With the development of social economy and the improvement of people’s living standards, people are more and more pursuing personalization, so many people will buy home sewing machines to make clothes at home. There are many types of sewing machines, which can be divided into various categories according to the purpose, stitch, thread hooking mechanism, and thread take-up mechanism. So which is the best home sewing machine? How to use the sewing machine? How to deal with the common problems of electric sewing machines? How to maintain the sewing machine? The following is a detailed introduction to the knowledge of sewing machines by me.
1 The composition of the sewing machine
Generally, the sewing machine is composed of four parts: the head, the base, the transmission and the accessories.
1. The main part of the head sewing machine. It is composed of four mechanisms: barbed material, hook thread, thread take-up and feeding mechanism, and auxiliary mechanisms such as thread winding, material pressing, and tooth-dropping.
2. The machine base is divided into two forms: platen and chassis. The platen of the table-type machine base plays the role of supporting the machine head and is used as a workbench during sewing operations. There are many styles of tabletops, such as one-bucket or multi-bucket folding Tibetan type, cabinet type, writing table and so on. The chassis of the chassis-type machine base plays the role of supporting and storing the machine head, making the sewing machine easy to carry and store.
3. Transmission part The transmission part of the sewing machine is composed of parts such as frame, hand crank or motor. The frame is the backbone of the machine, supporting the deck and footrests. When in use, the operator steps on the pedal, drives the rotation of the pulley through the crank, and drives the head to rotate through the belt. Most hand cranks or motors are directly mounted on the nose.
4. Accessories The accessories of the sewing machine include needles, bobbins, knives, oilers, etc.
2 Sewing principle of sewing machine
The core of sewing machine is the loop sewing system, and its loop sewing method is very different from ordinary manual sewing. On a machine needle, the eye of the needle is just behind the point, not at the end of the needle. The sewing machine only needs to pass the needle part through the fabric, the needle is fixed on the needle bar, and the needle bar is pulled up and down by the motor through a series of gears and cams. As the tip of the needle goes through the fabric, it pulls a small loop on one side and the other. A device under the fabric grabs the loop and wraps it around another thread or another loop of the same thread.
The simplest form of loop stitch is chain stitch. To sew a chain stitch, a sewing machine loops the same length of thread behind the thread. The fabric sits on a metal plate under the needle and is held in place with a presser foot. At the start of each stitch, the needle pulls a loop through the fabric, and a loop-making device, which moves in sync with the needle, grabs the loop before the needle is pulled out. Once the needle pulls out of the fabric, the feed dog mechanism pulls the fabric forward. When the needle goes through the fabric again, the new loop will go straight through the middle of the previous loop. The device that makes the coil will grab the wire again and make the coil around the next coil. This way, each coil will hold the next coil in place.
The main advantage of chain stitching is that it can be sewn very quickly, however, it is not particularly strong and if one end of the thread loosens, the entire stitch may come loose. Most sewing machines use a stronger stitch called lockstitch.
The most important elements of the overlock device are the hook and spool assembly. A spool is a coil of thread that is placed under the fabric. It is located in the center of the shuttle, which is rotated by a motor in synchronization with the movement of the needle. As with chain stitching, the needle pulls one loop through the fabric, it rises again as the feed dog moves the fabric forward, and another loop is pulled in. Instead of joining the different coils together, though, this stitching mechanism joins them with another piece of thread that’s unwound from the spool.
3 How many types of sewing machines are there
1. Classification by use
There are three types of sewing machines: household sewing machines, service industry sewing machines and industrial sewing machines.
2. Classification by stitches
Can be divided into single-thread lock stitch, double-thread lock stitch, single-thread chain stitch, double-thread chain stitch, multi-thread chain stitch There are ten kinds of thread-covered chain stitch, multi-thread covered chain stitch, three-thread overlock stitch, double-thread compound chain stitch, imitation hand stitch and wireless stitch.
3. Classification according to the hooking mechanism
It can be divided into five types: hook hook, hook hook, single hook hook, double hook hook and rotary hook five kind.
4. Classification by thread take-up mechanism
Can be divided into needle bar thread take-up, cam thread take-up, connecting rod thread take-up, sliding bar thread take-up, Seven types of rotary thread take-up and gear thread take-up.
4 Sewing machine purchase
1. Electric household electric household sewing machines have functions such as automatic threading, buttoning, and buttonholes. , The sewing effect is good, and it can meet the sewing needs of ordinary households. When choosing, you need to know the attached functions: for example, how many stitches can be provided, whether it supports double-thread bidirectional sewing and overlock, whether the sewing speed is controllable, whether it provides pedal control, etc.
2. The electronic household sewing machine is equipped with a microcomputer inside, and also has functions such as automatic thread trimming, embroidery, speed control, etc., but the price is higher. When purchasing, it is best to choose more sewing stitches, strong ability to eat thick, low noise, and more convenient and practical.
