There are several reasons why your Brother SE600 Sewing and Embroidery Machine may be producing noise during operation. Here are some common causes and possible solutions:

1. Unbalanced machine: If the machine is not properly balanced, it may produce more noise than usual. Make sure the machine is sitting on a level surface and adjust the feet or use a vibration pad if necessary.
2. Loose or worn parts: Loose or worn parts, such as screws or belts, can cause vibration and noise. Inspect the machine for any loose or damaged parts and tighten or replace them as needed.
3. Lack of lubrication: The machine may produce noise if the moving parts are not properly lubricated. Consult the manual for recommended lubrication points and apply lubricant as needed.
4. Incorrect needle or thread: Using the wrong needle or thread can cause the machine to produce noise. Make sure you are using the correct size and type of needle and thread for your project.
5. Tension issues: Improper thread tension can cause the machine to produce noise. Check the thread tension and adjust it as needed.
6. Dirty or clogged machine: A dirty or clogged machine can cause the machine to produce noise. Clean the machine regularly, following the instructions in the manual.

If the noise persists after checking and addressing the above issues, it’s recommended to contact Brother customer support for further assistance.