Handling dimensionally unstable fabrics has always been a problem for apparel manufacturers. Use of pins or pin tables is common for laying of yarn dyed checks and stripes in spreading, but its usage for dimensionally unstable fabrics like moss crepe, georgette, etc. is still rare. Use of pins in industry is also to reduce slippage while layer cutting is done by the straight knife. Some progressive units use pins during relaying of block cut components and then achieve final cutting of multiple layers by using band knife, thus saving precious time, opines Dr. Prabir Jana, Professor, NIFT, Delhi.
Use of pins or pin tables for aligning stripes and checks while laying fabric is not common among manufacturers. Although some use branded solutions, others use customized solutions. Use of pin tables can also be in various stages of laying fabric and different branded solutions are available for the same.
Some usages of pins and pin tables for aligning stripes and checks, while laying fabric in cutting room applications are:
To reduce ply slippage while layer cutting by straight knife;
To reduce ply slippage while transferring fabric blocks to band knife;
To align checks and stripes during layering;
To align checks or stripes while relaying block cut components.
Why use pins or pin tables? It is used to reduce ply slippage during layer cutting by a straight knife or while transferring fabric blocks to band knife which are rare and are generally solved by customized solutions by temporarily fixing pins either at both ends of lay or at specified intervals (based on repeat size) alongside the selvedges.
Why aligning of stripes and plaids are required? Aligning of longitudinal stripes (stripes along the length of fabric) in a striped fabric or longitudinal stripe components in a plaid fabric one over the other is required during spreading of multiple layers of fabric so that while cutting bulk layer location of stripe is at same place of all pattern components in the cut stack. This is required for different matching requirement (e.g. matching pocket with front stripe) during sewing process. It should be kept in mind that use of pin table is not possible in such fabrics that has some special finish/coating; for example waterproofing, water repellent, etc.
How pin table works? Pins are generally attached at the spreading table in such a way so that only tip of the pin protrudes minimally over the horizontal plain height of the fabric layer. As the number of layers increase, layer height as well as pin height also increases gradually. While layering, the operator ensures that stripes are superimposed one over the other and the presence of pins during the spreading process physically ensures that fabrics are not moved between plies. The mechanism of lifting and lowering of pin is critical and varies in different brands. After the spreading process is over, the layers are stapled or locked to ensure no inter-ply slippage takes place when pins are taken out of layer, before the cutting starts.
Why use continuous pin table?
Continuous pin table can be used while layering fabrics as per marker length. The system has matching line in patterns and marker planning with net patterns (except pockets, flaps, etc.) This is followed by adjusting needles in the pin table longitudinally and vertically – exactly according to maker. Thereafter, fabric is spread on pin table and is matched to the marker, simultaneously ply by ply, resulting in manual or automatic cutting of lay. This type of pin table consists of slotted aluminum top and needle bars underneath. Each needle bar has pins positioned inside the slots of the needle top. The height of the needles can be adjusted by rotating the needle bar. The system offers the following features:
The height of the needles can be adjusted by rotating the needle bar;
Different diameters of needles (1.0 mm, 1.4 mm and 1.8 mm) are available for different types of fabric and all needle tops are rounded;
Distance between successive pins across width is 14 cm, however selected pins can be switched on and off as desired;
Table width ranges from 66 inches to 94 inches;
The needle bar position can be adjusted longitudinally with minimum distance of 15 cm;
The needle bars can be set with maximum inclination of 12.5 degrees.
The continuous pin table system offers the following advantages:
(a) As the marker is planned with net patterns (no block cutting), saving of fabric in the range of 3% to 15% is possible. Also saves cutting time by 50%;
(b) As marker is planned independently from certain repeat, the same marker can be used for different fabrics;
(c) Unique needle bar inclination can accommodate spiral stripes of circular knit fabrics, thus avoiding stretching and distortion.
Why to use pattern blocking pin table (for relaying blocks and band knife cutting)? Continuous grid pin tables are costlier options and often not preferred. Modular pattern blocking tables can be used effectively for single garment marker or relaying blocks, for band knife cutting. These are tables of smaller size. Table tops are two layered – while the top layer is fixed with the table stand and have pinholes in horizontal and vertical grid, the bottom layer has pins protruding through the pinholes. Here also, pins can be dismounted, if not required at certain grid points. This type of pin table can be easily fabricated in-house as per size requirement. There are colour grid lines ruled into 5 cm squares on the table top and an option to use laser light guides, which can make pattern matching between two needles easy. Height of the needle can be adjusted to a maximum of 100 mm by operating the handle. Needles are specially coated to avoid damaging fabric. Table top size of 1.8 m x 1.2 m to 1.8 m x 3.6 m is available.
There are also pattern blocking tables with magnetic needle hold mechanism. These pattern blocking tables are of smaller size and needle mechanism works differently. Minimum work area of 55 cm x 95 cm to maximum 95 cm x 175 cm is available. The work table has punched surface area and needles can be set based on plaid location. The height of individual pin can be altered easily as a patented magnetic holder holds the pins. Thread marking is also possible wherever required.
Why needle plates are important? These are very useful utilities which help in fixing lays along with the paper marker. This reduces inter-ply slippage and the whole lay remains distortion-free. This has advantage over using small weights as the cutting master needs to keep shifting the weights while cutting. Generally people use big pins with plastic tops which are difficult to handle as chances of tilting of pins is always there.
Post a Comment