Solving Your Sewing Problems
Bulletin 06
Contents
Common Sewing Problems
Needle Thread Breakage
Bobbin / Looper Thread Breakage
Thread Fusing
Skipped Stitches
Imbalanced / Variable Stitching
Staggered Stitching
Variable Stitch Density
Seam Pucker
Common Sewing Problems
Causes and Remedies
There can be many reasons behind the problems that arise while sewing and knowing the cause of these problems and a solution for each particular cause is essential. These problems can be minimized by avoiding errors during handing of materials / machines and by following the right working methods.
Some common sewing problems are:
- Needle thread breakage
- Bobbin or looper thread breakage
- Thread fusing when the machine stops
- Skipped stitches
- Imbalanced / variable stitching
- Staggered stitching
- Variable stitch density
- Seam pucker
The causes and solutions for each of the above problems are discussed in the following sections.
Needle Thread Breakage
| Cause | Remedy |
|---|---|
| Misaligned off winding from thread package. | Ensure that the overhead guide is directly above cop stand pin, at 2½ times the height of the thread package. Use a foam pad to prevent package tilting. |
| Trapping at package base. | Reduce the thread stand height to prevent vibration and spillage. Use a foam pad to prevent trapping after spillage. |
| Thread trapped at thread guide. | Can occur after thread breaks. Rethread correctly. |
| Snarling before tension disc. | Increase the wraps on pre-tension thread guides and reduce disc tension. Ensure discs are smooth. |
| Excessive tension. | Use a stronger thread or adjust tension. |
| Broken check spring. | Replace and adjust. |
| Sharp edges on throat plate, hook point, needle guard, bobbin case, needle groove or eye. | Polish rough edges and replace if necessary. Replace the needle being used with a higher quality needle. |
| Thread fraying at needle. | Use finer thread or coarser needle, as appropriate. |
| Excessive needle heat; groove or eye blocked with melted fabric. | Improve the fabric finish. Change to a better needle, style and finish. Apply needle lubricant via thread. Use a needle cooler. |
| Hook overheating. | Ensure adequate oil supply. Check the needle to hook clearance. |
| Poor quality thread. | Change to a correctly finished thread of better quality. |
Bobbin or Looper Thread Breakage
| Cause | Remedy |
|---|---|
| Badly wound thread on the bobbin. | Adjust bobbin winder alignment. Use pre-wound bobbins. |
| Tension too tight or bobbin over-running. | Adjust bobbin case tension. Insert a washer or a spring to prevent over-running. |
| Sharp edges on bobbin case or spring or looper eyelet. | Polish edges and correct surfaces. |
| Bobbin case not fitting correctly. | Check the size/type of bobbin for flange distortion. |
Thread Fusing when the Machine Stops
| Cause | Remedy |
|---|---|
| Poorly finished or incorrect thread. | Use better quality thread. |
| Densely woven fabric that is poorly or harshly finished. | Improve fabric finish. Change to more suitable needles. Apply needle coolants. |
| Damaged or overheated needle after thread breakage. | Change the needle. |
Skipped-Stitches
| Cause | Remedy |
|---|---|
| Hook, looper or needle failing to enter thread loops at the correct time. | Check machine clearances and timings. Check if the needle is inserted and aligned correctly. Use a needle with a deeper scarf. |
| Thread loop failure caused by incorrect needle size / style for thread size / type. | Change needle size / style. |
| Thread loop failure due to incorrect setting of thread control mechanism causing thread loop starvation. | Reset to standard and check loop formation with a strobe. |
| Flagging of fabric due to poor presser foot control or too large a throat plate hole. | Re-adjust the presser foot pressure. Change the throat plate to match the needle. |
| Needle deflections or bent needle. | Use a reinforced needle, reset the needle guard and replace the needle. |
| Incorrect sewing tension in the needle or under threads. | Re-adjust the tensions. |
| Poor thread loop formation. | Check with a strobe. Change to superior spun polyester or filament based corespun threads. |
Imbalanced / Variable Stitching
| Cause | Remedy |
|---|---|
| Incorrect sewing tensions. | Check for snarling, adjust thread tensions. |
| Incorrect threading. | Rethread machine. |
| Needle thread snagging on bobbin case or positioning finger. | Polish bobbin case surfaces. Reset positioning finger and opening finger. |
| Variable tension due to poor thread lubrication. | Switch to superior quality threads. |
Staggered Stitching
| Cause | Remedy |
|---|---|
| Needle vibration or deflection. | Increase needle size or change to a reinforced or tapered needle. |
| Incorrect or blunt needle point. | Change the needle. |
| Incorrect needle-to-thread size relationship. | Change needle or thread size as appropriate. |
| Feed dog sway. | Tighten the feed dog. |
| Poor fabric control, presser foot bounce. | Reset the presser foot. Change the feed mechanism. |
Variable Stitch Density
| Cause | Remedy |
|---|---|
| Poor fabric feed control. | Increase the presser foot pressure. Change to a more positive feed mechanism. |
Seam Pucker
| Cause | Remedy |
|---|---|
| Variable differential fabric feed. | Improve the fabric feed mechanism. Replace worn out feed dogs. Reduce the maximum sewing speed. |
| High thread tension. | Keep the bobbin tension as low as possible and set the needle thread tension accordingly. |
| Incorrect thread balance. | Ensure proper balance between the top and bottom thread. |
| Improper thread type. |
Use threads with controlled elongation. Properly maintain tension guides. |
As a Coats customer, you have access to the finest techinal expertise in the thread industry. Our technical consultants are available to assist you in finding solutions for all your shop floor issues. They can give you insights on improving your sewing processes, which will help you deliver products with better quality.