HOW TO BRING VALUE TO THE COMPANY The use of scheduling Planning and scheduling requires craftsmanship. Just like the brew master, who can smell if processes are running well, the head planner can make efficient schedules based on his long experience. He knows the work in process and the available capacity by heart. Previously the brew master was challenged to improve efficiency after which process control systems have optimised most of the production processes. Now its turn to the planner who is faced with management demands to continuously improve the supply chain. o retain competitive advantage, assets must be used more efficient and the responsiveness must be increased without giving in the high standards for quality and safety. IT support becomes a necessity for the planner to achieve this goal. Besides that the management does not like a single point of failure with all planning expertise concentrated on one person. T Scheduling challenges Let us first have a look at the importance of planning and sched- uling in the brewing and beverage industry. Although customer orders are often known months ahead, operational planning is still a challenge. The production process consists of a series of steps with specific starting times dependent on the previous step. The duration of a step may be influenced by process conditions and raw material characteristics. Material planning needs to ensure sufficient stock levels, taking into account factors like shelf life and prevention of spoilage. Capacity planning is responsible to provide the necessary storage tanks and routings as well as the packing line needed to deliver customer orders in time. Also tightly linked to the production are maintenance, cleaning, inspection, and quality assurance which must be planned. Getting all different kinds of planning synchronised with each other can be complex. If not properly organised it may happen that the output of one planning is used as input to another and the other way round. Then an optimum can only be found by iteration. Often without realising this situation exists when planning activities Overview BBT sequences – March 1 to 31, 2011 BBII 6/2011 · 29 take place at separate departments. The only iterations take place when typically information on paper is exchanged during regular meetings. Without instant calculation or simulation this is seldom the right setting to find the most efficient set of schedules. A structured approach To prevent cross-linked dependencies between schedules usually the full process of planning and scheduling is divided over multiple, hierarchical layers. Often these layers are addressed as strategic, tactical and operational planning. They all aim to match demand and supply over a period of time in order to satisfy their goals. But the goals and the external inputs are different at each level. For every lower lever in the hierarchy the time frame is shorter and the resulting schedule more detailed. In general all top layers are referred to as planning focused on resources allocation. The lower levels are referred to as scheduling and considered the activity to set a starting time for tasks and assign resources to those tasks. On each layer demand as well as resource capacity are based on forecasts and historical experience. For example the sales and operation planning is based on current sales forecasts, increased consumption in summer and a planned mayor maintenance operation in winter. Using this input it will divide the yearly production into monthly targets. Subsequently to meet these monthly targets, in a master schedule, production orders are created. They take into account the available stock levels, expected new deliveries and the normal production capacity. At the level of detailed scheduling physical quantities of material are assigned to the orders and orders are assigned to a specific time slot on specific equipment. Design considerations So far a planning board can do the job for straightforward planning. It becomes difficult when 30 · BBII 6/2011 planning involves many choices with dependencies and a variety of consequences that cannot be predicted. Spreadsheets designed for this task have been extended over the years. Even with a strict policy, the drawback of spreadsheets is that copies will be made, formulas get adjusted and exceptions are added. Eventually, stuffed with formulas, some of which likely to be obsolete, it is doubtful if they generate the most efficient schedule. They certainly fail to incorporate exceptions like production disturbances. For example a polluted batch may cause a delay of the concerned production order as well as a temporary drop in capacity. Detailed scheduling software is able to determine if this can be compensated by starting a new production order or adjusting the recipe in a next production step. Like car navigation software it can determine if, taking the deviation, you still can reach your target in time. If not, the alternative schedule indicates which production orders are delayed. This is reported to the master schedule which interprets this information as a disturbance to be controlled at that level. For resource planning most input information can be retrieved from a limited number of administrative systems with relational databases. The frequency of issuing a new plan is low enough for missing data to be entered manually. For a purchase order of raw material a rough estimation of the available stock combined with the forecasted speed of consumption are enough to determine the quantity to order. For detailed scheduling on the other hand exact figures are required. The task to process a 1000 hl batch of a specific blend can only start if fixed amounts of specific lots are allocated, if the routing from the storage tanks of these lots is available and clean, and if the process equipment is capable of executing the recipe. Manual entry of this kind of data is no option. Information can only be provided by automated systems. The complete sets of conditions that determine if an action is allowed to start are called business rules. Usually this is all the plant specific knowledge that exists mainly in the mind of the head planner. Within a scheduling project a large portion of all time is spent on translating that knowledge into software expressions. If the right scheduling software is selected then implementing should be relatively easy. It only becomes difficult when exotic business rules do not fit in and complicated solutions need to be found. Possible benefits Suppose all process automation is up to date, providing any kind of information and a software package was selected suitable for all the business rules involved, what possible gains are achievable? This is an important question that determines your business case. The more detailed a production schedule is, the better it is known when resources will be needed. Then suppliers can deliver smaller quantities just in time, reducing the need for stock levels and the risk to pass its shelf life. Based on quality analyses of received material, either the product mix or the process steps must be adjusted. Even if the change is relatively small, instead of sticking to the original schedule, rescheduling may lead to a far more efficient one. Periodic maintenance of equipment may be incorporated in the production schedule by not allocating it for some time. In the maintenance schedule personnel and spare parts may be allocated. An instant failure cannot be scheduled. However based on what-if scenarios the planner can predict the consequences and switch to the best alternative schedule, keeping costs at a minimum. And efficient scheduling can reveal spare production capacity which allows attracting more volume to produce. Recent projects that implemented scheduling software announced large reductions. Either they claim a 34 per cent shorter lead time, 50 per cent less planning effort, or 25 per cent in safety stock. Anyone longing to achieve the same results should first investigate what is feasible in his or her specific situation. If for example an OEE study has revealed that better scheduling could improve the efficiency of the packing lines, the actual result could appear to be that stock moves from storage tanks to the warehouse. Ask yourself if this justifies your financial investment. Will the expected result be in line with your business strategy and really reduce your costs or increase customer orders? From a critical point of view this example shows that scheduling should be implemented with policy. Conclusion There is a considerable chance that the benefits of planning and scheduling software will be worth the investment. But be aware that the actual benefits depend on a proper design to make it fit for its purpose. This purpose must be well defined and realistic. Then the business rules that determine the scheduling constraints must be specified in terms that can be implemented into the software. And to generate the best possible schedule the necessary data must be available and preferably be connected to the scheduler directly. Only then the resulting schedule will really support the planner and bring value to the company. 䡺 Stefan Salger Manager Business Development Beer & Beverages Actemium Germany, BU Ravensburg, [email protected], www.actemium.de Michiel van Vlijmen Client Manager Actemium Netherlands, BU Veghel, mvvlijmen@ actemium.nl, www.actemium.nl