Repeated Perimeter Melting in Fuse 1 -- Build Chamber Gets Stuck

Support & Troubleshooting Fuse 1
1

Hi everyone,

We are experiencing a persistent perimeter melting / over-sintering issue with our Formlabs Fuse 1.

Symptoms

  • Powder at the perimeter over-sinters and hardens

  • This hardened mass physically blocks the build chamber piston

  • As a result, the motor cannot move (only ~5 mm travel)

This makes the build chamber appear “failed”, but the root cause seems to be the over-sintered powder, not the chamber itself.

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What we’ve tried

  • Firmware updated

  • Connector pins checked & cleaned

  • Quartz heaters (L/R) replaced

  • Build chamber replaced (issue recurred)

  • IR sensor housing cleaned

  • RTD sensor previously replaced

Support feedback

Formlabs suggested a faulty RTD, but since it has already been replaced and the issue persists, we suspect another cause.

Question

Has anyone experienced perimeter melting specifically (not global melting) and identified the root cause?

We are wondering if this could be related to:

  • Laser power / calibration

  • Thermal control instability

I’ve attached an image showing the over-sintered perimeter region.

Any insights would be greatly appreciated. Thanks!

2

We’ve had this problem several times as well. The first time, we were told that our IR sensor cone was not installed correctly and was therefore interfering with the sensor.

The second time, we were told that the contacts to the build chamber might be loose or dirty and that we should check them, which I personally find the most plausible explanation. The fine powder could interfere with the contacts, so I now vacuum them out regularly.

The third time, we were told to replace the heating rods and the air heater. We did not do this; instead, we stopped using the build chamber afterwards and haven’t had any issues since. We strongly suspect that the problem is actually related to the build chamber itself or its contacts.

3

@Seunghoon Perimeter melting is usually directly associated with the build chamber. This could be the plug not being fully connected, or broken or dirty pins.

Please take a look at the Melting SLS support page and follow the steps under “Perimeter Melting” to ensure that the plug and the port are clean and undamaged. If the issue persists, I recommend opening a support case so that we can look into the logs and do a deep dive into the printer.

4

If the issue recurred with a different build chamber perhaps that narrows it down to the fuse side of the connector?