CAD & Pattern Department:

CAD & Pattern Department

Computer-aided design (CAD) is the use of computer technology for the design of objects, real or virtual. CAD often involves more than just shapes. As in the manual drafting of technical and engineering drawings, the output of CAD must convey information, such as materials, processes, dimensions, and tolerances, according to application-specific conventions.

CAD may be used to design curves and figures in two-dimensional (2D) space; or curves, surfaces, and solids in three-dimensional (3D) objects.

CAD is an important industrial art extensively used in many applications, including automotive, shipbuilding, and aerospace industries, industrial and architectural design, prosthetics, and many more. CAD is also widely used to produce computer animation for special effects in movies, advertising and technical manuals. The modern ubiquity and power of computers means that even perfume bottles and shampoo dispensers are designed using techniques unheard of by engineers of the 1960s. Because of its enormous economic importance, CAD has been a major driving force for research in computational geometry, computer graphics (both hardware and software), and discrete differential geometry

v     It is not in use in ABM Fashion Ltd.

Pattern

An ornamental design in a fabric . Pattern may be produced either by the construction of the fabric ,by applying designs, by other means. For printing, embossing,or embroidery.

18.1.1 Pattern making tools

v     Pattern paper

v     Stright pins

v     Stright pins holder

v     Scissors

v     Pens

v     Pencils

v     Rullers

v     Curve rules

v     Hanger hooks

v     Push pins

v     Magic mend scotch

v     Black twilltape

v     Notcher

v     Tracing wheel

v     Awl

v     Metal weight

v     Measuring tape

v     Taiilor’s chalk

                                                                       

Pattern making

Foundation patterns that are chosen as a base to develop bias cut garments are not reliable; but they do serve the purpose of creating pattern shapes of  the design. The garment is cut and joining using the long stitch by machine, by basting, by pinning when placed on the form to hang over night. The bias part of the garment will stretch beyond its original shape in the fitting to the curves of the form. The garment is marked between the original lines of the pattern and the adjusting markings.The differences are trimmed from the patterns where they occur new pattern shapes emerge from the corrections that are smaller and shorter than the originals to offset bias stretch. When cut again for the final test fit, the bias instructions include two methods for the management of and the adjustments to the pattern.

