APPAREL MANUFACTURING - I 3(1+2)

Lesson 7 : Pattern Grading

The Pattern Grading Process

This process automatically generates multiple sizes of a digitised pattern piece according to the inputed data which, amongst includes:

1. The special piece number of component. Most systems have a piece file or library in which each basic type of component is stored in a separate section. Each section has its own unique coding and this acts as the primary identification for components.
2. The piece number itself. This is the number of the piece within its particular section of the piece file.
3. A written piece description. Typical descriptions could be top sleeve or back lining, etc., and this method simplifies piece identification.
4. The grainline of the piece. Apart from being used to position pieces correctly when planning markers, it also acts as the X axis when digitising the pattern.
5. The grade points. These are the cardinal external or internal points which have grading rules applied to them: for example, the front neck point or a skirt dart position, etc.
6. The intermediate points. These are located between grading points and move in accordance with them.
7. The grade rule data for every grade point. This data defines the movement of a grade point for one size. The grading rule data itself can be derived from one of two methods.

Method 1

The actual growth between sizes can be defined by digitising a graded nest. Usually this nest consists of the base size and the largest size required, where all of the peripheral and internal vectors are straight lines between the largest and smallest sizes, intermediate sizes are only entered when there is a grade break caused by the use of different grading increments for one or more points on the pattern piece, i.e., the vector is no longer a straight line.

Method 2

This is based on a previously established grade rule library which is a file containing the measured distances by which a point will change when a specific rule is applied. Each grade rule has a unique number and is not generally restricted in its application to one type of garment only.