My Printer Build

K8200 3D Printer K8200 - Your printer, creations, and ideas for imp
#1

I just finished building my printer and it was fun.

I only encountered three problems during the build:

On the Y axis the cable for the heater bed turned out to be a little too short. THis could be my fault. I probably did not check the cable length properly. Not a big problem though. I removed one of the cable ties and now the bed can move all the way forward and backward.

Second problem was the end switch of the Z axis. Somehow it was activated by the bottom edge of the Z train’s left alu plate and not by the adjustment screw. So I could not properly adjust the Z axis. I think this would be no problem if the alu plates would be mounted the other way around ( with the smaller 10 mm side down and the 15 mm side up ) But I double checked the manual and it says I mounted the plates correct. Then I tried to place the switch a little further to the left but this was not possible due to the length of the screw holding the switch. If I placed a spacer between the switch and the motor bracket I could not fit the nut on the switch screw. Finally I realized that the fan screw was a little longer than needed so I decided to exchange the fan screw and the switch screw. This allowed me to place the switch exactly below the adjustment screw. See the pictures.

Last problem is that the X axis movement is a little ‘bumpy’. Could this be due to the center hole of the toothed pulley not being properly centered? I don’t know if you can see it in the pictures I took but the pulley in fact more resembles the shape of an egg. This is the only flawed piece I found in the whole kit but I think it’s a rather critical part of the printer.

All in all a great assembly kit. I am looking forward to do more prints as soon as I get more PLA filament and my X axis problem is resolved somehow.

#2

I made a quick video of the pulley in action. As soon as it starts turning you can clearly see that it is egg shaped.

http://tinypic.com/r/w9egxy/5

#3

To remedy the problem with your Z axis endstop you could lower the whole Z motor assembly along with the motor bracket by one cm. This way you will be able to lower the setscrew a bit more and the endstop will not be triggered by the Z carriage anymore.

The X pulley is indeed not up to spec please post your address so we can send you a replacement part.

#4

Thanks for sharing your nice result
Good luck with the printer! (once you have a good pulley)

#5

Nice thanks. I will send you a PM with my address ( as soon as I find the PM button ).

Edit: I checked the other posts: I got my printer from Reichelt too. Real name is Moritz D. in D-14662

#6

Hello!

Can you say me how long did it take to build the printer?
I’m going to build the printer in my final examination of my mechatroniker education!

greetz Marcel M. from Germany

#7

hello,

i estimate the build took me +/- 16 hours, but the second time (or when you are a fast builder) it would probably take me about 8 to 10 hours

gr

Marco

#8

The replacement pulley arrived :slight_smile: Thanks

With the new pulley movement was a lot smoother. Although I still had some vibration issues so I decided to print a belt tensioner. Now printing is super smooth. :slight_smile:

The build time was about two days. On the first day I assembled the mechanical part: frame, motors and stuff. Then the second day I did the wiring, electronics, testing and adjustments.

Here are some more pictures:

The completed case:

and the belt tensioner ( I uploaded the design here if you’re interested )

#9

Nice addition, thx for it.

Ark.
PS: Found both my pulleys wobble and cause wave shaped planes on the sides of my printed testobjekts (cube 10mm x 10mm x 10mm).
:wink: of course the first layer plane is just that planar

#10

The wave shaped sides is due to the Z wobble. I still had this pattern on my prints even with round pulleys and proper tensioned belts.

What helped was clamping the motor to the frame with a large hose clamp and a little metal plate as spacer.

Now the motor can’t move and all printed layers have the same height :slight_smile:

#11

I had fixed the problem with the Z-Axis by another way.

For the Axis holter on the top i desing a new part , becase the original is not stable an begins to wobble.
Stepper and z-axis i connect with an flex coupler.

This is a pictute of the Messuhr holder i have printet after modifikate the printer.

I had uploadet the axis-holder to thingiverse.com/thing:135151

#12

Very nice but,
Normally this reinforcement should not be necessary

Did you oil the shafts and threaded rod?
This is important to remove stress from the plastic holders and motors.

