Process planning requires: determining the processes to be used; the development of operation flow charts; production layouts; routings and operation (process) sheets; setup charts and machine tool layouts; equipment selection and sequence; material handling details; tooling requirements; inspection plans for quality assurance and quality control; and much more. Computer-aided process planning (CAPP) systems are expert computer systems that collect and store the knowledge of a specific manufacturing situation, as well as general manufacturing engineering principles. A jig is a device used to locate and hold a work piece while guiding or controlling a cutting tool. A fixture is simply a locating and holding device. The five basic types of assembly systems in use today are single-station assembly, synchronous assembly, non-synchronous assembly, continuous-motion assembly, and dial (rotary) assembly. Facility layout may be defined as the planning and integration of the paths of the component parts of a product to obtain the most effective and economical interrelationship between employees, equipment, and the movement of materials from receiving, through fabrication, to the shipment of the finished product. The main activities of PM are lubrication, parts replacement, machine adjustments, and overall inspections. There are three approaches to the maintenance of production equipment: (1) corrective maintenance; (2) preventive maintenance (PM); and (3) predictive maintenance. Methods engineering and work measurement form another component of process engineering. Methods engineering focuses on analyzing methods and equipment used in performing a task, on either existing processes or future jobs.