Tajima TFMX-C Thread Breakage Troubleshooting Guide

1. Incorrect Thread Tension high likelihood

How to tell

Thread breaks frequently, stitches appear too loose or too tight, or the thread snaps when pulled gently from the needle. Upper thread tension that is too tight will cause the thread to snap, while too loose can lead to looping and tangling, eventually causing breakage. Bobbin tension issues manifest as loops on the top or bottom of the fabric, or the bobbin thread breaking.

Fix

1. Adjust the upper thread tension. Turn the tension knob counter-clockwise to loosen, clockwise to tighten. Aim for a balanced stitch where the bobbin thread shows approximately 1/3 on the underside of the fabric.
2. Check bobbin case tension. Hold the bobbin case by the thread and let it hang. It should slowly drop a few inches, then stop. If it drops freely, it's too loose; if it doesn't drop, it's too tight. Adjust the small screw on the bobbin case to achieve this balance.
3. Ensure the bobbin is wound evenly and inserted correctly into the bobbin case, with the thread feeding in the correct direction (usually clockwise when viewed from the top of the bobbin).
4. For machines with automatic tension sensors, calibrate the sensor according to the machine's manual if consistent tension issues persist.

TENSION BASE, ELECTRICAL PARTS

Parts involved: Thread path & tension → Rotary hooks & bobbin cases → Sensors & switches →

2. Worn or Incorrect Needle high likelihood

How to tell

Needle breaks, skips stitches, or causes thread to fray and break. Inspect the needle point for dullness, burrs, or bends. Ensure the needle scarf is facing the correct direction (usually towards the back of the machine). Using a needle that is too small for the thread or fabric can cause excessive friction and breakage.

Fix

1. Replace the needle. Always use a new, sharp needle of the correct type (e.g., DBxK5) and size for your thread weight and fabric type. Refer to your machine's manual for recommendations.
2. Ensure the needle is inserted fully into the needle bar and oriented correctly, with the scarf facing the rotary hook. Tighten the needle clamp screw securely.
3. Verify the needle is not bent by rolling it on a flat surface.

NEEDLE BAR CASE 1

Parts involved: Needles & needle bars → Screws, springs & small parts →

3. Thread Path Obstructions or Damage medium likelihood

How to tell

Thread snags, frays, or breaks consistently at a specific point in the thread path. Visually inspect all thread guides, tension discs, and the take-up lever for lint, debris, burrs, or damage.

Fix

1. Thoroughly clean the entire thread path, from the thread stand to the needle. Use a soft brush, compressed air, or a pipe cleaner to remove lint, dust, and debris from thread guides, tension discs, and the take-up lever.
2. Inspect all thread guides (ceramic or metal) for nicks, burrs, or grooves. Replace any damaged guides.
3. Check tension discs for smooth operation and ensure they are free of debris that could prevent them from closing properly.
4. Ensure the thread take-up spring is functioning correctly and not bent or broken.

UPPER THREAD HOLDER, TENSION BASE

Parts involved: Thread path & tension → Screws, springs & small parts →

4. Poor Quality or Mismatched Thread medium likelihood

How to tell

Thread breaks frequently despite correct tension and a clear path. The thread may appear fuzzy, have inconsistent thickness, or feel brittle. Using thread not designed for high-speed embroidery or the specific fabric/design.

Fix

1. Use high-quality embroidery thread specifically designed for high-speed machine embroidery. Ensure the thread is suitable for the fabric type and design density.
2. Inspect thread spools for defects, tangles, or uneven winding before use.
3. Store thread in a controlled environment to prevent degradation from humidity or temperature fluctuations.

Parts involved: Threads & supplies →

5. Improper Bobbin Winding medium likelihood

How to tell

Bobbin thread breaks, or loops appear on the top or bottom of the fabric. The bobbin may be visibly unevenly wound, too loose, or too tight.

Fix

1. Ensure bobbins are wound evenly and smoothly, without being too loose or too tight. The thread should lie flat on the bobbin.
2. Replace old or damaged bobbins, as they can cause uneven thread release.
3. Verify the bobbin is inserted correctly into the bobbin case, allowing for smooth, consistent thread release.

Parts involved: Rotary hooks & bobbin cases →

6. Excessive Machine Speed low likelihood

How to tell

Thread breaks primarily during high-speed sections of a design, especially on delicate fabrics or intricate details. The machine may sound strained.

Fix

1. Reduce the machine's operating speed, particularly for delicate fabrics, intricate designs, or areas with high stitch density.
2. Consider breaking down complex designs into smaller sections or adjusting design parameters (e.g., stitch density) to reduce stress on the thread.

Parts involved: Control panels & displays →

7. Misaligned Needle Guard low likelihood

How to tell

Thread snaps against the needle guard, often with a distinct 'ping' sound, or shows signs of fraying where it contacts the guard. This is more common during high-speed operation.

Fix

1. Carefully inspect the needle guard's alignment. It should be positioned to prevent the thread from snapping against it without interfering with needle movement.
2. Adjust the needle guard position as per your machine's maintenance manual. This typically involves loosening a small screw, repositioning the guard, and re-tightening.

NEEDLE BAR CASE 1

Parts involved: Head & mechanical parts → Screws, springs & small parts →

8. Worn or Damaged Thread Spool Holder low likelihood

How to tell

Thread snags, tangles, or experiences inconsistent tension as it unwinds from the spool. The spool holder may be bent, rough, or not spinning freely.

Fix

1. Inspect the thread spool holder for any damage, burrs, or misalignment. Ensure the spool spins freely and smoothly on the holder.
2. Clean the spool holder regularly to remove any dust or debris that could obstruct thread flow.
3. Replace any damaged spool holder components.

Parts involved: Thread path & tension → Screws, springs & small parts →