Unit 2: Process planning and capacity
Production Planning and Control notes · PTU syllabus (MBA 955-26)
On this page
Unit summary
Process planning and capacity decisions turn product designs into efficient production. This unit covers product design analysis, process sheet preparation, line balancing, advanced facility location methods — dimensional analysis and Brown and Gibson's method — types of layout, rough-cut capacity planning and CRP, and work study, method study, work measurement and PMTS.
After this unit you can
- Analyse product design and prepare process sheets
- Balance assembly lines
- Apply advanced facility location methods and choose layouts
- Plan capacity and apply work study and PMTS
PTU syllabus topics
- Product design analysis
- process sheet preparation
- line balancing
- advanced facility location methods (dimensional analysis, Brown and Gibson's method)
- types of layout
- rough-cut capacity planning and CRP
- work study
- method study
- work measurement and PMTS
Cycle time
Available time / required output
Minimum stations
Σ task times / cycle time (round up)
Line efficiency
Σ task times / (stations × cycle time) × 100
Balance delay
100 − efficiency
Topic 1
Product design analysis
- Analysis for production: functionality, manufacturability, standardisation, simplification, material selection, tolerances, cost (value analysis), reliability and maintainability.
- Tools: design for manufacture and assembly (DFMA), value engineering, failure mode and effects analysis (FMEA).
Topic 2
Process sheet preparation
- Process sheet (operation sheet): lists operations in sequence with machines, tools, jigs and fixtures, set-up and run times, inspection points and materials for each part.
- 1
Study drawings and specifications
- 2
Determine operations and sequence
- 3
Select machines, tools and fixtures
- 4
Estimate set-up and operation times
- 5
Prepare route and process sheets
- 6
Review and approve
Topic 3
Line balancing
Cycle time
Available time per period ÷ required output
Minimum workstations
Σ task times ÷ cycle time (round up)
Efficiency
Σ task times ÷ (workstations × cycle time) × 100
Balance delay
100 − efficiency
Example
480 minutes a day, output 96 units → cycle time 5 minutes. Total task time 22 minutes → at least 5 workstations; if 5 are used, efficiency = 22 ÷ 25 = 88%.
- Heuristics: largest candidate rule, longest operation time, most following tasks, ranked positional weight.
Topic 4
Advanced facility location methods
- Dimensional analysis: compares sites using the ratio of cost factors raised to their importance weights — product of (cost at site A ÷ cost at site B)^weight; a value below 1 favours site A.
- Brown and Gibson's method: combines objective factors (costs) and subjective factors (community, climate) into a location measure.
Objective factor measure
OFMi = (1 ÷ Ci) ÷ Σ(1 ÷ Ci)
Subjective factor measure
SFMi = Σ (factor weight × site rating)
Location measure
LMi = X × OFMi + (1 − X) × SFMi, where X is the weight on objective factors
- Choose the site with the highest location measure.
Topic 5
Types of layout
Layout is the arrangement of machines, departments, workstations and storage within a facility. Objectives: smooth material flow, minimum handling, efficient use of space, safety, flexibility and worker comfort.
Process (functional)
Similar machines grouped together
Job and batch production, hospitals
Product (line)
Machines in the sequence of operations
Mass production, assembly lines
Fixed-position
Product stays; workers and machines move
Ships, aircraft, buildings
Cellular (group technology)
Cells of machines for families of parts
Medium-volume, varied parts
- Line balancing: in product layouts, assign tasks to workstations so that each takes about the same time (cycle time = available time ÷ required output).
Topic 6
Rough-cut capacity planning and CRP
- RCCP: checks the MPS against critical resources using bills of resources — quick, approximate.
- Capacity requirements planning (CRP): detailed check of MRP planned orders against each work centre's capacity, period by period; produces load profiles.
- Resolving overloads: overtime, alternate routings, subcontracting, rescheduling, adding shifts.
Topic 7
Work study
Work study is the systematic examination of methods of doing work to improve the use of resources and set performance standards. It has two parts: method study and work measurement.
Method study
Find the best way to do a job
Work measurement
Find the standard time for the job
Topic 8
Method study
- 1
Select the job
- 2
Record present method
Process charts, flow diagrams, string diagrams
- 3
Examine critically
Questioning — what, where, when, who, how
- 4
Develop a better method
- 5
Install the new method
- 6
Maintain it
- Recording symbols (ASME): operation (circle), inspection (square), transport (arrow), delay (D), storage (triangle).
- Principles of motion economy: use both hands, minimise movements, fixed locations for tools, gravity feed, comfortable workplace.
Topic 9
Work measurement and PMTS
Work measurement determines the time a qualified worker needs to do a job at a defined level of performance.
Normal time
Observed time × rating factor
Standard time
Normal time × (1 + allowances)
Example
Observed time 4 minutes, rating 110%, allowances 15%. Normal time = 4 × 1.10 = 4.4 minutes; standard time = 4.4 × 1.15 = 5.06 minutes.
- Techniques: stopwatch time study, work sampling, predetermined motion time systems (PMTS, MTM), synthetic data.
- Uses: manpower planning, costing, incentive schemes, scheduling.
- Predetermined motion time systems (PMTS): standard times for basic motions (reach, move, grasp, position, release) from tables — MTM (methods-time measurement), work factor, MOST; 1 TMU = 0.00001 hour (0.036 seconds).
Key terms
- Process sheet
- Document listing operations, machines and times
- Cycle time
- Time between successive units leaving a line
- Balance delay
- Idle time percentage on a line
- Location measure
- Brown and Gibson's combined site score
- TMU
- Time measurement unit in MTM
Quick revision
- Design analysis; DFMA; FMEA.
- Process sheets and planning steps.
- Line balancing formulas and heuristics.
- Dimensional analysis; Brown and Gibson; layout types.
- RCCP vs CRP; work study, method study, work measurement, PMTS.
Important exam questions
Practice questions written to the PTU exam pattern for this unit's syllabus: short answers (Section A style) and long answers (Sections B and C style).
Short-answer questions
- Q1.What is a process sheet?
- Q2.How is cycle time calculated in line balancing?
- Q3.What is balance delay?
- Q4.State the Brown and Gibson location measure.
- Q5.Distinguish RCCP and CRP.
- Q6.What is PMTS?
Long-answer questions
- Q1.Explain product design analysis and process sheet preparation.
- Q2.Solve a line balancing problem (numerical).
- Q3.Explain dimensional analysis and Brown and Gibson's method of location.
- Q4.Explain capacity planning and work measurement including PMTS.
Stuck on this unit?
Message SBS on WhatsApp for help with Production Planning and Control, or to ask about studying MBA at Synetic.