ABSTRACT. Production planning and control is concerned with implementing the plans, i.e. the detailed scheduling of jobs, assigning of workloads to machines. PDF | The main purpose of this research is to develop and deploy an Article ( PDF Available) in Production Planning and Control 25(9):I-I. PRODUCTION PLANNING AND CONTROL. What is ppc? “The highest efficiency in production is obtained by manufacturing the required quality of product, of.
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Production planning and control is a tool available to the management to achieve Thus production planning and control can be defined as the “direction and. This book contains the course content for Production Planning and Control. ourseMaterial%5Cmmzg%5CMOMLpdf> Accessed 30 November Figure 1: Architecture of Control System. Important functions covered by production planning and control (PPC) function in any manufacturing system are shown.
A Contractor has a requirement of cement that amount to bages per day. Often the more specific a schedule is the better it can be used as a production control device. This probability distribution is in terms of some interval of time. It is prepared on the basis of type of manufacturing process involved. L by Moving Range Chart:
To coordinate a number of different department groups so that a fine balance of activities may be maintained. To promote fuller utilization of plants. To assist labour towards right and greater earnings. To train staff in the effective performance of their duties. The basic cycle of events in the control are Action, Feedback, Evaluation and Adjustment. Since these events are dynamically in continuous they take the form of a closed-loop circuit. There are seven essential steps in the establishment and application of operating controls.
These steps will be discussed in their normal sequence and is diagrammatically represented in figure 1. A Operation: The first step in the control cycle is operation.
In this step, the act of doing something, some faults will be obvious and, therefore, easily corrected. Other faults will be more deceptively concealed requiring the steps that follow to reveal them so that they can be dealt with. B Measurement: The second step is so measure what is being done. In the field of quality control for example, variations in physical, chemical, electrical, dimensional and other properties are measured.
In production control, all operations are measured to determine the time required for their performance and the capacities of equipment with which work is done. C Capabilty Studies: Analysis of measurements in step two, aided by many reliable statistical technique gives an accurate projection of what actually can be done. In production control we need to know quality process capabilities so that scrap and defer losses can be figured. Studies of process capabilities tell us what we can do.
D Objectives: After we discover what we can do, we are ready to figure out what we should as this may either be more or less than our capabilities. This decision then leads to plans for using excess capabilities on other plans to increase capabilities either for quality or quantity so that the objective can be met.
E Evaluations: As the information is fed back from operations, it is compared with plans and objectives other evaluations are used to adjust budgets and costs.
F Adustment: The last step in production control is adjustment. Production control adjustments are complicated because they often require increasing or reducing quantities based upon past operation and sales in quality control adjustments are made to maintain product quality requirement within limits.
The figure 1. In it, image two rotating sequence on the basic elements of action, feedback and evaluation that come logure in compound adjustment.
This is based on the current information. It we shoot at the target but cannot tell how close to the balls eye or bullet hits out next shot is likely to be no better than first. But if we do know where the first shot has hit, we can adjust the aim for next one and thus improve our marksmanship. Information received after the performance of an action in time to be used as the basis for future, performance is known as feedback, it is the vital control.
The keys to successful plant implementation are feedback and flexibility. Information must be provided to measure actual progress against the planned and when discrepancies exists, the manufacturing enterprise must be flexible enough to shift, if necessary. This implies the establishment of details, benchmarks during the planned period. Measures of progress, explicit statements concerning the assumptions made about the operating environment and a formal procedure for analyzing the process.
It is a goal. The plan must indicate how this will be done, when the various steps will begin and be completed and what assumption underline the plan and goal. As the plan is being implemented, frequent checks are required to determine whether or not things are proceeding on schedule e. The cause behind any discrepancies must be examined. Only then we will know whether to speed up or slow down present rate or progress or a shift is required?
The highest efficiency in production is obtained by manufacturing the required quantity of product of required quality, at the required time by best and cheapest method. To certain this objective management employs PPC tool which coordinates all manufacturing activities.
The main functions of PPC are the coordination of all the activities, which exist during production or manufacturing. I Materials: Raw material, standard finished parts, finished parts of products must be available while starting the operation within the time.
II Methods: The purpose of this function is to analyze all methods of manufacture and select the best method according to the given set of circumstances and facilities. It determines the sequence of operations and the division of product into the assemblies and sub-assemblies, modified by the limitation of existing layout and work flow. Methods of manufacturing have to be related to the available production facilities coupled with a detail study of equipment replacement policy.
Maintenance policy, procedure and schedules are also functions connected with managerial responsibilities for equipment. Design of economy of jigs and fixtures constitutes some of major duties of PPC. IV Routing: Routing determines that work will be done on the product of parts as well as where and How it will be done.
It estimates the operations, their path, sequence proper class of machines and personnel required for these operations. An analysis of the article do determine what to make and what to purchase. Decision as whether to fabricate a component or purchase it from elsewhere.