3. The biggest feature of portable mini sewing machine is its small size, easy to carry and simple to use, and it is only suitable for sewing thin clothes. Therefore, when selecting, the coordination of the needle plate, feed dog and upper and lower thread of the sewing machine should be closely coordinated.
4. Embroidery machine The embroidery machine is controlled by a microcomputer and can design embroidery patterns by itself. There are two types of needle bar swing and fabric movement. The embroidery machine has many built-in patterns, and can also embroider some independent patterns such as letters, cartoon animals, etc., but it cannot be modified after embroidery. It is recommended to choose an embroidery machine with its own design software, which can design embroidery patterns by itself, with complete patterns and powerful functions, and can complete complex patterns; secondly, the precision of the embroidery machine is high, and only high-precision embroidery patterns can be detailed and beautiful.
5. Overlock sewing machine The overlock sewing machine is mainly used for overlocking and preventing garment seam from fluffing. It is generally used for sewing T-shirts, sportswear, underwear, knitting and other fabrics. Common overlock sewing machines include single-thread and multi-thread overlock. The single-thread stitches are sparse, and the denser the multi-thread stitches, the greater the elasticity, and the firmer the sewing. When choosing an overlock sewing machine, you should choose according to the sewing items. If you sew the edge of a blanket, you can use a single-thread overlock; if you sew ordinary knitted garments, both double- and triple-thread overlocks are fine; if you sew the outerwear or shoulder sleeves and other parts with high friction, you need a four- or five-thread overlock .
5 How to use the sewing machine
Holding the machine: Hold the machine base with the four fingers of the right hand, and place the thumb on the top of the body cover naturally, and hold the machine steadily .
Threading: Gently pull the sewing thread from the spool, through the lead, and then into the thread tensioning tab. Then pass through the lead wire. Temporarily place the end of the thread beside the needle, and move the threader from the front of the needle to the joint part of the machine, through the hole of the needle, and then introduce the end of the thread into the small hole of the threader, exit the threader and pull out the first thread for about 2 -3cm crimping plate can be pressed and ready for use.
Place the cloth: Use the right index finger to lift the pressure plate, put the fabric ready to be sewn, the thickness is no more than 0.8 mm, flatly under the pressure plate, and gently put back the pressure plate to press the fabric.
Sewing operation: Hold the fabric with the left hand, press the top of the upper cover gently and quickly with the thumb of the right hand, and press the top of the cover to the bottom, and then press the thumb down again. Send out, the right hand of the machine is gradually moved to the right, and the left hand is holding the cloth to gently move the object to the left according to the sewing rhythm, until the sewing ends;
End: When the sewing is over, cut the thread with scissors, Pull up the pressure plate to take out the fabric, pull out the last section of thread from the reverse side of the fabric to be sewn, make it pass into the next section of the loop and pull it tight and tie a knot, the stitch is firm; do not use dead pull at the end of sewing The fabric method is used to pull the thread end, so as not to damage the needles and stitches.
6 Common Problems of Electric Sewing Machines Problems in Sewing Materials Improper adjustment of the moving mechanism. Treatment method: replace the needle with a new one, loosen the screw of the bobbin spring, and readjust the differential mechanism.
2. The bottom of the sewing material is “gnawed” to form a grid tooth mark
Analysis: The feeding teeth are too sharp and the pressure of the presser foot 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 too blunt. Treatment method: Replace the needle with a new one.
4. The sewing material is stagnant
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 adjusting screw.
5. The sewing material goes back and forth
Analysis: The feed dog is too high. Treatment method: adjust the feed dog.
6. The sewing material cannot be sewn backwards
Analysis: The feed cam shifts. Solution: Adjust the position of the feed cam.
7. The sewing material runs obliquely irregularly
Analysis: The feed dog is installed crookedly or the feed dog screw is loose. Treatment method: correct the feed dog and tighten the feed dog screw.
Operational failures
1. Machine head rotation sluggish
Analysis: wrong lubricating oil, especially vegetable oil; dirt in shuttle bed Too many; connecting rod screws, taper screws are too tight.
Treatment method: after flushing with kerosene, refill the sewing machine oil; clean the shuttle bed; loosen the screw to ensure its clearance.
2. Half-circle stagnant, half-circle slippery, or a stagnant point per revolution
Analysis: Shuttle bed inner wheel There is a thread head, which is not only half-stagnant during operation, but also accompanied by violent shaking and noise; the position of the feed dog is too high or the dirt accumulates in the gap between the teeth, so that the feed dog collides with the needle plate when it rises.
Treatment method: clean the shuttle bed and add a little sewing 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 back, and the needle plate is touched; the needle bar The installation position is too high, and the needle clip touches the casing.
