1. The technical requirements of the process of laying material
(1)The surface of the fabric should be flat
When laying the material, must make each layer of material are + points flat, the surface of the fabric can not have wrinkles, ripples, distortion and so on. If the fabric is not flat, the cut out parts and the sample will have a large error, which will inevitably cause difficulties for sewing, and will also affect the product design effect.
The characteristics of the fabric itself is the main factor that affects the smoothness of the fabric pavement. For example, if the surface of the fabric has a fleece, the friction between the fabrics is too large, and it is not easy to produce sliding between the fabrics after contact, so it is difficult to spread the fabric. On the contrary, the surface is very smooth, the friction between the fabrics is too small, the lack of stability, easy to slide off, but also difficult to lay flat. Then there are some tissue density is very large, or the surface has the coating of the fabric, its breathable performance is relatively poor, laying material between the air left in the fabric will make the fabric bulge, resulting in surface unevenness. Therefore, it is very important to understand the characteristics of various fabrics and take corresponding operation measures when laying materials. For some fabrics with their own wrinkles, paving material before the necessary finishing means to eliminate the wrinkles of the fabric itself, in order to ensure the quality of paving material.
(2) The edge of the fabric should be flush
When laying the material, make the edge of each layer of material are aligned vertically up and down, there can be no discrepancies. If the edge of the fabric is not aligned, cutting may cause defects of incomplete cutting against the edge, resulting in cutting substandard products or scrap.
As the width of the fabric always has a - a certain degree of error, in the laying, to make both sides of the edge of the fabric can be well aligned is more difficult. Therefore, when laying the material generally to a side of the fabric as a benchmark, usually called the "mouth". When laying material - - must ensure that the edge of the fabric lining up, the maximum error can not exceed the soil 1mm.
(3)Minimize tension
To lay out the pile of fabric, but also to make the surface flat, and to ensure that the edge of the fabric aligned, it is necessary to exert a certain force on the fabric and make the fabric produce - - a certain tension. Due to the role of tension, the fabric will produce elongation and deformation, especially the stretch rate of the fabric is more significant. This deformation will affect the accuracy of cutting, because the fabric in the state of stretch deformation cut out of the piece of material, after a period of time, the deformation will naturally remove and restore the original shape, so that the size of the piece of material reduced, can not maintain the size of the sample. Therefore, when laying the material, we should try to reduce the tension applied to the fabric to prevent the fabric from stretching and deformation.
Volume fabric itself has a certain tension, such as direct laying material will also produce elongation deformation. Therefore, before laying the fabric in rolls, the fabric should be bulked and placed in a relaxed state for 24h before laying.
(4)Keep the direction consistent
For the fabric with directional, laying material should keep the same direction for each layer.
(5)Correct the stripes
For fabrics with stripes, in order to meet the requirements of the product sewing, the stripes of each layer of material should be squared up and down when laying the material. It is not easy to align all the stripes of each layer of fabric, therefore, when laying the fabric, we should cooperate with the material arrangement process and use the positioning pins to align the stripes of these key parts.
(6)The length of paving material should be accurate
The length of laying material should be based on the scribing sample, in principle, should be consistent with the length of the layout. If the length of laying material is not enough, it will cause incomplete cutting parts, causing serious consequences to the production. If the length of laying material is too long, it will cause the fabric to be wasted, offsetting the results of the scheduling process to save efforts. In order to ensure the length of paving and not to cause waste, paving should make the fabric longer than the row of material chart 0.5 ~ 1cm. In addition, should also pay attention to the paving and cutting two processes not too long apart, if the time between too long, due to the retraction of the fabric, will also cause inaccurate paving length.