These are based on relative cost, technical consideration purchasing policies, availability of equipment, personnel, skill. An analysis of article to determine what material are needed: This depicts the additional material needed Figure 1. A determination of manufacturing operation and the sequence. This section establishes the operation necessary to manufacture the proper sequence on route sheet and operation sheet.
Determination of lot sheet. It depends primarily upon the manufacturing involved. If the product is to be manufactured strictly to a sold order, the customers order plus a certain average or allowance of stock, the lot size depends upon the primary of economic lot quantities etc.
Determination of scrap factor: Is the anticipated normal scrap encountered in the course of manufacturing. Analysis of cost article: It includes cost accounting department for cost estimating of product.
Factors Affecting Routing Procedure: Manufacturing type employed. Availability of plant equipment and its component parts. Characteristic of physical plant equipment and its component parts. Human elements. V Estimating: When production orders and detailed operation sheet available with specification feeds, speed and use of auxiliary attachments and method, the operation time can be worked out.
It may be consequently results in wide scatter of operation times and unduly large fluctuation and perhaps instabilities in time schedules. Machines have to be loaded according to their capabilities performance the given and according to the capacity. Machine loading is carried out in connection with routing to ensure smooth work flow work estimating, to ensure that the prescribed methods feeds and speed are best utilized. Careful analysis of process capacities so that flow rates along the various production lines can be suitable coordinated.
The distinction between planning and scheduling is largely semantically and based upon difference in detail and time period. The schedule is very detailed plan for an immediate and relatively short time period. The difference between the plan and the schedule can be illustrated by looking at the objectives. The plan may ask to double production within two years. The schedule will to produce units of articles during week number 1, units during week and so on. Scheduling often refers to the specific determination of what is going to the production during the next few weeks or months.
This involves determination of the individuals machines that are going to produce the items when they will be started and completed what quantities lot or Batch sizes they will be produced and with what materials. But many other activities are also scheduled such as maintenance, movement of goods and materials and oven staff meetings. In essence, a schedule is a detailed statement of how when and where specific resources are going to the employed to produce specified output or results.
At this levels of detail, the schedules is often in separable from the control system e. On the hand, the budget is also an integral part of the control system for monitoring expenditure. The schedule thus provides a short range sequence of activities one for which we must have sensitive controls and rapid response time. Scheduling can be very simple or very complex. Perhaps the most simple type schedule can be illustrated by an example drawn from cottage industry. A worker may be asked to produce as given number of work carvings or square meters of handloom fabric per week.
The control is very simple and consists primarily of a count made each week, when the goods are lifted by employer.
Decision Rules: The scheduling function is such a detailed process that it must usually be delegated to middle or lower management levels.
Consequently, the schedulers, of themselves, are actually not in position to relate their activities to the overall company goals and objective. Yet their function is vital to the achievement of such ends. Consequently, it is necessary to establish decision rules which will help tie the two levels of management together.
Decision rules for scheduling should be fairly specific. Not only do they serve the purpose of linking the scheduling function with the attainment of total organizational goals but they provide consistency in scheduling practice so that people can be interchanged, so that schedules can be interpreted uniformly throughout the organization, and so that even one concerned will under stand the process. They also make it possible to place much of the scheduling detail work on computers.
Decision rules can take many forms. The selection of the particular rules will largely depend upon the particular circumstance for which they are required. Competitive made of conditions, internal cost structures, the nature of the product, capacity consideration etc will all have their effect.
Schedule the longest jobs first. Schedule jobs in the order they are received. Schedule the job with the earliest delivery dates first.
Schedule jobs on a random basis. Schedule first those jobs with the use production facilities for which we have the greatest idle capacity. Schedule all jobs first which requires operation in department 1. Schedule customer As order before all others. Each of these rules usually in combination with others provides a means of regarding tasks.
There are an almost unlimited number of possibilities including the converse of some of the above and these are provided solely for illustration. It is worth noting that such decision rules are applicable to all scheduling processes not only these which deal with production operations. Companies often experiment of determine the specific set of rules which make sense for their particular situations. This can be very useful and save considerable relief and confusion as follows the testing of such rules without the disruption of production.
Again, there is a caution involved in the use of decision rules. It is extremely difficult to design any set of rules which will cover every situation.
Consequently, decision rules must be considered only as guidelines, not absolute, and flexibility must exist to deviate when necessary.
On the other hand, it is probably sensible to require a through explanation every time a deviation is authorized, lost deviation from the rules become more common than applications of the guidelines. If the rules are well constructed they should tend to maximize benefits to the firm as a whole and should not be changed capriciously by individuals who cannot see the impact of such changes on overall corporate goals.
However, this also implies the need for continuous review procedures to make sure that the rules are in tune with present conditions. A point often overlooked is that if decision rules for scheduling are not formally and explicitly established, they usually evolve in through default. Each person involved in the scheduling process will usually have his own method-perhaps one that makers sense only to him, but still a method.
