categories of waste
- overproduction
- transport : inefficient workplace planning, unnecessary movement
- process waste: overly complex design or excessive documentation
- unnecessary inventory
- rejects
- waste
- waiting : process delays
- unnecessary motion : wasted movement during production
- cycle time
- time to complete a process; stemming from Henry Ford
reducing cycle time
- Juran
- define process for cycle time reduction
- list activities in selected process
- create process map
- list time taken for each activity
- identify waste activities
- eliminate waste and update process
Theory of Constraints
- Eli Goldroth
- systems are like chains
- constraints : elements which limit them and prevent them from achieving goals
- constraint is weakest link in chain
- only one constraint at a time; other elements are non-constraints
- focus on fixing constraint
- focus on continual improvement
principles regarding core problems
- challenge assumptions to solve core problems
- undesirable effects reveal core problems
- solving core problems eliminates undesirable effects
- high level viewpoint that involves systems rather than processes
operation measures
- throughput (T)
- T = selling price - cost of production
- rate at which system generates money
- inventory (I)
- money tied up in system, either investments or physical
- operating expenses (OE)
- money spent running system and turning inventory into throughput
other measures
- net profit
- ROI
- production
- turnover