Printing creates "wavy" surface along the Z axes

K8200 3D Printer
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This is my third post on forum. My last post was

My very 1st print (the cover box of the K8200) was somewhat wavy in the Z dimension. I expected a smooth, even surface, but the surface was rather wavy:

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So I took my time, installed the blender software, watched quite a few youtube videos, how to design a few 3d objects as well as prepare them for printing.

I wanted to design a couple of objects that could provide me different reference points along different dimensions. This includes:

(1) an object of three-cycles-and five rectangles: 3C4R:

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(2) a half cylinder 1/2C:
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There are two apparent problems with the print:

  • the surface is not even along Z dimension
  • the edges of the print bent upwards as print progresses

The 3C4R was fixed to be manifold using some web site (suggested by k8200 software)

The circles of the 3C4R are of diameters 50mm, 100mm, 150mm and the print nicely approximates the sizes. The width of the edges of rectangles should be 3mm, but they vary substantially (always bigger than 3), usually 3.5 to 4mm:

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It is five mm above the surface (+5 mm of along Z axis for the print)

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and for the 1/2C (30mm wide, 50mm height):
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The videos how the actual print took place are here:
3C4R: https://www.youtube.com/watch?v=XfiQ6Twm55c
1/2C: https://www.youtube.com/watch?v=0glDOzOlL8U&t=7s

The settings (printing and printer are as in PLA does not flow through extruder, if it does, flow is not uniform - #36 by arturas - K8200 3D Printer - Whadda forum - Community Help and Support)

I also have (at least must have) the screenshot video of the k8200 printing software while printing 3C4R. The PLA was at 190 degrees Celcius, and the bed was 50 degrees celcius.

The 1/2C print was different: the PLA was 190 degrees, but the bed was not able to keep up with the temperature (it dropped down to 45 degrees or so: why?) This infos could also be seen in the youtube video.

How can I adress these two problems?

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The uneven sides are Z wobble
You may want to look at getting the K8204.
If you would like to make it better you should look at the K8203 as well
If you get the K8203 you will need to get the K8204 with it.
K8204 link https://www.vellemanusa.com/products/view/?id=527453
K8203 link. https://www.vellemanusa.com/products/view/?id=527450
The bed cooling off
This is a large surface.
Is the any wind blowing on the bed?
What is the temp of your room?
I keep my room at 74F 76F

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Hi @Wrong_Way,

Thanks a lot for the very fast response. I am very impressed.

So this is the Z wobble. Once you mentioned it, I have a feeling that the Z Axis is not perfectly even. In fact It is rather uneven. I mean, this is a large piece of metal, which is rather hard to bent with fingers/hands… Did it got bent in transportation? I’ll post a video tonight, to show the unevenness.

The upgrades look impressive. I mean especially the prints after the upgrades. Your links have “buy from Velleman USA” buttons, which are pretty nice. Since I am in Europe, I’ll have to look for the parts locally. From your description I understand that you suggest to upgrade, and this should be done in this order: first K8204, then K8203. The product I’d need be looking is called “K8204” and “K8203”, right? (just to avoid some trivial mistakes in ordering)

To comment on the bed cooling off: there’s no wind. The room temperature is 68-73F (20-22C). The bed temperature was set to 122F (50C), but I could put my hand on the bed for s hort period of time, meaning, that the very top surface temperature is not a lot above 104F (40C). I have a temperature-meter, but I since I lent it, I’ll have to wait to get it back.

Thanks!
Arturas

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Arturas,
This is the way I upgraded mine I started with the K8204 that helped alot.
Since I had a lot of the 3mm PLA I waited until I used all or most of it before I did the K8203.
This way you can do it in stages and use the 3mm PLA or ABS then switch to the 1,75mm
73F maybe still a little to cool for the bed also look at where it is blowing.
If it is blowing on the bed you may need to slow it down.
I printed one of these for mine and it seemed to help the bed heating.
https://www.thingiverse.com/thing:158729
I also spray a light coat of cheap hair spray on the bed (you have to clean the printer more often) on my bed that makes the project stick to the bed better.
Velleman sells these in Europe since I am in the USA that’s my go to site.

I hope this helps.

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Hi @Wrong_Way,

This is extremely helpful. I am afraid I have this attitude of rushing through things too fast, then I hit problems and keep wondering what’s going on. Getting an advice on how to upgrade (what and how) nicely slowed me down. I almost rushed into buying all materials immediately. I’ve read a little that the extruder reduces in size (and becomes more smooth and precise), it did not occur to me that this changes the thickness of the PLA. Thanks a lot!

W.r.t. the thingy to improve bed heating: shoot, this is nice to hear. I still cannot imagine how the parts gets on the bed. Do you think you could send a picture of your printer with the part on it?

The hair spray sounds a fantastic idea. This piece of advice you’d not get in high school! And cleaning is definitely better than having your printout bent by a half an inch.

As promised I uploaded the video on the wobbling of the X axis. Can you have a look? Once I’ve took a shot, I must admit that it is less dramatic as I thought. What do you think?

https://www.youtube.com/watch?v=Kq_FtY89CJ4

A side question: did you manage to set up the cura software with the printer? I’ve looked at the forum entries (that spans a long period of time and multiple versions of cura), but was not able to set it up properly. What are your opinion about cura or other 3d printing software?

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I will post a picture when I get home.
I reinstalled the stock print head because I found a couple of reels of 3mm PLA I want to use up but will put the K8203 back on when I’m done with those.
Cura yes I did get it setup.
However I run my printer off of a Raspberry Pi with Octoprint.
With this setup I have a webcam on it so I can watch and control the printer from my phone.
I did not set it up to go through my fire wall because if I am not at the house I do not want it running.
I am currently setting one up for my K8400 and hope to have it done this weekend.