Om lect 05_a(r0-aug-08)_manufacturing planning & scheduling_mms_sies

Manufacturing Planning & Scheduling

N.K.Agarwal

PPC

• PPC concerned with decision making regarding– What to produce?– How to produce?– Where to produce?– When to produce?– Who will produce?– How much to produce?

• PPC is the organisation and planning of manufacturing process

• PPC– Co-ordinates supply and movement of materials and labour– Ensures economic and balanced utilisation of machines and

equipments, and– Other activities related with production

• To achieve the desired manufacturing results

Production Planning & Control(PPC)

• Production Planning involves– Formulation– Co-ordination, and– Determination of activities

• In a manufacturing system

• Production Control involves– Process of maintaining a balance between various activities

involved in production planning providing• Most effective and efficient utilisation of resources

Production Planning & Control(PPC)

Production Planning

• The function of the management that decides– The resources the firm will require for its future

manufacturing operations, and– Allocating these resources to produce the desired output in

required amount at least cost

• Production planning prepares– Procurement plans for materials and personnel,– Establishes work procedures and control,– Prepares and issues work authorisation,establishes finished

goods inventory control, and– Maintains alternative plans of action

Production Planning-Procedures

• Categories of production planning procedures– Routing– Scheduling, and– Loading

Production Planning-Procedures

• Routing means determination of path or route over which each piece is to travel in being transformed from raw material into finished product

• Routing generally involves the following– Whether to make/buy– Form and shape of the material– Division of work to be done into operations

Production Planning-Routing

– Choice of machines/ work centers on which each operation should be done and its duration

– Sequence in which operations are to be performed– Division of operations into work elements– Choice of special tooling– Economic lot size of production order quantity– Estimation of amount of scrap

Production Planning-Routing

• Scheduling is– Deciding when and where each operation in a production

process is to be executed, and– Establishment of time table at which to begin and/or

complete each event or operation involved in a procedure

Production Planning-Scheduling

• Developed by reviewing market forecasts, customer orders, inventory levels, facility loading & capacity information regularly

• Plan for future production of end items over short range planning horizon

• An important link between production and marketing

Master Schedule

Functions of MPS

• Translating aggregate plans into specific end items• Evaluating alternative master schedules• Generating material requirement• Generating capacity requirement• Facilitating information processing• Maintaining valid priorities• Utilising capacity effectively

MASTER PRODUCTION SCHEDULE- FLOW CHART

FORECAST & CUSTOMER ORDERS

AGGREGATE PLAN

TENTATIVE MPS

TRIAL FIT ON

MRP SYSTEM CRP SYSTEM

ARE MATERIALS ADEQUATE ?

ARE CAPACITIES ADEQUATE ?

FIRM MPS

TO MRP & CRP SYSTEM

DOMESTIC & INTERNATIONAL

REVISE MASTER SCHEDULE

REVISE MASTER SCHEDULE

END PRODUCTS & SERVICE PARTS / SPARE PARTS

CAPACITY REQUIREMENT PLAN (CRP)

YESYES

NO NO

MPS Environment

• Make – to – stock– Production by the company in batches– Carries finished goods inventory for most of the end items– Mostly consumer products– Orders from warehouses mostly– Lot sizes of orders based on economics

Efforts to prepare MPS are relatively less

• Make – to – order– Companies do not carry finished goods inventory– Builds customer orders as needed– Customers expected to wait for the design & manufacturing

lead time• Example: Buildings, Jewellary making,Ship building

– Lot size and number of products depends upon customer orders

– Many product designs, products and orders to be included

Efforts required to prepare MPS are more

MPS Environment

• Assemble –to – order– Customer delivery times often less than total lead times

– Flexibility maintained in manufacturing

• Basic components and sub-assemblies produced

• Final assemblies taken up only against customer order

– Typical with very large number of possible end items made from combination of basic components and sub-assemblies

– Example: Automobile manufacturing, Fork lifts with different specifications

– End items not scheduled

– Schedule units stated in planning bills of materials

– Common parts and options form the MPS planning bill

MPS Environment

• Objectives– To plan new work orders on the basis of spare capacity

available– To balance the work load in a plant– To maintain delivery promises– To check the feasibility of production programmes

Production Planning-Loading

PPC-Production Control

• Production Control is the procedure – To regulate an orderly flow of materials, and – Co-ordinate various production activities

• To accomplish the objective of producing the desired item

– In the right quantity of desired quality at the required time by the best and the cheapest method

» To attain highest efficiency in production

PPC-Production Control

– Proper co-ordination of the operation of various sections/ departments responsible for production

– To ensure timely supply of raw material at the desired place and of prescribed quality and quantity to avoid delays in production

– To perform inspection of semi finished and finished goods and use of quality control techniques to ensure manufactured goods meeting required specifications

