Computer integrated production planning

Prepared by B.venuM.Tech(CAD/CAM),

ASST. PROFESSER, MeRITS

Production PlanningProduction Planning may be said to be a technique of

forecasting ahead every step in the long process of production, taking them at right time and in the right degree and trying to complete operations at the maximum efficiency

In the words of Kimball and Kimball Jr – “The planning of industrial operations involves

four considerations, namely, what work shall be done, how the work shall be done and lastly, when the work shall be done.”

PRODUCTION CONTROLProduction control is the process that keeps a watchful

eye on the production flow and size of resources along with the location, of any deviation from the present action and to arrange for the prompt adjustment so that the production may run according to the original or revised schedule

In the words of Henry Fayol – “Production control refers to ensuring that all

which occurs is in accordance with the rules established and instructions issued.”

• Inputs like materials, men and machines are efficiently used

• Factors of production are integrated to use them economically

• Division of work is undertaken carefully so that every available element is properly utilised

• Work is regulated from the first stage of procuring raw materials to the stage of finished goods

• Questions like what, when and how to be manufactured are decided

Characteristics

• Determining sequence of operations for continuous production

• Planning plant capacity for future production programmes

• Issuing co-ordinated work schedules to concerned persons

• Maintaining sufficient inventories to support continuous flow of production

• Evaluating performance of workshops• Maintaining production schedules to ensure

delivery at proper time

AIMS N OBJECTIVES

• Preparation of production budget• Devising manufacturing methods and

sequence of operations• Deciding type of machines and equipments• Preparation of operation sheets and

instruction cards• Estimating men, machine and material

requirements• Undertaking time and motion studies• Preparing master schedules

AREAS OF PRODUCTION PLANNING

Production planning and control is important for the following reasons -

• For Increasing Production – Main purpose of production planning is to arrange inputs. Production control programme minimises idleness of men and machines. It thus helps in raising industrial output.

• For co-ordinating plant activity -In planning production is carried out in a number of processes and thus activities are synchronized for smooth working.

NEED OR IMPORTANCE

• Sub-dividing the master schedule into manufacturing and subsidiary orders

• Routing• Scheduling• Despatching• Expediting• Tool keeping

AREAS OF PRODUCTION CONTROL

• For Cost Control – A properly planned system of production will help in controlling costs by not only making full utilisation of various inputs but also by increasing output and lowering overhead expenses per unit.

• For Rationalisation of Production Activities – In production planning, the process of entering of raw materials and converting them into finished goods is planned in such a way that everything is done in sequence or routine. It regulates flow of inputs to run production system smoothly

Following are the limitations faced by production planning and control –

• Based on Assumptions – Production planning and control is based on certain assumptions. In case the assumptions prove correct, the planning and control will go smoothly. But if they go wrong, process of planning and control will go weak.

• Rigidity – Under production planning and control, there is rigidity in the behaviour of employees and it may not help in smoothening flow of work.

LIMITATIONS

• Difficult for small firms – This process is time consuming and therefore not affordable for small firms

• Costly – It is a costly device as its implementation requires separate persons to perform functions of planning, expediting, dispatching etc.

• Dependence on External Factors – External factors like natural calamities, change in technology, government controls etc reduce effectiveness of production planning.

• Planning• Routing• Scheduling• Despatching• Follow-up and Expediting• Inspection

ELEMENTS OF PRODUCTION PLANNING

It is the first element of production planning and control. Planning is deciding in advance what is to be done in future. An organisational set up is created to prepare plans and policies. Various charts, manuals and production budgets are also prepared. Planning provides a sound base for control. A separate department is set up for this work.

PLANNING

Routing is determining the exact path which will be followed in production. It is the selection of the path from where each unit have to pass before reaching the final stage. The stages from which goods are to pass are decided in this process.

In the words of ALFORD and BEATY – “Routing is the specification of the flow

sequence of operations and processes to be followed in producing a particular manufacturing lot.”

ROUTING

The following steps are taken for completing a routing procedure –

• Deciding what part to be made or purchased

• Determining Materials required• Determining Manufacturing Operations

and Sequences• Determining of Lot Sizes• Determining of Scrap Factors• Analysis of Cost of the Product• Preparation of Production Control Forms

ROUTING PROCEDURE

Scheduling is the determining of time and date when each operation is to be commenced or completed. The time and date of manufacturing each component is fixed in such a way that assembling for final product is not delayed in any way.

In the words of KIMBALL and KIMBALL – “The determination of the time that

should be required to perform each operation and also the time necessary to perform the entire series, as routed, making allowances for all factors concerned.”

SCHEDULING

• Master Scheduling – It is the breakup of production requirements. It is the start of scheduling. It is prepared by keeping in view the order or likely sales order in near future.

• Manufacturing Scheduling – It is used where production process is continuous. The order of preference for manufacture is also mentioned in the schedule for a systematic production planning.

• Detail Operation Scheduling – It indicates the time required to perform each and every detailed operations of a given process

TYPES OF SCHEDULES

Despatching refers to the process of actually ordering the work to be done. It involves putting the plan into effect by issuing orders. It is concerned with starting the process and operation on the basis of route sheets and schedule charts.

