Cutting Equipment for fabrics
This is the major operation of the cutting room, when the spread fabric is cut into garments. Of all the operations in the cutting room this is the most decisive because once the fabric has been cut, very little can be done to rectify serious mistakes.
Different types of tools and equipment and some of their main features are given below:
Hand Shears are used when cutting samples and limited quantities of garments. The cutter must control the shears keeping the cut edge layer adds to the difficulty of accurate cutting, the patterns are often traced in tailor's chalk on the top layer of fabric. Hand shears are limited to the cutter's physical strength, but usually no more than two layers of fabric due to the loss of accuracy as the shears lifts the fabric off the cutting table. This method is slow and unproductive.
The Short Knife
The Short knife is an alternate method to hand shears. The short knife is still in use in sloping and cutting leather apparel. The short knife slices through the fabric, scoring the table in the process much the same way as slicing vegetables on a cutting board in the kitchen. Fabrics cut this way must be heavily weighted, as the short knife pushes as it cuts through the fabric, distorting multiple layers of fabric. Ten to twelve layers of fabric may be accurately cut this way. Since leather must be cut singly (one layer at a time to facilitate cutting around the natural flaws in each skin), the short knife is used. The short knife is one way that round knife cutters can accurately cut notches in the edge of a taller lay of fabric.
Electric Powered Cutting Machines
Electric powered cutting machines are used most often in mass production of fashion apparel. Capable of cutting through many plies of fabric, these machines are used throughout the world. Cutting machines all have inherent advantages and disadvantages, and the correct choice of machine for the application (use) will yield the best cutting quality. All electric powered cutting machines have some common components. The electric motor is located above the cutting blade. The cutting blade is mounted in a "standard" which supports the blade and the weight of the motor. The base plate holds up the standard, and usually has ball bearing rollers that make it easier for the cutter to move the machine about on the cutting table.
Straight Knife or "Up and Down"
The Straight Knife or "Up and Down" (Vertical Knife) is a machine with a straight vertical blade. Straight knives are available from 3" to 14" tall, capable of cutting lays from 2 ½" to 13 ½" in height. Depending on the density of the fabric, this may represent a wide range of plies. When encountering notches, the straight knife may be used to cut notches by pushing the blade into the notch mark on the patterns above each bundle.
The Round Knife
The round knife utilizes a circular blade that cuts cleanly through fabric much the same way that a circular wood saw cuts through wood. The blade at the cutting-edge rotates down toward the table continuously providing a cleaner cut close to the table surface. The straight knife chops the fabric down close to the table surface. Additional advantages of the round knife are that it can cut without pushing the lay as it cuts, facilitating cutting on slippery fabrics. Continuously slicing downward, it also makes cutting very dense fabrics easier. The disadvantage of the round knife is that at the cutting edge, the blade is not vertical. Therefore, cutting accuracy is sacrificed as the lay get higher. Both round knife and up and down knives are on-table cutting methods.
Die Cutting is an off table cutting method that provides cutting quality close to perfection. Steel rule dies used most often in fashion manufacturing, are made with a wooden form wrapped by a sharpened steel cutting edge. These are less expensive than cast-steel dies. A die is required for every part in every size that must be cut. . In this process, Fabric blocks are included in the marker for the parts to be cut by die. The blocks are shifted off the cutting table. At the cutting machine (known as a "clicker‟), the dies are placed (by size, etc.. as needed.) down on the cloth, and the machine head presses the dies down through the fabric lay. Every part comes out the same exact shape and size when die cut correctly. A limitation is the height of the cutting die. The tallest cutting die can only cut approximately 2 inches in height. Taller blocks of fabric need to be separated and cut several times.
Band Knife Cutting is another off table cutting method. The block of fabric is moved to the band knife cutting machine. The Band knife is similar to the butcher or wood working band saw. A continuous blade passes down through a table top cutting surface. The operator guides the block of fabric to the blade. Cutting accuracy is achieved by using thin wooden forms the shape of each pattern to be cut. The band knife is particularly useful for high pile fabrics like terry, or velvet, as well as soft knits.
Notchers are either manual or electric machines used to make notches in the edge of a cut bundle. Unless cutting notches while cutting with the up and down knife, notchers are necessary for creating notches.
The Cold notcher is a manually operated, spring-loaded device with a short blade mounted on a plunger. Placed at the edge of the bundle, the cutter lines the blade up with the notch. In a single stroke downward, the notch is cut into the edge of all of the fabric plies.
When the fabric is a soft weave or knit, the cut notch will be lost in the edge fraying during handling each part. To create a more lasting notch, a hot notcher is used. The hot notch utilizes a vertical heated edge which burns a notch into the edge of the bundle. The temperature is controlled, so as to leave a brown burn mark without melting or doing excessive damage to the fibers.
The ink notcher is similar to the hot notcher Instead of burning a notch into the edge of the fabric; this device leaves a trace of UV marking ink on the edge of the fabric. This ink is visible under UV lights at the sewing station.
Advance Cutting Tools for Fabric
Advanced cutting tools for fabric are specialized heavy duty tools for the cutting of fabric after spreading of fabric. These are specially designed with integrated system like servo cutting, computerized, laser, water-jet, plasma and ultrasonic cutting systems.
Sewing Threads and Sew-Ability
The smallest failure in thread performance results in losses on investments in material, equipment, garment engineering, and labor. Hence, it is important to know your thread thoroughly. Enhancing thread knowledge, analyzing thread parameters, the right selection procedure and use of thread plays a major role in achieving good sewing performance and the desired seam quality.
Why do fabrics shrink? Shrinkage in Fabrics!
During the manufacturing process of fabric or we call it fabric processing, fabric comes in lot of tension and stretches when it moves from one machine to another which causes stretching in fabric structure and when this tension is removed, and fabric is relaxed it tends to get back in its original structure causing shrinkage.
Worsted Yarn Manufacturing Process
A fine smooth yarn spun from combed long staple wool. Worsted yarns are more tightly twisted than the bulkier woolen yarns. The soft, heavy yarn is strong and durable and is often used for sweaters. Worsted yarns are also used for fine dress fabrics and suit materials.