2. The procedure and method of laying material
(1)Identify the front and back of the fabric and directionality
Before laying material, first of all, should identify the positive and negative side of the fabric and directional, only correctly grasp the positive and negative side of the fabric and directional, in order to correctly lay the material according to the process requirements. The directionality of the fabric, through observation, hand touch and comparison, is generally easier to determine. Some fabrics have obvious differences between the front and back, it is also relatively easy to identify, but some fabrics are not very significant differences between the front and back, such as not carefully identified will be wrong, so before laying material to carefully identify the front and back of the fabric.
(2)Laying way
In actual production, there are two main ways of laying material: one is one-way laying material, the other is two-way laying material.
① One-way pavement: this pavement is the front of each layer of material all facing in one direction (usually more upward). With this way of laying material, the fabric can only be unfolded in one direction, between each layer of fabric to cut, so the efficiency is low. The characteristic of this way is that the direction of each layer of material - consistent, easy to control.
② two-way laying material: this way of laying material is a positive and a negative fabric alternately unfolded, forming each layer between the face and face relative, lining and lining relative state. In this way, the fabric can be continuously unfolded in two directions, and there is no need to cut between each layer, so the efficiency is higher than one-way paving. But this way is characterized by the direction of each layer of material is opposite, easy to cause the error of cutting operation.
In the production, according to the characteristics of the fabric and the requirements of the production of luggage products to decide which kind of laying method. Color plain fabric, because its surface itself does not have directional, positive and negative side also no significant difference, such fabrics can be used in two-way laying way, so that the operation is simplified, improve efficiency. Some fabrics, although divided into positive and negative, but no direction, can also be used in a two-way laying way, so that the row of materials more flexible, conducive to improving the utilization of fabrics. If the fabric itself has the direction, in order to make each product with the material direction of the same - consistent, laying material should take a one-way laying way to ensure that the direction of the fabric consistent. Sewing products need to be on the grid, paving material should also be on the grid, and should take a one-way paving material, otherwise it can not do the effect of the grid.
(3)The connection of fabric
In the process of laying material, each cloth can't finish laying a layer at the end. In order to make full use of the raw material, the cloth needs to be connected in a layer when laying. In what part of the articulation, the articulation length should be how much, this needs to be determined before laying material.
To determine the method is: first draw the material layout on the bed, and then observe the distribution of each cut piece on the chart, find out between the cut pieces in the weft up the less interlaced parts, these parts will be used as the part of the cloth between the articulation. The length of the interlacing between the cut pieces in these parts is the length of the articulation of the cloth when laying the material. After the articulated parts and the articulated length are determined, markings are drawn on the edges of the cutting bed, and then the cutting chart is removed and the laying of the material can begin. Every time you reach the end of a piece of cloth, you must join it with another piece of cloth at the marked place, and if you exceed the mark, you should cut off the excess cloth. The other piece of fabric is overlapped with the previous piece of fabric at the marked joint length, and then the material continues to be laid. The longer the length of the material, the more articulation parts should be selected, in general, every 1m or so on average, one articulation part should be determined.
At present, most of the luggage products mainly rely on manual paving. Manual paving is highly adaptable, no matter what kind of fabric, no matter the length of paving, and no matter what way to pave, manual paving can be well done. However, the labor intensity is high and does not adapt to the requirements of modern production. In order to reduce the labor intensity, on the basis of manual laying some auxiliary equipment, for example, installed in the cutting bed with a track of the fabric carriage, the fabric on it with human push can be unfolded, and then by hand the fabric neatly. Some use electric motors instead of manually pulling the fabric. These auxiliary equipment can effectively reduce labor intensity, improve production efficiency. Now, the bag production has begun to use automatic paving machine for paving operations. This equipment can automatically spread the fabric, automatic alignment of the fabric edge, automatic control of the fabric tension size, automatic cutting fabric, the basic replacement of manual operation, so that the paving material to achieve mechanization, automation. However, the adaptability of automatic paving machine is not as good as manual paving, fabric varieties, performance often changes, affecting the use of the effect. In addition, if the requirements of the laying of materials on the grid, you can not use the laying machine, but also manual laying of materials.