Keep up the good work

#13

Yes i did oil the z-axis and shafts.
The first problem was wobble by stepper motor.
Then i changed to an flex axis coupler.
The result was bether, bit i saw thad the holder on the top starts to wobble.
So i open the two screws on top of the axis (so it is not fixed in high) and the result was mutch bether.
But some times the layer high was not exact.
I had checked this with the messuhr. (some times it jumps ±0,03mm)
Now is the new top holder the fixing point for the z-axis high (and not the stepper).
The diferece of the layer high is max ±0,01mm (0,01mm is the resulution of my messuhr)

#14

Okay the hose clamp was no optimal solution. So this time I replaced the threaded rod with a proper Trapezoidal Spindle.

Not too expensive, around 10 € for a one meter long 8x1.5 spindle. There are cheap matching plastic or steel nuts too but I didn’t want to make a compromise again and bought a 8x1.5 nut made from red brass. The nut didn’t fit in the original nut holder so I had to print my own matching Z follower parts.

I’d also print one of eytec’s top spindle holders but I’m currently out of square nuts and it seems with a straight spindle the original small spindle holder is good enough.

The flex coupler could be printed too. I still bought a professional alu flex coupler because it fits better with the alu profiles :slight_smile:

Now the Z wobble is almost completely gone. With the LED light directly from above you can still see a pattern but if you look from the side you’ll notice the amplitude is below 0.1 mm.

#15

This looks very promising.

A combination of this and edirol’s improved Z motor holder (Z-Motor holder replacement) might bring the whole thing one additional step further.

By the way:
Wouldn’t it improve things further to have the Z-motor on top and the spindle sitting at it’s bottom with a fixed holder at it’s lower end?

Thus the motor’s bearings wouldn’t have to carry the spindle’s and the whole Z traverse assembly’s weight, and given a reasonably precise fixed spindle holder the wobble thingy should be decreased futher.

Of course, the motor would have to be configured to turn counterclockwise, this can be achieved by either changing the controller firmware or by re-wiring the motor, so it shouldn’t be a big hurdle.

#16

Hi, by my solution the spindle holder on the top had to carry the weight of the wholle Z traverse.
The nut on the top of the spindle pulls up the spndle, so there is no wight on the z-motor.
The flex motor coupler is a litle bit streched. :wink:
So you must not mount the z-wotor on top.

#17

@motoritz

Did you change anything in Marlin/Firmware because of the different flank lead?
The M8 threaded rod has a 1.25 lead and the trapezoidal spindle has 1.5, so fewer steps are needed for the same height.

kind regards
Daniel

#18

Yes, I forgot to mention I had to update the steps per unit setting and recompile the firmware.

3200 steps / 1.5 mm = 2133.3333333333333333333333333333 steps per mm

2133.333333… is a pretty odd number and somewhere I read that the steps per layer should be a multiple of the microstepping multiplier (x16). So I rounded the value down to 2112 steps per mm. This means the stepper can make 33 full steps per layer ( 0.25 mm ). Might be a problem when printing very tall objects because the value is about 1% off from the real value. However with this value the 10mm calibration cube printed exactly 10.0 mm high.

#19

eytec,
am loving your work,
the mods you have on yours, look the business, you obviously know what you are doing.
thanks for sharing the z clamp design.
do you have the other parts on thingiverse?
i’m liking your flat bet gauge holder, blower nozzle, universal joint!:slight_smile:
have you modified your flatbed adjuster system, i imagine you weren’t happy with the stock solution.

thanks very much for your time,
keep up the good work, your an inspiration:)

gary:)

#20

Thanks erikthecat, for the nice compliments.
normaly i share all the things by thingiverse.com/eytec/designs
The last days i print on a mirror ordered by Amazon
amazon.de/s/ref=nb_sb_noss?_ … 5x20%2C5cm )
they are 205x205x1,75mm and hade 180g.
The flat bet leveling system i had not modifikatet, (with the mirror it is easyer to kalibrate so other things are higher priority).
In the future i will make something like this for z-endstop: thingiverse.com/thing:146695
The next days i will start to print ABS and NYLON. (In the moment it runs the first testprint with NYLON 645)

Bluetape is only used for the nylon, PLA i print direct to the miror surface