case #2hi-ho yoyo

Hi-Ho Yo Yo, Inc.Case Analysis - FINALS

Hi-Ho Yo Yo, Inc.

It was a little 9:00 on a Monday morning when Jeff Baker walked into your office with a box of

donuts.

“I’ve been talking with Anne about a problem we have with short-term capacity in our pad

printing operations. You know, that’s where we print our logo on the Custom lines of yo-yos.

We have received more orders to pad printing in a way that will enable us to meet out due date

commitments in the best way possible. Would you have time to look on the order list (attached)

and see what kind of schedule we should follow to do that? By the way, you have established

quite a reputation in your short stay here. You have a talent for really explaining why your

recommendations are the best approach in a way that all of us “over-the-hill” managers can

understand. Please be sure to do that for me too. I want to understand why your recommendation

is the best schedule and what the trade-offs are for other possible schedules – and none of that

philosophical college mumbo-jumbo. Remember, I came up through the ranks. I don’t have one

of those sheepskins on my wall,” he says with a laugh.

Since the schedule was back to normal after that MRP (Material requirements planning) report

you did for Anne, you agreed to look at the information. After that compliment, how could you

say no? “Try to get back to me within a couple of days,” Jeff said as he left your office.

After a few minutes with your old operations management text, you call the production control

office to confirm the pad printing schedule. They confirm that pad printing runs one eight-hour

shift per day. They tell you that due to a make-up day for flooding in June, pad printing will be

running 23 days in July, beginning Friday, July 1 (they will work three Saturdays on July 9, 16,

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and 23, and take a one-day holiday for July 4). You thank them for the information and then you

begin to develop your plan.

Even though Jeff lacks a college degree, from what you have seen, he is very sharp. And

obviously he knows good work when he sees it since he liked, and apparently understood, your

past work. You resolve to cover all the bases but in a way that it as clear as possible.

PAD PRINTING ORDER LIST

Job Date Order

Received

Set-up Time Production Time Due Date

A 6/4 2 hrs 6 days 11 July

B 6/7 4 hrs 2 days 8 July

C 6/12 2 hrs 8 days 25 July

D 6/14 4 hrs 3 days 19 July

E 6/15 4 hrs 9 days 29 July

Note: Setup time is to set up the pad printer at the start of the job. Setup includes thoroughly

cleaning the printing heads and ink reservoirs, installing the new pad(s) and ink supply, and

carefully aligning the machine. Setup at the beginning of a new day with the same job is

insignificant.

Examine the following rules and write a report to Jeff Baker summarizing your findings and

advise him on which rule to use. Rules: FCFS, SPT, DD and CR.

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CHAPTER I

Time Context

Hi-Ho YoYo, Incorporation is an organization that customizes logos for yoyos. Currently

they are beginning to see an issue with rising orders and they wish to continue to meet there

order process deadlines. These are ordered on June but then they will only start on July due to a

make-up day for flooding. So Mr. Jeff asked for what is the scheduling to be followed in order

to meet the constraints. Several rules will be evaluated in order to determine the best method of

inventory scheduling. The four rules to evaluate are: First Come, First Serve (FCFS), Shortest

Processing Time (SPT), Earliest Due Date (DD), and Critical Ratio (CR) methods.

CHAPTER II

Viewpoint

Job sequencing is an important task to determine, because it is either going to slow down

the production process or speed it up. An Operations Manager should determine the best method

based off the needs of the organization, which in this case will require that all jobs are completed

prior to their due dates. In this sense, having a job done before the due date is a priority rule of

the organization. According to the book, Operations Management, “Priority rules are simple

heuristics used to select the order in which the jobs will be processed.” (Stevenson) Job

processing times and due dates are very important pieces of information when applying these

rules. If the sequencing rule takes in account when applying theses similar setups to other jobs,

then this setup will lead to reduced setup times, which will save the organization time and

money. Being able to control time, as far as controlling overtime within the production plant,

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will go far in enabling an organization to save by eliminating overtime paid to employees. Not to

mention the customers will be satisfied to receive a product on schedule as well.

