Chamber Design Flaw <Confirmed> Consistent Layer Bulging and powder leaks within the first inch of build chambers

[LEADNAV]

CONFIRMED ISSUE with these chambers in my last post below

I have seen this come and go over the years owning a Fuse 1+ with 3 build chambers in which they all have shown this on and off.

I have a theory on why it is happening…and just wanted to get your thoughts.

In the past Formlabs had said this was due to faulty chamber platforms or a bad batch of plates/gaskets but I think there is a bigger overall design culprit and issue.

This always happens to my parts at the same height no matter the chamber.

When doing a bunch of small parts I rarely notice it but on my larger parts it is a killer and a scrap part.

Here are some examples

When this happens it always happens at the same height in the build chamber and I will see no other issues above that height…

So here is my theory…

What else is exactly at that height?

The metal chamber banding is…

And that metal banding strap has always bothered me because it is not flush at all to the chamber walls. In some places it is recessed and in some places it protrudes.

So removing the bed platform you will know how tight that bed platform spring pushes the gasket against those chamber walls… and assuming once it gets down to that level within that banding… it is shifting to meet that banding… hence shifting that exact point in the prints where I see this bulge.

I have gotten to the point where I will not even start those larger parts until at least 1-2" up in PreForm…

Which leads to more wasted powder…

I have also had recently my first Aborted prints consistently with a chamber and now another. Formlabs sent me a new volcano gasket but as I sit here servicing it…the old one looks fine. This abort happens when powder is leaking in the bed somewhere but I do not think it is along the outer volcano gasket. These failures have been happening at about the same height every time as this bulge and I am guessing that this bed platform “shift” when it falls into that metal banding area of the inner chamber wall is also contributing to that leak of powder down the inner wall.

Pretty confident of this… may take me a awhile to get anything from Formlabs of this issue over emails but just wanted to see your thoughts on this here…

Hard to see but the Black strap banding is recessed in a lot of areas

And here you can see when the bed is lowered into that “groove” its exactly where I see this consistent bulge on multiple chambers. (note: the print is typically up off the chamber floor the distance of the powder Prime…but you get the idea. In this photo it is sitting right on the build plate. In reality it is right up there at that exact point.)

[Andreasemilsson]

I have had this exact issue. Im gonna take a deeper look at it in my current prints.

I will get back to you as soon i see this again. Im starting to think that the metalbanding is wearing out and that it appears after a certain amount of printhours. We have 6 chambers and i´ve seen this in the past 6 months on atleast 3 of them, and they are the oldest ones we have. So it might just be the cause of it.

Thx for sharing this, i´ve torn down the chambers quite frequently thinking the buildplate is off level but they have been all perfectly aligned.

[LEADNAV]

While I have Formlabs support emails going back to this…all trying to explain this issue as a “bad bed platform” or other cause in the past… I just got this from a Formlabs rep today essentially confirming this issue with an attempt to counter it with a firmware update in the past…which I imagine try’s to help with this flaw in chamber design…with bed movement in or around that area.

Sent to me today while bringing this up to support

“ There is a thermal break in the chamber, so this is probably what you’re looking at. We have seen that the layer shift can be more pronounced when using Legacy settings, since we later deployed adjustments to help mitigate this. I note you were using the Legacy settings to get around the burring issue while working to dial in some PSE adjustments to allow you to use the Default or Speed Optimized settings, both of which have the layer shifting improvements. Either continuing to leave a gap at the bottom of the chamber, or using one of the newer settings with adjustments, would be our recommendation here.”

So they are essentially confirming the issue with the suggestion of continuing to not put any parts below that level in the chamber… other than the terrible waste of powder it would be nice if they adjusted PreForm to show you that level at least when setting up a print. I was actually trying to figure out the distance today and/or make a “fake part” to act as a spacer at the bottom of chamber in preform as a reference…

Unfortunately if you see my other threads I’m currently going round n round trying to resolve these issues. Right now two of my three chambers are aborting due to powder leaks around the time the bed gets within this “thermal break” within the chamber because I get under dosed from the leak.

