What do you mean by loose seams?

Question 1: What are seam wrapping and flat seam wrapping? They are all edge wrapping machines with different names. Flat sewing is another kind, which deals with real woven fabrics. Complete and comprehensive functions, decorative patterns, studs, buttonholes, embroidered letters and so on.

Question 2: What is the general concept of tension suture formation?

Carding (carding)-A yarn woven by carding only one end.

Combing-The yarn impurities at both ends of the fiber are less and the fiber is straighter with a combing machine.

Blended yarn-a yarn in which two or more fibers with different properties are mixed together.

Single yarn-formed directly on the spinning frame, once untwisted, it will spread out, called yarn.

Stranded yarn-two or more yarns are twisted together, which is called thread for short.

Sewing thread-the general term for sewing thread for products such as clothes.

New spinning-different from traditional ring spinning, one end is free, such as air spinning and friction spinning. The yarns are twisted together without twist.

Yarn count-an index used to express yarn fineness, which mainly includes English count, metric count, Tex number and Denier number. There are many more.

About distortion

Definition: by twisting the fiber structure of the line, the relative angular displacement between the sections of the line is generated, and the straight fiber is inclined with the axis, thus changing the structure of the line. Twisting can make the yarn have certain physical and mechanical properties, such as strength, elasticity, elongation, luster, feel and so on. , expressed in twist per unit length, is often used as twist per inch (T.P.I) or turns per meter (T.P.M).

Torsion: 360 degrees around the axis is torsion.

Twisting direction (S direction or Z direction): the oblique direction of the helix formed by the rotation of the yarn around the axis when the yarn is vertical. The diagonal direction of the twisting direction of S is consistent with the middle of the letter S, that is, the right hand direction or the clockwise direction. The oblique direction of the twist direction of Z is consistent with the middle of the letter Z, that is, the left-hand direction or the counterclockwise direction.

The relationship between twist and strength: the twist of a thread is directly proportional to the strength, but after a certain twist, the strength decreases. If the twist is too large, the twist angle will increase, and the luster and feel of the thread will be poor; If the twist is too small, it will cause hairiness and feel loose. This is because the twist increases, the friction resistance between fibers increases, and the strength of the thread increases. However, with the increase of twist, the axial component of yarn becomes smaller, and the stress distribution of inner and outer fibers is uneven, resulting in inconsistent fiber fracture.

In a word, the fracture properties and strength of wire are closely related to the twist, and the twist and twist direction depend on the needs of finished products and post-processing, generally Z-twist direction.

Selection of suture

Under specified conditions, the ability of suture to form good suture while maintaining certain mechanical properties is called seamability, which is a comprehensive index to evaluate the quality of suture. According to the material, thickness, texture, color, sewing style, sewing equipment or sewing means of sewing materials, the following principles can be generally followed when choosing sewing threads and needles with matching types and specifications:

1. Coordinate with fabric characteristics.

It can ensure the unity of shrinkage, heat resistance, wear resistance and durability, and avoid shrinkage caused by excessive difference between thread and fabric. Generally, thin thread is used for soft and thin materials with small needle, and thick thread is used for hard and thick materials with large needle.

2. Coordinate with sewing equipment

Left-handed sewing thread is selected for flat sewing machine, which can be twisted when sewing to maintain the strength of sewing thread.

3. Coordinate with sewing form

The wrapping (stretching) sewing machine adopts fine cotton thread, which makes the sewing material not easy to deform and wrinkle, and the chain stitch is beautiful and comfortable. Double-thread suture should have good extensibility. Crotch, shoulder seam should choose solid suture. Wear-resistant stitches should be selected for eyeliner marks of buttons.

Step 4 coordinate with the type of clothing

Special purpose clothing, such as elastic clothing, needs elastic stitching, and fire-fighting clothing should use heat-resistant, flame-retardant and waterproof stitching.

Question 3: What is a sewing machine? Flat sewing machine, also known as special sewing machine, stitches it sews are chain stitches. This stitch method is mostly used for collar rolling, hemming, hemming, flat sewing, hemming and trimming of knitted garments.

Question 4: What's the difference between sewing machine and sewing machine? The sewing machine can only sew some staples such as cloth, while the flat sewing machine can sew thicker materials such as tents.

The needle and wire used are different, and the power of the motor is different.

Question 5: What's the difference between plain sewing, hemming and hemming sewing machines? Selvage sewing machine is also called special sewing machine. It sews chain stitches. This stitch is mostly used for collar rolling, selvage, selvage, selvage and so on.

