British Standard Institute has prescribed the following four techniques of production control (i) Routing (ii) Scheduling (iii). Dispatching (iv) Follow-up expediting. Follow-up includes Inspection and Corrective measures. All the four constituents are closely interrelated. We shall discuss all of them.
Routing refers to a systematic method of accomplishing a work which is carried on from one step to another according to well- defined and well-set routes during the production process till the transformation of a particular piece into a finished product. As a matter of fact, production planning starts with routing.
Definitions According to Kimball and Kimball Jr. “Routing may be defined as the selection of paths or routes over which each pride is to travel in being transformed from raw material into finished, products.”
According to JR. Batliboi, Routing means determining the most advantageous path of flow to be followed in the sequence of operations and processes from department and machine to machine, till the material in raw state is converted into finished product.”
Bethel Atwater, Smith and Stockman Jr. “Fundamentally, routing determines what work will be done or a product or part as well as where and how it will be done.”
Thus, it establishes the operations, their path and sequence and the proper class of machines and personnel required for these operations …it is also connected with the field of product development in designing product that can be, readily manufactured…it is, closely allied with plant and industrial engineering in setting up the most efficient operating methods and handling and back-tracking.”
The objective of routing is to determine the best and cheapest sequence of operations and to ensure that this sequence must be followed. Each product is routed, separately on a sheet of paper. This route sheet shows the sequence of operations and the machines and tools required for the production. Routing also exercise a great influence upon the design of the factory building and the machines.
For a new product or part, the routing procedure consist of seven principal steps;
(i) An analysis of the articles to determine what to make and what do purchase. Product analysis will help the manufacturer in deciding as to what parts should be manufactured and what may be purchased.
(ii) An analysis of the article to determine what materials are required. The product analysis into components and units determines the kind, grade or quality and quantity of each required.
(iii) A determination of the manufacturing operations and their sequence. Technical experience aided by an accurate knowledge of machine layout tells its capacity.
(iv) A determination of the lot sizes. Customer’s order plus rejections determine the size of the lot.
(v) A determination of scrap factors. Prudence dictates anticipated normal scrap encountered in the course of manufacturing.
(vi) An analysis of the cost of the article. Costing department determines the cost of the article still routing section of the production control department should have the necessary data. Direct material and labor costs are ascertained.
(vii) The organization of production control forms. It is essential to collect complete information relating to various production control forms, such as job cards, inspection cards, move tickets, tool tickets.
Routing includes the planning of where and by whom work shall be done, the determination of the path that work shall follow and the necessary sequence of operations., it forms aground work for most of the scheduling and dispatching functions of planning department.” – Spiegel and Lansburgh
Scheduling is the next step of Routing. It arranges the different operations involved in manufacturing in order of priority, fixing the time and date when each operation is to be commenced and completed. Sprieget and Lansburgh define Scheduling as follows : .
“Scheduling involves establishing the amount of work to be done and the time each element of the work will start, or the order of work. This includes allocating the quality and rate of output of the plant or department and, also the date or order of starting of each unit of work at each station along the route prescribed.”
According to James L. Lundy : “Work scheduling consist of the assignment of starting and completion times for the various operation to be performed.”
According to Bethai, Atwater, Smith and Stachman Jr. : “Scheduling is that phase of production control which rates the work in the order of its priority and then provides for its release to the plant at the proper time and in the correct sequence. Thus, scheduling is concerned with when work shall be performed on a product or part.”
According to Alford and Beatty ” “…Fitting specific job into a general time-table, so that orders may be manufactured in accordance with contracted liability, or, in mass production, so that each component may arrive at and enter into assembly in the order and at the time required.”
Types of Scheduling
Scheduling can be of three types
(i) Master scheduling. Dates on which the production is to be completed.
(ii) Operation scheduling. Time required to finish a job.
(iii) Detail operation scheduling.
