What are the production flow layouts?
- Fixed product:
- Constructions- power- and ship building
- Few products (one piece)
- Production system special for each project
- Generic and flexible equipment
- Process layout (functional)
- Machine oriented
- Sequence flexibility
- Many different products in small volumes
- Batch flow, cell
- Porduct oriented
- High value added in the group
- Few prodcts, few variants in higher volumes
- Line flow
- Product oriented
- Mass production, even and high demand
- Machine or operator controled
- Low flexibility, dedicated equipment
- Continuous flow (e.g. oil)
- High level of automation
- Phydically linked units
- Production measured in tons, liters, meters etc.
- Limited product range
What are the advantages and disadvantages with line layout?
+ Easy to standardize - better quality and performance
+ supports specilization
+ Minimize the planning
+ Lower Lead time
- Lower flexibility
- High investments costs
- low utilization
- high system losses
What is cycle time
The time it take for one station to preform the tasks assigned to a station
What is takt time?
The maximum time of production line has available before the product goes forward
What is disturbance?
Any breakdown or problem in one more stations resulting in a stop or hogher cycle time
what two senarios os there for production flows?
- Fixed stations: Known number of stations, therfore minimize the takt time as much as possible
- Fixed takt time: In order to reach the takt time, minimize he amount of work stations and resources used.
What is balance losses?
Balancing loss is the proportion of time allocated for processing but not used.
B = (NC-T)/NC C = highest cycle time, T=total time, N = numer of stations
What is the precedence relations?
The work tasks to the performed are related to the other tasks. Therefore, some tasks have to be performed before the other are made.
Write down which process need to be after eachother in a table and draw up the precedence diagram. se picture.
- Rank position weight: arrange the list of tasks by the time for all following tasks including itself, sarting with the biggest.
- Largest candidate: Arrange the lists of tasks by task time
What are the disturbances in a production flow?
- Set-up losses
- Idle time: blocked, starved
- Brakdowns
- Small stoppages
- Cycle time variations
- Balancing losses
what are the steps of ToC ?
Theory of constrains
Is a methodology for identifying the most important limiting factor that stands in the way of achiving a goal and then systematically improving that constraint until it´s no longer the limiting factor.
- Identify the system´s constraint (s)
- Decide how to exploit the system´s constraint(s)
- Subordinate other resources to the constraint(s)
- Evalutare the system´s constraint(s)
- If in any the previous steps a constraint is broken, go back to step 2, and iterate
