Check the Trimming Area for Debris

The most common cause is a “bird’s nest” (tangled threads) or debris preventing the cutting mechanism from moving freely.

  • Turn off the machine for safety.
  • Remove the needle plate (usually involves loosening two flathead screws with an offset screwdriver).
  • Inspect the area around the hook and the moving knife (silver piece). Clean out any accumulated lint or tangled threads thoroughly. A specialized tool or long-handled scalpel may be helpful for wedged threads.
  • Manually check if the moving knife can slide smoothly.
  • Manually Engage and Disengage the Trim

    If the knives appear stuck in an open position, you might be able to manually cycle them.

    • With the power off and the needle plate still off, locate the manual engagement lever (refer to your manual for its specific location).
    • Depress the lever while turning the main shaft (at the rear or side of the machine) by hand. You should feel the roller engage with the trim cam and the knives should cycle and return to their closed position.
    • Once the knives are properly seated and closed, release the manual engagement lever.
  • Perform a Trim Test via the Control Panel

    After cleaning and manually checking, turn the machine back on and try a system test (if available on your SWF model).

    • Access the machine’s test functions (often under an M-Setting or Menu button).
    • Navigate to a Trim Test option and run it.
    • Listen to the mechanism and observe if the knives cycle correctly and fully return to the home position.
  • Check the Trim Sensor

    If the physical mechanism is clear and moves, the issue might be with the sensor that detects whether the knives are in the correct position.

    • Ensure the sensor and its associated components are clean.
    • If the sensor is faulty, it will keep sending a signal that the trim is incomplete, causing the message to loop. This may require professional service.
  • Power Cycle the Machine
    • Turn the machine off.
    • Unplug it from the power source and wait a few minutes.
    • Plug it back in and turn it on again.

    • If the problem persists: the machine likely has a persistent mechanical fault with the trimming system or a faulty sensor/motor that needs professional repair.