Determination of setting time and heat source performance
During the working process of the stenter setting machine, its temperature is the main factor that affects the quality of heat setting. During operation, after the fabric is heat set, the original wrinkles are eliminated and the surface smoothness is improved. The dimensional thermal stability and other wearing properties of fabrics are closely related to the heat setting temperature.
The setting time of the stenter setting machine is another main process condition for heat setting. After the fabric enters the heating zone, the time required for heating and setting can be roughly divided into the following parts:
1. Heating time: After the fabric enters the heating zone, the time required to heat the fabric surface to the setting temperature.
2. Heat penetration time: After the fabric surface reaches the setting temperature, the heat penetration time required for the fibers inside and outside the fabric to have the same setting temperature.
3. Molecular adjustment time: After the fabric reaches the setting temperature, the time required for the molecules in the fiber to adjust according to the setting conditions.
4. Cooling time: The time required for the fabric to come out of the drying room and stabilize the size of the fabric for cooling.
The setting time usually referred to by the stenter setting machine often refers to the time required for the first three items, excluding the fourth item to a certain extent. If one item is regarded as a preheating effect, then the setting time only refers to the time required for the second and third items, that is, the time required for heat penetration and molecular adjustment.
The time required for heating and heat penetration depends on the performance of the heat source, the weight of the fabric per unit area, the thermal conductivity of the fiber and the moisture content of the fabric. The tension on the fabric during the heat setting process has a certain impact on the setting quality, including the dimensional thermal stability, strength and breaking elongation of the fabric.
The thermal stability of the warp direction increases with the increase of the warp overfeed during shaping, while the thermal stability of the weft direction decreases with the increase of the width stretching degree.
The average single yarn strength of the fabric after shaping is slightly higher than that of the unshaped fabric, and the change in the weft direction is more obvious than that in the warp direction.
The elongation at break of the fabric after setting decreases in the weft direction as the stretch degree increases, while in the warp direction it increases as the overfeed increases.
Analysis on control of shaping process conditions of shaping machine
In the process of using the stenter setting machine, the quality of the cloth can be further improved through soft processing to make it meet customer requirements. In addition, it can also make it less likely to be scratched on the cloth guide wheel; in addition, the use of tenter setting machine equipment can also help to keep the fabric surface flat and dimensionally stable, and can also eliminate wrinkles and creases formed during the dyeing and finishing process. .
It should be noted that in order to achieve such an ideal effect, during the operation of the stenter setting machine equipment, it is necessary to reasonably formulate suitable setting process conditions.
First of all, the setting temperature is generally determined by referring to the elastic shrinkage and thickness of the fabric. If the set temperature is too high, the strength will decrease, the elasticity will decrease, and the fabric may change color. On the contrary, if the temperature is too low, it will cause the fabric to curl, the width to be unstable, and the shrinkage rate to be large.
The second is to reasonably control the speed of the tenter and setting machine equipment. Normally, its running speed mainly depends on the length of the setting area and the setting temperature. If the speed is too fast, the styling effect will be affected, and fine wrinkles may not be removed during the dyeing and finishing process. On the contrary, if the vehicle speed is slow and the temperature is high, it may cause the fabric to turn yellow and reduce its elasticity.
In addition to the above two conditions, another process parameter that needs to be reasonably controlled is the overfeeding of the stenter setting machine equipment. Generally, after determining the fabric width, you also need to set the appropriate overfeed amount and tension.
It should be noted that during the operation of the stenter setting machine equipment, the selection of this parameter will affect the weight, elasticity, and wrinkles of the fabric surface. For example, if the fabric tension is small, the overfeed is large, and the cloth surface is uneven, it will be difficult to eliminate the fine wrinkles produced by the fabric during the dyeing process. On the contrary, high tension and small overfeeding amount will cause curling during heat setting.
Common quality problems in post-processing of setting machines
The stenter setting machine is very important for the post-processing of textile products. However, there are some common problems during use.
Frequently Asked Questions 1: The fabric produced by the stenter setting machine is contaminated with color or oil stains or color stains.
To solve this problem, the recommended correct steps are:
1. Turn off the stenter setting machine and check whether there is this problem before production;
2. If it is found that there is one, it can only be worked after the consent of the shift leader. If there is none originally, issues that should be paid attention to include: whether the cloth has been dyed before.The latter is a finished product that is easy to color; whether there are cloth strips on the needle board; whether there is oil on each support rod before entering the oven; whether the chemical materials are uniform during whitening or pad dyeing, etc., and handle it according to the actual situation.
FAQ 2: There are scratches on the fabric coming out of the stenter setting machine.
For this problem, you should first check whether there has been such a problem before. If so, you need to get the consent of the shift leader before starting work. If there is no such problem, you should check whether the front cloth of the machine has been rubbed against hard objects or the rollers are damaged. Burrs, whether the edge holder wheel is pressed too tightly, all of the above will cause scratches on the cloth coming out of the stenter setting machine, and must be adjusted before starting work.
Frequently Asked Question 3: The fabric coming out of the stenter setting machine has a moon-curved shape and the needles are missing, and there are dead wrinkles when rolling.
In the same way, first check whether there are any such problems before, and if so, you can proceed with the work after obtaining consent. If it is not there originally, you need to check whether the needle feeding on the machine is normal. Overfeeding may cause the needle to come off, the edge brush is bad, the edge wheel is too high, the pressure is not adjusted properly, the needle or needle plate is not aligned, and the cloth is not fed properly. Curling, the above will cause problems such as needle loss or curling when the tenter setting machine comes out of the fabric, and it must be repaired before it can start working.
Frequently Asked Question 4: The tenter and setting machine produces selvedge snagging.
For this problem, it is recommended that the correct operation method is: first check whether the needle surface of the needle plate is normal and whether there are any traces of scratches. If the brush bristles fall out, it will directly affect the needle surface and cause the needle tip to become hairy. As a result, the stenter setting machine has a problem of snagging on the edges of the fabric coming out, and it needs to be replaced before it can work.
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