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I've got an interesting one - see what you make of this.

I print a lot of tall tubes - some thin (about 12mm o/d, 4mm i/d), and some thicker up to about 20mm o/d, 12mm i/d.

Recently I noticed a curve in a print, and then in another. Looking back through old prints, I've realised that this curve has been present for a while, to a greater or lesser extent.

Looking at the printer from the front where the LCD is, in every case the tube appears straight up until about 90mm / 3.5 inches height. Then it drifts very slightly to the left, as you're looking at it. Then it starts to drift back to the centre, finally returning to normal at about 140mm / 5.5 inches height.

The drift seems to be the same in every print. Does this ring any bells for anyone? I'm going to have to have a long hard think about this - something very particular must be wrong for the error to be so consistent.

Total shot in the dark - is the belt on one of your towers warped and/or missing a tooth?

That sounds like a lead - how do I check for that?

Ie. the warping - I'm about to check for the missing tooth just now

Can't see anything, but I'll have to take the belts off to be sure

While I do, here's a picture of a print, showing the curve ;

Might try a trial print with the model rotated on the print bed.

PLA, ABS, or something else? Is the deflection along the same vector as your layer fan?

donaldlindsay wrote:That sounds like a lead - how do I check for that?

I'm not sure of an easier way to do it, other than removing all the belts and laying them side by side, making sure that the teeth line up evenly.

If you have some spare cash, it might just be worth it to buy new belts and throw the old ones away, just to be on the safe side.

http://seemecnc.com/collections/parts-a ... iming-belt

I'd say check the extrusions for straightness first. The second thing is to look for anything with a mechanical period that could be causing your problem. For example the cheapskate wheels have a circumference of 2.9".

If you go even higher does the curve repeat?

Is that a musical instrument?

It certainly is!

That's pretty much all I print - working woodwind instruments. I'm drawing designs for whistles and bagpipes. In fact, I'm about to start making some of them for sale, after prototyping them on the Orion.

Poor printer. So it's looking likely that it's going to need taken to pieces. I've downloaded the Rostock Max assembly guide, as being the closest thing I can find to a Haynes manual.

(poor printer as in it's not feeling well - not 'its rubbish')

>> "PLA, ABS, or something else? Is the deflection along the same vector as your layer fan?"

You know, I think it is.

I'm printing ABS. I've got various coloured ABS prints, all show the same curve if I look carefully.

The layer fan is a possibility - but would that be consistent with it only starting to curve away when it gets close to 4 inches height?

The cheapskate wheels too - I'll try some tall tower prints at low layer height, and see if the curve repeats.

Got it!

If you start to see a curve appearing, particularly in tall, slim prints, that causes the model to bend a little towards the left from probably about 90mm, resolving back towards the centre at about 140mm, then chances are that your hot end mounting nut has worked itself a little loose, causing the bowden tube to lean on the hot end when it gets to a certain height. In giving the heights above, I'm referring to an Orion since I assume most of these will have about the same length of bowden tube etc. The problem would probably manifest itself differently on a Rostock Max.

I had the belts out of the cheapskates, and all the sides off, and re-tightened every screw on the machine looking for this problem - been through the Rostock Max Assembly Guide and the videos to get it all tuned up right. It's done it the world of good!

Nice, I would never have thought of that, but it makes perfect sense!

Well, it took me a while.

Funnily enough, I should have checked the hot end first, having fairly recently had it apart to change the resistors. It was a case of "can't be that, already checked that", but it seems that nut really needs to be on tight. It does get wobbled around a lot.

The test that found the problem out was when I manually lowered the towers to the problem zone, watching everything while I did it. Sounds obvious, but it's all a learning curve!

Learning curve, heh. Glad you got it sorted.

Congrats on finding the problem.

Things like this are the reason i bought the stock Kit... I wanted to know every piece in and out.. Had i gone with the orion id be as clueless as ever.
well done on fixing the issue...
my daughter would love to print a woodwind (plasticwind)... shes three and is full of hot air

dunginhawk wrote:Things like this are the reason i bought the stock Kit... I wanted to know every piece in and out.. Had i gone with the orion id be as clueless as ever.
well done on fixing the issue...
my daughter would love to print a woodwind (plasticwind)... shes three and is full of hot air

You might want to print out some ear plugs, or ear muffs before you print her a musical instrument.

My daughter's about the same age, and I've printed her some penny whistles to play with!

I'll send you the files if you like

donaldlindsay wrote:My daughter's about the same age, and I've printed her some penny whistles to play with!

I'll send you the files if you like

Sure send the files!