Analysis and Solution of Thread Breaking on Heavy Material Double Needle Sewing Machine
In the daily sewing process, whether it is woven or knitted and other garment processing equipment, it is always inevitable that work failures such as broken needles, broken threads, jumpers, wrinkled fabrics, and the thickness of the seam will not go away. It happens very frequently and is tricky to deal with. Therefore, it is necessary to analyze and discuss the problem of thread interruption in the sewing process in the clothing industry.
The problem of thread breakage can be summarized as how to quickly make a correct judgment and take corresponding measures from the specific thread breakage phenomenon, and how to correctly solve the fabric-needle-stitch coordination relationship in different types and scales of sewing operations. Part.
Determine the specific disconnection phenomenon and take corresponding measures
No matter what kind of garment processing machinery, even the commonly used flat sewing machine with relatively simple structure, there are more than ten thread-passing parts (many thread-passing parts of the sewing equipment make the bottom and upper threads change in an orderly manner, and The direction of the thread, the corresponding friction force with a certain degree of relaxation is obtained when the distance of the transmission line is shortened, which is the necessary condition and key to ensure the interweaving of the suture). cause an unnecessary waste.
To put it simply, the broken lines in the sewing process are usually in three shapes of broken ends, namely, straight ends, short hair ends and long hair ends.
3. The broken thread head is in the shape of a long hairy head. Another form of broken thread is that the thread head is in the shape of a long hairy head. It is essentially that the twist of the suture is destroyed during the sewing process, and the stitches that were twisted together are broken first. The bad phenomenon of the last one after the stock is broken again. The reason for this failure is not only due to the wrong selection of the suture rotation, but also due to the unexpectedly large friction resistance caused by various reasons. The upper thread of most sewing equipment (the bottom thread of any sewing equipment has no left or right rotation) adopts left-handed thread. Only a few models, such as the left straight needle of the lock-type double-needle machine and the arch sewing machine (imitation hand sewing machine), must use the right-hand thread as the upper thread before they can be used, because these devices are damaged during operation. The twist of the left-handed thread. For example, the left rotary shuttle of the double-needle machine at this time is very easy to penetrate between the suture strands with damaged twist and cause the third form of thread breakage. If there is no right-handed thread that can be used instead, the solution is to adjust the left hook to be as close to the needle as possible without touching the straight needle when the hook tip hooks the thread, and the hooking phase is guaranteed not to cause jumper faults. Delay as much as possible under the conditions generated. The purpose of this is that the thread bubble formed by the needle is too small and the twist is not easy to be destroyed.
If it is not due to the wrong selection of the rotation direction, the reason is very simple, it is caused by the excessive local friction at the thread-crossing part, but it is more troublesome to eliminate in practice.
First of all, avoid the use of gourd-shaped sutures (exaggeratedly speaking, this kind of thread is seriously uneven in thickness, and frequently alternately appears excessively bloated and approximately transparent, commonly known as "garbage thread"), and then look at the situation of the suture passing through the needle hole of the machine , Usually the diameter of the suture is about 80% of the small diameter of the needle hole of the oval machine. Thick needles and thin threads affect the stability of the bubble formation, resulting in skipping during the sewing process, and sometimes causing two kinds of breakage. The reason for the thread phenomenon; while the thin needle and thick thread directly destroy the twist of the suture at the thread hole, which must be one of the reasons for the three types of thread breakage.
Excluding the above two phenomena, you need to calm down and carefully check each line passing part one by one, whether the line is still smooth when the necessary friction force is obtained, and if it is not smooth enough, what is the cause? Corrosion: Equipment that has not been used for a long time or that is poorly maintained is easy to corrode, and this phenomenon is particularly serious in the relatively humid south of my country. When the suture is dragged over the corroded thread-passing part instead of sliding, the surface finish of the fiber is damaged and the thread is broken. The method of elimination is to carefully remove the rust with sewing machine oil or replace the part.
