Grey 45° connector 4
Grey connector 2
Green rod 8
Red rod 4
Yellow rod 1

Step 23:

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Attach the parts made from step 21 and 22 to form the print bed

Step 24:

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Attach the corners of the print bed (from step 23) onto the parts from step 19


Death_Dealer (author)2017-08-26

A finish to this tut would be really cool:) trying to make one myself currently. Found all the part on amazon for ~$200. And i think i might have most knex needed might have to buy a small pack to replicate what is here 1-1. Great work, looking forward to seeing this go further.

ropeframeanimationsy (author)2017-02-22

HI man, this is SO GOOD!

Please i want to make one, i need help, i am using 28byj-48 stepper motor (cheap that the one your using) and i dont know how to mount that and if i need to buy a belt or puller or what? Also i dont have a rerap board, i have a arduino and cnc sheild, i could use a 3d pen to repalce a extruder but how do i put it in a spindle on the board? anyway thanks for awsome project.

EricB44 (author)2016-05-19

In one word fantastic. I'm looking forward to the rest of your instruction.

Thanks Eric!

DIY Hacks and How Tos (author)2016-05-18

Great looking 3D printer. I think that this is the first printer that I have seen made from knex.

Thanks Jason!

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