– Also responsible for product design and development

Production Control- Levels

• Three levels in production control– Programming

• Planning the output of product for the factory as a whole– Ordering

• Planning the output of components from suppliers and production departments

– Dispatching • Considers each processing department in turn and plans

the output from the machines, tools and other work centers so as to complete the order by due date

• Ordering is– Process of placing orders, also known as work orders, to

the suppliers and the processing departments for the materials and other parts needed to manufacture the product, and

– To arrange the ordering quantity and delivery schedule in such a way

• That all items are delivered in time to meet the production programme

Production Control- Ordering

• The decision of assigning various jobs to different machines is known as Dispatching

• Functions – To check the immediate availability of materials– Ensuring availability of all production and inspection aids for

use– Obtain appropriate drawings and specifications– Collate jobs, operation layouts, routine etc. with the design

Production Control- Dispatching

– Processing information or inspection schedule– Assign work to definite machine, work place and men– Issue necessary materials and tools etc. to the required

point for use– Issue production note indicating the start and finish time of

the work– Inform progress regarding start of work– Instruction to start the work– Maintain all production records

Production Control- Dispatching

• Follow-up/expediting or progressing is checking production activities so that production may be carried out as per plan– Involves measurement of output against plan, analysis of

performance for short-falls and following up the line management to apply corrective action

• The chaser is responsible for observing that any detail which is overlooked or not properly executed is set right

Production Control- Follow - up

• Scheduling becomes complex due to– Delivery dates have to be promised for work orders against

customers’ orders– Production lots tend to become small & many require

machine change over– Possibility of assigning / reassigning workers & machines to

various work orders

– Schedules to be specific and detailed machine wise to bring

orderliness

Scheduling of Process – Focused Production Systems

Scheduling of Product - Focused System

• Relatively fewer standard product designs• Production usually on produce – to – stock & sell basis• Finished goods inventories are maintained • Production rates of individual products exceed their

demand– Much less pre production planning concerning route sheets, job

instructions, process plans and product designs– Schedules based on economic production runs for products without

firm delivery commitments– Major scheduling concerns are

• Timing of production line change over• Length of production runs

• Reduces cost of production by minimising wastage of material and economic utilisation of resources

• Leads to lower investment by means of efficient and balanced utilisation of resources

• Promotes employee morale by avoiding all sorts of bottlenecks

• Enhances customer satisfaction and confidence

PPC - Importance

MPS and Shop Floor Planning & Control

• MPS and shop floor planning & control results in – Low inventory levels, – Minimise the manufacturing cycle time,– Full utilization of production services, and– Helps in the development of positive customer relations

• By meeting the promised delivery dates

References

• Production Operations Management : Aswathappa / Bhat

• Modern Production / Operations Management: Buffa / Sarin

• Operations Management : Donald Waters

• Manufacturing Planning & Control Systems : Vollman / Bery / Whybark

• Operations Management: R.G.Schroeder

Thank You

PPC - Objectives

• Determining the nature and magnitude of various input factors to manufacture the desired output

• To co-ordinate labour, machines and equipment in the most effective and economic manner

• Establishing targets and checking these against performance

• Ensuring smooth flow of materials by eliminating bottlenecks in production

• Utilisation of under employed resources• To manufacture the desired output of right quality and

quantity at right time

Production Planning-Objectives• Systematic co-ordination and regulation of various

activities • To maintain proper balance of the activities for

efficient production• Determination of raw materials, machines, equipment

etc. and other inputs for desired output• Anticipation of business changes and reacting to

them in proper manner• To have optimum usage or resources with optimum

cost and time • To provide alternative production strategies in case of

emergencies

• Various types of proformas to record details of production process at different stages also to be designed

• In manufacturing plants, routing of an order carried out using Route Sheets

Production Planning-Routing

Route Sheet

Manufacturing Order no.

Drawing no. Date of completion

Description of the item

Remarks

No. of pieces on order/Economic lot size

Spoilage allowance

Total items to be produced

Material description

Purchase Order no.

Time/ Piece

Tool Description

Quality of material allotted.

Stores requisition no.

Due date.

Setup time/lot operation no.

