Circular area of print failure - Moai130

Hello.

I’ve been toying around with Moai130 for about 2 years now. Tinkering around and trying out differents kinds of printing projects. However, after I managed to tear my PDMS vat I decided to finally jump into using FEP vat. As calibration has always been such a pain, I managed to acquire one easy to level build plate. It is easier to level, true, but with my big hands it is just different kind of pain in the butt to level. In any case, I’ve tinkered with this thing a lot.

So! Now follows the problem I’ve not yet managed to solve. Even after reading through multiple threads here that have had kind of similar issue, they have not solved the problem or those threads just halt without final answer. Did they succeed? Did they give up? Nobody knows. Issue is as follows:

I have certain area on my build plate that doesn’t print out well. It is an area of circular shape that about 2" or 6 cm in diameter. This area does print out the initial “anchor” layer on the build plate. However, this initial layer is thinner at this specific area. Here are few pictures of this:


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Why does this flat area form? Why is it at this specific point? What kind of things might cause this? What steps should I take to solve this one?

There are also another issue that is apparent in this picture:
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This one shows that after the initial support pegs have been printed (if they have been printed at all) there appears some level of tearing near the edge of “green” area of the build plate (“green” as in Asura preview). I know this issue follows from the large surface area, hence larger peel force, that needs to applied on the model so that the printed layer separates from the vat. This would be solved by tilting the model on slicing phase. However, these models suffer if they are to be tilted so this is a limit I have to work with.

I have tried multiple different prints with differing settings. Beginning from the recommended settings for FEP vat, followed by lessening of laser power to lessen the layer tearing and that did work to the degree as seen above. However, the “circular area of poor print” persists. It occurs also when models are tilted.

Now follows settings that I have currently on the Moai130 and in Asura.
Here is the initial slice preview image from Asura for reference:
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Here is the support peg settings screenshot from Asura:
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Here are images showing Moai130 firmware version and current settings:
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What steps should I take to fix this “poor print” area?

Cheers,
Jinx

Please send it by email so that the peopoly technical team can follow up and deal with it in time.

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@JinxedProject The EZ plate will come with it’s own problem.
The issue that most users have is not pressed the EZ plate down or pressed too hard when they tighten the screws.

From the picture, it seems that you lack some pressure on the green area of the vat.
You can either increase the z reset position by 1-2 value or re-level the vat,
How is your leveling?

I’ve previously tried adjusting that z-reset position upwards by steps of 1 between prints for three prints. If I recall correctly and judging from old print anchors I have stored for taking to trash, the circular area changed position from the “green” edge closer towards the center (where it is at now). This is based on my memory so I don’t have pictures of this and I cannot replicate this at this time.

However, now that I think about it, I do remember there was something odd going on when leveling the plate. I was erring on the side of caution when applying force on the easy-level-plate. So this might be the source for the issue. I will try to re-level the vat today. Place a test print for overnight printing and I’ll report on it tomorrow morning.

I have not re-printed leveling check pegs after the initial FEP-calibration and I don’t have those stored. If the issue is from improper pressure from VAT-leveling, then above re-leveling should fix above problem (if I apply enough pressure this time that is).

Now I’ve made re-calibration of the easy-to-level plate. Following the guide shown in the wiki and applying more pressure on the plate while tightening the screws.

I followed this with an overnight testprint of larger area. Circular print are failure persists. I was going to post few images showing the issue but still limited to one image. Therefore here is an image of the plate anchor after I snipped those twisting/floating ship prints off. Places where proper pegs printed out ok can be seen.

I did also do DIY_test print with those test pegs and results are as follows:

  • A = 10.39
  • B = 10.45
  • C = 10.10
  • D = 10.14
    From this I’ve gathered that something is slightly tilted towards the left side of the pinter. These are (compared to recommended wiki references) way off if preferred height is ~10.7.

However, recommendation on wiki for easy-to-level plate states something towards: “Don’t touch the calibration screws that are used with the normal plate.” So how should I proceed? Do screw calibration or change the reset position (by a lot)?

