With the development of social economy and the improvement of people's living standards, household sewing machine products that have long faded out of people's vision are re-entering millions of Chinese households with a new image of lightness and flexibility, diversified functions, and fashionable appearance design. The maintenance of common failures should also cause us to attach great importance accordingly. Today, let’s take a look at sewing machine repair failures and repair methods.
Sewing machine maintenance failure
1. Feeding failure
1. Sewing material wrinkles
Analysis: The needle tip is broken, the bottom thread tension is too large, and the differential mechanism is not adjusted properly.
Treatment method: replace the new needle, loosen the bobbin spring screw, readjust the differential mechanism.
2. The bottom of the sewing material is "gnawed" to form a tooth mark
Analysis: The feeding teeth are too sharp and the presser foot pressure is too high.
Treatment method: Use oilstone to grind the tip of the feeding tooth and loosen the pressure adjusting screw of the presser foot.
3. There is a thread under the sewing material, and there is a sound of breaking the fiber when sewing
Analysis: The needle is broken or blunt.
Solution: Replace with a new needle.
4. The sewing material stagnates
Analysis: The feed dog is too low and the presser foot pressure is too high.
Treatment method: Raise the feed dog and tighten the pressure regulating screw.
5. The sewing material goes back and forth
Analysis: The feed dog is too high.
Treatment method: adjust the feed dog.
6. Can not sew backwards
Analysis: The feed cam is shifted.
Solution: Adjust the position of the feeding cam.
7. The sewing material goes diagonally irregularly
Analysis: The feed dog is crooked or the screw of the feed dog is loose.
Solution: Correct the feed dog and tighten the screw of the feed dog.
Sewing machine maintenance failure 2. Operation failure
1. The head rotation is stagnant
Analysis: The wrong lubricating oil is added, especially vegetable oil; there is too much dirt in the shuttle bed; the connecting rod screw and the conical screw are installed too tightly.
Treatment method: After washing with kerosene, refill the sewing machine oil; clean the shuttle bed; loosen the screws to ensure the clearance.
2. When sending, half circle is stagnant, half circle is lightly slippery or there is a stagnation point for each circle
Analysis: The inner wheel of the shuttle bed has a threaded end, which is not only half-turn stagnant but also accompanied by violent jitter and noise; the position of the feed dog is too high or dirt accumulates in the tooth gap, which makes the feed dog collide with the needle plate when it rises.
Treatment method: clean the shuttle bed and add a little sewing machine oil; clean or lower the feed dog; replace or straighten the needle bar.
3. The machine head is stuck and cannot move
Analysis: The position of the feed dog is too far forward or too far, and the needle plate is touched; the needle bar is installed too high, and the needle clamp touches the casing.
Treatment method: adjust the position of the feed dog, re-align the needle, and adjust the height of the needle bar.
4. The noise comes from the needle mechanism
Analysis: The wear and tear of the needle bar, needle bar cover, and small connecting rod are too large; the small connecting rod screw and the needle bar crank screw are loose.
Solution: Replace the new needle bar, needle bar cover, small connecting rod and other accessories; re-tighten the small connecting rod screw and the needle bar crank screw.
5. The noise comes from the feeding mechanism
Analysis: the large pointed cone screw is worn or loosened, the feeder touches the needle plate, and the stitch length adjustment mechanism is loose.
Processing method: grinding or re-adjusting the large-pointed cone screw, re-adjusting the needle plate of the feeder, re-adjusting or tightening the screw of the needle pitch adjustment mechanism.
6. The noise comes from the shuttle mechanism
Analysis: The wear of the shuttle and the shuttle bed causes the gap to be large, and the gap between the shuttle and the shuttle holder is too large to cause shock.
Treatment method: replace the new shuttle and shuttle bed, etc., adjust the spacing or replace the new shuttle and shuttle holder.
7. General noise
Analysis: The upper shaft, lower shaft and sleeve are worn out, causing the upper and lower shafts to move; or the machine lacks oil.
Treatment method: replace the upper shaft, lower shaft and shaft sleeve with new ones, or adjust the gap between the upper and lower shaft planes, pay attention to maintenance, and add lubricating oil on time.
Sewing machine maintenance failure Three, stitches
1. The noodle thread is floating
Analysis: The clamp pressure is too small. Treatment method: Tighten the thread clamp to increase the tension of the cotton thread.
2. The bottom line is floating
Analysis: The bobbin spring is too loose. Solution: Tighten the bobbin spring screw to increase the tension of the bottom thread.
3. The stitch length is long and short
Analysis: The presser foot pressure is too small. Treatment method: Tighten the pressure regulating screw.
4. A thread sleeve appears on each needle under the sewing material, which is like a towel thread sleeve
Analysis: The cloth feeding and thread take-up actions are not compatible.
Processing method: adjust the cloth feeding cam screw to make the cloth feeding and thread take-up actions harmonized.
Sewing machine maintenance failure 4. Broken needle failure
1. Broken needle for sewing thick materials
Analysis: The needle is too thin or bent, the sewing material thickness is uneven, and the needle bar moves too much.
Treatment method: Replace the thick needle with a new one, adapt to slow down the sewing speed and help feed the material by hand, replace with a new needle bar or needle bar cover.
2. Short stitch length keeps stitching, long stitch length breaks
Analysis: the action of the feed dog is lagging, the feed dog is unqualified, and the needle breaks when the machine needle touches the back end of the feed dog.
