Velleman K8200 3D printer (a unsolicited review)

Community General Discussions
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K8200_aka_3-drag.jpg

       This is my third 3d printer and overall I like it.  But there are things others should consider before choosing it as a project.  

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       I have been using it for the last week and it is growing on me.  Once the stops are adjusted and the bed is leveled it works flawlessly.

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      I picked this printer because it was cheaper and faster then ordering the pieces separately.  

     I ordered it from MatterHackers and it was shipped from Velleman in Texas (USA).  It arrived in about 3 days with standard shipping.  The packing was very good,  The inner box alone would probable have been OK.  Sorry about no unboxing photos but I had not intended to write this at the time.  Most of the parts are in clearly marked bags the others are east to identify.  The injection molded plastic parts are excellent quality.

     The assembaly instructions are better written then most,  Almost as good as Heathkit was.    A lot of the stress was pulling the 90 deg brackets out so I could correct something.

     The first and biggest problem are the 90 Deg. brackets.  It comes with 20 but you only need 14 (and could easily cut that down to 12)  These brackets will need lots of work before you can use them.  you will need to be able to slide them along one extrusion while holding another at 90 degrees.  5 pair need to make a perfect 90 deg angles.  Spend the time to test fit them and sort out the most perfect pairs and the rest of the build will be a lot easier.

    The second thing was that bag #26 had the wrong setscrew in it.  Don't panic,  the screw is in bag 28.  

     Leveling the bed is a pain but exact.  The rest of the assembly nits i picked where:

          The instructions should have you wire the limit switches before mounting.    The end stop wire is Orange not Red.   I ran out of the small heatshrink(some nits are smaller then others)   The bed thermistor wires are Red Brn not Blk Wht.   

     I love the last line in the assembly instructions "Make sure to read and understand these next chapters, because they contribute a whole lot to the printing quality of the K8200."  The User manual that is referenced on the MaterHackers site is about converting the K8200 to a milling machine.

     The information you need to set it up can be found here: http://www.k8200.eu/manual/printing.   You will need at least 3 hands excellent eyesight and a very tiny non-conductive screwdriver.  

     The instructions assume you are using Repetier but after half a day I switched to MatterControl and its been farily smooth since then.  I'm still in the tuning stages.  My preferred toolpath is Slic3r using Repetier as a front end and g-code viewer and build plate filler on my desktop computer and transferring the g-code to my printing computer.  (Not 3DSlicer A viewer for MRI's and other 3d medical images.)

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Repetier Patched as i was writing this and i haven't tried the new version.  Now i just drop the .stl in MatterControl and come back when it is done.

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In Conclusion:

     I feel I got a good value for money.  If it had better 90 deg. brackets I would not hesitate to recommend it.  But with the extra elbow grease you end up with a lot for your money.  Also note it is a kit for the 3drag RepRap.

( Before Johnny Storm asks I didn't see a way I could post this under reviews since I am not an official "reviewer".)

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I absolutely love mine. The
I absolutely love mine. The construction time is crazy. It took me two days over a weekend and that was non stop! But you get the reward of a very cheap printer that is surprisingly good. Almost perfect, if not for the infuriating inbuilt z-axis wobble.
The z-axis wobble causes the sides of your prints to have horizontally ridges with about ~ 0.5 variance. You can make smoother prints by changing your extruder settings, but these prints are made with a finer filament ( the travel is faster making a finer filament) but these prints will lack high strength needed for robotics. I’ve read lots of mods for this wobble, such as a flexible z-axis coupler which I have on order, but no-one ever reports being able to get rid of the wobble completely. The wobble is caused by the z-axis coupler being off centre and the z-axis stepper being mounted out of alignment with the rod which tugs on the frame causing printer head to slightly change it distance from the rod on every layer. I know that these are issues that can be resolved but I really begrudge having to spend the time experimenting with the setup because it takes too much time away from the printing. I am currently printing a full size 6 DOF robot arm with the potential to lift 2.5 kg at 30cm. It’s utterly amazing what can be achieved with it.

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I should add, if you just
I should add, if you just use the Velleman printer settings that they provide, you won’t see much of the z-axis wobble, I think they achieve that by making the layer height correspond to multiples of a full z-axis rod twist. I.e. If each layer is made by twisting the z-axis exactly 360 degrees or 720 , the coupler will be offset the same amount for each layer. I changed a lot of the settings to try to get stronger prints. I may go back and spend some time playing with the layer height and extrusion rate settings to get my settings closer to having 360 or 720 degree turns per layer height.

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to get rid of the wobble

Get a trapezioidal steel bar for the z axis, and put a counterweight on the other end of the z axis, to keep it pulled up.

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suggested upgrades

The kit usually gets you a barely working printer, to get a better and reliable printer i suggest you to get yourself:

-RAMPS electronic kit (the custom board is unreliable after some time)

-12v 20-30A power supply, i had faults because of the default one

-glass on the hot bed and hair spray to get more adhaerence

-hot end MK8 or better, the default extruder it’s easy to jam

- z axis trapezioidal bar instead of the stock one

-heat bed MK2 to reach higher temperatures and faster heating time

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I mostly agree

     I will probably not but a gen7 based board again. Adjusting the current is just too difficult.

     I don’t see the cross beam being a problem, I think the poor quality of the 90 deg. Brackets make it imposable to get everything square. And except for those brackets I think the print quality is good for the lowest priced machine I would consider buying

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I’m not in love yet, But we are seeing a lot of each other.

I was looking at the drop in Z-axis upgrade but I am going to try belt tighteners first.

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workin on it

struggled with mine.  prints have ridges all the way through print  got last november now its august.  but have nothing but time for it.  experienced x axis vibration couldn’t find until the bearing pulley blew out last week…fixed that one. Glass helped greatly am now reliably printing but not turning out a smooth print.  needs much sanding throughout. have considered extruder and temp issues but after reading here maybe z axis wobble.  threaded rod definately not true. totally new to 3d printing and figuring out while I go.  using repetier software and I like it. 

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Hi! Whad do you think about FlashForge Finder (found it here)? I’m planning to print d&d fifures on it

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I reviewed it, This is a good site. I have a printer but I don’t know how is the Method of fixing filter in a printer. Kindly guide me.

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Really good printer. One of my friends has the one and I am also thinking about buying it.

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Thanks for helping. I understood the Method of fixing filter in a printer.