The Kossel 3d Printer project

It has been a long time coming but I have decided to construct a Kossel 3d printer, Kossel is a type of delta printer, the main difference from traditional printers is instead of using the Cartesian system (left to right, front to back and up and down), it uses 3 arms driven by motors and belts to vary the position of the hotend, Meaning the print bed stays perfectly still during a print.

This will be my second 3d printer back in December 2015 I brought a Hictop Prusa I3 kit and assembled it, I have been fiddling, tweeting, upgrading and playing with it ever since.

My plan is to modify many aspects of the original Kossel design by Johann C. Rocholl as I go with the purpose of building a custom printer exactly the way I want it. This will be a fairly slow build over the next couple of months and the intention is to post about every aspect of it, as a sort of build log.

To start off the construction process of I have brought the necessary 2020 black aluminium extrusions from technobots which will form the main frame of the printer.

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Currently I am in the slow process of printing all the plastic parts of the base frame. The motor mounts alone take about 4-5 hours depending on quality settings. One of the main considerations I have taken is the heat which is going to be generated from the printer, mainly from the motors and heated bed.

My normal printing material is PLA (PolyLactic Acid) however the melting temperature of PLA is around 70C. To make the printed parts stronger and less likely to less to have problems I have opted for using ABS (Acrylonitrile butadiene styrene) which has a higher melting temperature 110C The main downside is that I have never used it before and it is currently pushing my heated bed to its powers supplies limits. As it needs the heated bed to be about at least 100C or the print curls as it cools, my original hictop power supply is only rated for 20 amps with the motors, extruder, probe, control board and raspberry pi, it is being pushed a little. I have found I can get away with printing at about 95C if I cheat a little and use washable glue stick on buildtak (Sounds like a bad idea, but it works). I have also ordered a more suitable 33 amp power supply. Anyway for the time being i’m not getting the best prints but they are looking pretty good for the current state of my Hictop Prusa I3.
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The main modification I am making to the original Kossel base frames parts is replacing a lot of the wasted space with vents to allow lots of air through the printer to keep things cool, Also adding holes for wires that can go through the centre of the aluminium extrusions which can be used for Leds etc.

I have a spare Raspberry 3 and touch screen display lying around, So I am going to design case that fits on the front of the Kossel which a couple of rocket switches for turning LEDs and the printer on/off. I am hoping to use touch ui for OctoPrint however I am yet to test it, Worse case I can spend an evening throwing together a basic UI. This should remove the need for having a dedicated LCD for ramps as I hardly ever use the one I already have.

Anyway that is it for now, I shall post again once I have the frame together.

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