Since there is no unified category for FUSE printers, I write the question here in troubleshotting.
Has anyone tried printing from 100% used powder?
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Welcome to the forums Kostbone.
I have tried and failed several times experimenting with this.
Even the sift gives you a warning if you go below 50% refreshrate, so that should be a major red flag not to go below 50%.
That they market the nylon at 30-50% refreshrate is a complete lie as it will never work,
Nylon 12 nor Nylon 12GF can do that.
What i think alot of ppl is missing is that lets say you have a printer going with 100% new powder,
When that remaining powder goes into the sift, it is concidered recycled powder. You mix at 50% refreshrate and pour that into the hopper of the printer and 50% of that material is now concidered used and thus the quality has started declining. Cause as soon as the fresh powder has been heated up, it looses it integrity and becomes harder for the printer to sinter.
What this means is that after 5-10 prints with a refreshrate of 50% you can basically empty the sift cause the material is basically dead and not going to print good.
Have you sometimes noticed that the cake is stiffer to break apart when extracting the parts?
Well, my belief is that this occurs when the powder goes bad. As i have noticed this behaviour several times when the powders lifespan is coming to an end. Only way is to discard that powder and fill up with new powder, and pretend like it is raining when the cost of material is skyhigh at approx 110 dollar for a kg.
If someone else has opinions/thoughts on this matter, Feel free to jump in the discussion.
Edit: We have both Fuse 1 and Fuse1+ and especially the Fuse1+ the powder has a shorter lifespan than in the Fuse1. I have read some speculations that this is caused by heat leaking into the hopper on the Fuse1+. Not confirmed by Formlabs tho.
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Then I will also join the discussion:
We use the normal PA12 and always print with a refresh rate of 30%. We have experimented with somewhat higher rates, 35% and 40%. However, these have not really produced different results than 30%.
Currently, our sift is set at 33% to somewhat compensate for the used powder portion when brushing the parts off a bit more thoroughly.
We actually push as much powder as possible from the printed build chamber into the sift. Among them is also a accordingly large amount of used powder. Therefore, we have set the specified minimum 30% to 33%.
At this refresh rate, the components are no longer as Tough as at higher refresh rates. Thin components are more brittle and can be broken through more quickly. In most cases, however, we can compensate for this by orienting the parts accordingly in the build space, by building up moving parts such as spring clips or clips along the Z-direction.
Our very first print on the Fuse1+ with PA12 had a 100% rate, of course. Here the parts were extremely resistant. The first test objects had a wall thickness of about 2mm and could hardly be broken with bare hands. Therefore, we want to experiment again with 50% and 55% in the future.
We occasionally have components that we have to dispose of because they have thermally distorted areas. Here, however, I am still undecided whether this is due to the refresh rate. We are currently trying to rule out other causes, such as the build chamber and humidity.
I would not have tried to print with 100% used powder myself, as this is not recommended by Formlabs and other manufacturers without reason. Nevertheless, it is interesting to hear that it has been tried. Many thanks at this point for the report.
The warning for below 50% refresh rate must be due to the PA12GF, as we do not get such a message here with PA12.
Unfortunately, the reports with PA12GF are still very mixed, which is why we will stay with PA12 for now.
Whether the material properties at 30% refresh rate are sufficient for the user, I think everyone must try out for themselves. However, I would call it printable in any case.
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Unfortunately, it is very complex and difficult to achieve a higher fill rate. In order to be able to use 100% of the purchased nylon powder, it is necessary to fill the chamber with at least 30% of the parts, unfortunately, in reality I only manage to fill about 15%. If the parts are in good shape, I can sometimes get to 25%. But that’s the maximum. Once a year I managed even 31%. However, filling the chamber to, for example, 50% is nonsense. I tried it once - not actually printing, but just filling the chamber in the computer, and in order to reach 50%, the parts were in the shape of a cuboid, lying down and of a suitable size that they just fit in the chamber. However, in reality this is never achieved and so I have 85% unused powder that accumulates.