Garment Manufacturing Technology—Md. Saiful Azam     

Pattern Makers

Pattern makers are given the difficult task of turning a sketched fashion design into a practical blueprint of a garment.  Often, designers change their minds after the first sample is made and a pattern must be modified drastically, while maintaining the correct fit.  e-fit Simulator gives pattern makers a sample much earlier in the process, allowing designers and apparel developers to communicate quickly and effectively. A pattern is a 2-dimensional representation of a 3-dimensional object; ultimately the garment will be worn by someone, and the pattern maker is responsible for the way that garment fits.  Many pattern makers use e-fit Simulator to test their pattern blocks and basic shapes while they are drafting the pattern, to make sure that the balance and slopes of the garment are correct, much the same way that tailors work with muslin slopers on a fit form. http://www.tukatech.com/products/efit/ Marker It is a thin paper which contains all the necessary pattarn pieces for all sizes for a particular style of garments. It gives special instructions for cutting. It can be done both manually and computerized method. Ø      In computerized method all information’s are stored in the pre-fashioned data file and an operator helps the computer to make the best choice. Ø      Maker width is taken according to the fabric width. Fabric spreading should be done by taking the guideline from maker width. Points should be considered before maker making: Ø      Fabric width must be higher than maker width (1/2”). Ø      Fabric length must be higher than maker length (1”+1”). Ø      When pattern pieces are laid down on the layer of fabric, the grain line should be parallel to the line of the warp in a woven fabric and Wales in knit fabric where pattern pieces are laid across the layers, the line is kept parallel to weft / course. Ø      All the pattern pieces of a garment should be alone the same direction when laid down on an asymmetric fabric. Ø      Length of cutting table should be considered. Ø      Plan for garments production should also be considered. Ø      For the efficient marker, it is required to ensure the following things: Ø      One should be easily see the full length. Ø      To know about the appropriate width. Ø      The marker starts with the large pattern pieces. Then fits the smaller pieces in the gap of the larger pieces. Thus the fabric wastage is minimized and efficiency is increased. Ø      After that the patterns are shuffled in various directions to reduce the marker length. It also helps to increase maker efficiency. Marker drawing & Preservation of patterns Ø      Carbon Papers could be used for duplication of markers in case of non-CAD markers.—In case of Nike orders it is not allowed---efforts be made to obtain computer markers from a close by plant.. Ø      The pattern/marker being suggested by HO team is only a starting point for the cutting incharge to work on better fabric utilization. Cutting incharge should try out different markers to maximize fabric Ø      A Parts Checklist has to be maintained by the marker drawer to ensure coverage of all parts in the lay. Ø      Pattern should be verified for required allowances, tolerances, notches and embellishment placement marks, grain line, nap direction indications before marking. Ø      Constant usage of patterns results in wear & tear of pattern, this has to be regularly monitored and worn out patterns to be replaced even daily if the case demands to ensure cutting quality. Ø      Cello tape could be used to preserve the edges of the pattern boards –for big quantities plastic boards could be used to duplicate the pattern for marker drawing Ø      If the patterns are worn out, it has to be replicated & cross-verified for required measurements, allowances and tolerances. On satisfying these factors the worn out pattern has to be replaced. Ø      Worn out patterns are to be destroyed after conformation on the correctness of the specifications mentioned in tech pack. Ø      Lay sheet on which the marker is drawn is torn in the middle & stickers are pasted consisting details like PO no, Serial no, Fabric code no, Lot no. Hence easy identification of cut panels. Lay Preparation: Ø      Layers shall collect lay slip, cutting job card, lay sheet from the minusing person. Ø      Layers shall lay the fabric according to the lay slip details. Ø      Layers shall collect rolls of only one shade and one width for the lay at a time ,if any shade change is noticed then use separators- i.e. lay sheet has to be placed for identification. Ø      The cutting incharge has to decide upon the kind of lay such as – face-to-face, face to back, face up, face down, grain line, nap direction during the PP meeting stage upon the analysis of the garment. Ø      Use lay separator sheets to separate rolls of different shades if used in the same lay—the shade category should be mentioned on every lay separator sheet also. Ø      Lay Precaution: Ø      During laying the layers should check the lay-to-lay shade variation & also center to selvedge variation as a part of online check procedure. Ø      QC shall inspect the lay for lay tension, width, length, grain line, nap direction etc. Ø      End wastage for laying of fabric shouldn’t be more than 1 cm. Bulk Cutting 1.       Lay wise manpower requirement must be planned. 2.       Cutters must be trained on the methods of accurate cutting, especially for parts with deep curves. If possible diagrammatic representation of the direction of movement of the cutter needs to be illustrated. 3.       Cutters shall inspect the cutting machine for oil leakage, straightness of the blade, sharpening quality, evenness in sharpening of the blade, dust accumulation before cutting. 4.       Cutters shall cut lay as per the mark up using straight knife m/c and move the parts to band knife as per the discussion in PP meeting. 5.       QC shall inspect all the cut parts using patterns and initiate corrective action upon the detection of defect. 6.       Prepare 1st cut bundle inspection report; notify fabric defects and cutting defects to FM/PM. 7.       QC should have a cutting checklist against which 1st bundle audit has to be conducted. Checklist should have details of allowances, tolerance included in pattern, notches and embellishments placement markings details. 8.       The size of the straight knife for cutting lightweight fabrics should be 6” only. 9.       Straight knife must be uniformly sharpened from top to bottom as frequently required,. This ensures even sharpening along the full 10.   length of the knife/blade. 11.   Note: If sharpening of blade is uneven / inconsistent, it would result in uneven depth of notch marks and variation in cutting too... 12.   For Band knife cutting , patterns preferably made of tin should be used. 13.   The patterns used for band knife must be changed regularly upon monitoring the w ear and tear on the pattern, due to frequent usage. 14.   Wear and tear on the pattern, due to frequent usage.  Marker types used in the industry Marker : It is a thin paper which contains all the necessary pattern pieces for all sizes for a particular style of garments. It gives special instructions for cutting. It can be done both manually and computerized method. o       In computerized method all information’s are stored in the pre-fashioned data file and an operator helps the computer to make the best choice. o       Maker width is taken according to the fabric width. Fabric spreading should be done by taking the guideline from maker width. Manually marker making type is used in ABM Fashion Ltd.