In the words of JOHN A. SHUBIN – “Despatches put production in effect by

releasing and guiding manufacturing order in the sequence previously determined by route sheets and schedules.”

DESPATCHING

Following two procedures may be used for despatching –

• Centralised Despatching – Under this, orders are directly issued to workmen and machines. It helps in exercising effective control.

• Decentralised Despatching – Under this procedure all work orders are issued to the foreman or despatch clerk of the department or section. It suffers from difficulties in achieving co-ordination among different departments.

DESPATCHING PROCEDURES

“Follow up or expediting is that branch of production control procedure which regulates the progress of materials and part through the production process.”

Follow up Procedure – Progress may be assessed with the help of

routine reports or communication with operating departments. The follow up procedure is used for expediting and checking the progress.

FOLLOW UP & EXPEDITING

Inspection is the process of ensuring whether the products manufactured are of requisite quality or not.

Inspection is undertaken both of products and inputs. It is carried on at various levels of production process so that pre-determined standards of quality are achieved.

Inspection ensures the maintenance of pre-determined quality of products.

INSPECTION

Activities of production planning

Production planning: It is a pre-production activity. It is the pre-determination of manufacturing requirements such as manpower, materials, machines, and manufacturing process.

1. Aggregate production planning2. Master production planning3. Material requirements planning(MRP-1)4. Capacity planning

Activities of production control • It is concerned with determining whether the necessary resources to

implement the production plan have been provided or not.1. Shop floor control2. Inventory control 3. Manufacturing resource planning (MRP-II), and4. Just-in-time (JIT) production systems.

• Aggregate production planning: Aggregate planning is concerned with determining the

quantity and timing of production for the intermediate future a head, setting employment, inventory, and subcontracting.

Master production schedule:1. The aggregate production plan must be converted into master

production schedule(MPS)2. MPS is a listing of the products to be manufactured, when they are to be

delivered, and in what quantities.

MATERIAL REQUIREMNT PLANNING(MRP)

• MRP is a computational technique that converts the master schedule for final products into a detailed schedule for the raw materials and parts used in the final pr oducts.

• Information needed for MRP:The following informations are needed for MRP1. Demand for all products2. Lead times for all finished goods, components, parts and raw materials.3. Lot sizing policies for all parts.4. Opening inventory levels.5. Safety stock requirements

• Inputs to MRP:1. Master production schedule2. Bill of materials file, and3. Inventory record file.BOM: designates what items and how many of each are used to make up

a specified final product.BOM FILE: is used to compute the raw material and component

requirements for end products listed in the master schedule.

• Inventory record file: The inventory record file contains the following three segments:1. Item Master data segment: it provides the items identification

by part number and other data, such as lead time, cost, and quantity.

2. Inventory Status Data: It provides a time- phased record of inventory

3. Subsidiary data segment: It provides subsidiary data such as purchase orders, scrap or rejects, and engineering changes.

Benefits of MRP1. Reduced inventory levels2. Better production scheduling3. Reduced production lead time4. Reduced setup cost5. Reduced product changeover cost6. Better machine utilization 7. Improved product quality8. Quicker response to change in demand

Capacity planning• Capacity planning is concerned with determining what labour and

equipment resources are required to meet the MPS• Capacity planning is used to identify the limitations of the

production resources so that unrealistic master schedule is not planned.

Shop floor control• Shop floor control is concerned with monitoring the progress of

orders in the factory and reporting the status of each order to management so that effective control can be exercised.

• FUNCTIONS OF SFC:1. Scheduling ,2. Dispatching, and3. Follow-up or ExpeditindPHASES OF SFC:4. Order release,5. Order scheduling, and6. Order progress

INVENTORY CONTROL• Inventory control is concerned with:1. Minimizing the cost of holding inventory;2. Maximizing service to customers.• Inventory control includes a variety of techniques for managing

the inventory of a firm.

MRP-II• An expansion of the material requirements planning systems to

include other portions of the productive system was natural and to be expected.

• MRP II is an integrated information system that synchronize all aspects of the business.

• MRP II is defined as a computer based system for planning, scheduling, and controlling the materials, resources, and supporting activities needed to meet the MPS.

• MRP II functions:1. Management planning2. Customer services3. Operations planning4. Operations executions5. Financial functions

Just- in- time production systems• JIT is a management philosophy that strives to eliminate sources of

manufacturing waste by producing the right part in that place at the right time.

• JIT also known as lean production or stockless production.Objectives of JIT:The JIT is applied to achieve the following goals;1. Zero defects2. Zero setup time3. Zero inventories4. Zero handling5. Zero breakdowns6. Zero lead time7. Lot size of one

Benefits of JIT• Lower inventory cost• Lower scrap and waste costs• Improved quality and zero defect products• Improved worker involvement• Higher motivation and morale• Increased productivity• Reduced manufacturing lead time• Improved product design and increased product flexibility• Adherence to delivery time