Thread Breaks

Possible Problem Area

Solution Checklist

Material thickness setting may be incorrect

1. Check the material thickness and adjust if set too high or too low.
   
   If material thickness is set too high, too much thread is being fed into the system, and you may see some of these symptoms: looping, popping thread breaks, and no bobbin showing on the back of the fabric.
   
   If material thickness is set too low, not enough thread is being fed into the system, and you may see some of the following symptoms: pulling, puckering, fraying thread, thread breaks, and bobbin showing on the top of the fabric.

Stitches may be too short and/or too dense

1. Check the design for short and/or dense stitches, and edit the design to remove them.
   
   One effective method of removing dense stitches is to run the Stitch Proximity Filter.
   
   One way to remove short stitches is to open Design Filter (Tools->Design Filter ). Adjusting the setting of After 1 Short to After 0 Short will filter ALL stitches of 4 points (the default Short Stitch Length) or less from the design.

Bobbin Tension, Bobbin Thread, Bobbin Case

1. Check bobbin tension.
   
   A range of bobbin tension is acceptable. As you gently bounce the bobbin case - holding the thread with your hand - it should drop approximately 2 - 4 inches / 50 - 100 mm, but bobbin tension can be as loose as when you hold onto the bobbin thread and let the bobbin case hang, it should begin a slow but steady drop. Adjust the bobbin tension if it is outside of this range.

2. Make sure that the bobbin has been placed correctly in the bobbin case (click here for instructions).

3. Inspect the bobbin case and make sure it is not damaged and that it is clean (click here for instructions).

Needles / Needle Depth / Needle Plate

1. Check needle orientation.
   
   If a needle is installed backwards, turned too much, or turned to the left, thread breaks can occur. It is recommended that the eye of the needle be tilted 5° to the right; however a range of needle orientation is acceptable.  The eye of the needle can be facing directly forward or be tilted to the right by a maximum of 20°.

2. Inspect needle(s) for damage such as burrs, scratches, and dullness. Replace if necessary.

3. Make sure you are using the correct needle(s) for the size of thread being used.

4. Check needle depth to make sure that it is correct.

5. Verify that the needles are centered in the needle plate. The needle needs to pass approximately through the absolute center of the hole in the needle plate without rubbing or hitting the needle plate. If this isn't the case for the majority of the needles (i.e. most needles are far off to the right or left), refer to the needleplate centering procedure.

6. Inspect the needle plate hole to be sure it's free of nicks, burrs or anything that may cause the thread to fray. Replace if necessary.

Thread / thread path

1. Make sure the machine is threaded properly (see Upper Threading for instructions).

   Make sure that there is no misguided thread.

   The thread should be centered in the groove under the thread feed rollers.

   Make sure that no thread is caught or wound around the thread feeder gears.

   Make sure the red pinch rollers are down.

2. Make sure you are using high quality thread. Look for kinks, frays, or thread which seems to unravel and/or twist during use. If the thread is suspected to be bad, exchange with a high quality thread to try and isolate the problem.

3. Be sure the thread tubes, which pass along the center of each thread cone, extend at least 1" beyond the end of the cone. Otherwise, the thread may become tangled.

4. Be sure the thread cones are fully seated against the thread tree base. If not, the thread could become entangled beneath the cone.

Thread feeder / Pinch rollers

1. Inspect thread feed & pinch rollers for wear and/or damage (see Thread Feeder Roller Inspection and Cleaning for instructions). Replace if necessary.
   
   If you can easily pull thread without lifting the pinch roller, the thread feeder roller may be worn / damaged and should be closely inspected.

Fabric and hoops

1. Check how the garment is hooped; garment may be hooped too loosely.
   
   The fabric should be very taut in the hoop, similar to a drum. Depending on the fabric, if it is slipping in the hoop, you may need to wrap the bottom hoop with a fabric "seam binding."

2. Make sure the hoop arms are attached securely.
   
   It is important that the arms are securely attached to the machine. If you can wiggle the hoop arms side to side, they are too loose. Click here for instructions on tightening.

3. Make sure hoop arm bracket clips are secured tightly.
   
   When you slide the hoop underneath the bracket clips, both sides should snap securely into place. If either side of the hoop can move front to back or is not seated underneath the clip, the hoop may move during sewing. Click here for instructions on tightening.
   
   A quick test to see if the arms and/or clips are loose is to sew a fill pattern inside a border. You will likely notice poor registration. The concentric circles on the AMPASS or BRAVOPASS design are good for this as well. You will notice more distortion in the X direction than in the Y direction.

4. Check the backing you are using.
   
   Inadequate backing allows fabric to be pulled into the needle plate hole. If needed, increase the number of backing pieces or change backing type.

5. Review the weight of the garment being sewed.
   
   If you are sewing a particularly heavy garment, try sewing at a slower speed to see if the thread breaks become less frequent.  Furthermore, if there is an abundance of material hanging outside the hoop, be sure it hasn't become tangled with adjacent hardware.

6. Make sure the hoop isn't hitting the needle plate.
   
   On occasion, due to frequent use and possibly rough operation, it may be that the hoop arms and/or the hoop itself become bent downwards.  As a result, if sewing very close to the hoop perimeter, the hoop may hit against the needle plate causing a thread break.  Examine the hoop arms; if they are bent down, contact Melco Service.

Rotary hook

1. Check the hook timing and the hook gap; one (or both) may be out of adjustment.

2. Check to make sure the rotary hook is rotating smoothly & sufficiently oiled.
   
   If it is not, clean, oil, and if the problems persist, replace.

Horizontal or vertical bars at startup, or soon after (also called miss-starts).

• Hook timing and hook gap

• Make sure tail length (length of thread tail left after a trim) is adequate

• Make sure that thread is being held in trap (in grabber assembly) during trims

• Check the under thread presser spring

• Inspect thread feeder rollers & pinch rollers for wear and/or damage

At the startup of the small lettering

• Hook timing

Small lettering (after startup)

• Needle depth

• Hook timing and hook gap

• Needle orientation

• Make sure the needle plate is centered

• Inspect thread feeder rollers & pinch rollers for wear and/or damage

Triangles & Fill

• Hook timing. Hook timing is the most frequent cause of thread breaks in this area

• Inspect thread feeder rollers & pinch rollers for wear and/or damage

At the startup of the circles

• Hook gap

Circles (after startup)

• Burrs on needle plate hole

• Needle orientation

• Hoop may be hitting needle plate

• Inspect thread feeder rollers & pinch rollers for wear and/or damage

Diamond

• Needle orientation

• Hook gap

• Inspect thread feeder rollers & pinch rollers for wear and/or damage

Horse and Buggy

• Needle orientation

• Inspect thread feeder rollers & pinch rollers for wear and/or damage

Spiral and Starburst

• Needle orientation