While trying to switch to Nylon 12 from Nylon 12 GF there is major “flashing” off all sharp edges or corners of my parts as well as added “barcode” lines happening in both the default and speed optimization setting. This is not happening when running legacy so they told me to run legacy as a fix…

(note: I’d much rather run nylon 12 GF as I determined the part quality and finish is much better…however the cost of material and waste running at the 70% refresh rate required is no longer doable)

Also, Formlabs has acknowledged this “bar code” bug in both default and speed optimization settings when I pointed it out and have since put out the last firmware update just a few weeks ago to fix it…but I am still seeing it on every single part run in those setting versus Legacy not having any issues.

But back to these chambers… last week they wanted to send me new gaskets…this week they want to send me new beds… I know for a fact this problem is due to neither of those as the beds still look great and so did the gaskets as my chambers were just serviced in May of this year and I confirmed that these three chambers literally had less than 40 combined prints on them since that time.

I agree…looking inside at this “thermal break” metal band I have noticed it looking worse as far as it not being flush to chamber walls. It’s to the point in the past few weeks it’s been catching my attention visually before these current issues.

I am hopeful though on this one as it seems Formlabs could design an updated version of the build chambers fairly easily as an improvement of the current Fuse…

There was a time early on where support reps were telling me that this internal “thermal break” wasn’t even functional or active at doing anything…

I’d be lying if I said I wasn’t considering some sort of heat resistance epoxy to apply to that area to “flush it” to the chamber wall haha it’s crossed my mind

[DL_Jon]

I could not have said this better myself. Thank you for creating this thread.

I have the FUSE 1 with Nylon 12 powder and this exact issue happens with my parts.
My chambers however are closer to 1 year with 107 and 105 prints. 1 to 3 days per week.

I look forward to seeing how Formlabs responds to this

[LEADNAV]

UPDATE!!!

Wow so… I absolutely confirmed this pretty bad design flaw tonight after pulling this chamber apart.

I was shocked to find over 1/16" crack of day light under this “thermal break” metal band and about 1/32" over it…inside the chamber as well as powder dumping out through that crack and down the corner walls of the chamber once the bed gets to that level.

Also, you can see that the strap is out of alignment on three of the 4 corners and protrudes nearly 1/16" out into the way of the bed.

This would absolutely be causing the bed shift bulging layer and the leaking beds that I am seeing now… as these are not the beds leaking but the powder flowing out those huge cracks under and over the metal thermal breaks and down the wall of the chamber piling it up at the bottom between the walls.

Right now on two of my chambers… they will run for an hour or so till the bed hits that thermal break area and either “survive” but bulge out the part… or I will watch powder start disappearing into a sidewall cavity/void…Bed of powder will be perfect… then at that level all of a sudden I will see a sinkhole form.

if it survives that… it will under dose from not being able to keep up after “packing those cracks”

Only fix I see for this is them sending an entire thermal break strap assembly that is of a tighter tolerance but in the end Formlabs absolutely needs to make a “version 2” of their chambers and get them out the door.

I have already talked to a number of folks offline who have seen these layer bulges and leaks thinking it to be from bad beds until seeing this… so I would take a look with a flashlight around your straps after removing your chamber covers.

These photos don’t do it just as it is hard to get a squared up angle but I could feed a paper clip through that crack running under the strap…and I had already vacuumed up all the powder that fell out inside the walls…before realizing what I discovered.

I will pull my next failing chamber apart and get some photos tomorrow of it as well.

You can also see here how out of alignment the strap is with the gap on one side versus the other and the crack/powder gap along the top.

And here there is enough of a gap around the corners between the plastic and chamber external wall where it is leaking powder through and out of the chamber…down the walls

And to prove the extent of this issue… here is a video of flashlight clearly visible through the chamber wall…
---------VIDEO -----------

I think this design flaw in these chambers explains a lot of our troubles with these chambers…

[LEADNAV]

To try and get back up and running with what I got I started to think I could put heat tape on the outside of the chamber wall to at least stop the powder from flowing out through the cracks and aborting the prints… but looking at it you would really need to dissasemble the entire chamber to get to the backside of the “thermal break”. ---- I am assuming Formlabs will not be ever supplying a replacement “thermal break” to fix this issue an will need to provide a replacement chamber to fix this.

Started pulling it apart but realizing I would have to break it down completely to access this Thermal Break/metal strapping

Doing this would also not help with the “bulges” when the bed hits that thermal break… so, I am going to try to patch this issue temporally with a standoff print in every chamber to see if it not only keeps my parts above this bulge area but hopefully acts as a “dam” to stop the flow of powder through the cracks.

