First, the purpose of shearing wool
After weaving, untwisting or napping, the pile fibers on the surface of pile fabric have different lengths, and sometimes it is necessary to cut the pile flat. Or knitting terry fabric needs to cut the surface terry neatly, which is the purpose of shearing machine. The shearing process can generally be divided into pre-shearing, final-shearing and fancy-shearing. Pre-shearing can reduce the pressure of primary shearing on final shearing and ensure the quality of final shearing. Flower scissors are used to cut suede into desired patterns, mainly depending on the type of knives.
Second, the general structure of shearing machine
Tension roller (cloth tightener): located at the front end of the machine, it controls the tension of the fabric by adjusting the wrapping angle between the roller body and the fabric.
Brush device: The fabric passes through the brush before shearing, which can remove the floating fibers and sundries on the surface, pull out the hidden fluff fibers, straighten out the fluff direction, and be beneficial to shearing the fluff flat. Generally, it can be divided into bristles or nylon soft brushes and wire brushes for brushing clothes. Soft brush has a soft effect and steel wire brush has a strong effect. According to the technological requirements of the fabric.
Ironing roller: the fiber is ironed under hot pressure, and the curled part is initially stretched, which straightens the plush direction and is beneficial to shearing.
Beating roller: generally wing-shaped, it is used to beat and loosen the fabric suede and remove debris. But the strength is weak, and it is impossible to untie or comb the fluff.
Unwinding roller (unwinding roller): generally, there are thread unwinding plate, thread unwinding roller, bending roller unwinding device, telescopic plate unwinding device, conical roller unwinding device, etc. Thread expanding rollers (active or passive, front expanding or rear expanding) are commonly used in shearing machines, which are made of turning and winding. Due to the relative sliding between the roller surface and the fabric surface, the yarn nozzle produces the weft component of friction on the fabric. The factors that affect the expansion efficiency are: warp tension of fabric; Surface relative linear velocity; Angle size; Fabric texture characteristics; Thread cross-sectional shape, helix angle size (generally 15. ), lead (generally 24~48mm), etc.
Cloth guide roller: generally, there is a guide roller (behind the cutting area) to determine the fabric speed, and the speed difference between the guide roller and the brake roller (in front of the cutting area) can adjust the fabric tension in the cutting area.
Spiral round knives and flat knives: high hardness, good dynamic balance, roundness and straightness, sharp cutting, proper positive pressure, good surface smoothness and lubrication, straight warp of round knives (commonly used Ф148, Ф185) and number of knives (commonly used 20, 24), and the shearing efficiency can use the number of scissors per unit length.
N (times/cm) = [rotary speed of circular knife r/min x number of blades]/[cloth speed m/min x 100]
It can be seen that the more the number of blades, the higher the efficiency, but a certain blade spacing (20~45mm) is conducive to fiber entering the cutting nozzle and dust removal, reducing the friction between the two blades. With the increase of straight warp, the relative speed of the two knives increases, which is beneficial to shearing, but the friction between the two knives intensifies. Because the circular blade and the flat blade form an inclination angle, the shear force can be decomposed into tangential effective force and axial sliding force. The file marks on the tool holder can effectively prevent the fiber from sliding axially. The choice of file thickness (number of teeth per cm) is related to the kind of fabric to be cut and the technological requirements. Generally speaking, the finer the teeth, the better the smoothness of cutting fluff, and it is more suitable for cutting soft fluff. The choice of flat knife is related to the raw material characteristics of the cut fabric, which requires high straightness, good elastic recovery and wear resistance (the knife edge is not easy to anneal and soften). (See attached table for selection). In addition to the selection, the grinding and grinding of the two knives are very important. We must strictly follow the process regulations to ensure the quality. The flat tool rest should have high rigidity and will not vibrate when starting.
Knife holder (tweed holder): Make the cut fabric run to the corner of the tip of the knife holder to make a sharp turn, and the tension of the inner and outer layers changes, so that the fluff fibers can enter the knife edge vertically, which is convenient for fixed-length cutting. It requires higher straightness, adjustable parallelism with the blade and better wear resistance. At present, we have three kinds of tool holders with different cross-sectional shapes to choose from to adapt to different kinds of fabrics (see attached table for selection). Besides the shape of the cutting edge, other structural forms can also change the shearing effect and style. For example, some design airflow channels in the tool rest, and high-pressure airflow blows out under the cloth when it passes, so that the fluff stands up for shearing; Some design the tool rest into different units that can control the height and cut out suede with different patterns.
