1. Define Loading.
Loading can be defined as the study of the relationship between load and capacity at the places where work is done. The information provided by loading is used (1) to ensure the efficient utilization of the plant and labour in a factory, (2) to help in the setting of reliable delivery promises, (3) and to assist in the forward planning of the purchase of new plant.
2. What are the aims of loading? Aims of Loading
1. To check the feasibility of production programme 2. To assist in the efficient planning of new work. 3. To assist in balancing the plant to the existing load. 4. To assist in the fixing of reliable delivery promises.
3. Define Scheduling.
Scheduling means – when and in what sequence the work will be done. It involves deciding as to when the work will start and in a certain duration of time how much work will be finished.
4. Define Production Schedule.
A production schedule is similar to a railway time table and shows which machine is doing what and when. A production schedule, is a statement of target dates for all orders or operations in hand and reveals their starting and finishing dates. Scheduling finalizes the planning phase of Production Planning and Control System.
5. What are the external factors that affect scheduling? External Factors
1. Customer’s demand
2. Customer’s delivery dates, and
6. Mention few internal factors that affect scheduling. Internal Factors
1. Stock of finished goods with the firm.
2. Time interval to process finished goods from raw material. In other words – how much time will be required to manufacture each component, subassembly and then assembly (i.e., the final product),
3. Availability of equipment and machinery; their total capacity and specifications.
7. What are the advantages of the Master Schedule? Advantages:
1. It is simple and easy to understand 2. It can be kept running (i.e. current),
3. It involves less cost to make it and maintain.
8. What are the disadvantages of a Master Schedule? Disadvantages:
1. It provides only overall picture, and 2. It does not give detailed information.
9. Mention few applications of a Master Schedule. Applications
It finds applications:
1. In big firms, for the purpose of loading the entire plant, 2. In Research and Development organizations, and
3. For the overall planning in foundries, computer centres, repair shops, etc.
10. Define a Master Schedule.
A master schedule resembles central office which possesses information about all the orders in hand. A master schedule is thus updated continuously; it depicts a running total of the
11. Mention few techniques employed for loading and scheduling.
Some of the techniques (besides master schedule) employed for Loading and Scheduling purposes are:
(a) Perpetual schedule; (b) Order schedule;
(c) Loading by schedule period; (d) Commercial devices.
12. What is perpetual scheduling? Perpetual Scheduling
Like master scheduling, it is also simple and easy to understand, is kept current, involves less costs and can be maintained by clerical staff. But, the information which it provides is very gross and at the same time it is not clear from the chart – when the work will take place.
13. Mention some of the Commercial Devices used for Loading and Scheduling.
Some of the Commercial Devices for Loading and Scheduling are : (a) Produc-Trol Board,
(b) Sched-U-Graph, (c) Board master,
(d) Magnetic boards, and (e) Roll charts, etc.
14. What is Manufacturing Schedule?
A master schedule is too general to permit adequate day-to-day planning by line supervision, and is usually unnecessary in a small organization.
15. What is Gantt chart?
The Gantt Chart was developed by Henry L. Gantt. It is frequently used to keep track of multiple machine schedules. Gantt chart is actually a modified bar chart, wherein load is marked against a time scale with one horizontal bar or line allocated to each machine.
16. Name the two basic types of Gantt Char.
1. Order Control Chart 2. Machine Load Chart
17. Define Progress control.
Progress control means – trying to achieve the standards set, i.e. a certain level of efficiency or a certain volume of production in a specified duration.
18. Name the two principles of expediting.
The work within the organization can be expedited by the following two principles: (i) The exception principle and
(ii) The fathering principle
19. Define Exception Principle.
In exception principle, the scheduling group (on the basis of progress reports), explores the jobs behind the schedule. The expediting group takes up such jobs, procures necessary materials, tools, etc., i.e., (expediting group) solves all problems related to these jobs and intimates the scheduling group to reschedule them.
20. Define Fathering Principle.
According to fathering principle each expeditor is made responsible for a job or a group of jobs for which he arranges the tools, materials, equipment, etc. Such a system works very well for controlling large projects.
21. Define Operation Time. Operation Time:
It amounts the time required to manufacture each part, to make one subassembly and to execute one assembly. This information can be had from the operation sheet.
22. Define Line of Balance.
LOB is a manual planning and scheduling technique similar in nature to MRP (Material Resource Planning).
This method was developed by the U.S. Navy during World War II. It is most appropriate for assembly operations involving a number of distinct components. In essence, it employs the principle of management-by-exception through a comparison of progress of individual components with the time schedule for completed assemblies.
23. What are the advantages of Line of Balance technique?
The L.O.B. is a simple and useful planning and control technique, its main advantages being.