It is a great pity that it is not possible to use 100% of the used nylon powder, for example, on your own parts or test parts. I wouldn’t mind if the strength of the parts was lower, or if the part suffered in terms of surface quality. If I needed to print a part for myself and not for a customer, I wouldn’t mind worse features. When I tried to print 100% used nylon PA12, everything went well, the only problem was that the powder was more difficult to spread. He’s basically stuck. I’ve tried burying it while printing, unfortunately it has to be done every ten minutes or so, and since the prints last all day, it’s nonsense. If I didn’t, I only managed to print for about 2 hours straight.
So I am looking for an alternative to dispose of the used powder. It is also a great pity that the automatic packing is not ideal. It can’t compare to manually comparing parts in the chamber.
Hi everyone.
I’ve only received our Fuse 1 a few days ago and the first print was quite perfect.
but the second and third weren’t. we started to see some structural shift, bad surface finishes.
Not sure if it’s because of my model placement orientation.
On top of that. the first sift machine we received were faulty and leakes powder from the bottom and got replaced.
Some of the powder might be contaminated because a member accidently mix the powder on the floor back into the sift into the used powder.
Our environment is extremely humid and we are not sure how to solve it yet. We are extremely worried it will impact the quality (as it seems our second & third print have clear defects. )
We indeed are discussing with reseller here how to solve it. either we should store used powder and fresh powder in a low humidity box or he suggested for one add some IR lamp in the hopper to help keep it dry.
But as it seems from Andreasemilsson it is better not advised.
i mean my colleagues had a fuse 1 too.
And keeping the powder dry seems to be a big deal. we both agree the assembly tolerances/finishes and the anti-humidity design (if any) are quite poor on both fuse 1 and sift. makes me wonder if it’s really a USD$60000-worth machine (here for us)
I second that… even if you trust the PreForm estimate in powder usage for a job, we have no real idea yet how much powder we are using per job due to this factor that you mention.
Some of our designs are sheaths (for tools etc.) and while trying to run Nylon 12 GF for a year at 50% refresh, what you are mentioning we saw as well. Where the powder internal of the part would be easy to knock out in the sift to then it being like concrete and needing to blast just that loose powder out in the blast cabinet.
I think the sweet spot for us has been going to a 70% refresh for Nylon 12 GF. Yes, with the fixes we may be able to actually go back down to 50%… but the parts themselves defenitly are not as strong and more brittle for our smaller more intricate designs and you start seeing what you bring up. Where the Sift recycled powder flips to being unusable. So I think 70% refresh keeps that recycling going naturally because you obviously are upside down on the Sift ratio at that point so every few jobs we have to do a 0% refresh into a cartridge…and dump that into the trash so the recycled hopper does not overflow.
Lots of wasted material and yes 30-50% refresh is highly false advertising.
The high cost of material for this system is absolutely killing its potential and usage for production running possibilities.
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And here it is! I made a vibratory collapsing mechanism to avoid stopping the print by rubbing it badly. I was able to successfully print an entire chamber from 90% recycled powder. I still preferred to use 10% of the new powder. The print was successful, unfortunately the parts suffered from surface defects. I believe that this is due to the fact that the powder degrades by repeated heating. The parts I printed are intended for my use only. I noticed that the degradation is mainly from the underside of the parts, not from the top. I have a lot of used powder. I want to try some more tests when the time comes. I have some of my products where the deformations from the powder used are almost invisible and the shape is very simple and substantial, so I got up to 70% chamber filling, which is amazing. However, if I were to use up all the used powder for these parts, I will never use them in my life 
(approx. 50kg of powder). So I use 2 kilos of powder. I still have to find a use for the rest. I’ll try to get at least an 80/20 or 85/15 ratio of old and new powder with my mechanism.
