How to cut jeans

First, the work content of the cutting department

The cutting department is the first production department in the garment production process. The work of the cutting department is to cut raw materials such as cloth, lining and lining into the required shapes of clothing, such as front piece, back piece, sleeve piece and collar piece. To sew clothes, you must first cut the pieces of each part. Therefore, cutting is the first process in the garment production process.

The workload of cutting departments in different garment factories may be different, some are very small and some are very large, so the process and specialization of cutting departments are also different. Generally speaking, the cutting department is mainly responsible for the following four tasks:

1. Making and copying layout drawing: When cutting clothes with a piece of cloth, the patterns placed on the cloth should be close together to minimize the gap between them. The main purpose of typesetting is to save cloth as much as possible. Layout is a kind of pattern arrangement diagram, and drawing layout diagram is a process operation of sketching arranged patterns on fabric or paper. Pay attention to the following matters when typesetting: save fabrics, arrange patterns closely together, and improve the utilization rate of fabrics as much as possible;

Pay attention to the grain direction, and the grain arrangement direction should be consistent with the direction required by the process;

Each bed needs a cutting layout.

Copying the layout of the bed can meet the requirements of the same layout when cutting each bed.

2. Cloth pulling or auxiliary materials: the cloth is stacked layer by layer on the cutting machine until the number of layers required by the process is completed. This spreading process is called spreading or spreading.

The following matters should be paid attention to during paving: the paving length and number of layers should be correct;

The selvage should be aligned, and the paving method should be implemented according to the process requirements;

The cloth surface should be flat and try to pull the cloth without tension;

Pay attention to eliminating defective fabrics;

Pay attention to the process requirements of grid transfer belt;

The paving thickness shall not exceed the maximum cutting height of the cutting equipment.

3. Cutting: The following matters should be paid attention to in the cutting process: according to the process requirements and fabric performance, choose cutting equipment and cutting knife type;

Pay attention to the cutting accuracy of clothes and fix the fabric when cutting;

The fixed marks on the cutting piece should be marked, such as the position of the knife eye and the position of the pocket.

4. Bundling: Due to the large number of cut pieces, in order to avoid confusion and mistakes in clothing collocation, the cut pieces should be classified and bundled after cutting.

The steps of sorting and bundling are as follows: arrange the stacked pieces on the cutting machine in turn and divide them into appropriate bundles;

Write down the color, style number, size, quantity and bed times of each cutting piece in detail on the working ticket;

Attach a working ticket to each cutting piece. The work ticket can indicate the situation of each piece of clothing, and also indicate which employee completed the process, so as to facilitate the search. Work standards are cut out and sent to the factory management department, which is also used to calculate wages, which is helpful to control production.

4. 1 The tied clothes can be bundled together and put into the storage basket for transportation.

Second, the industrial structure.

1. Make a pattern

The efficiency and quality of layout are influenced by the paper quality of pattern, the storage of pattern and the preparation of symmetrical pattern.

1) pattern quality? When the pattern is put away, the edge is easy to wear. If the paper is too soft, it is difficult to draw its color along the edge with a pencil or drawing powder. Therefore, for a certain batch of clothing orders, the pattern should be made of high-quality and tough thick paper, and its shape and edges are not easy to wear after repeated use.

2) storage of patterns? The pattern may be damaged or lost if it is not stored properly. Damaged patterns are difficult to control during layout, which affects the quality of cut pieces. If the pattern is lost, the loss will be even greater. In addition to wasting time and material resources, the missed pattern will be re-cut, and the cut piece is likely to be different from the original color, resulting in color difference defects. Formal pattern storage should be to assemble patterns into a set, hang them on the crossbar with hooks, put them in cabinets and lock them in designated pattern storage rooms.

3) Preparation of patterns? Many clothes are symmetrical, such as left sleeve and right sleeve. In order to save time and effort, generally only one symmetrical pattern is prepared, and then the number to be cut is indicated on it, such as 2 or 4 pieces. But for typesetting workers, one piece of cutting and one piece of pattern is the best, otherwise it will increase the difficulty of typesetting and make mistakes easily.

2. Production mode design and material saving

The production pattern is drawn according to the prototype pattern. The prototype pattern is used to sew the sample clothes, and the model puts on the sample clothes to show the customers. After confirming and signing the purchase contract, it is necessary to further modify the sample clothes and make production patterns.

