Importance of preventive maintenance of harvesters

Brazil is the largest producer of sugar cane in the world and it is one of the main crops produced in the country. Due to this great demand, agricultural operations are increasingly aggressive, technological and of great intensity. During the harvest, operations can last 24 hours, every day of the week, with shift rotations between employees.

The great mechanical demands of the equipment reflect the great need for reliable and highly efficient maintenance. One of the best ways to achieve this goal is through preventive maintenance, where we can prevent certain damages and consequently unexpected equipment stops, at the same time creating a constant assessment regarding maintenance expenses.

Sugarcane harvesters are of great importance in this process and represent the highest maintenance cost for the fleet. They are responsible for cutting, collecting, shredding and transporting the sugarcane billets to the transshipment tractors in the field, starting the CCT - Cutting Loading and Transport process and a small failure could result in the stoppage of all subsequent processes, including the plant. .

The PDCA cycle perfectly fits this need, in the constant improvement of harvester maintenance and in guaranteeing the reliability of this maintenance, greater consistency in costs and greater availability of the fleet.

Sugarcane is a seasonal crop, making it subject to several variables, which are not in the control of producers, such as the weather, for example. Preventative maintenance allows greater cost control, allowing maintenance to no longer be considered as another variable, increasing the predictability of expenses and machine availability.   

NEED FOR RELIABILITY IN THE PROCESS

Due to the seasonality of sugarcane cultivation, its harvest period is pre-determined and the schedule for each stage, if not followed, can result in major losses for the company. Sugarcane needs to be harvested, transported and crushed to produce sugar or alcohol as final products.

Therefore, planning is a key part of these operations and correct management of the stages is essential. Currently, some companies in the agricultural sector still work with a culture of corrective maintenance only, or a false preventive one, where they carry out maintenance only after damage has occurred, or with inefficient schedules, which leads to unpredictability of equipment downtime and low availability. , which could represent an increase in maintenance costs, as some other components that were ready end up being damaged due to the unexpected breakdown.

For preventive maintenance to be as efficient as expected, it is necessary to have well-designed processes with efficient quality control, with effectiveness in management and quality. Managers are key players in these actions, with a well-designed action plan. They will be responsible for ensuring the effectiveness of these actions in the field and in the workshop.

Sugarcane agricultural activities are carried out with great intensity and consequently great mechanical demands on equipment. The harvesters work up to 17 engine hours every day, and with large loads of processed sugarcane, in hostile areas, soil variations, climate variations and with constant rotation of operators.

One way to guarantee the availability and mechanical reliability of this equipment is correct maintenance and especially preventive maintenance, which will anticipate possible problems and equipment breakdowns.

Preventative maintenance will ensure greater availability and greater forecast use of this equipment, guaranteeing a more reliable schedule and avoiding possible disruptions to the sugarcane operation as a whole. However, all preventive maintenance must be properly planned, controlled and monitored, to ensure quality, so the PDCA Cycle is a method that perfectly suits this reality.

PLANNING, CONTROL AND ANTICIPATION

With the increase in machine technology, there was also a greater demand for better prepared professionals, mechanics with greater knowledge and dynamism, moving away from the more conventional line of labor, towards a more specific one in diagnostics, combining mechanics and electronics, demanding more professional and thus a higher cost of specialized labor.

The increase in the mechanical availability of harvesters allows for a resizing of the fleet, including studies on reducing the number of harvesters per harvest front. By increasing its availability, costs will be better diluted, reducing costs in Reais (R$) per ton of sugarcane, consequently reducing operating costs.

With the constant mechanical and technological growth of agriculture, the automotive maintenance sector is increasingly becoming a key part of the success of the business, which can result in large gains in the operation or even large costs in the final result.

The entire automotive maintenance sector is currently monitored by a Maintenance Planning and Control sector - PCM, which provides access and control over all information generated by maintenance.

Costs are demonstrated monthly through the CRM – Repair and Maintenance Cost, where the costs spent on parts, third-party services, internal services and tires are specified, with the items that will make up the CRM being at the discretion of each company.