@JinxedProject There should be a maximum 0.1mm difference between the leveling pegs.
With the EZ build plate, you will adjust the 4 crews ON the build plate to secure its position, only press slightly.
To adjust the pressure, which relates to the peel force, you need to adjust the z reset position.
So first, loosen the screws, and lowers the vat manually until you find the build plate fully touch the vat. Then tighten the screws, reboot the Moai, and have a dry run to see if the build plate is pressing too hard or not touching the vat. After that, adjust the z reset accordingly.

Leveling was done exactly as you described. Using the screws on the easy to level build plate. I’ll repeat this process again. This time following the keyword “slightly” - I think I might have applied too much force previously.

On a side note: What is the size (height in mm) of single step (delta of 1) with the z reset?

After re-calibration of the easy-to-level plate, I got the following values:

  • A = 11.10
  • B = 11.24
  • C = 11.10
  • D = 11.25

So delta is around 0.15. I do have to note that I did do the tightening with “crossing” pattern in order: A, C, B, D, applying slight pressure at points A and C.

@JinxedProject sorry for the late reply,
the build plate is now mostly leveled. You should increase the Z reset slightly, it will decrease the height of the pegs. The preferred result is about 10.8~10.9.
On the Z reset, 1 value = 0.1mm. This should give you an idea on how much you should go

No worries. It was weekend. I don’t expect prompt answers during weekends.

I modified the Z reset to 1820 (raise by 3 steps) so that the calculated range should be within that preferred result range. I placed another print into the queue. I’ll report on how it went tomorrow.

I’ve now tried out another print and the result are the same as before recalibrations and adjusting. Here is the picture:

As can be seen, the area persists.

@JinxedProject keep on increasing the z reset, I’m seeing some improvements on the printed area.

I raised the Z reset from 1820 to 1822 and did a print. Here is the result:

Still some issues but the form has changed a bit. I raised the Z reset now to 1825 just to try out. Another print is underway. Will see how it turns out. If you have ideas or pointers, I do appreciate them.

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can you show the placement of the models in Asura? and mark where it fails to print

Yes. Had to recreate the placement (without supports) in Asura. Here you go. Purple area is the area in which things don’t stick properly. Yellow area is where supports are starting to print but fail eventually.

Usually it would be the other way around, the green zone has better prints while the red zone does not. Since the red zone has a higher peel force.
You can try to increase the PM reset, so that the vat tilts more, creating a clearer separation between each layer.
Also you can create some test models, to avoid wasting resin

PM reset is already 65, I’ll try to raise it a bit more.

Last print I tried doing had that failure area grow larger. Now I’m lowering the Z reset backwards to 1823. Center of said area is still around the same spot as in previous cases.

As a short update: I changed the PM Reset to 70 and placed a small project print into the works while also avoiding placing anything in the problem area. Print came out perfect, even when some of the models were edging the problem area.

Now I kept the settings as mentioned above and placed another print into the queue. This time I placed few test models into the problem area. I will report tomorrow how it turns out. If everything is fine. I’ll post short recap on what the initial problem was, and how it was worked out so that others with similar problem would find proper solution (as I find it annoying to dig through series of posts for minor changes that add up into a proper solution in the end - I’d rather give “conclusion” for those who need it).

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As far as this goes, there’s nothing wrong with your Moai.
You just need some more adjustments with leveling, that’s all.
You can also ask on the fb group for leveling tips as well.

Good to know that the machine itself is fine. :smiley_cat:

I did finish the latest print:

This time placing larger model on the problem area and now the surrounding models (that in previous print were on the edges of problem area) took issues as well.

You say this is just adjustment/leveling problem. I’ll happily put more time into this to get this working properly. Now I know I can print properly with at least part of the plate. However, now my works are limited in size. (Aircraft carriers won’t fit in any other way than in diagonal alignment, hence I’ve avoided printing them sofar.)

I’m trying to figure out the physics on this. My resin is Wanhao SLA resin (don’t know if that company even exists anymore, resin itself is quite hard so low laser power (54) seemed to avoid layer separataion in earlier prints. Should I try lower laser power still? Might it be that the layers are too fragile (too cured?) to be able to withstand the strain?

The kind of system facebook is, I’d rather not touch it even with long pole. Any useful information found only from there might as well not exists on internet as most of them are behind log-in wall. Even if it would be a treasure trove of information, it is out of my reach.