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Wobble
#1
I bought my my printer a couple of days ago and I am noticing that there is a wobble in the prints. I thought it was a Z wobble I shimmed the right side bearings now they are super tight and have no play. I also have checked my belts and they seem to be fairly tight. I still see this and I havent found someone addressing this problem

I took a few pictures and modifed the contrast so that is easier to see.

Ive printed (http://www.thingiverse.com/thing:242437) to make sure the holes are printed round and they are.


[Image: Wobble1.jpg][Image: Wobble2.jpg]
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#2
Some other possibilities --. It can be glass moving around, and it can be the slicer.

Kieth.
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#3
Hello Erick,
I have the same issue (at least I hope I'm understanding your problem correctly) Smile I have been looking on forums trying to find anyone with similar problems but was unsuccessful in finding any discussions on the topic. I have had my printer for about a month now and was able to do some testing to pinpoint the cause of the problem...
The issue unfortunately is caused by the print bed turning on and off to keep the set temperature (in my printer at least) Now, the way I realized that the build platform caused the issue was- I was playing with print bed temp setting (for unrelated reasons) in Simplify3D and noticed that while the bed was cooling a part of a model came out looking a lot nicer than the other part of the model. I have since printed a few parts to further test this theory:

This part was printed with the print bed heater turned off.


This part was printed with the print bed heater turned on.


Two parts side by side (heater OFF on left, heater ON on right).

Two parts side by side (heater OFF on left, heater ON on right).


This last part was printed with the print bed temp at 90C for the first 100 or so layers, and print bed heater turned off for the last 100 or so layers.


I am not sure what the power supply is rated for, but the printer is drawing 1.5amps from the wall (if my amp meter reading is to be trusted since the battery died immediately after taking said reading) which equals to about 180watts. So maybe the power supply is struggling to provide enough current to run everything at the same time?
For now though, I turn off the print bed heater using Simplify3D after the first layer is put down, witch works great for small parts since I don't need to worry about them warping/coming off the print bed. For larger prints I have no choice but to run the heater and live with the wobble Sad
Tom from the forum here has replaced his power supply with a 320watt one MicroCenter sells, I wonder if that would be the solution to my problem.
https://forum.voltivo.com/showthread.php?tid=8444

I'd be interested to hear if anyone else has/has had the same issue and if there are any known fixes for it.

Thanks,
Anton.

Edit:
By the way the parts in the pictures were printed standing up (1/4" foot print and about 4" tall)
Looking at Erick's pictures again I am not sure our issues are the same. Moderator please feel free to move my post if needed as I do not want to hijack this thread.
Thank you.[Image: IMG_0608.jpg][Image: IMG_0609.jpg][Image: IMG_0610.jpg][Image: IMG_0611.jpg][Image: IMG_0615.jpg]
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#4
I have been having this problem for weeks now, and I've been psyching myself up to tear down the printer again and apply some bearing retainer (609) to the right side of the z carriage (I had bit of a mishap the first time I tried this several months ago :unsure: )

I am really curious to try out your solution of turning off the heated bed after the first layer or two, Anton. Funny thing is, I don't think I used to have this "wobble" problem - it seems to have only crept up after swapping my broken stock 35W heater cartridge for a 40W replacement. So that may lend some credit to the PSU-being-underpowered theory. I will follow up with some resulting pictures once I give this test a shot![Image: IMG_20150327_241804776.jpg]
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#5
I finally got around to getting the rear cover off and looking at the PSU. My PSU says that it is capable of providing 200watt max, the printer is drawing about 180watt, that leaves the PSU with 10% headroom. 10% does not sound like a lot, especially considering potential differences in max output between the PSUs that the manufacturer used/tested to get certifications, and all of the rest of PSUs that were shipped to customers. Personally, I'm not comfortable knowing that the PSU is going full-tilt for hours at a time. If I get some free time in the next few weeks I might just temporarily connect a PC PSU (around 400watt) I have lying around to see if it would resolve the issue. The PSU someone suggested from MicroCenter is no longer available Sad anyway, probably should test before spending 30-50 bucks on a new PSU.
Will update if I ever get around to it Smile
Anton
[Image: IMG_0638.jpg]
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#6
I'm about to test your theory, results will be up in an hour or two. A 350W version of the suggested PSU is available on Amazon for $40 http://www.amazon.com/gp/product/B00F0ZP...WYWVZ484P5

Let me know if you can get it working with a normal ATX PSU - I'd feel a lot safer too running with a 400W PSU. Also wondering if it would fit standing up inside the build chamber - do you think it would be too hot in there?
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#7
I think it should fit just fine (might not look too pretty though Smile ). Temperature-wise, I can't see it being a problem, plastic around the existing PSU exhaust vent seems a lot hotter to touch then any of the build chamber walls. Also there is no heat shielding of any sort between the build chamber and control board/PSU compartment, so I don't think it could be that much cooler in there anyway.

