production planning and control, scheduling methods and scheduling of bottlenecks

1. By
Edward
Sserwaniko

2. About the trainer
• Edward Sserwaniko
Qualifications
• B.Eng. Mechanical & manufacturing
• Masters in Business Administration
Current roles
• Asst. Production manager.
• HIRA Team leader
• IMS internal auditor
Companies
• Roofings Rolling Mills Ltd-permanent employee
• Kinyara Sugar Ltd-management trainee
• Kakira Sugar Ltd-internship
• Coca cola-internship.

3. Objectives of the training
At the end of the training ,trainees should have acquired
knowledge and understanding in the following areas:
• Elements of PPC.
• The need for PPC.
• Scheduling and scheduling methods.
• The need for scheduling.
• Scheduling of bottlenecks.

4. planning
Control

5. The need for a PPC based production system
• Last hour rush is avoided: production control reduces the
number of emergency orders and overtime. This reduces the
overheads.
• Bottlenecks get reduced: The incomplete work or work-in-
transit does not get piled up because production control
balances the line and flow of work.
• Cost reduction: PPC increases the men-machines utilization,
which maintains in process inventories at a satisfactory level,
leads to a better control on raw material inventories, reduces
costs of storage and materials handling, helps in maintaining
quality and limits rejections and thus ultimately reduces the
unit cost of production.

6. Need continued
• Optimum utilization of resources: It reduces the time loss of
the workers waiting for materials and makes most effective
use of equipment.
• Better coordination of plants activities: PPC coordinates the
activities of the plant.
• Benefits to workers: PPC results into better efficiency and
productivity, which leads to stable employment, job
security, improved working conditions increased job
satisfaction and ultimately high morale.
• Improved services to customers: PPC ensures production in
accordance with the time schedules and therefore,
deliveries are made as per the committed schedules.

7. scheduling
• Scheduling is the last stage of planning before a job is
started ,it Specifies when labor, equipment and facilities are
needed to produce a product or provide a service .
Application of scheduling in RRM
• Production
• Maintenance
• Projects
• Transport

8. Typical Scheduling functions
1. Allocating orders, equipment and personnel(loading)
2. Determining the sequence of order performance
3. Initiating performance of the scheduled work
4. Shop-floor control

9. 1.Allocating orders, equipment and
personnel(loading)
• Loading is the process of assigning work to limited resources.
Examples of resources could be people & equipment.
 Infinite loading:
Ignores capacity constraints, but
helps identify bottlenecks in a
proposed schedule to enable
proactive management
 Finite loading:
Allows only as much work to be
assigned as can be done with
available capacity – but doesn’t
prepare for inevitable slippage

10. 2.Determining the sequence of order
performance.
• Sequencing : process of prioritizing jobs at a work center.
Priority rules can be applied such as critical ratio, shortest
processing time,firstcome first served etc.
Examples of sequencing at CRM.
• Wide to narrow
• Thick gauge to thin gauge
• Preferred customer order.etc

11. 3.Measuring performance
• Job completion (flow) time:
Time a job is completed minus the time the job was first available
for processing.
• Average number of jobs in system: Total Completion Time / Total
Processing Time. Measures amount of work-in-progress.
• Make span:
The time it takes to finish a batch of jobs; measure of efficiency
• Job lateness: (used to measure customer service)
Whether the job is completed ahead of, on, or behind schedule;
• Job tardiness: (used to measure customer service)
How long after the due date a job was completed.
• Utilization = Total Processing Time / Total Completion (Flow) Time

12. Illustration for Measuring
performance cont’d
Example 15-5 Calculating job lateness and job tardiness
Completion
Job Date Due Date Lateness Tardiness
A 10 15 -5 0
B 13 15 -2 0
C 17 10 7 7
D 20 20 0 0
Average 0 1.75
Calculation mean flow time (MFT):
MFT= (sum job flow times)/ # of jobs
= (10+13+17+20)/4 = 60/4 = 15 days
Calculating average number of jobs in the system (WIP):
Average # Jobs =(sum job flow times)/ # days to complete batch
= (60)/20 = 3 job
Make span is the length of time to complete a batch
Make span = Completion time for Job D minus start time for Job A
= 20 – 0 = 20 days

13. 4.Shop floor control
• Assigning priority to each job .
• Maintaining information on each pending job (work-in-
process).
• Providing actual output data for capacity control purposes
• Providing measurement of efficiency, utilization and
productivity of manpower and machines.

14. Methods of scheduling
• Gantt charts
• Mathematical programming methods
• Load chart
• Priority decision rules
• Workforce scheduling

15. 1. Gantt charts
• Illustrates the
planned
schedule
compared to
actual
performance.
Mainly used in
project work.

16. 2. Mathematical programming methods
Linear programming methods:
here all the constraints and
objective functions are
formulated as a linear equation
and the equation is solved for
optimality.
PERT/CPM network model:
network showing the sequence
of operations for a project and
the precedence relation
between the activities to be
completed.
EST durati
on
EF
T
ACTIVITY
LST Slack LFT

17. 3. Load chart
• Illustrates the
workload
relative to the
capacity of a
resource.

18. 4. Priority decision rules
• used to determine which job has highest priority then
second, third and so on.
Symbol Priority rule
FCFS First come first
served
EDO Earliest due date
LS Least slack
SPT Shortest processing
time
LPT Longest processing
time
PCO Preferred customer
order
RS Random selection

19. 5.Workforce scheduling
Employees M T W Th F Sa Su
1 x x x x x off off
2 x x x x x off off
3 x x off off x x x
4 x x x x x off off
5 off off x x x x x
6 x x x x off off x
• This technique is
used to satisfy
minimum daily
staffing
requirements.

20. Scheduling of bottlenecks
• A bottleneck is any resource
whose capacity is less than the
demand placed on it. It can be an
employee, an equipment etc.
Examples
• A forklift needed by various
departments at the same time.
• A tipper needed by different users
• A crane having so many jobs at the
same time.

22. How to schedule bottlenecks
Theory of constraints(TOC) technique.
1. Identify the bottleneck(s) in the process
2. Exploit (fully utilize) the bottleneck(s)
3. Subordinate all other decisions to Step 2 - Schedule non-
bottlenecks to support maximum use of bottleneck
activities
4. Elevate the Bottleneck(s) i.e. find other solutions e.g.
capital investment if the bottleneck is not eliminated,
overtime ,subcontract, recruit etc.
5. Do not let inertia set in i.e. move on to solve the next
bottleneck(continuous improvement)

23. Capacity planning solution to eliminate
bottle necks
• Over time
• Flexible working hours e.g. shifts
• Recruit
• Subcontract
• Capital investment e.g. purchase of extra machinery

24. Why do we need scheduling?
• Meet customer due dates.
• Minimize lead time.
• Minimize work-in-process inventory.
• Maximize machine and labour utilization.
• Minimize idle time.
• Minimize overtime .
• Employee motivation.

25. Scheduling aids.
• The following software can help to develop schedules.
1. MS Project software.
2. POM software.
3.Ms excel.

26. conclusion
• Scheduling executes a company’s strategic business plan
and affects functional areas throughout the company
Thank you