CHAPTER III

Statement of the Problem

Sequencing is concerned with determining the order in which jobs are processed. Not

only must the order be determined for processing jobs at work centres but also for work

processed at individual work stations. When work centres are heavily loaded and lengthy jobs

are involved, the situation can become complicated. In this case study, the main problem needed

to address is how to meet the constraints such as due dates, delays, etc. and to satisfy the clients’

wants despite of the increasing orders. The company experienced a delay due to a make-up day

for flooding in the month of June which moves the production date of the order to July. In the

month of July, it is stated in the given case that there are 3 Saturdays (July 9, 16 and 23) that the

labours will continue working and they will have a holiday (July 4) aside from the weekends. So

given the constraints, how will be the operation manager will choose the best scheduling on the

given methods (First Come, First Serve (FCFS), Shortest Processing Time (SPT), Earliest Due

Date (DD), and Critical Ratio (CR) methods). In addition, Mr Jeff also wants to have an

understanding about the scheduling methods to be used in order for him to understand the

process.

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CHAPTER IV

Objectives

Job sequencing rules are used to determine the priority for processing jobs. They are

applied to tackle scheduling problems that generally lead to inefficient performance in

processing job orders. Of central importance is job flow time, which is the amount of time a job

spends in a shop from order placement to its completion and release. The average turnaround

time on job orders is its mean job flow time, which is one way of measuring a job shop's

performance. The main objective in this case study is to find the best rule to be followed in order

to solve the existing problem. The following are the other objectives to be met:

Defining the order in which jobs at a work centre will be administered.

Sequencing decision to be made in order to meet all the due dates and satisfy the needs of

the clients.

Educating staff in order to give then understanding about choosing the best schedule to be

made.

Meeting due dates of customers or downstream operations.

Minimalizing the flow time (the time a job spends in the process).

Reducing work-in-process inventory.

Lessening idle time of machines or workers.

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CHAPTER V

Areas of Consideration/Analysis

Scheduling relates to establishing both the timing and use of resources within an

organization. Under the operations function, scheduling relates to use of equipment and facilities,

the scheduling of human activities, and receipt of materials. In this case, there are facts given that

will help in order to end up into a decision of what method to be used.

“I’ve been talking with Anne about a problem we have with short-term capacity in our

pad printing operations. You know, that’s where we print our logo on the Custom lines of yo-yos.

We have received more orders to pad printing in a way that will enable us to meet out due date

commitments in the best way possible. Would you have time to look on the order list (attached)

and see what kind of schedule we should follow to do that?”

In the paragraph above, it was clearly stated the problem of the Hi-ho Yoyo

Incorporation. Their orders are increasing and they must find a way in order to meet due dates.

“After a few minutes with your old operations management text, you call the production

control office to confirm the pad printing schedule. They confirm that pad printing runs one

eight-hour shift per day. They tell you that due to a make-up day for flooding in June, pad

printing will be running 23 days in July, beginning Friday, July 1 (they will work three

Saturdays on July 9, 16, and 23, and take a one-day holiday for July 4). You thank them for the

information and then you begin to develop your plan.”

Moreover, this information was given by production call office in order to create a plan

and find a solution for the problem. The company needs to meet the orders within twenty-three

(23) days in the month of July; twenty three days only because it was stated that the workers will

have one holiday in addition to their weekends. But then, there are three Saturday that they will

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work. Each day the labourers will work for 8 hours. Given below is the illustration of the

working calendar of the company:

JULY

Sunday Monday Tuesday Wednesday Thursday Friday Saturday

1 2

3 4 5 6 7 8 9

10 11 12 13 14 15 16

17 18 19 20 21 22 23

24 25 26 27 28 29 30

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“Note: Setup time is to set up the pad printer at the start of the job. Setup includes thoroughly

cleaning the printing heads and ink reservoirs, installing the new pad(s) and ink supply, and

carefully aligning the machine. Setup at the beginning of a new day with the same job is

insignificant.”

In addition to the given table, the setup time is noted and the information about it is

given. Because of this, this will be added to the processing time.

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Yellow Working Days

Pink Weekends

Red Holiday


CHAPTER VI

Alternative Course of action

According to Stevenson, priority rules are simple heuristics used to select the order in which

jobs will be processed. In this case study, there are four rules given to be analysed in order to

resolve the current problem. The following are the rules:

1. First Come First Serve (FCFS):

This is a service policy that is based on attaining the customers or clients, in order to their onset

or demand. It means that, the one who comes earlier would be given priority in the sequence of

their arrival. FCFS discipline of service delivery does not take any other parameter into

consideration like quantity, monetary value of the order, etc. If we select this method of delivery

to our clients, we are bound to release the order in the sequence of date.