The following four points should be paid attention to in the process of making production samples according to the prototype: the prototype should be made according to the model's figure, and the production samples should be designed and made according to the size standard of the sales area;

The sample garment is mainly sewn by a sample garment sewing worker, while the mass-produced garment is made by division of labor under the operation of the assembly line in the production workshop. The production technology of the two is very different, so the mass-produced technology should be considered in the production of the pattern.

The structural design of sample clothes pattern is not necessarily the most reasonable and material-saving, so the design of production pattern should take into account the saving of fabric on the basis of not changing the style and shape of sample clothes;

The designer wants to change the dividing line of less important parts on the sample garment pattern, so that the fabric can be saved when arranging the production of the pattern.

Although the production mode must be revised, it is necessary to communicate with designers and typesetters to make the fashion design meet the requirements of technology and customers.

Third, the unloading technology and process

Layout, also known as typesetting layout, refers to the design process of a product layout diagram, which is to scientifically arrange all the pieces of various specifications within the specified fabric width under the premise of meeting the design and production requirements, and discharge the material quota with the smallest area or the shortest length. The purpose is to maximize the utilization rate of fabrics, reduce the cost of products, and provide feasible basis for processes such as material laying and cutting.

Because industrial layout is aimed at mass production of clothing, it is an important process in clothing production, with high technical content. According to the appearance characteristics of clothing, it ensures the specifications and quality of cut pieces and saves raw materials. Typesetting process designers must make reasonable typesetting under the guidance of certain theoretical basis and combined with practical experience and technology.

Looking at the layout technology, it mainly includes the following aspects:

1. Circuit board layout technology

In any typesetting case, samples must be drawn according to the size of the samples, because the samples made by the sample engineering department have undergone strict inspection and audit. Among them, various factors that may affect specifications and dimensions, including shrinkage and seams, have been carefully considered, which is the main basis of industrial drawing. Therefore, the shape and specifications of the drawings should be consistent with the intention of sample making.

2. Symmetrical layout technology of garment pieces

The pieces that make up a garment are basically symmetrical, such as the left and right front pieces, sleeve pieces and cap pieces of a coat. Hat shop, left and right pants. When making patterns, these symmetrical pieces usually draw only one pattern. Pay special attention to the front and back of a sample when laying out, so as to ensure that the cut piece is symmetrical. And pay attention to avoid leakage.

3. Precise line technology

Clothes should be close to each other. Without affecting the specifications and cutting quality, sometimes two pieces can share a line (usually a straight line), and cutting with one knife can save drawing a line and cutting a line, thus improving the efficiency of discharging and cutting cloth.

4. Nesting and drawing technology

Make full use of the shape of the pattern and the width of the fabric to arrange the pattern reasonably, thus saving materials and reducing costs.

The patterns of the garment pieces are large and small, and the edge shapes are different, including straight, oblique, square, round, concave, convex, long and short. When typesetting, the details should be arranged first, and then the samples should be arranged later, so that the gap between large samples can be fully utilized and small samples can be discharged; Secondly, when discharging, the straight edge of the template should be aligned with the straight edge, the bevel edge should be aligned with the bevel edge, and the flange should be aligned with the notch, so that the templates can be closely arranged with each other to reduce gaps; Thirdly, if the templates can't be closely nested and gaps inevitably appear, the gaps of the two templates can be merged to increase the gap, and then discharged into other small templates in the gap; Fourthly, the size and specifications of the garment pieces can match the layout, and they can "learn from each other's strengths" to effectively improve the utilization rate of fabrics.

5. Fabric texture orientation technology

Many fabrics, such as woven fabrics and knitted fabrics, have different properties in warp, weft and diagonal directions. Generally, the warp tensile deformation is small, the weft tensile deformation is large, and the diagonal direction is large. Different clothing styles or clothing parts can be divided into straight materials, horizontal materials and oblique materials according to design requirements and dress comfort requirements. Therefore, in the clothing pattern, each piece of clothing must indicate the warp direction, so that the layout personnel can have a clear technical basis.

When making patterns, the warp and weft directions must be accurate. Before making a pattern, the warp, weft and diagonal directions specified in the pattern must be clearly determined. The yarn direction of the pattern is related to the product structure and surface shape. Therefore, no matter how the pattern is drawn, you can't change the warp, weft and diagonal directions at will.

6. The principle of fabric appearance effect

The appearance effect here refers to the visual aesthetic requirements when fabrics are made into clothing. When discharging, there are usually the following situations that affect the visual beauty.

1) Plush fabric? This kind of fabric generally has piles arranged in the warp direction, which is called "reverse pile". When you look at this fabric from different angles, its color and brightness are different, and the touch in different directions is also different. Pay attention to the consistency of front and back pieces, sleeves, placket, pockets, collars and other plush directions. Otherwise, there will be differences in color and light, which will affect the visual beauty.

