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  1. #1
    Student
    Join Date
    Jan 2014
    Location
    Ireland
    Posts
    6

    Velleman K8200 3D Printer assembly tips

    I’ve finally received the Velleman K8200 3D printer kit… yeah! and I thought that I will share some tips & tricks useful during assembly.

    First of all – have a look into Velleman’s guide:
    http://www.k8200.eu/manual/building
    http://www.k8200.eu/manual/printing

    They also provide downloadable version of the guide. It’s a massive, 600+ pages PDF file:
    http://www.k8200.eu/downloads/0/asse...l_k8200_uk.pdf

    Ok, let’s start building this monster toy

    It took me about 8 hours to put the mechanics into one piece and then another 8-10 hours to solder everything together and calibrate it...
    I must say that the manual describes well all the steps, processes, etc. The whole process is very good documented.
    However, there are few moments that may discourage less experienced players…


    First, page 134 in the Assembly Manual – you have 2 vertical rods that are kept straight by 4 plastic elements. Then you have a Z axis carriage (built of 4 bearings). This was the trickiest part of the assembly, to make all these elements move smoothly...
    If you tightened one of the plastic elements more than the other ones – the rods are not parallel anymore. These bolts slide into the plastic holders which can bend a little bit if tighten too much.
    The other issue was with the carriage. Each bearing holder has 2 slots (not holes, just slots, so you see where this is going ) for 2 bolts, so the carriage has 8 bolts that need to be tightened – same story as with the rod holders – tightened too much and the plastic part slides out, making the bearing not in line with the rod...
    After expressing myself in a poetic manner (I didn’t know my dictionary is so extensive ) I sorted it out. Here is how you can do it:

    • tighten firmly 2 bottom rod clamps but leave the top ones slightly loose
    • start sliding the carriage up&down, tighten all of the bearing bolts (you may want to keep your finger on the plastic element, preventing it from sliding out)
    • if you feel the carriage starts to twitch – loosen your current bolt a little and try tighten another one
    • when you tightened all 8 bearing bolts – tighten those holding the rods on the top
    • start over again until all the bolts are firmly tightened (as you won’t get it in one go)



    Second, page 499 – don’t wrap the legs around the wire. This NTC has hair-thin legs. When you start wrapping the second leg – the weight of the wire will hang on the first leg. It is very easy to snap or rip the leg off. My tip: cut the legs leaving about 10mm, wrap the NTC to a piece of foam/cloth and clamp to a vice or use a ‘3rd hand’. You can clamp the 2 wires to the second alligator clip. Then simply solder the legs and the wires, slide the heat resistant sleeves and... job done The screw holding the thermistor in place is about 6mm off the bead hole in the heater block so it will hold the thermistor by the solder joints.


    Third, page 505. I didn’t tighten the nozzle enough – I was afraid of breaking off the thread – the nozzle/barrel are made of brass. After just 20 minutes of my first print – I got plastic coming out between the heating block and the white teflon barrel :/ DON’T WORRY, it is very easy to fix (Velleman say it is IRREPARABLE):


    • heat the extruder to 200 oC and from now on DON’T TOUCH it, use some pliers to hold or ask someone to help you
    • remove 2 bolts holding the extruder (page 508)
    • unscrew the white plastic barrel (page 495)
    • take 2 wrenches and tighten the nozzle (page 505)
    • screw on the white plastic barrel (page 495)
    • put the extruder back into its place and tighten the 2 bolts (page 508)

    Note: the heating block rotates over the barrel so you can rotate it if you can't reach the bolts.


    Fourth, page 567 – calibration. This is completely all over the shop. I don’t know why they have decided to put 4 adjusting knobs for all 4 corners instead of 3 points in a triangle shape. The other thing is that the heated bed (it is just a simple PCB with resistive traces) is not flat, it tends to sink in the middle. In my case it was 3mm difference between centre of the board and all 4 perfectly aligned corners (0.15mm from the nozzle). Quick trip to IKEA and I came back with these mirrors (http://www.ikea.com/ie/en/catalog/products/60074007/). I used clips to hold the mirror in place. After this change you need to be aware that:


    • the Z axis bolt (page 568) has to be adjusted as the nozzle needs to stop 3mm earlier
    • the printer settings must be changed to limit the printable area to 19x18cm (from 20x20 originally) – I took higher margin because of the clips holding edges of the mirror
    • heating takes more time (I have it set to 58 oC and it takes about 15 minutes to reach it in a warm room (+23 oC))


    If you have any questions, comments, suggestions – please let me know.

    Cheers,
    LJ


  2. #2
    8 hours? Wow! Including machine-shop time to attempt to square the "angular mounts" to keep the corners of the base square, and especially the uprights, cost most of 40 hours. The die-cast pieces had absolutely no surfaces against which to reference others. We had to machine each piece unto itself, by a professional machinist. Total mechanical assembly beyond that took nearly 30 hours, plus wiring 20 hours beyond that. all done by senior electro-mechanical engineers. Not a toy the the faint of heart.
    Now we are working on why, when the 15VDC is applied, the USB LEDs extinguish.
    One unhappy camper.

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