Solution: Adjust the positioning of the feeding cam, appropriately shorten the stitch length or change the feeding dog.
3. The needle is broken under the needle plate
Analysis: The needle position is low, the needle touches the shuttle, the shuttle bed is not installed properly, the tip of the shuttle touches the needle, the gap between the shuttle holder and the needle end is too small or too large, the shuttle holder touches the needle or loses protection Needle effect. Treatment method: adjust the position of the needle bar or the needle, reinstall the shuttle, and adjust the gap between the shuttle holder and the needle.
4. The needle is broken on the needle plate
Analysis: The sewing material is pulled too hard, causing the needle to bend, the presser foot screw is loose, causing the presser foot to slantingly touch the needle, the displacement of the cloth feed cam causes the sewing material to break the needle, and there is a hard object in the sewing material to break the needle. .
Treatment method: strengthen the operation practice, adjust the presser foot to tighten the screw, and adjust the position of the cloth feeding cam screw.
Sewing machine maintenance failure five, disconnection
1. The first needle is broken, and the broken thread is cut.
Analysis: The needle is installed reversely or the needle is not installed enough, which causes the needle to be too low. The sewing material is too hard, the needle is too thin or the presser foot pressure is too high.
Solution: Check whether the needle installation and the needle bar connecting shaft screw are loose. Change the needle or adjust the presser foot pressure.
2. The suture is curled at both ends of the broken ends with short whiskers.
Analysis: The thread is too tight or the thread is twisted during sewing. The suture is squeezed into the guide groove of the shuttle bed by the shuttle. The sutures are rotten, brittle and easy to knot, with poor quality, and burrs on the threaded parts.
Treatment method: change the pressure of the clamping piece and check the wire line to eliminate the winding. Check the wear of the shuttle, and replace the shuttle if necessary. Sand the threaded area and replace the suture.
3. The thread at the bottom of the sewing material is heavy, and the stitch length cannot be formed and the thread is broken, and the broken thread is horsetail-shaped.
Analysis: The feed tooth is too low, and the sewing material does not stop and the thread is too much and breaks. The feed and thread are out of step and are broken. The presser foot and the needle are loose, hindering the sewing material from running.
Treatment method: raise the feed dog, adjust the positioning angle of the feed cam, tighten the presser foot and the needle screw.
4. The thread suddenly breaks during sewing, and the upper thread fluctuates in a curved shape.
Analysis: The position of the shuttle bed is not installed with the noodle thread rolled into the shuttle bed. The bobbin case is locked at the end or suddenly shifted during sewing. Poor shuttle quality. The bobbin spring is too long or the core sleeve is oval.
Treatment method: readjust the position of the shuttle bed, reinstall the shuttle, and change the shuttle with the core sleeve.
5. The bottom thread suddenly breaks during sewing. The bobbin case is unqualified and the inner diameter is elliptical.
Analysis: The bobbin case is unqualified, and the inner diameter is elliptical, causing the bobbin to fail to rotate. The bobbin spring screw is too tight, so that the bobbin pressure is too small. The bobbin winding is too full or too loose and messy. The bottom thread is rotten and brittle and has knots, which prevents the bottom core from passing through the bobbin spring.
Solution: Replace the bobbin case, loosen the bobbin spring screw, rewind the bobbin thread, and replace the bottom thread.
Sewing machine maintenance failure six, jumper
1. Can't draw the bottom line.
Analysis: The shuttle thread is too short, the shuttle thread is clamped in the shuttle door, the needle is too high, and the shuttle cannot hook the thread loop.
Solution: extend the shuttle thread, check whether the bottom thread is jammed, and eliminate it. Needle bar connecting shaft firm screw loosen and move the needle bar up, adjust the needle bar down, re-align the needle, and tighten the fastening screw.
2. The needle bar moves.
Analysis: Needle bar hole, needle bar wear, needle bar connecting screw loose, needle bar displacement.
Solution: Change the needle bar cover, or choose a new needle bar, re-align the needle; and tighten the set screw.
3. One stitch skips over several stitches.
Analysis: The shuttle is worn, the tip of the shuttle is too blunt, and the needle is too high or too low.
Treatment method: change the shuttle, adjust the height of the needle bar or the height of the needle, and re-align the needle.
4. Continuous jumper or one stitch cannot be sewn.
Analysis: The quality of the needle is poor or the needle cannot be bent normally to produce a loop. The needle is too high, the thread loop cannot be caught, and the sewing material and sewing machine needles are not properly matched. Long-term use of shuttle, swing bed and other parts are severely worn or broken.
Treatment method: replace the qualified needle or straighten the needle. Adjust the height of the needle bar or needle. Under normal circumstances, the shuttle or shuttle bed can be replaced and overhauled if necessary.
5. Thin stitches without jumpers, thick stitches.
Analysis: The presser foot pressure is not enough, the needle is too thin, the thread hook mechanism and other parts are severely worn.
Treatment method: adjust the presser foot pressure, change the needle, replace the parts, and repair.
6. Sewing thick jumpers and thin jumpers.
Analysis: The needle plate's needle hole is too worn, the needle is too thick, the bottom of the presser foot is worn, or the presser foot pressure is too small.
Treatment method: change the needle plate, change the fine needle, change the presser foot, change the presser foot, or adjust the presser foot pressure.