Suction: install a dust hood at the cutting opening, mainly to suck away the cutting debris; At the same time, the negative pressure cavity formed by inhalation makes the linoleum fit the circular knife better, which is beneficial to uniform lubrication; The fast flowing airflow is beneficial to the cooling of the blade. Because the high-speed rotation of the circular knife will drive the surrounding airflow, it will have a certain blowing effect on the fluff fibers, so that the fluff will lie flat or stay away from the incision and cannot be cut flat. Strong air suction can eliminate or balance this blowing effect, making the fluff stand up and enter the knife edge. While ensuring the sufficient power of the suction fan, we should also pay attention to avoid the linoleum from generating too high friction resistance to the circular knife. When designing the shape of the dust hood, we should also consider the different axial airflow directions caused by the different left and right directions of the spiral knife.
Linoleum: Due to the close contact and high-speed sliding friction between the round knife and the flat knife, if the lubrication is not good, the cutting edge will produce high temperature, which will aggravate the wear and even anneal and soften. Stick an oil-soaked felt (usually wool felt with good oil absorption) on the surface of the circular knife, and you need to stick the whole tangent. Its functions are: providing lubricating oil for the round knife continuously, forming a vacuum suction cavity, cooling the knife edge, damping and so on. There are also certain requirements for the viscosity of lubricating oil, and it is generally recommended to use 20~30 mechanical oil.
Metal detector: it is used to detect metal inclusions on the whole width of the fabric before the shearing area to protect the shearing knife. Advanced products can show the location of metal, which is easy to find and reduces downtime.
Seam detector: When the seam thickness of the fabric suddenly increases, the detector will give an alarm to remind the operator to lift the knife and let the fabric seam protect the scissors. Or automatically lift the knife, but control the length of the cloth to reduce waste.
Electric edge suction device (open width cloth guide) (optional): prevent the fabric from shifting and curling left and right.
Centering device (optional): prevent the fabric from moving left and right.
Static eliminator (optional): Eliminate static electricity carried by fabric.
Third, the shearing process.
Different varieties and styles of fabrics need different processing techniques. For example:
Flat cutting: the fabric should be pre-cut, then sized and ironed, and finally finely cut. Products require smooth suede, straight and loose fluff, good luster and feel. Due to the hot light, the fluff fiber can be curled and stretched in dry heat, and the height of pre-cutting is lower than that of final cutting by 1~2mm, which can reduce the load and keep the fluff luster.
Fur-like plush (plush): It is required that the suede has a good sense of layering, the surface and middle bristles are flush, and the bottom fluff has a shrinking layer. Pre-cutting needs to cut all levels of wool flat, and there will be shrinkage of native sheep wool during sizing and setting. After ironing, the fibers whose surface does not shrink will be stretched and straightened, and will be cut flat after fine shearing. In this way, the plush layering effect of natural fur can be achieved.
Imitation of lamb hair: general products are pilled directly after pre-cutting or sizing. The size of wool balls is influenced by shear height and fabric thickness. When the height of wool is constant, the pilling of heavy fabric is smaller, while the pilling of light fabric is larger.
Velvet knitted fabric: Knitted terry fabric is sheared to form longitudinal fluff on the surface, and grey fabric is generally washed (or dyed and dehydrated) and evaporated before shearing. The fabric base yarn has good heat shrinkage and high strength; Terry generally uses cotton yarn, blended yarn, rayon or polyester yarn according to the wearing requirements, with low and uniform twist, weaving height of 2.5 ~ 3. 1 mm, and shearing is generally done twice.
Besides the rationality of the adopted technological process, the factors that affect the final shearing effect of fabrics are also the manufacturing quality and operation adjustment methods of the shearing machine itself, among which the selection of the shearing knife and the supporting knife and the sharpening adjustment are particularly important (see the relevant operation regulations for details). And:
Influence of pile direction: the different weaving States of the fabric determine that the pile has certain directionality. Plush is cut by the upward machine, and the fibers are easy to bundle and ripple after cutting. Reverse shearing on the machine will loosen the fibers, and the suede will be smooth after shearing.
Influence of fabric: The thicker the plush, the greater the shear load and the more difficult it is to shear. The thicker the fluff fiber, the better its rigidity and the easier it is to shear. The finer the fiber, the less rigid it is, and it is not easy to stand upright and disperse, and the suede is not easy to cut flat.
Walking shear: In order to prevent the fixed wear of the round knife and the flat knife, protect the cutting edge and improve the use efficiency, sometimes the round knife will walk horizontally when shearing.