Through CRM, indicators are created that allow knowing the cost in Reais (R$) per ton of harvested sugarcane.

The KPIs (Key Performance Indicator) are indicators that guided us throughout the harvest, seeking to achieve goals to improve operations.

Automotive maintenance has an annual budget, where monthly monitoring of what was budgeted vs. carried out is essential.

Today, we basically have corrective, predictive and preventive maintenance. Corrective maintenance, broadly speaking, is maintenance carried out after mechanical damage occurs, to correct problems, without programming, normally causing the equipment to stop instantly. This becomes very harmful to the operation and generates large costs, as damage may occur to several components, not just the component that generated the problem, and it is also not possible to develop an efficient action plan for this stoppage, which may result in a lack of equipment. in operation and with uncertain deadlines.

Therefore, in order to have greater consistency in expenses and predictability in downtime, preventive maintenance has become a key component, assisted by predictive maintenance (use of tools to predict the useful life of components).

Preventive maintenance depends mainly on planning, control and monitoring. In order to obtain the expected results, the PCM – Maintenance Planning and Control sector is essential for the success of preventive maintenance, where it will carry out programming, planning, control and analysis of the data provided. This sector is extremely administrative and its correct management will define the effectiveness of the results.

Preventative maintenance aims to prevent the occurrence of failures, breakdowns and avoid low availability. It is carried out through scheduled maintenance, at pre-defined intervals and according to each period, in the case of harvesters, according to the engine hour, following a previously prepared plan. It differs from corrective, as it seeks to prevent damage and occurrences and corrective only seeks to correct them.

For the Preventive Maintenance program to be successful, to achieve the expected result, good planning, qualified management, and constant monitoring and control are of fundamental importance, to guarantee the reliability of the service and control the costs of these maintenance. Thus, we verified that the PDCA Cycle method is ideal for organizing these processes and can be perfectly adapted to the reality of preventive maintenance of large fleets, guaranteeing process and quality management.

PDCA CYCLE IN PREVENTIVE MAINTENANCE

PDCA is a management method aimed at achieving goals, which can be goals to maintain and goals to improve, commonly applied in company management systems, generating the improvement of activities, guaranteeing the success of actions independent of the applied sector (FALCONI,1996 ).

PDCA not only identifies errors, but also investigates the causes and their possible elimination. It is a method with a relatively simple structure that can be applied in any organization, being a cycle based basically on Plan, Do, Check and Act.

Plan - Plan the work to be carried out

The first stage of preventive maintenance is planning. It must be carried out based on harvester histories, data obtained from the PCM (Maintenance Planning and Control), data on engine hours, mechanical services, lubrication, consumption, among others, thus generating a schedule for carrying out the initial checklist, which should be carried out a few days in advance, before the definitive preventive maintenance schedule.

This planning will allow strategies to be developed, set deadlines for the completion of this review, and will allow you to list the parts necessary for purchase by the supply sector and also the possible services involved. It also gives an initial idea of ​​the costs involved in this process, as well as the demand for internal labor until the service is completed.

Maintenance planning should also be aided by predictive maintenance methods, such as the use of oil analysis, wear measurements of some items, that is, any method of measurement and analysis that can direct preventive maintenance later to achieve success in carrying out tasks. maintenance.

Good maintenance and fleet-wide data management software will be a big differentiator at this stage, to ensure data reliability and monitoring in the following stages. There are several manufacturers and developers on the market, the important thing is for the company to be familiar with the tool and make the most of its resources.

Do – Do the planned work

After the planning has been carried out and reviewed by managers with their employees, it is time to execute everything that was planned, and for it to happen perfectly, it is necessary to follow the standardized procedures and the proposed schedule. Some unforeseen events may arise, but if planning is well prepared, unforeseen events can be easily overcome.

The processes must be followed faithfully, all based on work safety standards and company standards.

Preventative maintenance must follow the principles of anticipating damage, carrying out component assessments, replacements and preventive repairs, and can be assisted by predictive techniques.

