APPAREL MANUFACTURING - I 3(1+2)

Lesson 7 : Pattern Grading

Working Methods

There are no hard and fast rules as to how to actually produce the sets of graded patterns and the choice of working method is an individual question of accuracy and convenience. Some of the most commonly used methods are:

1. Nest or Stack Grading

The base pattern is used to grade all sizes, and each component has a common origin for the sizes graded from the same component. The actual cutting out can be done in one of the two ways:

1. A number of sheets of paper, equal to the pattern sizes required are stapled together and the components are cut out, starting with the largest size. Apart from not being a particularly accurate method, there are many components which have overlapping external and internal lines and this somewhat reduces the efficacy of this method.
2. A single sheet of paper is held underneath the grade nest and each individual size picked off with an awl or tracing wheel. The base size pattern is then used to complete the lines necessary for cutting out.
2. Mark and Cut

This is a very commonly used method whereby one size at a time is graded and then cut out. The usual way of working with this method is to start by grading one size up and down from the base pattern and then to cut them out. These patterns are then used for the next size up or down and the process is continued.

3. Vector Grading

This is sometimes called the Master Grade Method and is very widely used variation of the Nest Grade. Using common origin lines, the base pattern is graded to the largest and smallest sizes required for the particular set of patterns. Then the cardinal internal and external points are connected together by vector lines. The distance between the points to which the vectors connect is measured and then divided by the number of size intervals between the largest and smallest size. These divisions are marked on the vectors and are picked off or traced onto individual sheets of paper. The base pattern is then used to connect up the points in order to produce the outline of the component.




Fig. 5: Vector grading method

4. Nip Spacings

When preparing the original pattern, the pattern maker provides guides for accurate assembly through the provision of nips along the seams to be matched. The distances between these nips are based on the complexity and form of the parts to be matched. In most cases, there is no need during the grading to alter the distances between nips on most assembly seams.