Now it would like to find out in which company formlabs has the powder made, because there is a big margin. A manufacturer from another company contacted me and offers me the powder for USD 30 per kilo.
I have also been looking for other sources for the powder.
However, here you would need the same PA12. So not only the same polymer, but also the same material color and fineness.
Is there any further information on what kind of powder this should be/which manufacturer?
For that price of powder, I would change most of our components to SLS right away 
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That’s exactly the problem. There are two options. First, find a manufacturer that supplies formlabs powder or find a completely compatible powder from another manufacturer. This manufacturer tells me that their powder is completely compatible, that some of their customers use a FUSE printer and print from their powder, however they refuse to tell me who they are.
If the price for powder was up to 50 usd per kilo, I would also use the printer more and not curse so much about wasted powder and failed prints. Mixing original and non-original powder would also be a possible way. Unfortunately, all of these tests would be very expensive, and the price comes at a cost to a good result.
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We are quite experimental with our Fuse. For example, a few weeks ago we tried additionally moistening the powder before it goes into the printer. Something that the manufacturer EOS recommends for its powder and machines.
However, we did not notice any significant difference. I would therefore say that humidity does not play as big a role as one might think.
when printing for a longer period of time, you should notice that somewhat coarser, black lumps form on the rear rail, behind the build chamber, when you suck out the printer after printing. these seem to indicate the degree of moisture in the powder. in the tests with moistened powder, we had significantly more of these lumps here. the printing results, however, seemed the same. as soon as we stopped moistening, we probably had fewer lumps again.
a few of these lumps are therefore normal. if you find an extremely large amount on the rear rail after a print, i would take this as an indicator of very high humidity.
we would therefore be quite prepared to carry out other tests as well.
@Kostbone could you give us more information about the manufacturer here? we would like to take a closer look.
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I also like to experiment, so I have a lot of FDM printers from different manufacturers instead of making my life easier by only having one type. My farm is too rich in producers. Of course, it sometimes annoys me personally, because everyone needs a different setup and a different slicer, but it keeps me fit and I’ve also gained a lot of experience from it. For example, I don’t use any uniform printer profiles. When I put something into print, I set all the parameters myself from scratch based on my experience. No default profiles.
I also think humidity doesn’t play that big of a role because the powder dries perfectly with each print. Of course, it may re-moisten before it is used again, but a few cycles together with a dehumidifier are enough, and the powder is free of moisture. The problem will really be with the degradation of the powder by its constant heating and thus the release and release of Lauroctan. I am preparing a second chamber for printing where I will use 90/10 recycled powder. I prepared a set of parts that are just for me and the chamber utilization is an incredible 49%. That doesn’t happen often. However, I won’t use that amount of parts even in two years. We’ll see. I notice that with so much recycling, it is better to print the part vertically rather than diagonally. So now I have all the parts vertical. I am curious about the result.
As for the manufacturer of the powder, I’d rather write it to you outside the Formlabs forum. Contact me, for example, on FB - Black Print page.
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I have the Fuse 1+.
Aside from beeng a massive, tremendous, pain in the ass with a hard to count number of failures since week 6 from new there are some points that I can share regarding printing with old powder.
I use 100% old Nylon 12 powder most of the time as my parts are not sensitive to the Nylon specs and are used in conjunction with either carbon Fibre components or other 3D printed parts from ABS, PETG ect.
100% old powder will work on Preform 3.30 or older versions. Any preform version after 3.30 will result in badly underextruded parts. No idea why, just seen it happen.
The vast majority of problems that are caused by the use of old powder is caused by the particle size of 150 microns (the Sift mesh size) that eventually will build up after multiple uses trough the Sift. I use manual sift with 120 mesh.
A way to reduce brittleness of parts printed with old powder is to lower bed target temperature.
Also parts soaked in water for 24 hours after printing will be more resilient to barking.
