APPAREL MANUFACTURING - I 3(1+2)

Lesson 7 : Pattern Grading

New Dimension In Grading – Computerized Grading Technology

Computerized pattern grading can be said to have started in 1964 with the invention of a computerized digitizer by Dr. H. J. Gerber. By 1968, computerized pattern grading and marker planning systems had become commercially available since then; this technology has become a basic tool of clothing industries throughout the world.

Information flow
Computerized pattern grading is, in effect, graphic data processing applied to pattern grading and like all data processing requires three steps:

Step 1: Data collection

This starts at the same point as manual grading with a finished master pattern of the garment to be graded. The master pattern is converted, via the digitizing process, to a format of numbers which the computer can recognise and process. At this stage, there is also the input of alphanumeric data which includes:

1. The range and intervals of the sizes required.
2. The grade points of the pattern components
3. The grade rules which are to be applied to these points
4. The output form required i.e., a drawing or cut-out patterns.

During this input process, the computer must be instructed in precise terms, what is expected to accomplish. Thus, the generally allowable imprecision’s of manual grading are eliminated and are replaced by defined commands.

Step 2: Data processing

This is where all of the routing and unique manual grading procedures are carried out by the system. Many manual grading techniques which require great skill and craftsmanship on the part of the pattern grader become simple and direct when performed by automation.

Step 3: Data presentation

The principal output at this stage is the graded patterns and these are drawn out by the plotter according to requirements. The graded components can be presented as individual components or nested in full size or miniature scale. Alternatively, the patterns can be cut out, notched, and annotated in pattern paper, in full sized or miniature scales (fig. 6 and 7). Operational data is also generated at this phase via the line printer which produces hard copy reports and statistics for records and management information.

These three foregoing stages convert the master pattern into a set of graded patterns which can be used to plan cutting markers for manual or computerized cutting.

Fig. 6: Individual part grade	Fig. 7: Nested grade

System Description

The Pattern Grading Process

The principles of computer grading