When designing the pattern planning process on the fabric with inverted hair, we must first make clear the direction of inverted hair, the length and degree of inverted hair and the specific requirements of customer units, and then we can determine the direction of pattern drawing. For example, the fluff of corduroy fabric is very short, so in order to make the color of the product smooth, inverted wool (inverted wool) is often used. Some fabrics have long fluff, such as rabbit hair and artificial fur. If the fluff is upside down, dust will easily accumulate in the fluff gap, which will affect the appearance because of uneven hair direction. Therefore, for fabrics with long fluff, it is necessary to follow the wool.

2) Layout technology of reverse weave fabric The patterns on the surface of clothing fabric can be divided into two categories, one is irregular and directionless, and the layout is basically the same as that of plain weave fabric. Another kind of regular and directional flower patterns, such as inverted flowers, yin and yang squares, group flowers, etc., should be considered in the layout. First, the inverted relationship between figures, animals, flowers and still life in flower patterns should conform to people's visual habits; The second is to arrange the position of the pattern in the template according to the design requirements, and whether the pattern needs to be biased to one side or centered in the template for other changes. The layout should be coordinated and implemented to achieve the design intent.

3) Layout technology of strip and grid fabrics? The purpose of choosing striped fabrics for clothing is to look good. In order to achieve this goal, the connection parts of clothing must be aligned as required when discharging. If you scribble at will, regardless of the symmetry and overlap of the strips, it will destroy the appearance of the clothes. High-end clothing has strict requirements for stripes and squares.

There are two common methods to align strips and grids. One is to put the paper on the plaid cloth to expose the plaid flowers of the cloth and align the strips with the plaid. This is called the layout method. For this layout method, the method of laying lattice must be adopted when laying materials, which is generally used for mass-produced clothing. Another layout method is to align one of the strips with the grid, and the other is to enlarge the circular grid. After cutting the slice with a knife, the grid is cut symmetrically, which is called overlapping grid re-cutting method. Although this method has high precision, it is labor-consuming and time-consuming, and is generally used for the layout of high-end clothing.

7. When discharging, we should also pay attention to the following aspects.

1) Obtain accurate data during layout, such as manufacturing list, finished product sample, clothing sample, fabric width, cutting scheme, etc.

2) The total width of the layout should be 25px higher than the lower cloth edge and 1.5~50px higher than the upper cloth edge, so as to prevent the layout from being wider than the fabric, and at the same time avoid the inaccurate cutting caused by the thick cloth edge;

3) At the beginning and end of the layout, the layout of each pattern should be flush, and both ends of the layout diagram should be marked with the cloth head line and the end line perpendicular to the cloth edge to ensure that the layout diagram is square;

4) After layout, check whether the layout drawing is aligned according to the requirements of the sample, and whether each garment is marked with process marks such as specification, warp direction, cutting and nailing;

5) At one end of the layout diagram, the order number, model, size, number of pieces, fabric utilization rate, length and width of the layout diagram should be marked for verification.

At present, computer technology has been successfully applied in textile and garment industry, and CAD typesetting technology is also widely used in garment production. The main purpose of using CAD is to improve the productivity and flexibility in the layout process. However, only by mastering the basic knowledge of typesetting and following certain typesetting technical principles can the important role of typesetting be better reflected under different production conditions.

Fourth, the method and technology of cloth drawing

Rab refers to unfolding. According to the number and length of cloth drawing specified in the cutting distribution plan, the fabric is laid on the cutting machine layer by layer. Cloth pulling requires that the two ends of the cloth are vertical, the edge of the cloth is aligned with the edge of the cloth, and the cloth should be flat.

Drawing method can be divided into two categories: general drawing method and folding drawing method.

1. General method of drawing cloth

1) cloth face to cloth bottom (the hairiness direction is the same)? As shown in figure 5- 1, it is also called one-way pavement in the same direction.

Figure 5- 1? The cloth surface faces the bottom of the cloth (the hairiness direction is the same)

2) The cloth faces the cloth (the hairiness direction is the same)? As shown in Figure 5-2, it is also called one-way double-sided paving.

Figure 5-2? Cloth face to cloth face (same hairiness direction)

3) cloth to cloth (the hairiness direction is inconsistent)? As shown in Figure 5-3, it is also called bidirectional double-sided paving.