Cylinder sewing machine is suitable for sewing necklines and cuffs of various elastic fabrics, such as knitted underwear, sportswear, T-shirts, bras, waist skirts and elastic bands. Desktop sewing machine is a basic machine, which can be used for hemming sewing, and is suitable for hemming sewing of neckline and cuffs of underwear and sweatshirts. There are many kinds of desktop sewing machines. Various accessories can be installed to realize multifunctional sewing, which is widely used in various knitting materials, such as underwear, cotton and wool underwear, sweatshirts, T-shirts, men and women, and is also suitable for sewing various styles of knitted fashion, knitted jackets, jeans, etc. It can sew hemming, necking, elastic stitching, lace decoration, curved tooth edge and so on. , is a necessary sewing equipment for large-scale production plants. Because of the tight sewing,

Sewing machines can be divided into rolling collar sewing machines, elastic belt sewing machines and belt sewing machines. According to the machine form, it can be divided into platform sewing machine, hanging cylinder sewing machine and elbow cylinder sewing machine. Among them, the most commonly used are neck rolling sewing machine, elastic belt sewing machine and cylinder hanging sewing machine. The CW-500 and CW-600 models of Pegasus, F007 model of Yinjian and VF2400/2500/2600/2700 model of Yamato are widely used in the production lines of garment factories.

Question 6: What's the difference between sewing machine and sewing machine? A sewing machine is a kind of sewing machine, which is generally used to sew two or more materials. It can be sewn with four, three or five threads. Five-thread sewing machine means that the two threads on the left are separate stitches, just like the single needle of flat sewing machine, and the right is wrapped with three threads. Flat sewing machine is a three-needle wireless machine, which can also be changed into a four-needle six-wire machine for open thread decoration. You can use a flat sewing machine for a single needle, with one thread above and one thread below. The effect is that the stitch of the flat sewing machine is on the top, and the stitch of the chain sewing machine is on the bottom, with a loop button or double stitches. There are 2 stitches on the top, with a spacing of 0.56cm. The sewing machine needles are on the top and the net is on the bottom.

Question 7: Models and uses of sewing machines. The sewing machine is also called a special sewing machine. The stitches it sews are chain stitches. This stitch method is mostly used for collar rolling, hemming, hemming, flat sewing, flat sewing and hemming of knitted garments. In recent years, great changes have taken place in clothing styles, and sewing machines are often used to sew decorative stitches. Moreover, there are many kinds of stitch patterns sewn by sewing machines. For example, three-needle and four-thread sewing (No.407) can be changed to two-needle and three-thread sewing (No.406), or two-needle and three-thread sewing can be changed to two-needle and four-thread sewing or three-needle and five-thread sewing (No.602 or No.605).

I. Conveying Power System of Flat Sewing Machine

Because the flat sewing machine is mostly used for sewing knitted fabrics, two groups of feed teeth are used for conveying sewing materials, so that the two groups of feed teeth are relatively independent. The front and rear groups of feeding teeth can adjust the synchronous conveying action, or have the difference of speed. When sewing a knitted fabric with strong elasticity and two layers of light knitted fabric, the feeding speed of the feeding teeth can be adjusted to be faster or slower than that of the differential teeth. Correctly adjusting the feeding speed of feeding teeth and differential teeth can reduce the elongation and shrinkage deformation of sewn clothes and make them beautiful.

Second, the design of head shape

The design of the head type of flat sewing machine is mostly a high platform device. In order to meet the production purpose of various sewing processes, the head type is also designed as round mouth winding arm type, round mouth out arm type, round mouth into arm type and so on. The flat sewing machine head with high platform can be suitable for sewing plane parts with long stitches; Round-mouth arm-winding type is designed for sewing cuffs to roll or edge; Round mouth arm type is used for sewing cylindrical parts, such as sewing at the bottom of sleeves and sewing at the side of trousers; The round mouth into the arm type is designed for sewing the seam of the bottom stop; In addition, the high platform head can be equipped with oblique angle design to sew different types of pieces. Some sewing machines have a sewing accessory (sewing assistant) installed on the right side of the head. If it is used in the hemming operation, the sewing accessories can be connected to the right side of the needle plate to cooperate with sewing.

Third, the application of sewing machine in the production process

(a) for edge sewing

If smooth binding is used, wrap the raw edge of the cut piece around the seam with packaging tape. There are too many layers of sewing material on the seam. If it is tailored for the body, it may be uncomfortable to wear. However, if 602 (two stitches and four stitches) or 605 (three stitches and five stitches) sewn by the stitch sewing machine are used to wrap the burrs of the bundle, the number of layers of sewing material on the stitch can be reduced from five to three, or 406 (two stitches and three stitches) or 407 can be used. The sewing assistant for hemming can be installed on the flat sewing machine, which can not only reduce the thickness of seam, but also improve the working efficiency.

(2) sew again after sewing.

After the knitted garment is sewn with a wrapped needle, the seam of the seam is not suitable for sticking because it protrudes. At this time, the seam can be covered with stretch stitches. Make the protruding seam fit, but use special needle plate and presser foot to fix the seam, which is easier to control.