Sometimes this may be the best the alternative for a firm e. However, this should be explicitly determined. Otherwise, an organisation may be looking a major opportunity for improvement and enhanced efficiency. VII Diaspatching: It is important mechanism of production control. Meaning of this term is sending to destination or starting something on way.
When applied to production control, it means the assignment of work to different machines or work places which involves insurance of order and production form in order of their priority as determined by scheduling. In dispatching translated into reality or physical work which has been planned scheduling. Duties of Dispatching: Assignment of work to different machines of work place men. Movement of material from stores to the first process and from process.
Issue of tool orders, instructing the tool department to collect and make ready jigs and fixtures, in advance of time, at which the operation will commence.
Issue of more orders and collection of time tickets, drawings, instruction cards for all completed operations. Recording time of beginning and completing jobs hand calculate duration of, forwarding complete records to production department and time card pay roll department. Recording and reporting idle time of machine and operation. Dispatching Procedure: Manner in which schedule or orders are issued depends upon whether the dispatching decentralized or centralized in the Decentralized: The manufacturing schedules or work orders in blanket fashion to the foreman or dispatch clerk within department.
It is duty of foreman or clerk to dispatch the orders of material to each machine and operator. In centralized dispatching: This involves the dispatching of orders from central dispatching division to machine or work station.
Capacity and characteristic of each machine is recorded in central dispatching station. Regardless of type of dispatching it is customary for department to department themselves informed of the starting dates, progress of each order by means of wall chart visible index file or one of the several types of department dispatching boards. Dispatching Rule: Simple Rule: Earliest due date: Run the job with the earliest due date, results in good date performance.
First come first served: Run the job which arrived in the waiting line first. Result at low variance of manufacturing cycle time. Shortest processing time: Run the job which has the shortest set up plus machining for the current work centre.
Combination Rule: Minimum stock: Slack equals calendar time remaining minus processing time remaining or slack equals date minus present time minus set up and machining time all remaining operation.
Critical ratio: The critical ratio are made to order work is a slack type rule. Critical equals 0 to due date minus present time divided by number of days required to complete the job order.
VIII Expediting: Follow up which regulates the progress of materials and parts through the production process. This closely inter elated with activities of dispatcher to whom is delegated scheduling responsibility. Follow up is that novel tool which acts as a regulator of material and components parts when they are traveling on the path of performance as laid down by sheets and schedule charts. It serves as a catalytic agent to fuse the various separate an unrelated production activities into the unified whole that means progress.
To follow up purchased materials is responsibility or purchasing department. This can be accomplished most simply by filling one copy of requisition in a daily follow up file or in ticket file according to the date of materials is due to be received.
Work in progress: This follow up the work by checking the process and recording the production accomplished by production line for comparison purpose with preplanned schedules. It is the duty of follow-up men or expediters to advise the foreman as to the best sequence in which the orders can be run so as the required part in which order to be fabricated and brought it together at right time, place for the completion of finished product. Assembly and Erection: Responsibility for assembly and erection of products in assembly manufacturing is almost invariably rested.
When all the parts of an available, the follow up man permits assembly of election of products in start in case of large complicated product this is very necessary. IX Inspection: Another major control is inspection.
Its finding land criticism are of the importance both in execution of current program and both in planning stage of fibre undertaking when the limitations of the processor, method and manpower are known.
These limitations can form a basis for future investigations in evaluating the showed improving production methods. X Evaluating: Perhaps the most neglected, but on an essential link between control and forwarding is that of evaluating.
The essential task of dispatching and evaluating are concerned with the immediate issue of production and with measures that will be as certain fulfillment target. Valuable information is gathered limited in nature and unless provision is made so that all the accumulated information can be properly digested and analyzed data may be irretrievable lost.
Thus here the evaluating function comes in to provide a feedback mechanism on the longer term basis so that the past experience can be evaluated with the view to improving utilization of method and facilities.
This is the integral part of control function. Sates forecasting and 2 5 8 estimating Resource Methods Estimating Inspection. Preplanning Planning Control. The importance of material in manufacturing concern needs the explanation because in its absence production is not possible. But there are so many problems awarded with the management of materials, such as investment in materials idle funds, storage of obsolescence problem, wastage of material in handling etc.
Which require immediate attention of management. Material planning is the important activity of materials managements. Material planning means to develop a purchasing procedure. For procurement of materials, it is essential to know how much quantity is required. Based on the annual forecast, production schedules are made.
Working backwards on the schedules the dates on which the difference materials must be in plant, are calculated. Appropriate factor of safety should be used in working out latest date of arrival. The quantities required are also calculated with he help of bill of materials. Materials planning for project work can be done in the similar way, in such cases use of network techniques can be made to arrive at later date of materials. In batch manufacturing, where items are assembled in batches, certain components may be required in large quantities at infrequent intervals i.
