## Production Planning And Control - Dec 18

### Mechanical Engineering (Semester 7)

Total marks: 80

Total time: 3 Hours
INSTRUCTIONS

(1) Question 1 is compulsory.

(2) Attempt any **three** from the remaining questions.

(3) Draw neat diagrams wherever necessary.

**1** attempt any four

**1.a.**What is the status of PPC dept. depending upon the company's manufacturing processes?

**1.b.**What do you understand by the degree of centralization?

**1.c.**What are the ordering cost and inventory carrying cost? Explain the relationship between the two with the help of a neat sketch.

**1.d.**List down the details which a process sheet should contain.

**1.e.**Define the term dummy activity with respect to network diagram with the help of an example.

**2.a.**Illustrate different manufacturing methods. Give characteristics with one example of each

**2.b.**What do you understand by work order and subsidiary order? What are the rules for raising the work order?

**3.a.**An automobile manufacturer purchases 2400 castings over a period of 360 days. This requirement is fixed and known. These castings are subject to quantity discounts. Ordering cost is Rs. 70,000/- and storage cost per day is 0.12% of the unit cost. Determine the optimal purchase quantity if the supplier has offered the following unit prices for the castings.

Unit price = Rs. 1000 for q < 1000

= Rs. 950 for q ≥ 1000

**3.b.**An investigation into the demand for water pumps manufactured by Joy Engineering Pvt Ltd. resulted into the following historical data :

Year | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 |
---|---|---|---|---|---|---|

Sale (in hundreds) | 28 | 33 | 37 | 48 | 54 | 68 |

Project the trend of sales for the next **3** years

**4.a.**The processing times of 100 gears for the three conversion processes are given below:

**i.** In what sequence should gears be scheduled to minimize processing time of all gears.

**ii.** Determine the elapsed time.

**iii.** Find percentage utilization of the machines in the first 100 hours.

**4.b.**A workshop has four machines and four tasks for completion. Each of the machines can perform each of the four tasks. Time taken at each of the machines to complete each task is given in the table below. How should the tasks be assigned to machines to minimize requirement of machine hours?

**5.a.**Solve the LPP

Maximize $Z=4 X_{1}+3 X_{2}+6 X_{3}$

Subject to,

$2 \mathrm{X}_{1}+3 \mathrm{X}_{2}+2 \mathrm{X}_{3} \leq 440$ $4 \mathrm{X}_{1}+3 \mathrm{X}_{3} \leq 470$ $2 \mathrm{X}_{1}+5 \mathrm{X}_{2} \leq 430$

$\mathrm{X}_{1}, \mathrm{X}_{2}, \mathrm{X}_{3} \geq 0$

**5.b.**The activities and three estimates in days for the activities are given in the table below

Activity | 1-2 | 2-3 | 3-4 | 3-5 | 3-6 | 4-5 | 4-6 | 5-6 | |
---|---|---|---|---|---|---|---|---|---|

t_{o} |
2 | 1 | 0.5 | 0 | 1 | 1 | 6 | 3 | 4 |

t_{m} |
2 | 1.5 | 2.5 | 0 | 2.5 | 2 | 7 | 4 | 6 |

t_{p} |
8 | 11 | 7.5 | 0 | 7 | 3 | 8 | 11 | 8 |

**i.** Draw the network diagram.

**ii.** Determine the critical path.

**iii.** What is the probability that the project will be completed in 20 days?

**6.a.**Relationship of PPC department with other departments.

**6.b.**Two bin system

**6.c.**Forward Scheduling and Backward Scheduling

**6.d.**MRP I and MRP II