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New owner trying to get better quality.What is causing this?
#1
I have tightened the belts and have used how glue on the right z bearings andvthe left y bearings. The prints are fairly good but have this ridge pattern going up the model. The ridges are uniform in the distance they are apart so i dont think its the bed wobbling.

Has anyone else had this and managed to get rid of it?

Can someone post photos of some prints to show what sort of quality i should be getting. I currently have a self built reprap and the quality of its prints are better at the moment. I bought the da vinci because it looks more like a commercial product. Just need it to print like one now Smile

Matt[Image: 2015-04-1716.39.30.jpg]
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#2
Hi Matthew,

We had a discussion about this wobble problem in this thread https://forum.voltivo.com/showthread.php?tid=8591
There are a lot of pictures in that thread.
Maybe the ideas there will help. I've been struggling with this for a long time and still haven't found a solution. Yesterday I applied 609 sleeve retainer to my right z bushing and my banding actually got worse. Right now my guess is that the leadscrew is not centered - when the bed is at the bottom of the printer, there is obvious precession of the leadscrew that can be seen at the top. I'm thinking about ways to address this and will post if I have any improvements.

An obvious ting to check is if the glass on your bed can wobble. Seems like many people had trouble with that on early 1.0 models.
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#3
Easy, Z axe wobbles.

Put the bed halfway.
Unscrew the 2 screws on top of the z-carriage, holding the plate, on top of the hidden brass nut.
The let the z motor turn, and check 2 things,
Does the axe wobbles? Then unscrew the bottom metal connector from the motor to the screw, and put it together again, in such a way it does not wobbble anymore. You have to tighten the 4 inbus screws very evenly, and not to tight. It is not easy, but can be done.
Then you have to check, that the top of the z screw is perfectly aligned with the hole in the top side of the chassis, i had to put some spacers between the motor support at the bottom, to get this done.
After that, you have to align the 2 axes, begin with the left one. Unscrew the 4 screws at the top of the 2 rods.
You pull the carriage up, and check if the brass nut passes perfectly in the carriage, without changing the position of the z screw. Then fix the left rod.
Check again if the z screw goes in and out the carriage without pushing the z screw away.
Then you have to align the right rod in the same way.
Once this is done, reatache the plate which holds the brass z nut in the carriage, and you are good to go!.
And be surprised of what the DV can do for you;-)
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#4
Hey,

Thats sounds like a perfect solution. I was just looking at a tall model I printed and noticed that the lines are not visible near the top. So that would make perfect sense that the bottom of the rod is not quite center.

I didn't know about the adjustments on the bottom of the rod and just assumed that it was push fit into the metal collar.

Hopefully this will get my prints on par with my RepRap.

Thanks for the help, very much appreciated.

Matt.
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#5
Ok, So I have just had a play around with adjusting that metal collar at the bottom. Once I dropped the heat bed from it's screws, the z rod was indeed wobbling quite badly and I can easily see how that was putting pressure on the vertical bars and causing wobble.

However, I tried many times to get it straight and started to get quite frustrated with it Tongue. I could get it slightly better but couldn't stop it.

Then I had a thought!!! On my current RepRap, the Z rods are not held with a metal collar, Instead they have a silicone tubing around the motor and rod which is tightened up with a couple of plastic things. I have never has z wobble issues on my reprap and this now makes sense. The silicone is strong enough to turn the Z rod no problem, but allows a slight flex in the joint. This means that no pressure is put on the vertical smooth z rods but the up and down motion is still achieved.

I found a length of silicone tubing that I has left over from my car (Windscreen washer tubing). I have now replaced the metal collar with this tubing and whilst moving the bed up and down I can see no visible wobble and can't feel any pressure on the smooth rods.

It's nearly midnight here so I have just started a print going and will post results tomorrow. I'm hoping this may be a simple solution for a lot of people. Will keep everyone informed!!

Matt.
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#6
That sounds like a good plan. I too just spent the last hour fiddling with my coupler just as Rudy described. I could not make any improvement to the misalignment. Right now I am trying out printing a couple of different shaft coupler designs I found on Thingiverse. If one of them works, I'll let you know. Can you show a picture of your tubing type coupler?
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#7
At the moment I have just push fit the silicone. But I will add some clamps like on my reprap just to make sure it never comes loose. I have attached a photo of the coupling and a photo of my Print so far. It looks to be a lot better but difficult to tell until I get it out.[Image: DSC_0198.jpg][Image: DSC_0200.jpg]
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#8
Mat, i totaly agree with the "frustration" of not getting it right with the coupler.
I also tried the silicone, and a flexible coupler, but in the end i got it right with the coupler of XYZ. (problem is the size of the hole, it is about 0.1 mm to big.
If you still would like to try the original, just mount it, and tghten the 4 screws very very lightly. and the let the motor turn, whatch the wobble, try to push the Z in the right direction, tighten the 4 screws again a litlle bit more, and so on. In the end, my 4 screws are not really "tight" , but the Z screw is straight (let us say there is still 1 mm in it ;-)
Once you get that part done, the rest is fairly easy.
The reward will be sweet Wink
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#9
Well the print quality's now really close to being correct. Everything seems aligned and I can't see any wobble At all.

I do still see I slight banding on completely straight prints but was reading in another thread about a power supply issue. So may do some research into this next.

Anyway attached is my newest result. Smile[Image: DSC_0203.jpg]
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#10
I can now confirm that my last remaining banding issues is indeed the power supply. I ran a simple test cube print with the heat bed on, then ran a second print but set the heater to turn off after the first layer.

As you can see by the attached photo, the banding is completely eliminated when the heat bed isn't running.

Bit annoyed that a brand new printer obviously can't print with the current power supply, but oh well. Hopefully this thing will print perfect once I get the power supply swapped out with something a bit more beefy!

Matt.[Image: DSC_0205.jpg]
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#11
Thanks so much for sharing your experiences! This gives me hope that I'll get mine tuned up perfectly with a few more modifications!
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#12
Glad it helps. Short of it is as follows.

Hot glue on the x,y and z bearings (the ones that are not fully enclosed.

Replace the metal z rod coupling with silicone tubing (car windscreen washer tube). Secure with clamps if needed and leave a gap of about 5mm between the motor shaft and the z rob. This allows it to flex so the z rod doesn't push the bed from side to side.

Replace power supply with something that doesn't suck Smile. I'm in the UK so having trouble sourcing the perfect power supply at the moment but will have a proper look tomoz. I aim to get one around 300watts.

Apart from that it's a really good printer and is now working just as good as my Reprap which I spent around a year tuning to get it to where it is now :-P

Matt.
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#13
I think the best bet to reduce z wobble would be to upgrade the bushings supporting the bed. I see a lot of people try and secure the lead screw but I don't believe this has a significant effect. The 8mm metal shafts next to the lead screw are the ones supporting the bed. If there is any spacing in the bronze bushings it could cause wobble & the bushing would need to be secured into place without any wobble.
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