Thus the procedure can be developed by which those items required for assembly are available at the time required stocks of these items are not maintained or are maintained at a far lower level.
It require the knowledge of Production of Assembly schedule. Manufacturing capacity. Overall economy. Translation of the sales projections into long term requirements. On the basis of updated production plan adjusted to the latest sales demand to adjust the materials accordingly. To project the facilities required for the materials management. Setting up of consumption standards, for working out requirements.
To perform value analysis to determine the intrinsic worth of materials. To decide whether to Make or Buy. To keep inventories as low as possible. The Principal Types of Inventories Are: Production Inventories: Items which go into the final products raw materials and bought out components. Maintenance, Repair and Operating Inventories: Items which do not form a part of final product but are consumed in a prod. Processes, spare parts, Consumable items etc. In Process Inventories: Work-in-progress items which are partly manufactured and await the next stage in process.
Finished Goods Inventories completed products ready for dispatch. Miscellaneous Inventories: Which arise out of the above four types of inventory scrap, surplus and obsolete items which are not to be disposed off. Inventories are also classified as: This inventory results because of the transportation time required.
Coal, iron ores etc. Anticipation Inventory: These inventories are maintained to adjust with sudden change in demand e. Instead of producing more in particular season a producing less during rest of the year, inventories can be allowed to build up before the season. Decoupling Inventories: So these inventories are maintained purely due to the interest of management.
That large no. In this analysis, priority is determined by the money value of the importance of the item. Where, 10 — the column is total annual value. It is evident from the discussion that to have an healthy organization the pre planning and post-planning activities are to be ground property at the initial stage turning organization, after preplanning the links are connected with PPC department planning, evaluation, adjustment, feedback and overall control.
Ten functions of PPC as if ten Commandments to be followed in any manufacturing industry. Depending upon the nature of production and size of unit, these functions are glooming in determination position and when required. But it appears in one of other forms. In case, it has been evacuated purposely it fleets badly on the associated activities and ten departments involved thereon.
This has been depicted precisely in the data sheet. We observed that in almost all functions, PPC is the governing department and therefore it has been after every function, if not in existence. Therefore, PPC can be considered and value as a heart on the manufacturing of any type and any size. Therefore to have an healthy organization, less confusion in workers, proper feeding to top management to chalk out their dynamic policies, PPC department plays a very important and vital role in organization.
Naturally, it should be made more dynamic, powerful by shoulding more authorities and responsibilities on the experienced and conservative staff of PPC department. Gov P. Explain production control as a nervous system? Forecast is made of sales in Rs. There are 3 major purposes.
Direct Survey method. Related information method. Indirect Survey method. Market Research. Comparing with established product. Sales force composite method or Subjective opinion method. Limited market trial. Jury of Executive opinion. Projection method. Statistical method. Forecasting for a new product is difficult task as no past information is available to predict the future. By doing so, it is possible to predict, with some degree of certainly how the population will respond. Here economic, political, changes, customs, habits, social requirements are considered.
Agents, whole sellers, retailers etc. So sales figures can be compared. Some times limited selling technique is adopted to product acceptance of the product. Forecasting for Established product is explained below. Forecast based on an index in this method which directly varies with the sales volume is found e.
Through critical analysis of the marketing forces, changing pattern of socio-economics pressures, political changes in style, attitudes, fashion etc, we can diet the future demands of the product.
Here opinions of experts are invited about the sale in future. Based on the historical data, future can be projected to some extension. A line drawn through known information is projected into the forecast area to predict what the sales volume will be for future periods. Projection of future can be done either by time series Analysis or Correlation, regression Analysis tech. Time series Analysis: A time series is a chronological data which has some quantity such sales rupees, sales volume, prod.
Short period changes Seasonal, cyclic, irregular Long period tendency of the data to increase or decrease is called secular or basic trend. We are chiefly concerned with the general tendency of data. As long as we notice an upward or down word trend movement in the data over the whole period, we coriclude secular trend. There is secular rise in agriculture production in India. Because of since last 25 year it has been found that except for a year or two, the production is increasing.
Basic secular trend long term may be linear or non-linear. The important method of making inference about the future on the basis of what happened in the past is the analysis of time series.
After analysing the time series plant production, finance, personnel, marketing etc. Time series is a multiplicative model of 4 — components. Methods of Inspection or freehand methods — Once the given time series data have been plotted on a graph paper, a line is drawn through the points which in statisticians opinion best describes the avg. Methods of Averages: Here the values are selected of the years which are considered to be the most representative or normal.
Then a straight line is drawn. The avg. Thus these two points determine the position of a trend line. The trend line can be extended to estimate future values or intermediate values.
It is discussed later on. It is statistical analysis of past demand. In fact past offers best basis for decision on future action. On the other hand events like entry of new competition, product becoming calculated will tend to develop sale.
