University Of Jordan

Faculty of Engineering and Technology

Industrial Engineering Dep.

Work Systems and the Methods, Measurement, and Management of Work

Course Project

Instructor: Dr. Mazen Arafeh

Student Name:Reg. No.:

Areej Khalil Ismael0098025

Insaf Zaid Kilani0095415

Nadine Faisal Ibrahim0090169

Yazan Emad Saif0094463

Part 1 Cycle Time Measurement:

Our objective of part is to practically illustrate how cycle time measurement really works; which is widely used in industry to determine cycles' standard times, and other associated important numbers.

A number of cycle time measurement methods are used:

Estimation using Historical Records

Direct Time Study

Predetermined Motion Time Systems

Going down the list the accuracy of time obtained is better, however with accuracy increasing; effort and analysis time also increases.

In our project we used Direct Time Measurement followed by PTMS for the purposes of comparison between the two; also for the sake of simplicity we went to Gloria Jeans coffee shop and chose to determine the cycle time needed to make a special cold drink called Voltage.

The process of making this drink consists of multiple work elements, the identification of these work elements is made on basis of logical grouping as follows:

  1. Prepare a cup full of ice.
  2. Add milk to the ice cup.
  3. Add special flavor powders.
  4. Mix all ingredients in a blinder.
  5. Prepare a coffee flavor.
  6. Pour the mixed ingredients back in the cup.
  7. Add the coffee flavor on top.
  8. Deliver the ready drink to the counter.

In order to use PMTS method we had to break up these work elements into their basic motion elements, and identify the type of these motions by referring to tables 14.4 (a), 14.4(b), 14.4 (c), 14.4(d), 14.4(e), 14.4(g) and 14.4(j) By matching the best motion-description to the motion we have.

In order to record every movement and for purposes of accuracy we videotaped the worker while making the drink, violating the shops regulations.

The following pages contain detailed basic motion we recorded in this study, along with their corresponding TMU's obtained from the mentioned tables.

  1. Prepare a cup full of ice:

Getting the empty Cup:

Reach (A, 30.5cm) =9.6

Grasp (1C1) = 7.3

Move (B, 45cm) = 17

Position(S, easy to handle) = 5.6

Adding ice to the empty cup:

Reach (A, 40cm) = 11.4

Grasp (select) = 9.1

Move (C, 40cm) = 18.7

Position (S, easy to handle) = 5.6

  1. Add milk to the ice cup:

Getting the milk bottle and pouring milk into the cup:

Reach (A, 40.5cm) = 12.3

Grasp (1A) = 2

Move (B, 5.1cm) = 5.7

Position (S, easy to handle) = 5.6

Closing the milk bottle:

3 turns  90°/turn 5.4×3

  1. Add the special flavor powders:

Getting the powder container:

Reach (A, 40cm) = 11.4

Grasp (1C1) = 7.3

Move (B, 40cm) = 15.8

Adding powder to the ice cup:

Move (B, 15cm) = 8.9

Grasp (1C2) = 8.7

Move (C, 12cm) = 9.5 × 3

Position (S, easy to handle) = 5.6 × 3

Closing the powder container:

Reach (A, 15cm) = 7.0

Grasp (1A) = 2.0

Move (C, 15cm) = 10.3

Position (S, difficult to handle) = 11.2

Putting the powder container back in its place:

Move (15cm) = 8.9

  1. Mix all ingredients in a blinder:

Worker turns to the blinder:

Turn to the other counter = 18.6 × 2 = 37.2

Getting blender’s container:

Move (1m)  1-76.2 = 23.8

We must add 1 TMU for each 2.54 > 76.2

For 23.8  add 9.37= 9.37 + 24.3 = 33.67

Position = 21.8

Transferring the cup to the blinder's container:

Reach (B, 40cm) = 15.8

Grasp = 7.3

Move (B, 40cm) = 15.8

Position = 52.1

Move = 15.8

Position = 16.2

Release = 2

Closing the lid of the blender’s container:

Reach = 8.7

Grasp = 7.3

Move = 11.3

Position = 47.8

Position the blender's container on the blender:

Move = 11.3

Position (NS, difficult to handle) = 53.4

Setting up the blender:

Reach the cover = 8.7

Position the cover = 53.4

Reach to the bottom of the blender = 6.1

Turn on the blender = 2 sec

** Machine time "mixing ingredients using the blinder" = 19 sec

  1. Prepare a coffee flavor:which will not be taken into account since it was done as an internal work element while the machine was running.
  1. Pour the mixed ingredients back in the cup:

Getting the blinder's container with mixed ingredients:

Move the cover = 11.3

Reach the container = 8.7

Grasp the container = 7.3

Move the container = 20.4

Position the container = 53.4

**Pouring the drink in the cup = 10 sec

  1. Add the coffee flavor on top:

The worker turns to the counter:

Turn 2 turns = 2 × 37.2

The worker positions the cup:

Move (1m) = 33.67

Position = 16

Adds the coffee flavor:

Reach = 9.6

Grasp = 8.7

Position in the drink = 21.8

  1. Deliver the ready drink to the counter:

The worker delivers the drink to the customer:

Reach = 11.5

Move (1.5m)  1.5-76.2 = 73.8

29 + 24.3 = 53.3 TMU

** Total task time = 1010.04 TMU's

This is identical to 37 seconds

Total cycle time would be 37+19+10=65

The Direct time study using the video timer resulted in a cycle time of 70 seconds; we can suggest the following reasons to explain the difference between the two methods:

  1. Human in errors in recording every basic motion element, especially those ones that take a second or less.
  2. Errors in finding the best description for a specific motion element from the table.
  3. PTMS is known for its high accuracy, and this 5 seconds difference is maybe only due to better accuracy.

