Feeding failure
1. Fault feature: sewing material wrinkles.
Product reason: broken needle tip, excessive bobbin thread tension, improper adjustment of the differential mechanism.
Solution: Replace with a new needle, loosen the bobbin spring screw, and readjust the differential mechanism.
2. Fault feature: the bottom of the sewing material is "chewed" to form a tooth mark.
Product reason: The feeding teeth are too sharp, and the presser foot pressure is too high.
Treatment method: Use oilstone to grind the tooth tip and loosen the pressure adjusting screw.
3. Fault feature: the sound of the thread breaking the fiber when sewing the thread under the sewing material sound.
Product reason: The needle is broken or blunt.
Solution: Replace the needle.
4. Fault feature: The sewing material is stagnant.
Product reason: the feed dog is too low and the presser foot pressure is too high.
Solution: Raise the feed dog and tighten the pressure regulating screw.
5. Fault feature: sewing material goes back and forth.
Product reason: the feed tooth is too high.
Treatment method: adjust the feed dog.
6. Fault feature: the sewing material cannot be sewn backwards.
Product reason: the feeding cam shifted.
Solution: Adjust the position of the feeding cam.
7. Fault feature: The sewing material runs diagonally irregularly.
Product reason: The feed dog is crooked or the screw of the feed dog is loose.
Solution: Correct the feed dog and tighten the screws.
Trouble with stitch
1. Fault characteristics: The upper thread is floating.
Product reason: The pressure of the clamp is too small.
Treatment method: Tighten the thread clamp to increase the tension of the cotton thread.
2. Fault characteristics: The bottom line is floating.
Product reason: The bobbin spring is too loose.
Solution: Tighten the bobbin spring screw to increase the tension of the bobbin thread.
3. Fault characteristics: the stitch length is short and long.
Product reason: The presser foot pressure is too small.
Treatment method: Tighten the pressure regulating screw.
4. Fault characteristics: there is a thread sleeve under each needle under the sewing material, which looks like a towel thread sleeve.
Product reason: The cloth feeding and thread take-up actions are not in harmony, and the cloth feeding action is fast.
Solution: Adjust the cloth feeding cam screw to make the cloth feeding and thread take-up actions harmonized.
Operational failure
1. Fault feature: the nose is rotating sluggishly.
Product reason: wrong lubricating oil, especially vegetable oil. Too much dirt in the shuttle bed, connecting rod screw the nails and the cone screws are too tight.
Treatment method: After washing with kerosene, refill the sewing machine oil. Clean the shuttle bed and loosen the screws to ensure one fixed gap.
2. Fault characteristics: When sending, half circle is stagnant, half circle is lightly slippery, or there is a stagnant point for each circle. Shuttle bed When the inner wheel cable head is running, it is not only half-turn stagnant but also accompanied by severe jitter and noise.
Product reason: The position of the feed dog is too high or dirt accumulates in the gap of the teeth, 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 needle bar.
3. Fault feature: the machine head is stuck and cannot move.
Product reason: The position of the feed dog is too far forward or too far, and it touches the needle board. The needle bar installation position is too high, the needle clamp chassis.
Treatment method: adjust the position of the feed dog, re-align the needle, and adjust the height of the needle bar.
4. Fault features: the noise comes from the needle mechanism.
Product reason: the needle bar, needle bar cover, small connecting rod and other wear and tear are too large. Small connecting rod screw needle bar crank screw loose.
Treatment method: Replace with new parts and tighten.
5. Fault characteristics: the noise comes from the feeding mechanism.
Product reason: the large-pointed cone screw is worn or loose, the feed dog touches the needle plate, and the needle pitch adjustment mechanism is loose.
Treatment method: grinding or readjusting, readjusting, readjusting or tightening screws.
6. Fault features: the noise comes from the shuttle mechanism hit.
Product reason: 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, resulting in impact
Treatment method: Replace with new parts, adjust or replace with new parts.
7. Fault characteristics:normal noise.
Product reason: the upper shaft, lower shaft and sleeve are worn out, causing up and down movement, and the machine lacks oil.
Broken needle
Treatment method: replace with new parts, or adjust the gap between the upper and lower shaft planes, pay attention to maintenance, and refuel on time.
1. Fault feature: needle breakage when sewing thick material.
Product reason: The needle is too thin or bent, the thickness of the sewing material 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. Fault features: short stitch length keeps stitching, long stitch length breaks.
Product reason: 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. Fault feature: The needle is broken under the needle plate.
Product reason: The needle position is low, the needle touches the shuttle, the shuttle bed is not installed, the tip of the shuttle touches the needle, the shuttle holder
The gap between the two sides of the needle end is too small or too large, and the shuttle holder touches the needle or loses the needle protection function gap.
Treatment method: adjust the position of the needle bar or the needle, reinstall the shuttle, adjust the shuttle holder and the end surface of the needle.
4. Fault feature: The needle is broken on the needle plate.
Product reason: The sewing material is too strong by hand, which causes the needle to bend and the presser foot screw to loosen, causing the presser foot to skew and touch the machine.
The displacement of the needle and the feeding cam causes the sewing material to break the needle, and there is a hard object in the sewing material to break the needle.
Solution: Strengthen the operation practice, adjust the presser foot to tighten the screw, and adjust the position of the feed cam screw.
Disconnected
1. Fault features: the first needle is broken, and the broken thread is cut.
Product reason: The needle is installed reversely or the needle is not fully installed, which makes the needle 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. Fault characteristics: The suture is curled at both ends of the broken ends with short whiskers.
Product reason: 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 threaded line to eliminate the winding. Check the wear of the shuttle, If necessary, replace the shuttle. Sand the threaded area and replace the suture.
3. Fault features: the bottom part 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.
Product reason: the feed tooth is too low, and the sewing material does not stop and the thread is too much and breaks. Feeding and threading are out of step
Off. 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. Fault features: the thread suddenly breaks during sewing and the upper thread fluctuates in a curved shape.
Product reason: The position of the shuttle bed is not installed and the noodle thread is 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, change the shuttle with the core sleeve.
5. Fault feature: the bottom thread suddenly breaks during sewing. The bobbin case is unqualified and the inner diameter is elliptical.
Product reason: The bobbin case is unqualified, and the inner diameter is elliptical, causing the bobbin to fail to rotate. The bobbin spring screw can be screwed tight, so that the spool pressure is too small. The bobbin winding is too full or too loose and messy. The bottom thread is rotten and brittle, has knots, makes the bottom core cannot pass the bobbin spring.
Solution: Replace the bobbin case, loosen the bobbin spring screw, rewind the bobbin thread, and replace the bottom thread.
Jumper
1. Failure characteristics: Can not lead to the bottom line.
Product reason: 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 loose the needle bar and move it up, adjust the needle bar down, realign the needle, and tighten the fastening nail.
2. Fault features: the needle bar moves.
Product reasons: 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. Fault feature: one stitch skips over several stitches.
Product reasons: 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. Fault feature: Continuous jumper or stitch cannot be sewn.
Product reason: Poor quality of the needle or bending of the needle cannot produce a loop normally. The needle is too high to catch the thread the loop, the sewing material and the sewing machine needle are not matched properly. Long-term use of the 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 it can be more
Change the shuttle or shuttle bed and overhaul if necessary.
5. Fault features: thin seams without jumpers, thick seams with jumpers.
Product reasons: Insufficient presser foot pressure, too thin needle, serious wear of parts such as thread hooking mechanism.
Treatment method: adjust the presser foot pressure, replace the needle, replace the parts, and repair.
6. Fault features: thick stitches, thin stitches.
Product reasons: 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 is under pressure 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.
