Consistent layer shift


#21

Hi Ben,

I know exactly what you mean. After reading about other printers and their problems (even Form 2, that has an expensive resin tank and consumables, is prone to failing from time to time), or Prusa MK3 (a friend of mine got one and it came full of bugs), I realized the hole 3d printing market/processes/etc,… is still not very mature. But it´s damn anoying to have this sort of randomness. I´d try the basics again:

  • bloody screws
  • the table where Moai is mounted is firm? have you tryed moving it a bit (yes, I know…)?
  • power source is stable?
  • cables, all of them
  • VAT (I´ve heard cloudy/worn out VATs may give problems)
  • resin is clean? free of any debrees? deaired?

I´m pretty sure I´ll make a full check list for myself after all these problems. Another thing (and I consider this my mistake), I´ve added to many new variables at once. I´ve started with blue resin + PDMS VAT and got only good prints. But, decided to get hi-temp resin, without having much “mileage” and without being sure my chamber was properly heated. Then, I though it would be just a resin problem (and I still think my flesh hi-temp has something wrong, maybe due to transportation or whatever) and got gray-hitemp + new fep VAT + hew adjustable plate. Simply too many untested variables.

But, I also think the way the new fep vat and even gray hi-temp resin are advertised gives the idea that they´re “improvements”, but the fact for me is that they´re different approaches and harder to work with, also much less tested.

Anyway, if I can help you, count on me.

p.s.: I´ve spent almost two liters of resin going through all these troubles and variations and I pay almost 100% taxes over the resin price, ouch! That really sucks.


#22

Yeah I honestly don’t know what’s going on anymore lol.

I did a test shape and got a layer shift. I switched the galvo cables, did the test shape again, it was perfect. Did another test with the original sliced anubis model, got a shift, tried my test shape again, it was perfect. I redid the anubis model as per Leonardo’s recommendations above, aside from a slight issue where I didn’t have enough support, there is no clear layer shift. I’ve switched the galvo cables back over to their correct position and am doing another of my test shapes that should be done very soon and then I’ll try the anubis figure again.

I don’t know what to expect anymore. I’m glad I got the adjustable build plate, but I’ve already ditched the FEP vat and won’t bother using it again I don’t think. I’ve got another couple of vats on the way and the material I need to restore my first one, but I don’t want to try that without some spares on hand. So hurray for another 2 weeks of shipping and god knows how much in taxes.


#23

Seems my issue is miraculously fixed (for now). No idea what’s going on.

Checked the screws, all tight
table is solid and printer is level, both physically and the build plate
Power isn’t a problem, it’s constant, no fluctuations
Cables are all connected, switched the galvo cables over and back again but issue disappeared by then.
Vat - still in decent condition, starting to cloud in some areas but not where i was printing for these tests.
Resin is clean, strained, and free of dust - any left in the vat is covered when not in use.
Z Thread appears stable, no defects, no burrs or rough areas, moves smoothly

Only thing I can put it down to is perhaps bad slices. I used the .06 profile in Cura 3.4.1 but all my tests have been done at .08 to save some time and resin. Might be a problem with the profile? I have no idea.

Anyway, I’m going to continue printing and see what happens.


#24

Good point about the profiles, I changed mine from 60 to 80. And did the cilinder tests with the 100nm profile. I’ll do aonther test as well.


#25

use the latest beta with the new profiles I posted not long ago


#26

I’ll give it a try @matt3o


#27

Seems I might have been mistaken. After curing the other test piece it seems I have a layer shift from left to right. It’s only very slight but it’s definitely there. I’m so confused now. I don’t know what to make of any of this.

1st Test piece, printed with galvo cables connected to right boards = Layer shift front to back.

2nd test piece, printed after swapping galvo cables over = no layer shift.

3rd test piece, printed after swapping cables back to correct position = layer shift left to right.

I don’t know what to do anymore, thinking I’ll just give up and get an Ender 3.