Such considerations should be reflected in new forecast. In statistical method we are going to consider following 3 cases. Level demand with Random variation. An Upward Trend with Random Variation. Cyclic Seasonal Demand. General Approach To Statistical Forecasting: If we assume that use of statistical methods applied to past data is a realistic of forecasting future demands, we should then proceed as follows.
Make a plot of demand versus time. Determine which statistical technique to try. Evaluate the expected error. Make a decision to use the technique under consideration or attempt to find a being one.
Above approach is demonstrated by solving three examples below. Example 1. Level Demand With Random Variation. In this case demand remains essentially constant but super imposed random variation. Let up plot a graph between time and demand. From the graph it is clear that it is level demand with random variation about constant value of demand. That is we would forecast that demand will be 99 units for each of the next several months.
We want to evaluate this method arithmetic avg. This can be done by determining the standard error of estimation or standard deviation. Assumptions made: Demand data studied for the periods are truly representative of the demand. Same cause system will continue to be operative for some time into the future. Forecast is that the demand will be 99 units per month. The std. Example 2: Forecast by a liner forecaster.
Here, we require to find values of dl for that, substitute all value of time 1 to 12 in Eqn — 2 i. Again correctness of our forecast is a function of stability of the cause system. Example 3: Cyclic Seasonal Demand: Values in determinant: These values are shown below. Other methods of forecasting: Extending the moving avg. Each period, it new moving avg. In some cases, the moving avg. The following series relates to the production of a commercial concern of 8 yrs.
Year 75 76 77 78 79 80 81 Prodn Units. Assume a 3 — year cycle and ignore decimals. For forecasting. Exponential Smoothing Method: Therefore forecast can be revaluated for next observation, from old observation allowing an error.
The correctness will be achieved by fraction of the error. Verifying the const. Calculation for the M. Chart to verify the control given for forecasting.
Controlling the forecast of Ex. L by Moving Range Chart: Actions regarding forecaster are — 1 Revise it including new cause system. But action of data or forecaster should be taken only after a consideration of all aspects of the cause system. An analysis of data alone would generally be insufficient. In Ex. We have already checked its validity on M.
But the actual demand sale figure for seven month of next second year as under —. Again the rest for out of control condition should be applied. By doing so we find out the point for period 19 indicates out of control conditions. Therefore new forecast the basis of 19 period should be established. We shall use new forecaster in future until we will find evidence for out of control condition in the control chart.
So it is a continuous process. Explain various types of forecasts. Define production forecasting. Discuss the imp of sales forecasting for production scheduling.
What do you mean by Experimental smoothing forecasting. Why it is necessary to revise the forecasts? How do you want of central conditions using is moving range chart. Explain the forecasts based upon the averages. What is the std. For the forecasting of seasonal demand which method of forecasting you will suggest and why? What is the use of indicators and correlation analysis.
Application of production forecasting? Which are the factors influencing on forecast? What do you mean by forecasting? Brief out the diff. Planning and control are essential activities to the rapid expansion of industry and employment.
Control requires a particular pattern of activities to operate properly in a dynamic and imperfect world. It is difficult to improve because the behaviour of pattern of events difficult to understand and also because control have the emotional overtones associated with love of power and fear of being dominated. Therefore, it is essential to have a transferable for objectives analysis, as otherwise subjective emotions will present clear thinking on the desirable use of Techniques.
It is for this reason that specific Data sheets are reputed to introduce a diagrammatic rotation for recording and studying planning and control inspection to shows that without such a representation any decision and discussion of control is obsortive.
The Data Sheets thus aims at establishing a framework for the study and important of planning and Control so that working group which comprises of senior management technicians, supervisor, foremen, trade unionist, operations etc. This is evidently very tedius and complicated matter preparing the production orders but essentially to be maintained.
With appropriate modification to some what extent it can be copied down from other one. To pass information to everyone concerned. To authorise. To start the control system. To provide basis data for evaluation of performance like schedule, quality and cost wise. Obtain all specifications like drawings, materials quality, quantity. Outline the alternative methods of production and fix up the best one. Determination of sequence of operations using process chart.
Find out the operation time required. Prepare operation sheet with above data. Work out production master program. Prepare route cards and operation sheet. Check out the available time on machine and prepare schedule of timing of production. Machine loading charts for work distribution. Prepare job cards, materials requisition cards, tools and drawing requisition, inspection and alt other belonging.
Process charts: The process chart is usually drawn at the commencement of the investigation, because fact finding should proceed from examination of the whole factory. Operation process charts — Which constitute a general layout showing the principle operations and inspections, as well as the points at which the materials enters the process. Flow process charts — Which represents a more detailed picture, describing the activities associated with materials, men or machines and which record the sequence of operations, transportations, inspections delays and storages that occur.