Old powder needs drying before use, because it causes horizontal interference lines accross flat horizontal surfaces. The recouter faces greater resistance from old powder with relatively higher moisture content and the powder spreading ends up in a jumping sequence resulting in many random parallel lines accross every layer. The reason been the single sided recouter motion of the Fuse printers. A BIG DESIGN OVERSIGHT.
The use of old powder contributes to powder spill outside the build chamber. 100% old powder will cause a significant spill with some of the spill been roasted.
Best way to use old powder for longer periods is to make sure when the printed parts are dusted with the brush to leave the nearest 3 mm powder layer to the parts walls to be removed by the sand blaster and not to be returned in the Sift. The reason is because that powder that is in the 3 mm facinity of the parts walls is partialiy sintered (partially chrystalised) and as such, stiffer and will contribute to pooper parts quality.
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I will also contribute my experience. I’ve written before that I like to test printers. Unfortunately, you can’t do much testing with FUSE 1 or FUSE 1+, because it’s a closed ecosystem and you don’t have the option to change parameters. I think the manufacturer does this on purpose, so that no one can find a way to save powder, or how to use third-party powder, or they use RFID cards, and as I found out, they have to be used.
I was told that I don’t have to use them if I don’t want to. We probably had a misunderstanding with the technician. I was throwing them away, but my printer stopped printing. She started asking me to load the powder into the printer, even though it was physically in it. This way I lost about 50 kg of powder. Fortunately, when I called tech support, they traced the purchased powder because all containers and boxes are serial numbered and the movement, purchase and distribution of each package of fresh powder is completely tracked. They loaded me back with about 36 kg of powder. It’s not all that I have here, but at least I got some of it back. Even so, I am angry about the closedness of the system.
The only thing we can change is the temperature of the bed. +/- 5°C.
And now for my tests.
Since I have 50 kg of used powder here, I don’t want to throw it away. It is an expensive commodity. During the following tests, I discovered the following:
100% recycled powder can be used, but you will lose the strength of new powder. It is better to print the parts not at an angle, but perpendicular to the bed. The upper layers are sharper and the lower ones are more rounded, so when I needed the layers to be less visible, I put them on the lower side of the print, however, if a wall is at a certain angle, a defect may appear on it. That’s why I’m putting the parts in reverse now. Visible layer up. Although the scratches are more visible, they will not cause a defect. Sintered powder also clogs more in the hopper, so the screen needs to be removed, just like formlabs recommends for TPU printing. Ideal for printing with used powder are parts where you do not need such good strength and are simple in shape without bevels. Fortunately, I had a job for simple parts where the chamber was 20% full and I used up most of the powder used. The walls of the parts were 3mm and were very difficult to break.
I also noticed that after using the powder several times, the release of Lauroctan has almost stopped. The filter was almost always clean. However, for example, I preferred to clean the print chamber every time before each print in a separate vacuum cleaner for ash, where I keep the powder clean and no mess, and return the powder to circulation, however, I do not leave it exposed to high temperature all the time in the chamber.
When I need to print standard parts again, I mix a mixture of 70% new and 30% used powder and keep these powders separate. I found a way to quickly change powder within 15-30 minutes.
I would like to try printing 100% used PA12 with higher energy lasers, but this is not possible because formlabs does not allow to open the printing parameters. However, we generally know that PA12 GF needs more energy for sintering. Unfortunately, when I switch the profile to PA12 GF, the printer won’t let me start printing when there is PA12 in the printer. Buying for the PA12GF test is nonsense. Ideally, I would only need an RFID card with PA12GF.
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Very interesting stuff… the downfall of this system is the cost of material…PERIOD. If this came down it would absolutely change everything for production parts possibilities and yes the troubleshooting and random bad prints would also be at least acceptable in the cost of running the system.
Of course if you get past the “card swiping system”… Formlabs obviously watches and can see your entire print history and powder usage. So I imagine if they see you printing 24/7 with no recent purchase of powder from them…they can call you out regardless of the card swipe.