Figure 5-3? Cloth face to cloth face (inconsistent hairiness direction)

4) The cloth faces the bottom of the cloth (the hairiness direction is inconsistent)? As shown in Figure 5-4, it is also called two-way one-sided paving.

Figure 5-4? The cloth faces the bottom of the cloth (the hairiness direction is inconsistent)

When pulling cloth, you can use manual, semi-mechanical or automatic cloth spreader. The basic process of pulling a layer is as follows:

(1) Pull out the fabric with the required length from the cloth bag;

(2) overlapping the end of the fabric with the marks at the end of the upper row of plates on the cutting machine neatly;

(3) fixing the position of the end of the fabric with an iron or other tools;

(4) Straighten the fabric so that one edge of the fabric is aligned with the edge of the whole stack of fabrics to prevent the fabric from wrinkling or excessive tension;

(5) cut this cloth from the cloth, also called cutting;

⑥ The other end of the cut fabric should be stacked neatly with the opening mark of the row board on the cutting machine, and its position should be fixed with iron.

Repeat the above process until the required number of layers are laid.

The first drawing method is suitable for fabrics with positive hairiness. The second method is suitable for directional pile fabrics such as corduroy, and the friction of these fabrics makes it necessary to lay them face to face. The third way of drawing cloth is suitable for some fabrics without any direction restrictions. The fourth way of drawing cloth is suitable for some non-directional fabrics that cannot be laid on the cloth surface because of friction coefficient.

2. Folding cloth method

This paving method is to fold the fabric along the central warp texture, as shown in Figure 5-5. The middle folding of fabrics is generally carried out in the fabric finishing factory, and sometimes it can also be carried out by the bed cutting department of the garment factory. Plaid and wide striped fabrics are generally painted like this.

Figure 5-5? Folding method

3. Cloth drawing equipment 1) cutting machine

The cutting bed is generally composed of several parts, including a stackable table top, a support frame and steel feet with adjustable height. The structure of the cutting bed can be equipped with a cloth puller, and the table top is kept flat to facilitate cloth pulling and cutting, as shown in Figure 5-6.

Figure 5-6? Cutting bed

The cutting bed of each cloth drawing machine, knife shearing machine and other equipment is equipped with a compressed air device, which can make the multi-layer fabric float and move briskly. The cutting bed equipped with automatic cutting machine (such as CAM) and vacuum hair blowing table can make the fabric layer "rigidly" adsorbed on the table, which is convenient for accurate cutting.

2) Cloth puller

According to the movement mode of the cloth drawing machine, it can be divided into two categories: fixed installation and mobile. The cloth puller is fixedly installed, as shown in Figure 5-7. This cloth puller is simple in structure and suitable for small garment factories. The moving cloth puller holds it down.

Figure 5-7? Cloth drawing machine

The degree of automation is divided into two forms: one is manual cloth drawing machine; The other is semi-automatic and automatic cloth drawing machine.

Manual cloth puller and automatic cloth puller:

1 bracket? Used for placing fabric packaging.

Track 2? Installed on both sides of the cutting bed, the pulley of the bracket can move on it.

3 crossbar? Support fabric packaging.

(4) Auxiliary devices? Take the fabric out of the package.

⑤ fixture? Fix the end of the cloth in place.

The structure of the automatic moving cloth puller is complex, and the computer-controlled cloth puller can automatically complete the above four kinds of cloth pulling forms, and each layer of material is laid neatly, so that it can be laid completely without tension. Its components mainly include the following equipment:

(1) Walking device: the driving device for automatically moving the packaging support on the cutting machine. The moving speed does not need to be adjusted, and the walking speed can be automatically changed according to the tension during the cloth drawing process, including no speed regulator and fabric tension sensor.

② Cloth pulling mode control device: The cloth pulling machine can preset any one of the above four cloth pulling modes and automatically complete the cloth pulling mode after starting. Comprise a supporting turntable, a cutting machine and that like.

③ Automatic counting device: record and display the number of layers and laying length of cloth, and control according to the set laying length and number of layers.

(4) Positioning device: an alignment device used to stack the edges of each layer of cloth neatly, and it also has the function of aligning cloth strips.

⑤ Packaging loading and unloading device: automatic loading and unloading of cloth.

⑥ Air cushion paving table: There are many compressed air holes on the paving table, and the paved fabric layer can be gently moved to the cutting table on the compressed air cushion ejected from the holes, forming a cloth drawing and cutting assembly line.

V. Cutting technology

According to the shape of the paper on the cardboard, the whole bed cloth is cut along the pattern shape with a cutting machine, which becomes the cutting piece needed by the clothing.