Time allowance

• Objectives of Production control– Provision of raw materials , equipment, machines and labour– To organise production in conformity with the demand

forecast– Ensure utilisation of resources in the best possible manner

such that the cost of production is minimised and delivery date is maintained

– Determination of economic production runs with a view to reduce the setup costs

PPC-Production Control

Production Control- Techniques

• Programming: Objectives– Reliable delivery to customers– Even loading of the plant– Even loading of the labour in total man -hours per week– Efficient use of capital

• Lack of production programming in any manufacturing system results in late delivery to customers

SCHEDULING SERVICES

• ECONOMIC ACTIVITIES IN WHICH PRIMARY OUTPUT IS NEITHER A PRODUCT NOR A CONSTRUCTION

• VALUE IS ADDED TO THIS OUTPUT THAT CANNOT BE INVENTORIED LIKE CONVENIENCE, COMFORT, SECURITY, AND THE OUTPUT IS CONSUMED AS PRODUCED– TRANSPORTATION

– UTILITIES

– COMMUNICATIONS

– FINANCE, BANKING, INSURANCE, POST & TELEGRAPH

SERVICE OPERATIONS

• SERVICE SYSTEMS – DO NOT HOLD INVENTORIES– DEMAND ON THEM HIGHLY VARIABLE– OPERATIONS LABOUR INTENSIVE– PRIMARILY PERFORMED THROUGH PERSONNEL

• AS SUCH, PERSONNEL SCHEDULING BECOMES COMPLEX

SERVICE OPERATIONS

• ALSO KNOWN AS NON-MANUFACTURING OPERATIONS, CAN BE CLASSIFIED AS

– STANDARD SERVICES– CUSTOMER SERVICES

• CLASSIFICATION ACCORDING TO THE DEGREE OF STANDARDISATION OF THE OUTPUTS AND THE PROCESS PERFORMED BY THE SERVICE SYSTEM

SERVICE OPERATIONS

• STANDARD SERVICES– SYSTEMS MORE LIKE PRODUCT-FOCUSSED MANUFACTURING

• SERVICES STANDARD FOR MOST CUSTOMERS

• PROCESS ONCE BEGUN CARRIED THROUGH TO COMPLETION WITHOUT MUCH DELAY

• SIGNIFICANT DIFFERENCE WITH PRODUCT-FOCUSSED MANUFACTURING BEING THAT SERVICES PRODUCED ACCORDING TO CUSTOMER ORDER RATHER THAN FOR FINISHED GOODS INVENTORY

– TRNASPORT COMPANIES, FAST FOOD RESTAURANTS, POSTAL SERVICES, AIRLINES

• SOPHISTICATED SCHEDULING SUCH AS ON-LINE COMPUTER BASED SCHEDULING SYSTEMS USED

SERVICE OPERATIONS• CUSTOMER SERVICES

– SYSTEMS LIKE JOB SHOPS AND HENCE SCHEDULING MUCH LIKE JOB SHOPS

• SMALL SERVICES LIKE A DOCTOR’S CLINIC, SMALL RETAILERS, LOCAL TRANSPORT COMPANIES

– NO FORMAL SCHEDULING SYSTEMS EMPLOYED– SIMPLE SCHEDULING SYSTEMS SUCH AS APPOINTMENT

SCHEDULES, TOKEN SYSTEM, FIRST-COME-FIRST-SERVICE ETC USED TO ASSIGN PRIORITIES TO CUSTOMERS

– PART TIME WORKERS AND STAND-BY EQUIPMENT FREQUENTLY USED DURING HIGH DEMAND PERIOD

– HOSPITALS USE MORE SOPHISTICATED SCHEDULING SYSTEM• INCLUDING A MOST CRITICAL NEED CRITERIA ;FIRST-COME-

FIRST-SERVED

SCHEDULING PERSONNEL IN SERVICES

• USE OF WAITING LINES(BASED ON FIRST-COME-FIRST-SERVED PRIORITY) AS A BUFFER FOR DIFFERENCE BETWEEN CUSTOMER DEMAND AND SYSTEM CAPACITY

– ENABLES SCHEDULING PERSONNEL TO MAINTAIN UNIFORM SYSTEM CAPACITY FROM TIME TO TIME

• USE OF APPOINTMENT SCHEDULES TO LEVEL OUT THE DEMAND FOR SERVICES

– ENABLES SCHEDULING PERSONNEL SO THAT THE SYSTEM CAPACITY IS ALMOST UNIFORM

• APPOINTMENT SCHEDULES IN MEDICAL, LEGAL SERVICES• EMERGENCY CUSTOMERS ACCORDED PRIORITY AND REMAINING

SERVICED BY APPOINTMENT

SCHEDULING PERSONNEL IN SERVICES

• PERSONNEL SCHEDULES DEVELOPED TO ALLOW SYSTEM CAPACITIES WHICH MATCH THE CUSTOMER DEMAND

– SYSTEM CAPACITY VARIED BY VARYING NUMBER OF PERSONNEL TO WORK DURING EACH HOUR OF THE DAY

– PART TIME PERSONNEL MAY BE EMPLOYED DURING PERIODS OF PEAK DEMAND

• FOR EMERGENCY SERVICES LIKE FIRE OR POLICE, SCHEDULING DONE FOR 24 HOUR FULL CREW COVERAGE

– DURING PEAK DEMAND PERIODS, OFF-DUTY PERSONNEL CALLED IN AND COMPENSATED WITH OVERTIME PAYMENT OR TIME-OFFS