Below is an article written by Mereen-Johnson staff and published on the Woodworking Network:

Optimizing Lumber Rip

Ripping of random width lumber to create part blanks and stave material for wood products has for many years been accomplished using straight-line (single blade) ripsaws. The straight-line ripsaw provides great versatility in choosing what parts can be ripped from a random width board, but it is labor intensive and has limited production capabilities. 

When production demands outgrow the capabilities of a single straight-line ripsaw, manufacturers have two options: they can add more straight-line ripsaws, with additional labor required, or upgrade to a gang ripsaw. The latter is usually recommended, and manufacturers typically start off with a 12-inch width capacity gang rip with fixed blades on the arbor. 

A fixed blade gang ripsaw has some advantages and some disadvantages. Some of the disadvantages are that the gang ripsaw might not have the width capacity to have all the required sizes on the arbor and the set-up time required to change the arbor rip width configurations takes time away from producing parts. Also, the rip width combinations on the arbor may not provide good yield from random width lumber, but presorting the lumber by width prior to ripping to best utilize the different arbor set-ups will help in attaining better yields. 

On the other hand, some advantages for using a gang ripsaw include the fact that the rip width accuracy and parallelism is better than a straight-line ripsaw and can allow ripping narrower moulding blanks having less moulder allowance. The primary advantage, however, is its higher production capability over a straight-line ripsaw.

TO LEARN MORE READ THE COMPLETE ARTICLE HERE.

Gang Rip