The Advantages of Process charting: It is convenient means of presenting overall information on a factory in limited space and is a record for future reference. Detailed can be recorded on the chart in the factory when the job is observed, so that the chart relatives the mind of carrying. It forces the analysis of work to be made in a quick and logical fashion according to i the sequence in which the work is done ii the materials or things which do the work iii the type of work done iv The relationship between several production flaws.
It is used to explain proposals for rationalising work and improving methods to the parties concerned. After manufacturing the sub parts which will undergo various operation prior to final assembly. The program is based on the final delivery to be maintained and treated as zero base denoting the commencement of production by tails of the individual components on the charts by negative time units.
Since master program, include the information about the type of machine required and time consumption of performance the operation in question. Such type of data is to be collected first alter studying the manufacturing drawings of completion of programming, the effect of sequencing on final schedule will be available.
Case Study — The following are the sequence of operation. All parts are produced.
Parts are grouped in sub-assemblies. Sub-assembly 1 is subject to an operation before further sub assembly 4. Final assembly takes place. A - assembly operation Op - Refers to one of the operation.
The number of units to be undertaken can be governed by the number of cranes available, no. Therefore, the quantity is limited by available capacity of plant and is the basis for preparing the production program and only those quantity of units will be started manufacturing concurrently.
The first unit will be scheduled to come out of the production, taking into consideration the cycle time and special tools required. Tooling expenditure should lead the production program by a suitable phasing period. The accomplish above, We have man, machine, methods and money so that achieve and match all above resources with maximum possible utilization of 4 MTS. Therefore the problematic areas are 1. Quality - Batch wise quantity to be period and rate of manufacture 2.
Allocation - of work of machine and men to given array of task. Scheduling - to avoid clash of sequence of operation or interference of procedure. All above are interconnected problems because, time depends on machine capacity and other commitments, while optimum schedule can be prepared only after these allocation.
In view of matching both things, for some period, the production is stopped, during which the capacity of unit production line is utilized to produce the similar product or variety of goods in similar product or variety of goods in similar fashion. The interval between two production period is called production cycle which thus can be organised, in which each product is manufactured in determined quantities, corresponding to the total demand for it, throughout the cycle time.
The best batch size or the production quantity is to be analysed for each product separately disregarding the effect of other products on scheduling to cone up the rate of demand. Secondly, the best master program for each product is to be set up to account of plant capacity and the effects of batch sizes on cycle time to achieve profit level. Production cannot be continued with the potential demand without no stock, position.
Minimum stock level is to be analysed and maintain looking into delivery lead time, during purchasing the material. V is ratio which measure the amount of time spend on one product during cycle. In such orders given by stores are to be executed. Now the fact is that the consumption is continuous and when the production will resumes, the stock will not be available to feed the customer and supply from store will be stopped unless production starts promptly. Therefore intimation is to be given for production well ahead the stock becomes zero.
The safety margin of stock should be determined in such a way that stock will start building up to a pre-determined level at the completion of the production period. Instead of restarting production at 2, when old stock is fully consumed a new stock level at point 3, is required and therefore production must start at point 2 where 2- 2 production time required for accumulation of stock denoted by point 3.
So Q0 is a stock below which stock level should not fail. As mentioned above, the actual stock level at which the order for production is given is higher than Qu and from equation. The following four criteria will decide the policy for the selection of batch size.
Therefore, claim or high accuracy is hardly justified. Moreover the batch production is a dynamic affair and circumstances may rapidly change. He concerned with the effect by dividing a batch into number of lots and the time involved in waiting between operation.
But in fact, the production schedule cannot be prepared satisfactory to have these ideal batches only.
Therefore, the batch size with 1 limit can be used to have the desired flexibility while attempting the scheduling of the batch.
Naturally, total production cost per piece above the cost required while producing Qm, is to be allowed. Then it is possible to deviate from Qm to either side and select convenient batch size which will not increased in production cost y, above predetermined value.
The desirable degree of flexibility in selecting batch size will be ascertained for the likely increase in variable cost, while scheduling the number products. Effect of p on production cost cons tan t In earlier analysis c is neglected. But if, the ratio cost per piece is var iable KQm considered, the effect of p on y will be reflected.
When the ratio u is large, the slight increase in p is unlikely to cause a noticeable change in y, total production cost, thus caving room for a wide production range to be defined, while when the ration u is small, the reverse is the case.
As total cost per piece rise slowly beyond Qm, it is authenit to conclude that with marginal increase in Qm will yield rise in profit. Too much rise in Qm will release without profit or declination in profit per piece due to higher carrying cost. Batch profit shown by shaded Area where Qp is the batch size yielding max profit.
Constant cost content is relatively high. Such evaluation of performance does not depends only on the absolute figure of the profit. But it is linked with the figure of overall investment required. The ratio of the profit to the cost of the production run indicates the return n on the investment. The cost to produce the batch is. The time factor is of great importance hen turnover of the capital is considered. It would be desirable to achieve the same return, in a short period.
