Manufacturing Systems Flashcards
What are the characteristics of a project process?
Discrete, highly customised products Possible long production time Dedicated resources Highly variable production routes e.g. large engineering projects / construction
What are the characteristics of a job-shop process?
Products are generally similar but may be ‘one-offs’
Shared resources
High skill levels
e.g. tooling / patterns
What are the characteristics of a batch-production process?
More than one item at a time produced
Processes repeated whilst a batch is being produced
Individual processes can be similar to job-shop but management is different
Wide range of volumes
e.g. machine tools, automotive parts, customized electronics.
What are the characteristics of a mass-production process?
High volume, relatively low variation
Variants possible if they do not affect the basic process flow
Process highly repetitive and predictable
e.g. automatic packing lines, car factories, consumer electronics
What are factors that affect manufacturing efficiency?
Set-up time Through-put time Utilisation Flexibility Work in Progress inventory Control Resilience and disruptions
What is Group Technology?
The grouping together of parts or products into families by processing operations so that all members of a family are processed in a miniature factory called a cell
What influence does Group Technology have on the manufacturing industry?
Simplifying parts
Standardisation of processes
Visibility of part flow in production
What is meant by flexibility?
The amount of products, production batch sizes and lead times that can be handled by a productions system
What are the different types of flexibility?
Manufacturing Operational Customer Strategic Capacity
What are the characteristics of a job-shop system?
Combination of conventional and CNC machines
Low capital investment
wide variety of parts for low volume batch manufacture
Low level of system automation
Typically used in custom made part manufacturing environments.
What are the characteristics of a Flexible Manufacturing System?
Can be thought as an automated cell
High level system automation
Wide variety of parts in medium volume batch manufacture
Simultaneous manufacture of different parts
Bi-directional work-piece flow using AGV
Highly flexible
Planning and control is critical to maximise system utilisation
Typically used in aerospace industry and machine tool builders
What are the characteristics of Flexible Manufacturing Cells?
Multiple machines with similar capability
Wide variety of parts for medium volume batch manufacture
Bi-directional work-piece flow using RGV
High level of system automation
High capital investment
Typically used in repetitive part manufacturing environments
FMC vs FMS?
FMC generally described as two or more CNC machines doing similar tasks
FMS is two or more machines doing different tasks
What are the advantages of FMS?
Faster, lower-cost changes from one part to another which improves capital utilisation
Lower direct labour cost due to reduced workers
Reduced Inventory
Consistent and better quality
Lower cost/unit of output
Savings from indirect labour, reduced errors, rework, repairs and reject
What are the disadvantages of FMS?
Limited ability to adapt to changes in product or product mix
Substantial pre-planning activity
Expensive, costing millions
Technological problems of exact component positioning and exact timing necessary to process a component
Sophisticated manufacturing systems
