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ricecooker7654
9
May 2, 2014
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So I'm not sure how everyone else's experience with this kit are going, but I'm becoming more and more disappointed over the the wait and the money spent on this kit.
Although I knew their online instructions were minimal, it seems like alot of the kit was put together without much thought.
Several printed parts show warping, the lasercut parts are cut from a type of particle board which means poor strength on some of the thinner parts, and alot of the hardware doesn't seem to be sized appropriately (see picture. The arm should have full range of motion but it's blocked by the bolt). I realize the hardware issue is a issue fixed by a trip to the hardware store, but when I bought the kit I was assuming things like this wouldn't be an issue.
The condition the extruded beams were in was enough to make wonder what I was getting into. Most of them were already dirty and scuffed. But more importantly they were cut unequally.
Here's some of the pictures
http://imgur.com/a/6LVsu
I'm still going to try and make due with what I have available, but overall I'm none too impressed by this kit.
-drew
May 2, 2014
copterdriver
4
May 7, 2014
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Right there with you Drew. All of the extrusions I received had old tape on them and a few were dinged pretty good, which is not a good thing if it's the uprights especially. Cleaning the glue from the old tape with Goofoff took at least an hour. It's like these parts were left over from production and thrown in a bin. They were not wrapped at all in the shipping package, if they were even taped together they would have survived shipping better. The uprights are very critical, as the bearings ride on those, and any imperfections tracked over will be sent to the printhead.
I had a few printed parts that were broken on arrival, and a few that were very poorly printed. Hardware is very basic (cheap) and I was missing some parts. T-Shaped nuts: I had two that weren't even tapped thru. Replacements? No mention from Mixshop about warranty or replacement parts. A simple sheet of paper with a phone number/email for problems was not included, not even a Thank You for spending $500.
The particle board was a bit baffling to me as well until I realized you are supposed to use 2 of them on each of the carriages. One on the inside and one on the outside. I reduced mine to one and got smaller bolts but the arms will still hit the clamps for the belt on extreme moves. Two of the belt clamps snapped off immediately on tightening.
Seems like the wooden parts were an afterthought since the online "plans" only show one board in the assembly and the original shows printed carriages. I think all of that hardware is way too heavy on the carriages and will reduce the life of the motors considerably and possibly cause print quality to suffer. If I go with that dual plate idea I will make them 1/8" aluminum or titanium plates instead.
I found a Mini Kossel build guide by Blomker industries online. Pretty good reference for most of the assembly. Mishop site has no real instructions for this kit online. Just a bunch of photos. The blomker manual also references the measurements needed for setting offsets of the arms for the printhead, as built. This is critical for setting the correct geometry of the software to match your build dimensions.
No instruction included for the kit or components, ribbon wire that seems way too small, no assembly instructions for the heater or thermistor preparation. I did find some instructions for a Prusa kit that kinda described the installation of dual heat resistors on the Mixshop site. The thermistor is too large for the hole as well, especially after wrapping with Kapton tape.
If you have no Internet... good luck.
Still a good deal on the hardware I suppose, just disappointed there were no usable instructions for final assembly/testing:
How tight are the belts supposed to be?
How can you tighten a phillips screw you can't reach? (Socket head screws)
Mounting the fans. Why two? (one for extruder) Cable ties? I couldn't find a way to mount the fans with those that was functional. 1/8" Aluminum wire worked for me.
Assembling the 6 carbon fiber arms to the ball ends. ( I have 8, The ball inserts snap in.) I used 2 screwdrivers inserted into the assembled arm's ball ends and worked the rods until I had them all on the screwdriver shafts at the same time, with the screwdriver shafts parallel to each other and ball ends aligned. No glue at this point as they are very tight in the sockets.
The nut trap on the Carriage for the ball ends is too shallow or the part is too wide for the screws to fit the arms which required shaving down all 6 rod mounts considerably.
I'm finding daily that there isn't a lot of thought in this kit from a novice's point of view. If I had built a few of these before I'm sure it would make more sense. I have mine built but will disassemble and correct some things before final assembly. Most of the supplied wiring has been trashed and I have purchased a lot of new hardware to replace some of the supplied parts.
A short sample of PLA would have been nice for testing heater.
Overall... good hardware for the most part, just not a lot of thought for the consumer.
May 7, 2014
AndrewLekashman
2368
Input Club
May 7, 2014
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Hey, I looked into what you guys said, and I've discussed this with Mix Shop. I brought up the lack of build manuals, and they pointed me over to their blog, which is where they store all their documentation.
http://blogs.mixshop.com/blog/kossel-build-manuals/
I'm sorry you had to use an only mostly correct manual, I'll post a link to this in the product listing and hopefully future 3D printing enthusiasts will have an easier time.
May 7, 2014
ricecooker7654
9
May 7, 2014
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It's really not that good of a manual in all honesty. I knew that going in though. My main beef with the product is that of just the quality of everything.
The extrusions were dirty, sticky, and not even cut to the same length.
The printed parts didn't give enough room to get the screws in all the way for the nuts to catch on them as copterdriver said before me.
Again, not super excited about the quality of everything, but I'm going to make it work after spending this much time and money on it.
May 7, 2014
ricecooker7654
9
May 7, 2014
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I never even considered using two of the wooden parts for the carriages. I'd probably try it if I didn't already break one of them.
It's going to be one of the first things I replace on this printer in all honesty.
That and the effector. But I think that's just more preference of using magnets instead of the traxxas ends.
May 7, 2014
copterdriver
4
May 8, 2014
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This is a link to the original builders manual: http://reprap.org/wiki/Kossel
If you go by the Mixshop manual you will be shown only part of the assembly. The obvious parts, and they are missing a lot of angles in the photography that would help figure out orientation of parts for assembly. Nowhere does it mention any of the wiring components or hot end electronics other than endstops/microswitches. A picture of the wiring diagram is included but the hot end heater and thermistor assembly is never mentioned.
It's not a big deal as long as you don't mind wasting a lot of time trial fitting parts and scouring the internet for solutions. I have the time, a lot of people don't.
May 8, 2014
copterdriver
4
May 8, 2014
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The wooden parts will warp with changes in humidity unless painted. The build manual doesn't show the second wooden part in the assembly. There is no large screw supplied that will go thru the board and long enough to put a nut and washer on to attach it to the carriage. Two tiny screws and nuts, and a screw too short are all that attach the plastic to wood.
I replaced the axle bolts with a socket head cap screw that is 28mm long and assembled it like the "manual." The weight difference is considerable without all those nuts, long bolt, washers and the extra board. I think I can make this work temporarily.
I found this wheel assembly and will probably print something similar when I get the printer working. Some of the cheap bearings supplied are really loose and some preload would help. The tapered wheels I can make myself.
http://www.builda3dprinter.eu/shop/kossel-kit/rails-to-wheels-conversion-kit/
The magnetic arms will not make that much difference unless the carriages are running without play on the upright beams. The Traxxus ends are pretty tight and could probably be tightened more with the right socket, a vise and a hammer. Light and tight is the key for better precision and less wear on the machine.
Regardless, it's a fun process for me. Just wish some effort was put into documentation of the assembly of a few key things and attention to the rails being protected and clean before shipping. I live on the East Coast so my package was tossed around by UPS many times before it got here. Putting "Fragile" on a package just makes them throw it harder when loading... been there, seen that.
May 8, 2014
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