A high rate of return can be achieved only if stock level is kept to minimum and replenished by small batch quantity. This batch size is termed as economic batch size which yield maximum rate of return and is much smaller than, Qm, minimum cost batch. Brief out the maximum rate of return and the empirical method suggested by FE Raymond and P1 Norton to compute Qe, The smaller batch will entail higher production cost per piece, but this will require for less capital.
Raymond proceeded to find this method by using his formula for Qm. Modified by introducing f1 instead of 1, Where the factor f proper conservation of capital as he put it, the value of f as suggested by Raymond is. Where i - rate of interest paid on capital f - rate of return on capital excluding interest rate.
The maximum rate of return yields somewhere at the middle of Qm — Qe. In practice the fixed sales price is difficult to maintain and it depends on the following conditions. P is function of q in the quadratic equation. As p varies slowly with q the equation can be solved by stages. This shows that the real value of q lies between 0. Set uptime increases. Non productive time increases. Earlier, there were flexible relationship between attendant and his machines. Mass scale production cultivate the structure of jobs and the related work processes.
The proper division of work, machines, processes etc. The idle time means the unproductive period and naturally the relation of attendant with machine has to synchronized to achieve the maximum output. The exercise of machine loading is to be excentated for fixing up the quantities of product to be undertaken for manufacturing, by observing the definite quantity of orders or by computing batch size. To accomplish the task the basic data like. The breakdown of operations and sequence of operations.
The period of production run. The type of processes involved, and 4. The available machines. Therefore this is an assignment for the production engineers, after the receipt of the production program will be displayed in the graphical form, calls as bar chart, demonstrating the target period to produce the product.
This information will be separately carries on machine loading card individually, indicating the condition and capabilities with main specifications of machine, the prior commitment etc.
This chapter deals with the work analysis of operator with machines i. The relationship between productivity and nonproductive time, the assessment time, the assessment of the processes, process or machine capacity, the relationship between machine capacity and plant capacity, the factors impeding the machine output etc.
The machine output is nothing but the rate of production in number of pieces per unit time. Generally, the machine output is restricted to mass production by ordinary machines, automatic or semiautomatic machines where the sequence of operations are in definite form.
Therefore, machine output is inversely proportional to unit time cycle. In other words, the max output of machine is obtained when the cycles time is optimum minimum possible and when the further reduction in process cycle time is not possible.
This can be applicable, even if, the operator is handling more than one machines and the idle time of machine is preferably zero during cycle time. Sometimes, this can be achieved by altering the sequence of operations. The length of the cycle time is constituted by the attendance period add machine working time. Thus the cycle time is determined by the total activity time, even through, the concurrent activities by single operator exits.
Now further curtailing of process cycle time is only 1.
If, we think of activity chart, the various periods involved can be classified as under: Independent Activity, 1 2. Concurrent Activity, a 3. Idle time, i The idle time may be of machine in or operator, i. The independent activity means the activity which is not dependent on machine or the activity of each partners not dependent or each other i.
Concurrent activity means the activity can be performed by more than one partners, each of which is contributing, his time and efforts to achieve the worth object.
These factors are listed below: Above all, the product design should be dictated by the market demand. It is an important decision and therefore the entrepreneur should pay due effort, time, energy and attention in order to get the best results.
Manufacturing process is the conversion process through which inputs are converted into outputs. An appropriate designing of production system ensures the coordination of various production operations. There is no single pattern of production system which is universally applicable to all types of production system varies from one enterprise to another.
It is also known as mass flow production or assembly line production. This system ensures less work in process inventory and high product quality but involves large investment in machinery and equipment. The system requires comparatively smaller investment in machines and equipment. It is flexible and can be adapted to changes in product design and order size without much inconvenience. This system is most suitable where heterogeneous products are produced against specific orders.
Under this system the goods are produced partly for inventory and partly for customer's orders. Automobile plants, printing presses, electrical goods plant are examples of this type of manufacturing. Selection of manufacturing process is also a strategic decision as changes in the same are costly. Therefore the manufacturing process is selected at the stage of planning a business venture.
It should meet the basic two objectives i. Production is to meet the delivery schedule and costs are fixed prior to the contract. Different products are produced separately one after the other. Under this, the production run is conducted on a set of machines arranged according to the sequence of operations. A huge quantity of same product is manufactured at a time and is stocked for sale. Different product will require different manufacturing lines. Since one line can produce only one type of product, this process is also called as line flow.
Under this, the production run is conducted for an indefinite period. This is one of the major considerations in selection of manufacturing process. When the volume is low and variety is high, intermittent process is most suitable and with increase in volume and reduction in variety continuous process become suitable.
The following figure indicates the choice of process as a function of repetitiveness. Degree of repetitiveness is determined by dividing volume of goods by variety. Types of Production Processes b Capacity of the plant: Projected sales volume is the key factor to make a choice between batch and line process. In case of line process, fixed costs are substantially higher than variable costs. Therefore lead-time and level of competition certainly influence the choice of production process.