Burrs or grooves: When burrs or grooves are formed on the surface of the thread-passing parts due to inadvertent scratches or improper use, the integrity of the suture fibers will also be destroyed, resulting in thread breakage. A typical example is the sewing machine pick. The goose-head hook of the thread part, its thread-passing hole will be pulled out a groove by the suture during use, and the thin thread can barely pass through, while the slightly thicker thread is hard pulled by the dragging and grinding. Disconnection is inevitable. The exclusion method is to use a diamond file, fine emery cloth, sand bar or a polishing line with green oil on the surface to polish and slip the injured surface, and if it fails, only replace the parts.
Small local thread clearance: Strictly speaking, sewing equipment has a very fine division of labor in the sewing industry. Without machines, they are adapted to different work contents and divided into different work scopes. If the local thread clearance is small, it is mostly used across the range. equipment. For example, blindly replacing the equipment for processing ordinary sewing materials with thick needles and thick threads will inevitably cause the gap between the machine needle and the presser foot, feed dog, needle plate hole and other thread-passing parts to become smaller, resulting in poor conveyance and thread breakage. It is not recommended to rely on grinding to ensure the working gap, which will cause damage to the parts. It is recommended to replace the corresponding needle positions (ie, feed dogs, needle plates, presser feet, etc.).
Correctly solve the mutual cooperation between sewing materials, needles and sutures
This part of the content is about how to correctly view the mutual cooperation between sewing materials, machine needles and sutures. The cooperative relationship between these three should be to select the corresponding needle according to the characteristics of the sewing material, and then implement the suture on the basis that the type and size of the needle have been basically determined. material to determine the suture, and then consider the appropriate needle problem.
The market prosperity of the garment industry requires a wide range of sewing materials, complete types, novel product styles, and fine processing technology, which puts forward higher requirements for the above three elements.
In terms of sewing materials, in addition to ordinary and easy-to-process medium-thick natural fibers, it also includes thicker (down jackets, bedding, etc.), harder (tarpaulin, denim, etc.), and lighter (nylon, silk, etc.) , Sewing materials with high toughness (all kinds of leather and imitation fur, etc.) with different characteristics, in order to effectively avoid the work failure caused by the thickness of the seam, the wrinkling of the fabric, the wire drawing, the jumper, the broken thread, etc. Reasonable configuration of needles after processing equipment will be an important link.
Generally speaking, when processing ordinary sewing materials, you only need to use ordinary needles. At this time, you should pay attention to ensure that the needles will not be distorted when working (distortion will cause broken needles, jumpers, broken threads, etc.) as much as possible. The selection of needles with a small number (that is, the diameter of the working part of the needle) is to ensure the continuous threading and drawing of the sewing material (the integrity of the fiber); the second is to reduce the frictional heat generated between the needle and the sewing material. , so as to avoid the occurrence of disconnection as much as possible.
For chemical fiber fabrics, it is recommended to use SU type super needle for chemical fiber. The surface of the working part of this needle is coated with a layer of Teflon film, or PUS type super needle for chemical fiber with ceramic composite gold plating on the surface of the working part is used. The purpose of the special process treatment is to effectively avoid or reduce the special frictional heat generated during the processing of chemical fiber sewing materials, so as to prevent a series of fiber melting, thread breakage, skip stitches, and fabric breakage caused by needle heat. problem occurs. If the conditions for replacing the special needle are not available at the moment, the suture has to be filled with silicone oil at the passing part of the suture, and the suture coated with silicone oil can cool down the needle in a timely manner.
When processing some thinner and easy-to-spin sewing materials, use a ball-point needle with a spherical needle.
When processing tougher sewing materials such as leather, special-type leather needles such as diamond, triangle, and olive-shaped needle blades are selected to reduce frictional resistance during the sewing process and ensure the straightness of the needle during operation. Effectively avoid broken needle, jumper, disconnection and other accidents.
When processing thick and hard sewing materials such as tarpaulin and denim, HS needles (high-speed needles) can be considered. Compared with ordinary needles, HS needles are designed to reduce the friction of the fabric by the shape of the enlarged needle hole and the thinned part of the needle bar. The surface of the needle is specially treated so that the fibers melted by heat do not adhere to the needle.
sewing machine,Thick material machine