Production control and plant considerations

Division of labour

In the first clothing and footwear factories, one worker assembled and finished an entire garment or shoe. But this whole-garment system rarely existed after 1940 for ready-to-wear apparel. Sectionalization came into being for three reasons: (1) to increase productivity per man-hour, (2) to improve product quality, and (3) to reduce inventory-in-process time. The main function of production control is to schedule the operations required to produce the garment or shoe in such a manner as to hold the total processing time, or calendar time, to a minimum. This scheduling is accomplished by determining the operations required per garment to yield the desired quality with minimal processing costs (labour, utilities, capitalization) and by arranging these operations so that most of them may be done simultaneously in the least number of successive steps, or time units. If 24 operations are required to make a given garment, a schedule in which these 24 operations are performed in six time units, with four operations made simultaneously in each unit, is superior to a schedule requiring seven or more successive time units with four or fewer simultaneous operations in each time unit.

Unit flow and multiple flow

There are two basic section systems in assembly-line production: unit flow and multiple flow, or bundle or batch system. The unit-flow system is continuous; the unit moves to the next operation as soon as it has been processed by the previous operation. The multiple-flow system is intermittent; a given group of units moves to the next operation simultaneously as a bundle, or batch, after the last unit in the batch has been processed in the previous operation. Regardless of which flow is used, efficient production control depends on rapid synchronized movement of the garment sections.

Plant layout and materials handling

To minimize the cost of transporting and storing processed garment sections from the first operation through all the prescribed production sequence until completion, two factors are considered: the arrangement of processing equipment to minimize distances between operations and the utilization of labour, transport equipment, and utilities to minimize total cost per product moved.

Transportation equipment such as chutes, conveyor systems, and carts are utilized to transport the work through the successive operations. Some conveyor systems, such as Eton of Dalsjöfårs, Swed., incorporate a stationary synchronized extractor on the conveyor that extracts and disposes a sewed section to a mobile conveyor hanger.

The two types of plant layout are process layout and product layout. In process layout, equivalent processing equipment is grouped in the same area regardless of whether the product can be passed through successive operations without backtracking. In product layout, processing equipment is arranged in the succession required for making the garment in the prescribed sequence without backtrack and with minimal transport between successive operations. Most apparel and allied production is with product layout, but in a few instances the process layout is more economical.