Knife adjustment: generally, the cut of the cutting knife is above the supporting blade, where the vertical effect of fluff is the best, and the distance between them determines the cutting height; For fabrics whose fluff is not easy to stand up, our experience is to move the blade behind the supporting blade and bring the fluff into the cut by the rotation of the circular blade. The distance between the cutting opening and the supporting blade determines the cutting height.
Brief introduction of main shears produced by Haining Textile Machinery Factory
Since the enterprises switched to textile machinery in 1970s, relying on their own efforts and combined with the technical support provided by Shanghai No.4 Textile Machinery, N044 and ME506 single-blade shears were first developed. Subsequently, according to the market demand, a series of single-blade shearing machines for breeding such as MB373, ME503, ME504, ME505, ME503C, ME508, MB373B, ME509, ME509A, ME5 10 were developed one after another, which met some market demands and brought certain economic benefits to enterprises.
1.1 MB 373 single-blade shearing machine
Development time: 1989
Main parameters: width:1800; , 2200mm
Cloth speed: 7 ~ 3 1 m/min (stepless)
Spiral cutter: diameter 148, number of blades 20, rotating speed 750(800), 1000 r/min.
Recommended use: used for wool and worsted fabrics, and also used for shearing fabrics. It can be used to knit terry and pile fabrics after adding expansion roller parts. After replacing the brush roller parts (covered with metal bristle cloth), it has the function of grasping and shearing.
Main features: the spiral cutter is driven by a single motor, with two stages, a transverse device and a moving range of 10mm, which can be used for on-machine grinding. The fabric speed is adjusted by P Ⅳ CVT, and the tension is adjusted by the variable-pitch pulley (the speed difference between the paper guide roller and the brake roller). Tool rest can be replaced (round head, small platform, double platform).
3. me 503c single-blade shearing machine (improved)
Development time: 2009
Main parameters: width:1800; , 2200mm
Cloth speed: 5 ~ 35m/min (stepless)
Spiral cutter: diameter 180, number of blades 24, speed 250- 1200 stepless.
Recommended use: used for shearing and other knitted velvet fabrics (with two expansion rollers). After replacing the expanding roller (first gear), it can be used for wool and worsted fabrics, cotton fabrics and plush.
Main features: the speed and distribution speed of the spiral knife are stepless regulated by frequency converter. The spiral knife is equipped with a traverse device with a stroke of 16mm, which can be ground on the machine. Fabric tension is adjusted by variable pitch pulley (speed difference between guide roller and brake roller). Tool rest can be replaced (round head, flat head, double platform).
3. 3. MB 373b single-blade shearing machine
Development time: 2006
Main parameters: width:1800; , 2200mm
Cloth speed: 7 ~ 3 1 m/min (stepless)
Spiral cutter: diameter 148, number of blades 20, rotating speed 290, 1000 r/min.
Main features: This machine is an improvement of the original MB373 model, mainly improving the two-stage transmission of spiral knife, transverse device, fabric tension adjustment mechanism, seam detection device, electrical control and appearance. While retaining the applicability of the original MB373 machine, it is more convenient to use and more beautiful in appearance.
3.me 503 b (j) shearing machine
Development time: 2007
Main parameters: width: 2000mm.
Cloth speed: 5 ~ 35m/min (stepless)
Spiral cutter: diameter 180mm, number of blades 24, rotating speed 250~ 1200 r/min (stepless).
Recommended use: it can cut various concave and convex patterns on the surface of velvet fabric, with vivid three-dimensional effect and excellent decorative effect.
Main features: This product is a new shearing machine developed according to the ever-changing styles of shearing fabrics in the market in recent years, which fundamentally breaks the traditional single flat shearing mode. Through the specially designed shearing structure (the organization has applied for patent), users can design patterns according to market requirements or design by themselves, and make a flexible circular pattern bottom plate with concave and convex feeling. Then, the bottom plate is installed on the machine for specific shearing operation, and the suede fabric with the same pattern with concave-convex feeling can be processed. When the bottom plates with different patterns are replaced, the suede fabrics with different patterns can be processed, and the depth of the concave-convex feeling of the patterns can be adjusted according to different fabrics. The machine has the advantages of simple and reliable operation, flexible structural adjustment, high production efficiency and good market prospect.
5. MB 373B single-blade shearing machine (improved)
Development time: 2008
Main parameters: width:1800; , 2200mm
Cloth speed: 4.8 ~ 24; Or 9.6 ~ 48m/min (stepless)
Spiral cutter: diameter 148, number of blades 20, rotating speed 290, 1000 r/min.