It would almost be interesting to have a second machine just to “modify” and play with possibilities…
Look forward to watching this thread as there seems to be more combined brainpower here than I’ve experienced at Formlabs with Support. 
Good Stuff
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It would be interesting to sue formlabs as it does not give the option to use third party powders. Similar to what happens with internet browsers, similar to what happens with google, apple or microsoft, it should also apply here if you want full support, you have to use original powder, original parts and other things, but when you paid for the printer, it should be 100% yours and you can do with it as you see fit. This is not possible now because formlabs blocks any interference in their ecosystem. There should be an option to use and test the printer when you have spent your money on it and it is your property and to be fair, you lose your warranty for example.
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Im quite confident that the moneymaker for Formlabs and the Fuse series in particular is the powder and the ESP.
It´s ridiculously overpriced. To many that is a dealbreaker for sure.
Interesting thought about suing Formlabs for locking out third-party actors from their systems.
Where are you located Kostbone?
Owning the Fuse 1+ printer has been quite the journey, fraught with challenges and numerous failures since week 6 of its acquisition. However, amidst these struggles, I’ve gathered valuable insights into printing with old powder. My primary choice is 100% old Nylon 12 powder, as my parts typically don’t require the precision of newer materials and often accompany carbon fiber components or other 3D printed parts from materials like ABS or PETG. Interestingly, I’ve observed that 100% old powder performs well with Preform versions up to 3.30 but leads to severely underextruded parts with newer versions, though the exact reason eludes me. The main culprit behind issues with old powder seems to be its particle size, around 150 microns, which accumulates after multiple uses through the sift. To counteract brittleness in parts printed with old powder, I’ve found lowering the bed target temperature to be effective, along with soaking the parts in water for 24 hours post-printing. However, before use, old powder requires thorough drying to prevent horizontal interference lines across flat surfaces, which occur due to the printer’s single-sided recoater motion encountering resistance from moisture-rich powder. This phenomenon underscores a notable design oversight in Fuse printers. Furthermore, the use of old powder increases the likelihood of spillage outside the build chamber, with some powder even getting roasted. To prolong the usability of old powder, I’ve discovered the importance of ensuring that the nearest 3mm layer of powder to the part walls is left for removal by the sandblaster rather than being recycled through the sift. This partially sintered or crystallized powder, while stiffer, can compromise part quality if reused.
What do you mean by “underextruded parts?” Do you have a photo of this problem. I didn’t notice a difference between the preform versions. However, I don’t have a FUSE1+ printer, but the original, old FUSE1.
Yes, particle size is an issue. A powder that has been used several times has a larger number of larger particles. It is coarse and not so loose. It has a greater tendency to clog. Recoater then has a bigger problem with spreading.
Your comment about lowering the temperature of the bed is very interesting. The general thesis is that the more overburnt the powder is, the more difficult it is to sinter it and the more energy is required. That’s why I increased the temperature of the bed. I wanted to achieve more sintering of the powder. Unfortunately, increasing the temperature of the chamber is the only option to increase the thermal energy transferred to the powder, as we do not have the option to influence the laser beam by adjusting it. I work with lasers myself. I know how they work with metals, wood, plastics, etc. I would like to see options like frequency, speed, pulse length, power, line spacing and more. I will try lowering the target temperature of the chamber. I’m curious about the results. I will also try soaking the products in water. We know that moisture gives elasticity to overdried products, so we only accelerate this process. Good idea.
If you want to leave a 3 mm layer of semi-sintered powder on the surface of the part - yes, you will have less “damaged” powder, but you will unnecessarily increase the waste of powder, and we don’t want that. It’s a compromise.
If there was an opportunity and formlabs would take it up, I would love to become their tester. However, I don’t think they want to hear that.
I am now testing an interesting idea. I’ll let you know how I get on.
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I’m from Czech Republic. It’s in the middle of Europe.