Time needed to complete each detail operation of a given job. Scheduling Procedure This starts with ‘master schedule’. It is weekly or monthly breakdown of the production requirements for each product. With the receipt of new orders it is brought on schedule. If the machines are absorbed, then the required goods are taken to subsequent period. Dispatching Dispatching occupies third place in any control system. Dispatching gives the necessary authority to start the routed and scheduled work, it uses the necessary order, instructions and information relating to the work. It has been defined by different authorities as follows :
According to Alford and Beatty : “A good definition of dispatching is the routine of setting productive activities in motion through the release of orders and instructions, in accordance with previously planned time and sequences, embodied in route sheets and scheduled charts.”
According to James L.Lundy “The dispatching function involves the actual granting of permission to proceed according to plans already laid down. This is similar, in the case of the traveller, to his employer finally approving his vacation leave.”
According to Bethal, Atwater and others : “Dispatching the initial action element of production control, consists,
essentially of the issuance of orders in terms of their priority as determined by scheduling. It includes the assignments of work to the operators at their machines or work places. Thus, dispatching in effect determines by whom the work shall be done.”
According to Spriegel and Lansburgh “
Dispatching involve, the meeting of schedules by proper utilization of machines, workplaces, materials and workers, as designated by the routing. The dispatching unit of the planning department, thus includes all persons whose duty it is to see that orders are issued to the shop, that materials are at the work place, that tools are provided, that job cards are issued, and, in general, all necessary steps are taken to ensure that the schedules will be, properly carried out.”
The chief factors or activities included in dispatching are
(i) To see that the right materials are moved from stone to machines from operation to operation.
(ii) Instructing tool department to see to the issue of the right tools, accessories and fixtures in time before the commencement of each operation.
(iii) Issue of the production orders authorizing the work to be taken in hand in accordance with the predetermined dates and times.
(iv) Distributing machine loading and schedule charts, route sheets, operation instruction cards or sheets and identification tags for each works order.
(v) Issuing inspection orders directing type of inspection needed at various stages of production order, for inspection report.
(vi) Keeping a proper record of die various subsidiary orders issued with each production order for filing and reference.
The dispatching of respective orders in a factory where manufacture is serialized, is very simple. The organization for dispatching may be centralized or decentralized. Decentralized dispatching consists of issuing manufacturing schedules or work orders to the foreman or dispatch clerk within each department. Centralized dispatching involves the dispatching of orders from the central dispatching division directly to the machine or work station. Under this procedure, the capacity and characteristics of each machine as well as the backlog of work ahead of it are known and recorded in the central dispatching station and all dispatching is controlled from that point.
Expediting, also known as progress or follow-up, denotes hastening the movement of production process as a whole. Expediting, in fact, is a means by which the production plan and its implementation is coordinated, Expediting, thus, reveals any variation in the production plan. And in any variation is revealed that it is either corrected or variations, if situation demands, are accepted and plans, routes, schedules etc. are corrected accordingly. In the words of M.C. Shukla “expediting is the function of the management which is responsible for the movement of the work through the various processes as laid down in the production programme.”
Actual progress is expected to match with the corresponding plans. If, however, it fails to match, it is the function of follow-up action to do the needful and apply correctives so that it (the plan) may again be put on the right tracks and variations and deviations may be checked in time. Expediting, therefore, is a service function which ensures production according to set plans, routes and schedules.
According to Bethel Atwater, “Expediting is that branch of production control procedure which regulates the progress of materials and parts through the production process…follow-up serves as catalytic agent to fuse the various separate and unrelated production activities into the unified whole that means progress. It endeavors to see that the promise is backed up by performance.”
Expediting, therefore, is
(i) a production control procedure;
(ii) it regulates the production process as a whole;
(iii) it intrudes in the whole of production process with a view to ensure adherence to the production plan;
(iv) it function as catalytic agent;
(v) it functions to ensure unified activities of the whole production process; and
(vi) it ensure that there is matching relationship and perfect co-ordination between the promise and the performance.