#28

@matt3o @bendouglas86 @Ricardo_Rocha

Sorry for butting in but Ive been reading through your posts while I wait for new supplies…
I couldnt see this mentioned, but one similarity you both share on both your sets of pictures is that your lines appear to show the same spacing between them- maybe every 6 or 7 mm perhaps, and seem to come in at the same height on the model ?
So I was thinking it was weird the fault is measured,ie they dont seem randomly placed.
Have you checked the approx location of the lines in cura, maybe they kick in at the same layer height - perhaps the Cura slice is trying to give the moai 150 slices but the hardware is set at 149 ( I have no idea what Im talking about but you get the idea!) and the issue only comes in at layers that are similar, so layer 15, layer 25, 35, of 40,50,60 etc.
Dunno, just trying to throw in another option !
For the recors, I share the ‘meh’ ness on the Moai, but ive got it working to good enough, and to go further will involve a lot of careful time I cant give it yet. Ive also seem quite a few people have to send their Form2’s back with Vat and resin handling issues etc so as mentioned earlier, its 50/50.
Good luck !


#29

Thanks Teivion. The model looked alright in Cura and the slices seemed ok too. I’ve decided i’m just going to plough on. It’s quite likely it was an error in the slice, but it could well be a problem with the vat too as that’s been the only other constant with these prints.

I’ve prepared one of my own models to see what happens. The model is about 100mm tall and then there’s the 5mm of supports below so if there’s going to be anything showing up like in the anubis prints, it should show up in these too. I’ve got a couple of new vats on the way and I’ve got the stuff I need to recondition my current one, but I’ll wait until I get my spares before rushing in to doing that I think.

As for the Moai itself, I’m yet to get a result that an Ender 3 couldn’t produce for significantly less money and less hassle. They’re showing their Moai 200 off but if this one doesn’t work with a fep vat well I’ve got no faith in a newer, bigger model.


#30

I think my issues have been solved by updating to Cura 3.5 beta along with the new profiles.

I printed this at 80um and also used the new “polygon circumference” feature set to 0.07 instead of 0.1. Not sure if that helped much but this print is much improved and doesn’t show any obvious layer shifting. A little distortion around by the mouth on the right side, but I’m pretty sure that’s just me needing to tweak my peel settings as I think that’s probably caused by suction.

The teeth came out really well despite the fineness of them. I’m pretty sure a new vat will help out with this too, my current one is quite well used.


#31

Minimum circumference should be 0.1. If it’s 1 by default you probably have the wrong profiles or you need to clear the Cura config directory. Apart from that, nice print :slight_smile:


#32

My mistake I meant to type 0.07.
Updated previous post
I think I’m getting closer to better prints. I could likely get a way with far few supports in that print I think.


#33

I made a hell lot of tests and between 0.1 to 0.01 I haven’t noticed any difference in print quality (but slice time increases drastically). If you think you need finer details you may try 0.05. You can see the result directly on Cura from the layer preview.

The back of the head definitely has way too many supports. What resin do you print with?


#34

I’ve moved onto the standard black resin (having ran out of grey). So far I’ve got better results with it, so I kind of regret ordering more grey instead of black but it was dispatched before I could change the order.


#35

Great print bedouglas86

I wonder what VAT are you using (I struggling my FEP-VAT and on my way to put it aside)


#36

I’m using the standard PDMS vat. I gave up on the FEP after having a 75% failure rate on it. Seems it was a waste of money (starting to see a pattern here tbh)


#37

there is a learning curve, it’s a waste of money whether you are willing to invest the time needed to train yourself to the new medium or not.

It is true that I would be expecting more tutorials from peopoly.


#38

Yeah I understand that. It’s just super frustrating that there isn’t any useful information around from Peopoly themselves - even finding guides and documents is next to impossible on their website - there’s no useful central database, it’s all scattered around in random google docs and out of date wiki threads with horrendous formatting. I’ve given up browsing for this information now and fall to google to find it for me.

It’s only people like you on this forum that provide useful advice and information that has kept me trying to figure this thing out.


#39

So I try a print once more on 0.06 profile in Cura 3.5 and my shifting comes back.

Why? Why do things print out perfectly fine at 0.08 but screw up so monumentally at 0.06?

I have my PM motor speed set at 10, and reset position set at 60.


#40

that looks too regular to be mechanical. But it seems to happen only at the top so it could also be a problem with the leadscrew. Question is why it only happens at 0.06. Can you share the 3d model?