1. Like network analysis (PERT, CPM etc.). It formalizes and enforces a planning discipline which in itself is useful.
2. It is a simple but powerful procedure, which relies on several assumptions.
24. Mention few applications of LOB technique. Applications/Uses
- In many larger manufacturing firms, LIB is no longer used, particularly since the development of MRP II, which links shop floor control into an integrated system for material planning and control. However, LOB has some advantages in that it is more customer-oriented than MRP. Many small firms and non-manufacturing organizations still find it a useful technique.
- LOB technique has also been computerized. Several computer programs have been written and use of these, particularly where many operations are involved and progress reviews are frequent, simplifies the application of lines of balance.
25. Define MRP.
Materials Requirement Planning (MRP) is a technique for determining the quantity and timing for the acquisition of dependent demand items needed to satisfy master production schedule requirements.
26. What are the objectives of MRP?
1. Inventory reduction.
2. Reduction in the manufacturing and delivery lead time. 3. Realistic delivery commitments
4. Increased efficiency.
27. Define Dependent Demand.
The demand for an item depends on another item. The demand dependency is the degree to which the demand for one item is associated with demand for another item.
28. Define Lot Size.
The quantity of items required for an order.
29. Define Time Phasing.
Scheduling to produce or receive an appropriate amount (Lot) of material so that it will be available in the time periods when required.
30. Define Gross requirements.
The overall quantity of an item needed at the end of the period to meet the planned output levels.
31. Define Net requirements.
The net quantity of an item that must be acquired to meet the scheduled output for the period. It is calculated as, Gross requirements minus scheduled receipts for the period minus amounts available from the previous period.
32. Define Requirement explosion.
The breaking down of (exploding) parent items into component parts that can be individually planned and scheduled.
33. Define Scheduled receipts.
The quantity of an item that will be received from suppliers as a result of orders that have been placed.
34. Define planned order receipts.
The quantity of an item that is planned to be ordered so that it will be received at the beginning of the period to meet net requirements for the period. The order has not yet been placed.
35. Define Planned order release.
The quantity of an item that is planned to be ordered or it is a plan (quantity and date) to initiate the purchase or manufacture of materials so that they will be received on schedule after the lead time offset.
36. Define Lead time offset.
The supply time or number of time buckets between releasing an order and receiving the materials.
37. Define Master Production Schedule.
MPS is a series of time phased quantities for each item that a company produces, indicating how many are to be produced and when. MPS is initially developed from firm customer orders or from forecasts of demand before MRP system begins to operate.
38. Define Inventory Status File.
Every inventory item being planned must have an inventory status file which gives complete and up to date information on the on hand quantities, gross requirements, scheduled receipts and planned order releases for the item. It also includes planning information such as lot sizes, lead times, safety stock levels and scrap allowances.
BOM identifies how each end product is manufactured, specifying all subcomponents items, their sequence of build up, their quantity in each finished unit and the work centres performing the build up sequence.
40. Mention Basic scheduling problem.
Flower production scheduling for fluctuating demand (sometimes referred to as smoothing problems)
Batch production scheduling, when products are manufactured consecutively The assignment problem
Scheduling orders with random arrivals Product sequencing
41. Define priority sequencing.
”Priority Sequencing” is a systematic procedure for assigning priorities to waiting jobs thereby determining the sequence in which the jobs will be performed.
42. List criteria for sequencing.
Set up cost.
In process inventory. Idle times.
Average time to complete jobs. Average number to complete jobs. Average time the jobs are late.
The criteria like set up cost, inventory cost and idle times are primarily concerned with internal facility efficiency and other criteria reflect both customer service and internal efficiency.
43. List priority sequencing rules.
1. Fist come first served (FCFS): Gives top priority to the waiting job that arrived earliest in the production system.
2. Earliest due data (EDD) Gives top priority to the waiting job whose due data is earliest. 3. Shortest processing time (SPT): Gives top priority to the waiting job whose operation time
at work centre is shortest.
4. Least slack (LS): Slack is calculated as the difference of length of time remaining until the job is due and the length of its operation time.
5. Longest processing time (LPT). 6. Preferred customer order (PCO).
43. Define Dispatching.
Dispatching is the routine of setting productive activities in motion through the release of orders and instruction in accordance with previously planned times and sequences in the route sheets.
44. List Document raised by Dispatcher. Documents Raised by the Dispatcher Material requisitions.
Job cards: Which authorize the workman to start the work on certain material, indicate what to do
and also serves as a means of production progress.
Labour cards: Which are used to report labour time utilized and quantity of work performed and
to supply other information which are required in the preparation of production reports and payrolls.
Move cards: Which authorize the movement of materials as per requirements of the job and used
in production progress reports?
45. List duties of Dispatcher. Duties of a Dispatcher
1. The receipt and filing of all shop orders and associated documents. 2. Selection of jobs cards or other forms of instructions to the operations. 3. The issue of job cards or other forms of instructions to the operations.
4. Issue of instruction to setters regarding what machines are to be set up, for which jobs and when.
5. Issue of instruction concerning the movement of materials between work centres. 6. Issue of instructions concerning the issue and return to stores of special tooling. 7. The maintenance of records of production.