Part 2Work Sampling:

Universal for Industry of Dripping Irrigation Pipes is a company that is specialized in the manufacturing of anything related to watering of plants from regular water pipes, dripping pipes, drippers and high pressure pipes.

The company's factory is located at King Abdullah the second Industrial City; with a relatively moderate size theplant has 6 production lines that are used to produce different types of their products.

The production department was trying to assess the performance of two of those production lines which are in interest to them because of producing the most demanded types of their products which are GR16840 and GR16440, a work sampling study has been carried during a 19-day period (or a total of 456 hours) and the following data has been observed.

Number of Observations
Category / Line 3 / Line 5
Production / 187 / 379
Idle / 116 / 23
Set up / 77 / 54
Total / 380 / 456

Table 1: A Summary of the Work Sampling Study

Our Objective of collecting this data is to obtain information about the lines performances, lines utilization and allowances for machines operating on this line, and to also compare the performances of these lines relative to one another using statistical analysis approach.

A preliminary step before starting this analysis is to calculate proportion of samples spent at each category of the above mentioned in the table.

Table 2 shows values of proportion calculated from the sample.

Number of Observations
Category / Line 3 / Line 5
Production / 0.4921 / 0.8312
Idle / 0.3053 / 0.0544
Set up / 0.2026 / 0.1184
Total / 1 / 1

Table 2: corresponding sample proportions to each category

Category definition:

  1. Production: is when the line actually processing input materials.
  2. Idle: the down time of the line due to break downs or periodic maintenance.
  1. Set up: is when the line being prepared to the insertion of new materials to be processed.

1-A Line 3:

A.1 Running Production Analysis:

The proportion of samples obtained at which line 3 was operating on production is (0.4921), with a sample standard deviation ==0.0256.

Now the reason this line's production is relatively low is that it operates using old machines which require frequent maintenance to keep them running, and more setup steps at each cycle, although the production department still expects this line to be operating with at least 60% of its time to be spent on production.

Statistical Figures:

In order to get an idea of how well line 3 meets production expectations, a statistical test is to be made on the following hypothesis:

H: P1= 0.60

H: P1 0.60

Minitab was used, and test results were:

95% Upper Exact

Sample X N Sample p Bound P-Value

1 187 380 0.492105 0.535541 0.000

The following Minitab output shows a 95% two-sided Confidence Interval on production proportion:

Sample X N Sample p 95% CI

1 187 380 0.492105 (0.440755, 0.543579)

In order to determine how the tolerance about P. at this level of confidence the following equation is to be used:

= 0.05, which means at this level of confidence using a sample size of n= 380 observations, we'll have an uncertainty of 5% of

about the true proportion value, it's considered as an excellent tolerance around the true value and no need to collect more data.

A.2 Decision Summary using the above statistical figures:

Since is less than, we can conclude with a strong evidence that the population proportion is less than 0.6, thus this line doesn't meet the production's department expectations and management actions must be taken in order to replace the old machines with new ones, regarding the importance of the product manufactured on this line to the company's business or at least to use a different production line to produce this product.

A.3 Idle Time Analysis:

The corresponding 95% two-sided confidence interval on line's 3 Idle time obtained from this study is as follows:

Sample X N Sample p 95% CI

1 116 380 0.305263 (0.259320, 0.354271)

A.4 Set up Time Analysis:

The corresponding 95% two-sided confidence interval on line's 3 set up time obtained from the study is as follows:

Sample X N Sample p 95% CI

1 77 380 0.202632 (0.163354, 0.246613)

A.5 Suggestions:

From this study we find that line 3 wastes a good amount of time on set up, break downs and maintenance, one way to do reduce this non-adding value work is to run a motion study on these two categories in order to assess the steps each one includes and their importance and whether we can eliminate, combine some of them or even to find other ways that save more time to be used in production.

1-B line 5:

B.1 Running Production Analysis:

The proportion of samples obtained at which line 5 was operating on production is (0.8312), with a sample standard deviation == 0.0175.

Line 5 is a newly installed line with new machines which usemore developed techniques in the production of irrigation pipes. Apparently using new machines with decreases the set up steps required in each cycle and of course requires less maintenance. Efficiency of this line's performance is expected to be 85%.

Testing the two sided Hypothesis using Minitab gives the following output:

H: P2 = 0.85

H: P2 < 0.85

Exact

Sample X N Sample p 95% CI P-Value

1 379 456 0.831140 (0.793537, 0.864379) 0.294

Since is greater than, we fail to reject Ho; meaning that the performance of line three can be considered as meeting its expectations.

B.2 Idle Time Analysis:

The corresponding 95% two-sided confidence interval on line's 5 Idle time obtained from this study is as follows:

Sample X N Sample p 95% CI

1 23 456 0.050439 (0.032239, 0.074724)

B.3 Set up Time Analysis:

The corresponding 95% two-sided confidence interval on line's 5 set up time obtained from the study is as follows:

Sample X N Sample p 95% CI

1 54 456 0.118421 (0.090226, 0.151676)

B.4 Suggestions based on the statistical figures obtained above:

Proportion of samples detected at which line 5 was found to be operating is considered to a very good outcome, the same can be said about the number of samples at which line 5 was found to be idle, however those numbers can be improved by decreasing the set up steps and increasing the proportion of setting up, by running out a motion study on these steps, another way that can be used is to give workers who set up machines on this line a better training, since they are new and still not quite familiar with them.