Patterns initially are made in only one size. In order to produce clothing that fits various body types and sizes, the pattern pieces must be increased or decreased geometrically to create a complete range of sizes. The process of resizing the initial pattern is called "grading." Each company determines its own grade specifications for each size, and size specifications vary slightly from manufacturer to manufacturer.
Grading is the method used to increase or decrease the sample size production pattern to make up a complete size range. For example, the sample size 10 patterns must be made larger to accommodate sizes 12, 14 and 16 and smaller for sizes 8 and 6. Each company sets predetermined grade specifications, or rules. For example, a missy manufacturer’sgrade rules might call for increments of one and a half inches in width and a quarter inchin length for each size.
Today most manufacturers grade pattern on CAD systems. The pattern maker guides a cursor around the edges of the sample pattern on a digitized table. At each of the key points, he or she pushes a button to record a grade point. Each point is cross referenced by a grade-rule table stored in the computer, which enlarges or reduces the pattern automatically according to the predetermined direction.If the pattern was originally made by computer, data are already in the computer and can be enlarged or reduced automatically.
Pre-programmed grade rules for increase or decrease are automatically applied to the pieces of each grading location. Then the computer can print out the pattern in each new size. Manufacturers often use an out side service to make patterns, grade patterns, and make the marker
Although many small firms still use traditional grading methods, grading, like patternmaking, is becoming increasingly computerized. Using a CAD system, the pattern can be resized according to a predetermined table of sizing increments (or "grade rules"). The computerized plotter can then print out the pattern in each size. Because the productivity gains are so great, small to medium-sized manufacturers are beginning to acquire their own CAD systems for grading.
Alternatively, they may use an outside grading service to perform this function.
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