1. Cutting equipment

Figure 5-8? Straight cutter

1) straight cutter? A straight cutter is used to cut cloth. It is operated by hand and the cutter is vertical.

Do reciprocating motion to cut cloth. Suitable for cutting multi-layer fabrics, as well as bends and angles. Straight knife type

Cutting machine is the most commonly used cutting tool in cutting workshop. As shown in figure 5-8.

Advantages of this cutting machine:

(1) The production efficiency is high, and multiple layers of fabrics can be cut at one time;

(2) strong adaptability, can be used for various fabrics, and can meet the requirements of general precision cutting;

③ Easy to operate and carry.

Disadvantages of this cutting machine:

① The fabric fixing is not ideal, and the cutting accuracy is not high;

(2) Especially for small pieces, the cutter has a certain width, so it is difficult to cut a circular arc with large curvature;

(3) Top-heavy structure, thin fuselage and easy deformation of scabbard bracket, which affects the cutting accuracy.

In order to improve the operability of the straight cutter, the cantilever cutter is suitable for garment factories with high output, as shown in Figure 5-9. The cantilever system bears the weight of the whole direct cutting machine. The base of the straight cutter can be designed to be very thin, the width of the cutter is narrow, and the verticality of the blade is good. It can also adapt to the cutting parts with high cutting rate, improve the cutting accuracy, and save labor when the operator refreshes.

Figure 5-9? Cantilever cutting machine

2) Circular cutter? It is also a portable cutting machine, equipped with a circular cutting knife, as shown in Figure 5- 10.

Show. When the cutter cuts the cloth, the cutter rotates counterclockwise. It is generally used to cut clothes along a straight line, and some sharp bends can be cut under the condition of less cloth. It is often used in the sample room of general garment factories. The round knife is used in the sample room, mainly replacing scissors, which is rarely used in China.

The characteristics of the circular knife are: the cutting width increases with the increase of paving layers, and the cutting point of each layer of material has time difference, so it can be cut like scissors when the material is single layer or less; When multilayer, the width of the cutter increases, the cutting line is ideal, the bending position and angle position are not ideal, and the fabric fracture is neat and beautiful. It is also flexible and convenient to operate, like a straight knife cutter, but the cloth fixation is not ideal and the cutting accuracy is not high.

3) Knife cutting machine? The cutting knife of the knife-type cutting machine is belt-shaped, and when cutting, the belt-shaped cutting knife rotates counterclockwise. The operator picks up the fabric layer by hand so that the blade can cut along the mark of the pattern. Because the blade is very

Figure 5- 10? circular cutter

Narrow and vertical, so it can accurately cut high-quality workpieces, especially small workpieces with circular arcs, as shown in Figure 5- 1 1.

Figure 5- 1 1? Straight plow blade

Knives with knives are expensive and bulky, and need to be fixed in a certain position in the cutting workshop, occupying a lot of land, which is more suitable for large and medium-sized garment factories. Knife cutting machine can not directly cut the whole piece of Guangdong cloth laid on the cutting bed, so this cutting process is called secondary cutting.

4) Knife die? Knife die is used for punching and cutting. The mold is placed on the fabric layer, and the cut pieces are formed by the pressure of the punching machine. The cutting piece is very precise, and it is often used for small cutting pieces, such as collars, clothes, covers, lips and so on. The mold is made of metal and has a sharp blade. Figure 5- 12 shows some cutter dies. The manufacture of the die is complicated, the price is high, and the sharpening of the cutting edge is also difficult. Commonly used in large-scale production occasions, the style is stable.

5) drilling machine? Drilling machine is a kind of cutting tool, which is used to mark pockets, pleats and other positions. It is a common positioning tool for garment factories, as shown in Figure 5- 13.

6) hair hot stamping machine? Hair hot stamping device is an auxiliary positioning and marking device for cutting, which is used to mark the edges of natural fibers and knitted fabrics. These marks are used to show joint size and pleats.

Figure 5- 12? Kopis

Figure 5- 13? driller

Location, etc. A very thin blade is mounted on the cloth marking device. When the blade is heated to a proper temperature, a straight cut can be burned on the edge of the clothes. As shown in figure 5- 14.

Figure 5- 14? Thermal cutting device

7) Computer cutting machine? Computer cutting machine is a kind of cutting equipment under the computer grading and drawing typesetting system, also called CAM system, that is, computer aided manufacturing system. The movement of the cutter parts is directly controlled by the computer. The computer sends a signal to the cutting part, and the cutting knife part cuts out the required clothes according to the discharging data recorded in the computer memory.