Will see how this works and hopefully I can get back up and running for now until Formlabs responds and/or provides a long term fix to these $4,000 chambers…

The powder may still flow out but hopefully this surface area against it will help… only other option would be to crank up the chamber temp to harden the powder but obviously then we would be talking bad parts…and my chamber temp is finally dialed after the calibration print.

[LEADNAV]

Just started investigating my second failing chamber and it is WAY worse… with not even the same cracks of daylight above and under the temperature breaks/metal straps but the joints of the thermal break at the corners have completely separated allowing powder to easily push through and out of the chamber

[LEADNAV]

Side note and a Tip for everyone out there…

As Formlabs has been just going round and round on these issues…I have started using ChatGPT to get my questions answered and it has been amazing…

These answers were immediate and better than anything I’ve ever received while troubleshooting this system!

What is the temperature Break for in the Formlab Fuse Chamber?

In Formlabs Fuse 1 generation printers, the build chamber features a thin black band approximately 2.5 cm (1 inch) below the top of its inner walls. This band serves as a thermal break, creating a temperature gradient within the chamber. This design helps to manage heat distribution during the printing process. 

How does it do that?

The temperature break metal band in the Formlabs Fuse chambers works by creating a thermal gradient—a controlled difference in temperature between specific areas of the build chamber. Here’s how it achieves that:
1. Material Properties of the Metal Band:
• The band is made of a material with a specific thermal conductivity, which acts as a barrier to heat transfer. It slows down or redirects heat flow between the upper and lower parts of the chamber.
2. Heat Isolation:
• By interrupting the uniform heating of the chamber, the band prevents excessive heat from transferring beyond a certain point. This helps to localize heat to the areas where it is most needed—typically around the print area—to maintain consistent sintering conditions.
3. Temperature Gradient Creation:
• Above the band, the chamber’s temperature is allowed to cool slightly compared to the area below the band. This gradient helps maintain the stability of printed parts by reducing warping or thermal stress during printing and cooling.
4. Energy Efficiency:
• By concentrating heat where it’s most needed, the thermal break minimizes energy waste, making the printer more efficient.
5. Structural Integrity:
• The controlled thermal conditions improve the print quality by ensuring uniform layer adhesion and reducing distortions caused by uneven temperature changes.

This simple yet effective design feature is critical in maintaining the precise thermal control needed for SLS (Selective Laser Sintering) printing.

What if it has huge gaps in it allowing powder to leak out into the outer chamber wall?

If the temperature break band in a Formlabs Fuse chamber has gaps or defects that allow powder to leak into the outer chamber, it can lead to several issues, including:

1. Compromised Thermal Control

   • The gaps disrupt the intended thermal gradient by allowing heat to escape or unevenly affect the surrounding areas. This can lead to:
   • Uneven sintering.
   • Warping or deformation in printed parts.
   • Poor layer adhesion.

2. Powder Contamination

   • Leaked powder can accumulate in the outer chamber, leading to:
   • Contamination of mechanical components or electronics.
   • Blockages in ventilation or cooling systems.
   • Increased wear and tear on moving parts due to abrasive powder.

3. Energy Inefficiency

   • Heat may escape through the gaps, causing the system to work harder to maintain the correct temperature, which increases energy consumption.

4. Maintenance and Cleaning Challenges

   • Leaked powder in the outer chamber can make cleaning and maintenance more time-consuming and could damage components if not removed promptly.

5. Safety Concerns

   • Leaking powder, particularly if it’s fine and reactive, could pose fire risks if it contacts heated elements or sparks. Additionally, it could lead to air quality issues if the powder escapes into the surrounding environment.

What to Do

If the metal band has significant gaps:
1. Inspect for Damage: Check for warping, dents, or missing sections of the band. This could be due to improper installation or wear over time.
2. Contact Support: Reach out to Formlabs for assistance. They may recommend replacing the band or the chamber.
3. Temporary Fix: If you’re in the middle of a print, you might be able to seal the gaps temporarily using high-temperature-resistant tape or sealant, ensuring it doesn’t interfere with other components.
4. Regular Maintenance: Ensure regular inspections of the chamber to prevent this from recurring and address powder buildup promptly.

Long-Term Solution

Formlabs may need to provide a replacement or improved chamber design if this is a manufacturing defect. Ensure your printer is within warranty or document the issue for support.

