Topic 3-Manufacturing Systems Flashcards
What do low volume processes produce?
A high variety of products
What do a high volume of processes produce?
A low variety of products
What does the approach to managing an individual process depend on?
Where it falls on the volume-variety spectrum
What are the general approaches to managing groups of processes?
- Project
- Job shop
- Batch production
- Mass production
Project processes details
- Discrete, highly customised products
- May be long production timescales
- Dedicated resources
- Highly variable production routes
- Large engineering projects, construction
Job shops details
- Products generally similar but may be “one-offs”
- Shared resources
- High skill levels
- E.g. tooling, patterns
Batch production details
- More than one item at a time produced
- Processes repeated while batch is being produced
- Individual processes can be similar to job shop but management is different
- Wide range of volumes(depending on batch size)
- E.g. machine tools, automotive components, customised electronics
Mass production details
- High volume, relatively low variety
- Variants possible if do not affect the basic process flow
- Processes highly repetitive and predictable
- e.g. automatic packing lines, car factories, consumer electronics
What does management strive for?
- Low Resource Waste(high efficiency)
- High Goal Attainment(high effectiveness)
Concepts Affecting Efficiency of Manufacturing
- SET UP TIME- time it takes to set-up machines so as to switch production from one product to another, e.g. through changing tooling
- THROUGHPUT TIME- the length of time it takes a single product to undergo all stages of production
- UTILISATION- the proportion of available plant time that is spent generating value
- FLEXIBILITY- the range of products, production batch sizes, and lead times that can be handled by a production system
- WORK IN PROGRESS(WIP) INVENTORY- the amount of unfinished product on the shop floor
- CONTROL- ability of management to know and control the state of production at any given moment
- RESILIENCE TO DISRUPTIONS- the ability to carry on production despite something going wrong, e.g machine breakdowns
What are process layouts?
Different layout of resources(machines and staff) are required for the most efficient processing of product depending on the production-process group
What are the three main types of process layouts?
- Product Layout
- Process Layout
- Hybrid Layout
What does Cell Manufacturing facilitate?
Cells facilitate rapid flow and efficient processing of material and information
Group technology underpins cell manufacturing, what is it defied as?
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
Influence group technology has on manufacturing industry?
- Simplifying parts
- Standardisation of processes
- Visibility of part flow in production
TOO LITTLE OR TOO MUCH FLEXIBILITY
- Too much flexibility may be a bad thing- standardisation of activities could save costs so there is a missed cost-saving opportunity
- Too little flexibility can also lead to an economic penalty. For a highly standardised process there are high production changeover costs associated with changing tooling and starting and stopping production
- Automation can extend the flexibility of manufacturing systems
What are the types of Flexibility?
- Manufacturing
- Operational
- Customer
- Strategic
- Capacity
What is Manufacturing Flexibility?
- The capability of producing different parts without major retooling
- A measure of how fast the company converts its process(es) from making an old line of products to produce a new product
- The ability to change a production schedule, to modify a part, or to handle multiple parts
What is Operational Flexibility?
- The ability to efficiently produce highly customised and unique products
What is Customer Flexibility?
- The ability to exploit various dimensions of speed of delivery
What is Strategic Flexibility?
- The ability of a company to offer a wide variety of products to its customers
What is Capacity Flexibility?
- The ability to rapidly increase or decrease production levels or to shift capacity quickly from one product or service to another
What does Automation Provide?
- Automation provides more options to efficiently match the manufacturing system with the production process group
- But applicability of automation depends very much on the trade off between investment and turnover
- Essentially can you sell enough product to pay off the higher investment required for automated machinery
Automated operations
- Programmed control of manufacturing operations
- Storage of parts
- Automated transfer of parts between storage and production machines
- Identification of parts
- Orientation of parts
- Loading and unloading of parts
- Automated operation cycle
Automated setup
- Changeover of programmes
- Tool and fixture storage
- Transfer of tools and fixtures between storage and production machines
- Automated tool and fixture changeovers
What is Flexible manufacturing cell(FMC)?
Two or more CNC machines doing similar tasks
What is a Flexible Manufacturing system?
Two or more cells doing different tasks
Advantages of FMS
- Faster, lower-cost changes from one part to another which will improve capital utilisation
- Lower direct labour cost, due to the reduction in number of workers
- Reduced inventory, due to the planning and programming precision
- Consistent and better quality, due to the automated control
- Lower cost/unit of output, due to the greater productivity using the same number of workers
- Savings from the indirect labour, from the reduced errors, rework, repairs and reject
Disadvantages of FMS
- Limited ability to adapt to changes in product or product mix( ex. machines are of limited capacity and the tooling necessary for products, even of the same family, is not always feasible in a given FMS)
- Substantial pre-planning activity
- Expensive, costing millions
- Technological problems of exact component positioning and precise timing necessary to process a component
- Sophisticated manufacturing systems