Processing 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 needle bar, needle bar sleeve, small connecting rod and other wear and tear are too large; the small connecting rod screw , Needle bar crank screw is loose.
Treatment method: 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 loose.
5. The noise comes from the feeding mechanism
Analysis: the large pointed conical screw is worn or loose, the feeding dog touches the needle plate, and the stitch length adjusting mechanism is loose.
Treatment method: Grind or re-adjust the large pointed conical screw, re-adjust the feed dog touch plate, re-adjust or tighten the stitch adjustment mechanism screw.
6. The noise comes from the shuttle mechanism
Analysis: The wear of the shuttle and the shuttle bed causes a large gap, and the gap between the shuttle and the shuttle carrier is too large. large and impactful.
Treatment method: Replace with new shuttle and shuttle bed, etc., adjust the spacing or replace with new shuttle and shuttle holder.
7. General noise
Analysis: The upper shaft, lower shaft and bushing are worn, causing the upper and lower shafts to move; or the machine lacks oil.
Treatment method: replace the new upper shaft, lower shaft and shaft sleeve, or adjust the clearance between the upper and lower shaft planes, pay attention to maintenance, and add lubricating oil on time.
Faults in stitching
1. The upper thread is floating
Analysis: The thread tensioner pressure is too small.
Treatment method: Tighten the clamping thread and increase the tension of the cotton thread.
2. The bottom thread is floating
Analysis: The bobbin spring is too loose.
Treatment method: Tighten the bobbin spring screw to increase the tension of the lower thread.
3. The stitch length is long and short
Analysis: The pressure of the presser foot is too small.
Solution: Tighten the pressure adjusting screw.
4. Each stitch below the sewing material has a thread cover appearing in the form of a towel thread cover
Analysis: The action of cloth feeding and thread take-up is inconsistent.
Treatment method: Adjust the feed cam screw to make the feed and thread take-up actions in harmony.
Broken needle failure of sewing machine
1. Broken needle for sewing thick material
Analysis: The needle is too thin or bent, the thickness of the sewing material is uneven, and the needle bar moves is too big.
Treatment method: change a new thick needle, adapt to slow down the sewing speed and help feed the material by hand, change a new needle bar or needle bar cover.
2. Continuous needles with short stitches and broken needles with long stitches
Analysis: lag in the action of the feed dogs, unqualified feed dogs, and needles The needle is broken by touching the rear end of the feed dog.
Treatment method: Adjust the positioning of the feed cam, shorten the needle distance appropriately or replace the feed dog with a new one.
3. The needle is broken under the needle plate
Analysis: The needle position is too low, the needle touches the shuttle, the shuttle is not installed properly, The tip of the shuttle hook touches the needle, the clearance between the shuttle holder and the needle end is too small or too large, and the shuttle holder touches the needle or loses the needle protection function.
Treatment method: adjust the position of the needle bar or needle, re-install the shuttle, and adjust the clearance between the shuttle holder and the needle.
4. The needle is broken on the needle plate
Analysis: The sewing material is pulled too hard by hand, causing the needle to bend and the presser foot screw to loosen, causing the The presser foot slants and touches the needle, and the displacement of the feeding cam causes the sewing material to break the needle, and there is a hard object in the sewing material that causes the needle to break.
Processing method: strengthen the operation practice, adjust the presser foot to tighten the screw, and adjust the position of the feed cam screw.
Sewing machine thread breakage fault
1. The first needle is broken, and the broken thread head is cut.
Analysis: The needle is installed backwards or the needle is not installed foot, causing the needle to be too low. The sewing material is too hard, the needle is too thin or the pressure of the presser foot is too high.
Treatment method: Check the installation of the needle and whether the screw of the connecting shaft of the needle bar is loose. Change the needle or adjust the presser foot pressure.
2. The suture is curled at both ends of the broken end and has short whiskers
Analysis: the thread is too tight or the suture is being sewn Stirring occurs. The thread is squeezed into the shuttle bed guide groove by the shuttle. The suture is brittle and easy to knot, the quality is poor, and there are burrs at the thread-passing part.
Treatment method: Change the pressure of the wire clamp and check the wire passing line to eliminate the entanglement. Check the wear of the shuttle and replace the shuttle if necessary. Sand the area over the thread and replace the suture.
3. The lower part of the sewing material is heavy, and the stitches cannot be formed and the thread is broken, and the broken thread ends in a ponytail.
Analysis: The feed teeth are too low , the sewing material stops and the line is too much and breaks. The cloth feeding and the thread are out of step and are cut off. The presser foot and needle are loose, preventing the sewing material from running.
Treatment method: Raise the feed dog, adjust the positioning angle of the feed cam, and tighten the presser foot and needle screw.