I am very interested to find out if you also will get a better print with the heater off.
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#8
I grabbed a PSU I had sitting around and tried it in a couple positions inside the build chamber. On the right side it won't fit because the drip tray holder just barely comes too low. On the left side, if it's pushed back, it clears the build platform by 1 mm or so.[Image: IMG_20150328_135522675.jpg][Image: IMG_20150328_135651987.jpg]
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#9
No dice. I still get the wobble banding even with the heat to the bed turned off. So I can't say whether or not it's a power issue until I deal with the possibility that my bed is wobbling on the z-axis rails.[Image: IMG_20150328_145515921.jpg]
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#10
Oh well. I guess at least one potential reason for your wobble issue is now off the drawing board for you. Do you use Simplify3D or Repetier to control bed temperature? Right now I'm printing, among other things, two cylindrical objects about 3/4" diameter for a project I'm working on. I'm unable to see any appreciable bed movement when printing round objects, I do notice bed moving /vibrating quite a bit more when printing corners or zig-zag filling thin walls. Anyway, if the problem was with the bed movement, I would expect to see wobble that is not uniform: different, nonuniform defects from layer to layer. What I see in your pictures is that your printer (like mine) prints, a few layers at 10mm (just random number), next few layers at 9mm, and then next few at 10mm again, and so on and so forth.
There's nothing else quite like spending your day-off trying to troubleshoot print quality issues Wink Ha ha.
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#11
I use Cura as my slicer - there's a plugin called "Tweak At Z" that allows you to change various parameters at a certain height.

I always assumed that the banding was caused by the threaded rod not spinning perfectly straight but rather precessing a tiny bit around the z-axis. With each rotation, it would perhaps move the bed in a tiny circle. But I agree that the banding pattern doesn't seem to match that idea, since the bands look thicker and then thinner at each height rather than spiraling around the part.

Your PSU idea still makes a lot of sense to me, so I'd love to see the results if you upgrade to a higher wattage.
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#12
Got my new build platform glass+heater today (140watt instead of stock 130watt heater) and that extra 10watt at 12volts is apparently enough to turn the printer OFF during pre-heat stage of build. I think overcurrent protection shuts the PSU down (I'm going out on a limb here assuming this PSU has overcurrent protection). So there's definitely a new PSU in this printer's not too distant future. Took a quick look at the existing PSU again today, and there doesn't appear to be any plugs between the printer and the rest of the system, everything is wired directly into the PSU. That should make thing a bit more complicated.
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#13
Installed my new 320watt PSU a couple of days ago. Happy to report there is no more wobble (see attached). Everything else seems good as well (there is a bit of coil wine from the new PSU, but only when both the extruder and print bed are set to higher then normal temperatures at the same time). Going through an 8+ hour print, will update if anything goes wrong.[Image: IMG_0698.jpg]
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#14
Glad to see your wobble problem is fixed!

What PSU did you end up getting?

Are you planning on making a guide or showing pictures of how you installed it?
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#15
Thank you Cameron. I ended up getting this one: http://www.amazon.com/Solid-Gear-320-Wat...wer+supply But anything that is the same form-factor will work. You would only use 8 wire out of it. I was not planning on putting out a guide, but if you or anyone else is interested I can get one posted here.
Have you made any headway in figuring out what is causing wobble in your prints yet?
Anton.
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#16
Thanks for asking, Anton, and no, I haven't really made any progress yet. Very busy with school at the moment.

I was wondering, looking at that PSU, it looks like there are several 12V rails. Did you end up splicing any wires together? The reason I ask is that a few years ago I modified a standard ATX PSU into a benchtop power supply, and I had to get inside and combine all of the different 5V, 12V, etc. rail wires in order to have maximal amperage available.

When I did that mod, I also had to add in a resistor to act as a dummy load or else the PSU wouldn't turn on. I'd imagine this isn't necessary in this setting because the power supply is connected to a board.

I'm not really sure if this would fix my wobble problems at all, but I'm more interested in having a beefier PSU in the future as I intend to add in an exhaust fan, probably power a raspberry pi, perhaps use a bigger extruder motor in a bowden setup, and possible other ideas I haven't thought of yet. I'd like to have more power available, especially on the 12V rail.
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#17
Im also interested in changing the power supply. Specially since it might help with the wobble but as Cameron mentioned I am going to be adding and modding this printer so having more power is a good idea.
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#18
It is a single 12V rail. And it is rated for 207watt on 12V rail. I didn't have to mess with it too much, all I did was desolder a bunch of extra wires just leaving 2-3 extra on each of 12V ,5V, 3V rails in case I ever decide to add anything extra. I also removed the stock PSU wires with plugs attached, and soldered those into the new PSU, I just did this for peace of mind since stock wires are 18AWG and new PSU wires were 22AWG.
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#19
Hey, borrowing the original PSU wiring is a good idea! I never would have thought of it - that way you already have the proper connectors.

I'm always a little nervous when opening up a PSU and poking around in there though...
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#20
I know that feeling all too well Smile. My original intention was to simply cut the connectors leaving a bit of wire sticking out and use butt splices to attach to new PSU, but since the new wire was thinner I thought I'd better play it safe.
By the way, the connectors XYZ use are regular 4pin CPU plug (I think that's what it is at least) and the new PSUs already have one just like it, even the wiring is the same, so if it wasn't for the wire being thinner I would just have used that. Also, the wires on any PSU are way longer than what you'd need to reach the plugs on the printer board, so If you had some plug-bodies and pins, you could just crimp your own. That is probably the best way to do it, but I don't have any of those things.
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