Elements of Manufacturing Systems:
In manufacturing systems, value is added to an entity (product, material, component, etc.) by routing entities through a sequence of processing operations or stations and resources. Basic elements that are modeled and tracked in any manufacturing system include:
1) System entities: Material, parts, and components represent the entities in manufacturing systems. The entities are routed within the plant operations and use plant resources before departing the manufacturing systems as finished goods.
2) System resources:Manufacturing system resources mainly include machines, tools, equipment, and labor. Capacity and utilization design and enhancement at manufacturing resources are a focus of 3S projects.
3) Warehouses and inventory systems:Manufacturing systems are distinguished with warehouses for raw materials and finished items as well as work in- process buffers. This includes all types of storage systems, from simple part bins to automated storage and retrieval systems.
4) Material-handling systems:Manufacturing systems are characterized by extensive manual or automatic material-handling systems, including forklifts, conveyors, automated guided vehicles, power and free systems, and others.
5) Facility and physical structure:The layout and physical structure of a manufacturing facility often represent the best configuration of plant resources that facilitates flow and increases effectiveness. Different types of layouts and flow methods can be utilized to this end. Also, meeting certain requirements and codes is essential when designing the manufacturing facility.
6) Operating pattern:The operating pattern in a manufacturing system defines the number shifts per day, the working hours per shift, and breaks the distribution.
Design Parameters in Manufacturing Systems:
Model control factors include the set of parameters that can be changed by the manufacturing system designer in order to enhance the system performance. In 3S applications these factors are optimized with DOE to enhance process CTQs. Examples of manufacturing design parameters include:
1) Number of production resources
2) Capacity of production processes
3) Production batch size (lot size)
4) Schedule of input materials
5) Shipping schedule
6) Material flow and routing rules
7) Buffer capacity and location
8) Number of material-handling carriers
9) Speed of conveyance systems
Time-Based CTQs in Manufacturing Systems:
This represents the set of measures that can be used to assess the performance of a manufacturing system as well as to compare the performance of several process designs. In 3S applications these measures can be estimated from available accumulated model statistics (or from a special code) to compute the measures’ values. Performance measures in a manufacturing system include:
1) Manufacturing lead time
2) Throughput per hour or per shift
3) Total inventory level or cost
4) Utilization of production resources
5) Number of late production orders
6) Equipment availability
7) Percent of units built to schedule
