Session 4 - process design and analysis Flashcards
Objectives of process design
- To design or redesign a process
- To describe, evaluate and optimize
- Focus on areas which can be optimized
- Identify the areas which need more investment
- Minimize unnecessary movements in resoucres
Process flowchart
A visual diagram showing the sequence of tasks in a process. Helps identify inefficiencies, decision points and bottle necks.
Basic elements include: tasks or operations, flow of materials, decision points, storage areas and ques.
Flow chart symbols meanings
- Square is a task or operation
- Diamond decision point
- Upside down triangle: Storage areas or queues.
- Arrows: Flows of materials or customers.
Stage
Multiple activities that have been pulled together
Single stack process
Only one step / task activity
Multi stage process
Multiple connected tasks, linked through flows
Sequencing
Defines the order of operations for efficiency - the sequence in tasks will be performed
Pacing
Setting a fixed time for items to move through a process
Paced process
Each task must be completed in a set time
Non paced process
Work is completed at different speeds
Bottle necks may form, slowing production
Paced systems
Predictable, steady output
Blocking
When there is no place to deposit the item so it cant move forward
Starving
When a stage has no input and must stop
Bottleneck
- The slowest stage which limits system capacity
- Stage with resources with the highest utilisation
- Bottleneck determines the maximum capacity of the process system
Buffer
A storage in between stages to prevent stoppages
Utilization
Time activated / time available
Cycle time
Average time between succesive units being completed in the entire process or system
Output rate (throughput rate)
Units produced / time period
units produced per time
Paced Assembly line
Fixed time for each station
Formula for cycle time
Time available / customer demand
Throughput rate
1/cycle time
Steps to improve efficiency
- Perform tasks in parallel
- Change work order to optimize flow
- Reduce interuptions
- Invest in tech
Simulation software
Helps test potential improvements before implementation