2. Shortest Processing Time (SPT):

This process of scheduling is used for completion of work within the due date. This method

emphasizes on processing with the job which takes the least time. The division of the work is

done on the basis of input, processing time and the due date for the completion of assignment.

The flow time is calculated for the each part of the job, using the processing time, which helps in

determination of the overall time for the completion of work. This method is useful in single

machine environment.

3. Due Date Scheduling Technique (DD):

This technique of scheduling can be used with the reference of time either forward or backward.

When forward scheduling is used, it started with the date from which job order starts. It

calculates the period of time, from the day on which first operation was performed to all the

subsequent operation till the completion of the work. It determines the earliest time on which the

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work can be completed. When the technique of back scheduling is used for calculating the period

of time of the completion of work, the resources are allocated in reverse order keeping in mind

the deadline of the completion of work and come to the date on which must start the operation,

so that the work can be completed within the due date.

4. Critical Ratio:

Critical Ratio is an index number computed by dividing the time remaining until due date by the

work time remaining. As opposed to priority rules, critical ratio is dynamic and easily updated. It

tends to perform better than FCFS, EDD, and SPT on the average job lateness (delays) criterion.

The critical ratio gives priority to jobs that must be done to keep shipping on schedule. It is used

in conjunction with MRP systems and has broad industrial application. The critical ratio is

measure of urgency of any order compared to the other orders for the same facility. The ratio is

based on when the completed order is required and how much time is required to complete.

These rules assume that setup time and setup costs are independent of the processing

sequence. However, this is not always the case. Jobs that require similar setups can reduce setup

times if sequenced back to back. In addition to this assumption, the priority rules also assume

that setup time and processing times are deterministic and not variable, there will be no

interruptions in processing, the set of jobs is known, no new jobs arrive after processing begins,

and no jobs are cancelled.

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CHAPTER VII

Recommendation

Comparing the four methods, SPT is recommended to be used by the company because it

reduces average flow time for jobs. Since there are constraints such as they have to meet all the

orders within 23 days and the working hours is eight (8) hours per day, using this method they

will finished all the orders at the shortest period of time. Also, the flow time is calculated for the

every part of the job, using the processing time, which helps in getting whole time for the

completion of work.

In First come/first served method (FC/FS) it could not be applied because in this rule,

jobs are processed in the order in which they arrive. The orders must be finished in a shortest

period of time and not on how when the order arrived since they did not started the production on

June (arrival of orders) due to a problem. They started on July and this will not follow the rule.

Next, under Earliest due date method (EDD), it places the highest priority on processing

jobs with the earliest due dates. Job shop quality performance can be measured by the number of

late jobs, the average tardiness across late jobs or the average tardiness across all jobs. This

seems to work well if the firm performance is judged by job lateness. If this will be used, the

process will follow a track based on due dates of the orders and maybe it will not meet the time

constraints given.

Lastly the critical ratio method (CR), in this rule one must calculate a priority index using

the formula (due date–now)/ (lead time remaining). This rule is widely used in practice. However

in this rule, the sequencing of the jobs is done first by getting the critical ratio of each job then

selecting the lowest among them. Then it is repeated eliminating the job with the lowest CR

point until one job is left.

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By choosing Shortest processing time (SPT), the job with the shortest processing time

requirement goes first. This rule tends to reduce work-in-process inventory, average throughput

time, and average job lateness. So this is the most appropriate rule to be used in order to meet the

limitations.

CHAPTER VIII

Conclusion/Detailed action Plan

A report about the choosing the Short Processing Time method must be made and this

will be used for the production. It must in detailed information so that the schedule will be

followed. Other points to implement:

Align demand and delivery;

Increase flexibility and reduce response/lead times at key points in the supply

chain;

Enable lean operations: reduce inventories and costs while meeting delivery

commitments.

Cost reduction can be achieved by a schedule that considers all rules and

constraints. Ignoring a rule/constraint usually results in increased cost due to

reduced productivity, higher inventory, increased offline work, overtime etc.