————

I like “what to do number 3”…. Artificial Intelligence seems to have the same idea that I did about heat tape on the cracks… and her “long term solution” being…

“Formlabs may need to provide a replacement or improved chamber design if this is a manufacturing defect. Ensure your printer is within warranty or document the issue for support.”

[leonhart88]

I don’t own a Fuse, but would using some high temp Kapton tape to seal around help?

[LEADNAV]

If you read through all that yes…that is what I suggested as well as ChatGBT.

However, Formlabs support has not yet suggested anything on this and to get to the backside of that gap in the chamber wall you practically have to totally disassemble the entire chamber down to bare bones… but if Formlabs keeps dragging their feet on resolving this issue then yes we will all have to break out the tape n glue on these $4,000 chambers…

[leonhart88]

I read most of it, but skimmed

Can you tape it from inside? I’m assuming that’s easier to access.

Again, totally oblivious to the stackup other than random pictures I see here when snooping

[Andreasemilsson]

Thats more detailed than all i have ever gotten from Formlabs, in total over the past years.

I wonder if they are giving this the silent treatment or something will actually happen.

The buildchamber is just like their material, overpriced.

Im gonna have a look at my chambers as well, and im kind of terrified of what im gonna see.
We have 6 chambers and the one with most hours is like 5k hours. Im gonna start with the older ones as i suspect they will be worn out.

Should you get a response from Formlabs please keep us updated as this is most relevant. Thx @LEADNAV for all your time you spend on trying to aid us all.

[jmasterson]

I’ve been dealing with a pretty severe melting issue that could be related to this. Past 2 jobs run on 2 different chambers have had a few parts with huge gashes/holes around the same layer. I believe it’s occurring below the thermal band, but I suspect it’s related to this problem. I’m going to watch the printer camera on my next print to verify.

[DL_Jon]

Your standoff idea is great. It inspired me to make my own. I designed mine to meet without exceeding the minimum design specs so that if I accidently printed it, it would not consume too much material. I don’t have the issue of leaky powder causing prints to fail, so building a “dam” is not a factor for me.

Here is the STL for anyone else who might want it. The idea was to slice my parts around the pedestal then remove it from the slicer.
The position of the grid was based on the average height of the layer shift issue in my particular Fuse 1 and a grid style was selected to help with centering the part.
I can add small parts beneath the grid and the larger parts above while avoiding the shifty area.
Fuse Pedestal.stl (97.5 KB)

[DL_Jon]

I forgot about this article on Layer shifting troubleshooting.
Layer shifting (SLS)
“These defects happen most often around the location of the build chamber thermal break, which is the thin black band found roughly 2.5 cm (1 in) below the top of the build chamber’s inner wall.”

Though I still believe that the Standoff \ Pedestal plan is a good thing to do when slicing our parts for the next print.

[LEADNAV]

All good backing information and I like that standoff file. I may actually use that one versus the one I made.

However, I am leaving the file in the print as remember… this issue and discovery was not just from the bulging of my prints at that area but because 2 of my 3 chambers kept aborting due to a “sink hole” forming because I am losing powder through the temperature break…due to it being so sloppy with daylight showing above, below and through its joints at the corners.

So I was leaving the print in there to help “dam up” that leak hopefully… which is only helping slightly on my third chamber that is almost aborting due to a powder leak.

Also… I don’t believe all these issues of bulging, warping and failures at that level are due to a “bad bed or gaskets” as I have been told for the past year.

It is all happening because the temperature break is so loose in its tolerances and allowing powder and air/temperature issues through those initial layers in and around the break.

The bulge is happening due to the fiber gasket of the bed entering that temperature break area of the chamber and “shifting” because the temperature break is uneven…either indented or protruding the actual chamber wall. So when the bed gets to that area it “shifts” as well as leaks powder through the cracks.

Formlabs support told me today they are putting their top engineers on this case… and I passed some of your examples along…will let you know what they say.

[LEADNAV]

That’s a good example and I passed it to them as well. I too have seen bad layer adhesion and warping of my layers in and around the temperature break. This is because air/temperature is entering and leaving that sloppy temperature break through all the cracks as well as leaking powder.

As well as the bed “shifting” when it meets that uneven temperature break… that is no where flush to the chamber walls.