Did you replace the rtd at the same time?
No, we did not replace the RTD at the same time. The original RTD is still installed. We’re currently investigating whether it could be related to the issue.
@KuemmeMl I’m sorry to hear you’re still working to resolve the perimeter melting on your Fuse 1. To help keep you moving in the right direction, check our support page on SLS Melting. Make sure the pins are clean and unbroken, and that the plug is seated correctly when you place it. If the pins need to be cleaned, follow the steps in the guide HERE.
If you haven’t already, please try another build chamber to see if this is isolated to that specific build chamber.
One-Year Update: Fuse 1 Powder Melting Issue Still Unresolved
Unfortunately, I have to provide another disappointing update on this issue.
I originally reported this problem here in September 2025. Now, more than a year later, we are still experiencing the exact same failure mode: powder repeatedly melting and fusing inside the build chamber, despite extensive troubleshooting, maintenance, and component replacements.
Over the past year, we have replaced countless build chambers due to this issue. We have also replaced major components, including the air heater and the heating lamps. In addition, all recommended maintenance procedures are performed consistently and according to Formlabs’ guidelines:
- Refresh rate is always maintained correctly.
- Quartz tubes are inspected after every print.
- The printer is thoroughly vacuumed after every print.
- The optical cassette is cleaned regularly.
- The IR cone is cleaned regularly.
- All scheduled maintenance procedures are followed.
Despite all of this, the problem keeps returning.
The most recent failure was particularly severe. This was not a test print but a normal production job with actual parts. The print failed because the powder once again completely fused together inside the build chamber. This time, the situation is so bad that the build chamber is currently stuck inside the printer and cannot be removed.
What frustrates me the most is that throughout this process I have repeatedly uploaded diagnostic logs, photos, and additional information directly from the printer. However, many of the support responses I receive suggest that these files have either not been reviewed in detail or that the severity of the problem has not been fully understood. The latest response advised me to print normal parts and follow standard maintenance procedures, even though the failed print in question was already a normal production print and all maintenance recommendations have been followed for a long time.
At this point, the machine has become practically unusable for production. Instead of producing parts, it mainly produces scrap material and destroys one build chamber after another. The resulting costs from wasted powder, damaged chambers, machine downtime, and lost productivity have become significant.
After more than a year of troubleshooting, I would have expected a deeper technical analysis of the diagnostic data and a more concrete investigation into potential causes such as temperature control issues, faulty sensors, electronics, mainboard problems, or other hardware-related failures.
I will continue updating this thread if a root cause is ever identified. For now, however, the issue remains unresolved despite extensive maintenance, multiple component replacements, and ongoing communication with support.
Has anyone else experienced recurring powder fusion or complete build chamber melting on a Fuse 1 despite proper maintenance and adherence to the recommended refresh rates?
Does print log capture the actual temp readings across time, pre failure and during failure? Does the failure begin at roughly the same time start of print -failure, or is it random?
Hello, @KuemmeMl
My name is Mark, and I’m a manager on the EMEA Services team. We’re taking this seriously and we want to make sure we get your issue resolved. We’ll be reaching out directly very shortly.
The diagnostic file is with Formlabs, so I cannot assess whether it contains the actual temperature readings over time.
The failure does not occur at the same point in the process. We have already experienced it during the very first powder layers, and now it has occurred again in the middle of a print job. Therefore, the issue does not appear to be tied to a specific stage of the print.