(3) Lace sewing process

Because of the width between two or three stitches of stretch sewing, another kind of mesh sewing can cover the seam where the lace tape directly overlaps the cut piece. There is no need to fold the edge of the cut piece to prevent the edge from separating, which can reduce the thickness of the seam and make it more comfortable to wear. For example, women's knitted underwear is often sewn in this way.

(4) hemming and sewing process

In order to reduce the thickness of hemming seam, the edge of clothing is often sewn with hemming stitch first, and then treated with single folding seam or concealed seam, such as skirt hem, trouser legs and cuffs. , which can reduce the curling phenomenon that often occurs in the double-hemming seam at the bending position. However, this treatment needs to be completed in two processes: sewing after sewing. If the styles of the clothes match, 406 (two stitches and three stitches) can be used to make the single edge of the clothes tight. The two processes are combined into one to improve production efficiency.

(5) sewing on the elastic fabric

Because the elastic stitch is very elastic, it is especially suitable for sewing knitted fabrics or other elastic fabrics, such as knitted T-shirts and underwear. In addition, sewing thread can be wrapped into a net with decorative thread, which is both decorative and knitting &; ......& gt& gt

Question 8: If the cladding seam is flat seam, is it also flat seam? Hasu line

Cover seam edge seam

Question 9: Why can't the sewing machine lock the edge? Sewing machines (sewing machines) are generally used to sew fabrics up and down. Take more straight lines. Nowadays, multifunctional sewing machines have many decorative stitches. If equipped with sewing presser foot, simple sewing function can be realized through zigzag stitch.

(Professional explanation: A sewing machine is a machine that uses one or more sewing threads to form one or more stitches on sewing materials, so that one or more layers of sewing materials are interwoven or sewn together. The sewing machine can sew cotton, linen, silk, wool, man-made fiber and other fabrics and leather, plastic, paper and other products. The sewing stitch is neat, beautiful, flat and firm, with fast sewing speed and simple use. )

Sewing machines (also known as sewing machines and sewing machines) are used to sew various fabrics. Because most fabrics are easy to fall off after cutting, they need to be locked before being made into finished products to prevent fabrics from falling off.

The sewing machine is most suitable for weaving fabrics mainly made of cotton, polyester and polyester cotton yarn. This kind of fabric is characterized by its soft texture, high elasticity, breathability and sweat absorption, comfortable and casual wear, and rich personality. Knitted fabrics have other characteristics, such as shedding, curling, pilling, etc., so the sewing process of clothing needs special technology, so it is inseparable from sewing machines and flat sewing machines.

Hemming is the edge of sewing cloth. Because the knitted fabric is made of stitches in series, the cut garment edge is easy to fall off, so it is necessary to sew the garment edge first (commonly known as "hemming") and then sew it with a flat sewing machine. Flat sewing machine and overlock sewing machine are the main models for sewing knitted fashion.

The sewing needle is a stitch that is circularly sleeved on the edge of the sewing material by multiple needles. According to the number of stitches that make up the stitch, it is called (single stitch, double stitch ... six stitch sewing). Its characteristic is that it can wrap the edge of sewing material and prevent the edge of fabric from falling off. When the seam is stretched, there can be some mutual transfer between the top line and the bottom line, so the elasticity of the seam is better.

Some sewing machines include a flat sewing function. There is also a separate sewing machine.

Flat seams are mainly used for cuffs and hems (a few necklines) of knitted garments. The front is a straight seam with two or three stitches, and the back is a zigzag chain stitch. Elastic stitch is characterized by high strength, good extensibility and smooth stitch, which can prevent the fabric edge from falling off. Flat seam is often used for edge rolling, collar rolling, edge wrapping, flat seam splicing and trimming, which not only has high strength and elasticity, but also makes the seam smooth.

To sum up:

If you usually use woven (plain, woven) fabrics, sewing machines can basically meet the requirements. The edge of the cloth can be prevented from spreading by crimping. Add a sewing presser foot at most. If you are making clothes, you can consider adding zipper presser foot, sewing presser foot and locking presser foot. If you make household goods, you can consider adding pleating presser foot, embedding rope presser foot, embroidery presser foot and so on.

If you like knitting clothes, then sewing machines are essential. Sewing machine can be temporarily not equipped. You can lock the edge first and then sew it flat. However, when sewing flat, we must pay attention to replacing it with a round head machine needle to prevent needle jumping and damage to the fabric. Of course, it is necessary to adjust the pressure of the thread and the width and length of the stitch.

Question 10: why do I sew a sewing machine with a weight, and I have to sew two stitches and three stitches, that is, the stitches on the hem and sleeves? The sewing machine is finished, and the bottom line is completely loose. After 20 minutes, take out the cloth and you will be skilled. After stopping, turn the handwheel in the normal rotation direction of the machine until the needle bar is at the bottom, then turn the handwheel in the opposite direction until the needle bar is at the top (do not step on the presser foot during this process), and then step on the presser foot to take out the cloth. This is generally not told to others, and there are very few orders. Give points.