Hence it is very important for entrepreneur to consider all above mentioned factors before taking a decision regarding the type of manufacturing process to be adopted as for as SSI are concerned they usually adopt batch processes due to low investment. One of the major problems of small scale enterprises is that of low productivity small scale industries can utilise natural resources, which are otherwise lying.
Small scale sector can play an important role, similar to the one played by small scale industries in other developed countries. Planned production is an important feature of the small industry. The small entrepreneur possessing the ability to look ahead, organize and coordinate and having plenty of driving force and capacity to lead and ability to supervise and coordinate work and simulates his associates by means of a programme of human relation and organization of employees, he would be able to get the best out of his small industrial unit.
Gorden and Carson observe production; planning and control involve generally the organization and planning of manufacturing process. Especially it consists of the planning of routing, scheduling, dispatching inspection, and coordination, control of materials, methods machines, tools and operating times.
The ultimate objective is the organization of the supply and movement of materials and labour, machines utilization and related activities, in order to bring about the desired manufacturing results in terms of quality, quantity, time and place. Production control regulates and stimulates the orderly how of materials in the manufacturing process from the beginning to the end.
With the help of Production Planning and Control [PPC] the entrepreneur can schedule his tasks and production runs and thereby ensure that his productive capacity does not remain idle and there is no undue queuing up of tasks via proper allocation of tasks to the production facilities.
No order goes unattended and no machine remains idle. Proper PPC will help the entrepreneur to resort to just- in- time systems and thereby reduce the overall inventory. It will enable him to ensure that the right supplies are available at the right time. PPC will help the entrepreneur to reduce the cycle time and increase the turnover via proper scheduling. A good PPC will provide for adherence to the quality standards so that quality of output is ensured. To sum up we may say that PPC is of immense value to the entrepreneur in capacity utilization and inventory control.
More importantly it improves his response time and quality. As such effective PPC contributes to time, quality and cost parameters of entrepreneurial success. See figure 8. PPC Process Production planning: Production planning may be defined as the technique of foreseeing every step in a long series of separate operations, each step to be taken at the right time and in the right place and each operation to be performed in maximum efficiency.
It helps entrepreneur to work out the quantity of material manpower, machine and money requires for producing predetermined level of output in given period of time. Under this, the operations, their path and sequence are established.
To perform these operations the proper class of machines and personnel required are also worked out. In small enterprises, this job is usually done by entrepreneur himself in a rather adhoc manner. Routing procedure involves following different activities. It means working out of 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.
It mainly concerns with time element and priorities of a job. The pattern of scheduling differs from one job to another which is explained as below: Production schedule: The main aim is to schedule that amount of work which can easily be handled by plant and equipment without interference. Its not independent decision as it takes into account following factors. Master Schedule: Scheduling usually starts with preparation of master schedule which is weekly or monthly break-down of the production requirement for each product for a definite time period, by having this as a running record of total production requirements the entrepreneur is in better position to shift the production from one product to another as per the changed production requirements.
This forms a base for all subsequent scheduling acclivities. A master schedule is followed by operator schedule which fixes total time required to do a piece of work with a given machine or which shows the time required to do each detailed operation of a given job with a given machine or process.
Manufacturing schedule: It is prepared on the basis of type of manufacturing process involved. It is very useful where single or few products are manufactured repeatedly at regular intervals. Thus it would show the required quality of each product and sequence in which the same to be operated Scheduling of Job order manufacturing: Scheduling acquires greater importance in job order manufacturing.
This will enable the speedy execution of job at each center point. The small entrepreneur should maintain four types of schedules to have a close scrutiny of all stages namely an enquiry schedule, a production schedule, a shop schedule and an arrears schedule out of above four, a shop schedule is the most important most suited to the needs of small scale industry as it enables a foreman to see at a glance.
The total load on any section 2. The operational sequence 3. The stage, which any job has reached. The next step is the execution of the schedule plan as per the route chalked out it includes the assignment of the work to the operators at their machines or work places.
So loading determines who will do the work as routing determines where and scheduling determines when it shall be done. Gantt Charts are most commonly used in small industries in order to determine the existing load and also to foresee how fast a job can be done.
The usefulness of their technique lies in the fact that they compare what has been done and what ought to have been done. Most of a small scale enterprise fail due to non-adherence to delivery schedules therefore they can be successful if they have ability to meet delivery order in time which no doubt depends upon production of quality goods in right time.
It makes all the more important for entrepreneur to judge ahead of time what should be done, where and when thus to leave nothing to chance once the work has begun. Production control: Production control is the process of planning production in advance of operations, establishing the extract route of each individual item part or assembly, setting, starting and finishing for each important item, assembly or the finishing production and releasing the necessary orders as well as initiating the necessary follow-up to have the smooth function of the enterprise.
The production control is of complicated nature in small industries.