4. The thread suddenly breaks during sewing, and the upper thread fluctuates in a curved manner
Analysis: The upper thread is not installed in the shuttle bed and rolled into the shuttle bed. The bobbin case does not lock tightly or suddenly shifts during sewing. The quality of the shuttle is poor. The shuttle center spring is too long or the center sleeve is oval.
Treatment method: re-adjust the shuttle bed position, re-install the shuttle, and replace the shuttle with the center sleeve.
5. The bottom thread is suddenly broken during sewing. The bobbin sleeve is unqualified, and the inner diameter is elliptic
Analysis: The bobbin sleeve is unqualified, and the inner diameter is elliptical, resulting in the failure of the bobbin rotation. The bobbin spring screw is overtightened and the bobbin case pressure is too low. The bobbin winding is too full or too loose and messy. The bottom thread is brittle and has knots, so that the bottom core cannot pass through the bobbin spring.
Treatment method: replace the bobbin case, loosen the bobbin spring screw, rewind the bobbin thread, and replace the lower thread.
Sewing machine jumper failure
1. The bottom thread cannot be pulled up
Analysis: The hook thread is too short, the hook thread is caught in the shuttle door, the needle is too high, The shuttle cannot catch the thread loop.
Treatment method: Lengthen the hook thread, check whether the lower thread is stuck, and remove it. Needle bar connecting shaft firm screw loosens the needle bar and moves up, the needle bar should be lowered, re-align the needle, and tighten the fastening screw.
2. Needle bar movement
Analysis: needle bar hole, needle bar wear, needle bar connecting screw loose, needle bar displacement.
Treatment method: replace the needle bar cover, or select a new needle bar, re-align the needle; and tighten the set screw.
3. One stitch jumps after a few stitches
Analysis: The shuttle is worn, the tip of the shuttle is too blunt, and the needle is too high or too low.
Processing method: change the shuttle, adjust the height of the needle bar or the needle, and re-align the needle.
4. Continuous jumper or even one stitch cannot be sewn
Analysis: Poor quality of the needle or bending of the needle cannot normally produce loops. The needle is too high to hook the thread loop, and the three needles of the sewing material and stitching are improperly matched. Long-term use of shuttle, swing bed and other parts are seriously worn or broken.
Treatment method: replace the qualified needle or straighten the needle. Adjust the needle bar or needle height. Under normal circumstances, the shuttle or shuttle bed can be replaced and overhauled if necessary.
5. No jumper for thin seam, jumper for thick seam
Analysis: Insufficient presser foot pressure, too thin needle, hooking mechanism and other parts Severely worn.
Treatment method: adjust the pressure of the presser foot, change the needle, replace the parts, and carry out repairs.
6. Thick seam jumper, thin seam jumper
Analysis: The needle hole of the needle plate is too worn, the needle is too thick, and the pressure The sole of the foot is worn, or the presser foot pressure is too low.
Treatment method: change the needle plate, change the fine needle, change the presser foot, change the presser foot, or adjust the pressure of the presser foot.
7 Sewing machine maintenance
1. When the sewing machine is idle, place a layer of cloth under the presser foot, and cover the machine head with a cloth to prevent dust, moisture and sun.
2. The presser foot should be raised (half-raised) when sewing thick pieces, otherwise it may cause the needle and thread to break.
3. Remove the dirt on the machine head, do not use sharp objects such as toothpicks, needles, etc., to avoid damaging the parts.
4. The belt will become looser and looser after being used for a long time, and the machine will sometimes go or not. You can spare a self-made belt, which is firm and durable.
5. Special sewing oil must be used to lubricate the sewing machine. The sewing machine should be fully oiled after one or several days of continuous use. If oil is added between uses, the machine should be idling for a period of time to fully infiltrate the oil and throw off excess oil. Then use a clean soft cloth to clean the machine head. Clean the surface and the countertop to avoid soiling the sewing material. Then thread and sew the rags, use the movement of the sewing thread to clean them, and throw out the excess oil stains until there is no oil stains on the rags, and then proceed to formal sewing.
6. After the work is completed, insert the needle into the needle hole plate, lift the presser foot, and cover the machine head with a hood to prevent dust and debris from entering.
7. Before starting to work, first check the main parts, how heavy the pedal is, whether there is any special sound, whether the needle is normal, etc. If any abnormal phenomenon is found, it should be repaired in time.
8. After the machine has been used for a long time, an overhaul should be carried out. If any parts with greater wear and tear are found, they should be replaced with new ones.
9. For a newly bought or long-used sewing machine, wipe off the dirt before use, and then add 2 to 3 drops of oil to each running part, and idling for a few minutes before sewing again.
10. If the machine has been used for a long time, the panel should be removed, and the lower end of the pressing rod, the center hole of the pressure adjusting screw, the upper and lower ends of the needle bar, the small connecting rod and the needle bar of the thread take-up cam should be connected. Oil the shaft contacts.