Customer Relationship Management

Dealer Order Management

Material planning

Scheduling of feeder lines

Vendor supply chain management

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Job Date Order Received

Set-up Time Production Time Due Date

A 6/4 2 hrs 6 days 11 JulyB 6/7 4 hrs 2 days 8 JulyC 6/12 2 hrs 8 days 25 JulyD 6/14 4 hrs 3 days 19 JulyE 6/15 4 hrs 9 days 29 July

JobProcessing Time (days)

Flow time Days to Due date

A 6 6 7

B 2 8 5

C 8 16 19

D 3 19 14E 9 28 23Total 28 days 58 days 68 days

Based on the given information and initial table above, each method will be used for the

computation the criteria to be considered in choosing the best technique.

Sequence

Average Flow Time / Average completion time

Average Tardiness / delays

Utilization / Average # of Jobs at Work Center

Make span

Solution using FCFS Method:

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In HOURS:

FCFS Sequencing

Job

Set-up Time (hours)

ProductionTime (hours)

TotalProcessingTime (hours)

Flow Time (hours)

Date Due

Days Due

Hours Due

Hours Tardy

A 2 48 50 50 11-Jul 7 56 0B 4 16 20 70 8-Jul 5 40 30C 2 64 66 136 25-Jul 19 152 0D 4 24 28 164 19-Jul 14 112 52E 4 72 76 240 29-Jul 23 184 56Total 240 660 68 544 138Sequence A, B, C, D, EAverage Flow Time / Average completion time (sum of total flow / no. of jobs)(660 hours / 5 jobs) 132.00Average Tardiness / delays (total delays / no. of jobs)(138 hours / 5 jobs) 27.6Utilization / Average # of Jobs at Work Center (total flow time / total processing time)(660 hours / 240 hours) 240.00Make span 2.75

Job

Set-up Time (days)

Processing Time (days)

Total Time (days)

Flow Time (days)

Date Due

Days Due

Hours Due (8 hours per day only)

Converted into Days

Hours Tardy

A 0.0833 2 2.0833 2.0833 11-Jul 7 56 2.333333333 0B 0.1667 3 3.1667 5.2500 8-Jul 5 40 1.666666667 4C 0.0833 6 6.0833 11.3333 25-Jul 19 152 6.333333333 5D 0.1667 8 8.1667 19.5000 19-Jul 14 112 4.666666667 15E 0.1667 9 9.1667 28.6667 29-Jul 23 184 7.666666667 21Total 28.6667 66.8333 68 544 22.66666667 44

Sequence A, B, C, D, EAverage Flow Time 13.37Average Tardiness 8.833333333Make span 28.67Average # of Jobs at Work Centre 2.33

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Solution using SPT Method:

SPT Sequencing

Job

Set-up Time (hours)

Production Time (hours)

Total ProcessingTime (hours)

Flow Time (hours)

Date Due

Days Due

Hours Due

Hours Tardy

B 4 16 20 20 8-Jul 5 40 0D 4 24 28 48 19-Jul 14 112 0A 2 48 50 98 11-Jul 7 56 42C 2 64 66 164 25-Jul 19 152 12E 4 72 76 240 29-Jul 23 184 56Total 240 570 68 544 110

Sequence B, D, A, C, EAverage Flow Time / Average completion time (sum of total flow / no. of jobs)(570 hours / 5 jobs) 114.00Average Tardiness / delays (total delays / no. of jobs)(110 hours / 5 jobs) 22Utilization / Average # of Jobs at Work Center (total flow time / total processing time)(570 hours / 240 hours)

2.38

Make span 240

Solution using EDD Method:

EDD SEQUENCE

Job

Set-up Time (hours)


Total ProcessingTime (hours)

Flow Time (hours)

Date Due

Days Due

Hours Due

Hours Tardy

B 4 16 20 20 8-Jul 5 40 0A 2 48 50 70 11-Jul 7 56 14D 4 24 28 98 19-Jul 14 112 0C 2 64 66 164 25-Jul 19 152 12E 4 72 76 240 29-Jul 23 184 56Total 240 592 68 82

Sequence B, D, A, C, E

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Average Flow Time / Average completion time (sum of total flow / no. of jobs)(592 hours / 5 jobs)

118.40

Average Tardiness / delays (total delays / no. of jobs)(82 hours / 5 jobs)

16.4

Utilization / Average # of Jobs at Work Center (total flow time / total processing time)(592 hours / 240 hours)

2.47

Make span240

Another approach:

Job JOB TIME (Set up and Run Time) (in hours)

Date Order Received

Due Date

Days to Due date

SPTSequence

EDDSequence

A 6 days + .083 days (2 hours) = 6.083 days

6/4 11 July 36 days B B

B 2 days + .17 = 2.17 days 6/7 8 July 30 days D DC 8 days + .083 = 8.083

days6/12 25 July 42 days A A

D 3 days + .17 = 3.17 days 6/14 19 July 34 days C CE 9 days + .17 = 9.17 days 6/15 29 July 43 days E E

CR SequencingTABLE 1

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Job

Set-up Time

(hours)


Total Processing

Time (hours)

Date Due

Days Due

Hours Due

CR Ratio

A 2 48 50 11-Jul 7 56 1.12 LowestB 4 16 20 8-Jul 5 40 2.00C 2 64 66 25-Jul 19 152 2.30D 4 24 28 19-Jul 14 112 4.00E 4 72 76 29-Jul 23 184 2.42

Job CR Ratio ComputationA (56 – 0) / 50B (40 – 0) / 20C (152 – 0) / 66D (112 – 0) / 28E (184 – 0) / 76

CR SequencingTABLE 2 (Hour 48)

A FINISHED (1st)B 4 16 20 8-Jul 5 40 -0.50 LowestC 2 64 66 25-Jul 19 152 1.55D 4 24 28 19-Jul 14 112 2.21E 4 72 76 29-Jul 23 184 1.76

Job CR Ratio ComputationB (40 – 50) / 20C (152 – 50) / 66D (112 – 50) / 28E (184 – 50) / 76

JOB B = The job is on schedule. JOB D = The job is ahead of scheduleJOB C & E = The job is falling behind the schedule. And have some slack.

CR SequencingTABLE 3 (Hour 64)

A FINISHED (1st)B FINISHED (2nd)C 2 64 66 25-Jul 19 152 1.24 LowestD 4 24 28 19-Jul 14 112 1.50E 4 72 76 29-Jul 23 184 1.50

Job CR Ratio ComputationC (152 – 70) / 66D (112 – 70) / 28E (184 – 70) / 76

JOB C = The job is on schedule.JOB D & E = The job is falling behind the schedule.

CR Sequencing

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TABLE 4 (Hour 88)A FINISHED(1st)B FINISHED(2nd)C FINISHED (3rd)D 4 24 28 19-Jul 14 112 -0.86 lowestE 4 72 76 29-Jul 23 184 0.63

Job CR Ratio ComputationD (112 – 136) / 28E (184 – 136) / 76

JOB D= The job is on schedule.JOB E = The job is falling behind the schedule.

CR Sequencing

Job

Set-up Time

(hours)

Processing Time

(hours)

Total Time

(hours)

Flow Time

(hours)Date Due

Days Due

Hours Due

Hours Tardy

A 2 48 50 50 11-Jul 7 56 0B 4 16 20 70 8-Jul 5 40 30C 2 64 66 136 25-Jul 19 152 0D 4 24 28 164 19-Jul 14 112 52E 4 72 76 240 29-Jul 23 184 56Total 240 660 68 138

Sequence B, D, A, C, EAverage Flow Time / Average completion time (sum of total flow / no. of jobs)(660 hours / 5 jobs) 132.00Average Tardiness / delays (total delays / no. of jobs)(138 hours / 5 jobs) 27.6Utilization / Average # of Jobs at Work Center (total flow time / total processing time)(660 hours / 240 hours) 2.75Make span 240

Comparison of Sequencing Rules

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Rules

Average Flow Time

Utilization/ Average Jobs at Work

CentreAverage

TardinessFCFS 132.00 2.75 27.60 WorstSPT 114.00 2.38 22.00 BestEDD 118.40 2.47 16.40 GoodCR 132.00 2.75 27.60 Worst

In the table above, it is clearly shown what method to be used. Based on the average tardiness column, it clearly presented that SPT got the lowest point followed by EDD and the methods that gain bigger average tardiness is under FCFS and CR method.

Shortest processing time is generally the best technique for minimising job flow and minimising the average number of jobs in the system. Its chief disadvantage is that long-duration jobs may be continuously pushed back in priority in favour of short-duration jobs. Customers may view this dimly, and a periodic adjustment for longer jobs has been made.

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case #2hi-ho yoyo

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