Main features: The machine has improved the main drive of MB373B, changing the drive of guide roller (cloth speed) from the original stepless speed regulation of P Ⅳ to the regulation of deceleration motor controlled by frequency converter, and the control panel has knob operation and digital display, which makes its practical use more convenient and intuitive; At the same time, replacing the guide roller sprocket can obtain higher cloth speed, improve applicability and make the appearance more beautiful.
[6] ⒍ME508 single-blade shearing machine
Development time: 2005
Main parameters: width: 2600; , 3200 ; , 3600 mm
Cloth speed: 7 ~ 35m/min (stepless)
Spiral cutter: diameter186,205, number of blades 24, rotating speed 250~ 1200 r/min (stepless).
Main structural features: This machine is a wide shearing machine with the maximum effective working width of 3600mm, which is suitable for shearing wide fabrics. The diameter of spiral cutter reaches φ 186 and φ205, and the number of blades is 24, with high shearing efficiency and good running rigidity. The rotating speed is 250 ~ 1200 rpm, the frequency converter is stepless speed regulation, with transverse motor, and the knife can be sharpened on the machine; Pneumatic tension of conveyor belt makes the tension more stable. Adopt a tool holder that can be quickly replaced. When sewing, the swing tool rest is adopted, which makes the mechanism move more smoothly and avoids the impact and distortion of scissors. The guide roller, guide roller and discharge roller are controlled by frequency converter respectively, which can adjust the cloth speed and fabric tension stepless, and the cloth can be withdrawn by inching in the opposite direction, which is more convenient to operate. The spindle bearing of spiral cutter adopts double-support roller bearing and spherical self-aligning seat, which makes the spiral cutter run more flexibly and improves the dynamic bonding effect between blades. The flat tool rest adopts integral casting, which improves the rigidity and the working inclination angle is about 10, which is convenient for sharpening the knife on the machine. The adjustment of shearing height is driven by a single motor and displayed digitally, making the operation more convenient and intuitive. Combined detection, electroacoustic alarm, manual switch control tool rest clutch, simple and reliable structure. Spiral knife and flat knife are pneumatically engaged and disengaged, with constant pressure and convenient operation. Additional separation protection device makes the operation safer. Users can choose a variety of optional parts to meet different technical requirements.
⒎ME509 and ME509A precision shears
Development time: 2009
Main parameters: width:1800; , 2200mm
Cloth speed: 0 ~ 40m/min (stepless)
Spiral cutter: diameter 160, number of blades 20, rotating speed 200~ 1000 r/min (stepless).
Main structural features: this machine adopts automatic detection and control device for fabric tension in and out, and the fabric tension can be kept constant automatically. The guide roller, the guide roller, the cloth feeding roller and the cloth discharging roller are controlled by the frequency converter and driven independently. The cloth speed can be adjusted steplessly, and the cloth is returned with constant tension in the opposite direction; It can automatically make the cloth seam, and adopts the form of swinging tool rest, which makes the mechanism move more smoothly and improves the shearing quality and stability. Model ME509A is equipped with expansion device, which can be used to cut hemmed fabrics.
Attachment: Selection of Round Knife and Flat Knife
Flat knife
High-performance CV (Hu Ping Knife: made of alloy tool steel, suitable for natural fibers and light fabrics.
Super R4(H4) flat knife: made of high-performance alloy tool steel, with special raw materials and trace elements added. After quenching, the wear resistance and service life are improved. Used for synthetic fibers, such as polyester (polyester), polyamide (nylon yarn) fabrics and car cushions. It is also suitable for plush and carpets blended with natural fibers and synthetic fibers.
Super supra flat knife: made of high-speed steel, it is used for polyester (polyester), polyamide (nylon) fabrics, car cushions and other fabrics with high strength and difficult to cut. Good lubrication is needed. But cutting natural fibers has no advantage.
cutting disc
Selection of file number (tooth number/cm) of concave (elbow) blade;
9 teeth; Suitable for carpets
1 1 tooth; Suitable for velvet
13 teeth (gratifying), 15 teeth (good); Widely used (more than 80%), suitable for velvet, towels, fashion fabrics.
18 tooth; Suitable for very thin rayon and spandex (swimsuit fabric)
22 teeth; Suitable for cashmere and mohair.
Toothless; Suitable for curtain cloth
Type selection:
Novel concave blade
Composite steel blade