Check – Measure or evaluate what has been done

After preventive maintenance has been carried out and the equipment has been released, all the material and information generated is made available to the PCM for fleet planning and control. Costs are collected and times and movements recorded. The information will generate indicators, KPIs (Key Performance Indicators) that will guide managers' decisions.

The indicators will be defined according to the reality of each company and the most used are availability, diesel consumption, lubricant consumption, useful life of rolling stock, MTTR (Mean Time to Repair) and MTBF (Mean Time Between Failures), service time, maintenance and maintenance cost indicators.

To control costs, we must use CRM – Repair and Maintenance Cost, provided by the costs department, where we will have the costs of parts, third-party services, internal services, tire costs and lubricant costs. It can generate an indicator in Reais per ton of sugarcane (R$/ton), which will serve as a guide in management decisions and goal setting with the maintenance team.

Action – Act correctly on the identified difference

Monitoring, acting to correct and improve the quality of what was carried out throughout this planning and process, is of fundamental importance for the constant improvement of preventive maintenance.

Therefore, preventive maintenance is not completed when the equipment is released and after the services performed, but rather is a constant process within the company. After the equipment is released and in operation, we can monitor, through pre-defined indicators (KPIs), its performance and the results of this preventive maintenance and thus draw conclusions about possible improvements.

During the verification, if we identify any type of deviation, we must define and implement possible solutions to eliminate its causes. Where would fit best, preventive work, identifying possible future deviations, their causes and solutions. Starting a new cycle.

Quality tools integrated into the PDCA cycle

Some tools can be used to improve and maintain the expected results, and that fit the profile of automotive maintenance for large sugarcane agricultural fleets. In a very summarized way, we can mention statistical tools such as Stratification, which consists of grouping data from various points of view, verification sheets, which can be considered as checklists developed for this process, the Pareto Chart in order to make it evident and easy to visualize the themes and their importance, the Causes and Effects Diagram presenting the results of the process and its factors for evaluation and diagnosis, Histogram Charts and Scatter Diagram, and Reliability with failure time analysis and accelerated life test .

The quality tools integrated into the PDCA Cycle guarantee greater reliability in the method and processes involved, facilitating the monitoring and constant improvement of preventive maintenance, implementing a Quality Management system for this maintenance.

The tools used must also be in accordance with the profile and resources of each company, as well as the technical intellectual capacity, so that they result in good results, with reliability and guarantee.

Conclusion

The major disadvantages of corrective maintenance compared to preventive maintenance is that corrective maintenance has variable and unpredictable costs, as well as unforeseen equipment downtime, often simultaneously, and due to failures not detected early, reflecting the failure to deliver raw materials and other operations. .

With the preventive maintenance routine, we will have a notable consistency in maintenance costs, which will be better perceived after the first harvest, when the new cycle begins with all equipment already revised, due to the planning of this maintenance, resulting in the purchase of parts at better prices. , deadlines and labor defined for each service with pre-stipulated deadlines and values.

The availability of harvesters will present an increase and stability in its percentage, as it will result in a reduction in unexpected failures, as well as greater effectiveness and reliability in operations.

The PDCA must be implemented by the PCM – Maintenance Planning and Control sector together with Automotive Maintenance management, as all planning and control will be carried out by the PCM, as well as histories, schedules, survey of items used, costs, KPIs and other related information preventive maintenance.

The PDCA method is a simple and objective method, it fits into the current profile of the agricultural sector in Brazil, a sector that needs constant improvements, but there is still a long way to go in search of quality, continuous improvement, especially in the sectors operational and automotive maintenance.

DMAIC could also have been used, however, as it presents more complex, more advanced statistical tools, and considering the beginning of implementation work in the company, it would not fit at this time. PDCA will allow familiarization with quality methods to occur, by using simpler tools, thus ensuring the motivation of the entire team and achieving more snapshots of results in this initial phase. Subsequently, the implementation of DMAIC should be considered, as well as other existing methods.

The method can be used to carry out so-called linear maintenance, specific preventive renovations to the harvester during the harvest.

Kazuyochi Ota Junior, Ucam