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Modeling and Simulation of Drive Rolls with Rolling Bridge Input Line Painting CSN Araucaria - PR
This case study is based on process modeling and simulation of the moving operation of the crane PR # 07 entry of the painting line, aiming to study the care of logistical resources of the input line to enable the expansion of equipment production-line painting (LPC # 1) of the National Steel Company in its subsidiary located in Araucaria PR, simply called CSN-PR. Using the tool of discrete event simulation to analyze the current model, verification and implementation of possible solutions to the problem of bottlenecks in the movement of finished products off the galvanizing line (LGC # 1), field packing, stock movement, discharge of raw materials, wagon loading, exchange and supply of bucket paint line. These moves have shown concern for the care LPC # 1 (supply) due to the investment that the company will perform in line to increase production of 100mil tons / year to 130 thousand tons / year. The crane 07 (PR # 07) performs several drives, which can be summarized as: the removal of materials from LGC # 1, moving in the area of packaging, inventory movement, exchange of the bucket, dump truck, the car supplies transfer, wagon load of supplies and LPC # 1. The movement of materials taken from the LGC # 1 and moving in the packaging area, are also performed with the aid of the crane 08 (PR # 08), located in the same house.
The objective of this project is to study the handling logistics warehouse called A02 (LPC entry # 1) to identify bottlenecks and to indicate possible improvements or investments due to increased production, especially the best solution to the problem of bottlenecks in the movement of the coils storage of finished products called A02, located near the continuous line of paint - LPC # 1. Currently, PR # 2007 meets the needs of production and other activities mentioned above, but with the expansion project, PR # 07, can become the bottleneck. The investment for this expansion is high and it needs to be thoroughly checked the need / ability of accessories so that no future problems or stop production. Also an analysis of the possibilities for improvement by modifying the layout or verifying the need for investments in the plant, either increase the resources employed in this movement, is the expansion of infrastructure is necessary.
Its production flow is primarily focused on compliance with construction, white goods and in services to the automotive industry. The main raw material is coming from its headquarters in the city of Volta Redonda - RJ whose hot-rolled steel base after arrival in Araucaria RP receives various surface treatments, being a specialty of the unit. The process begins in semi continuous pickling (1 - LDS) with application of hydrochloric acid on the surface of the plate in order to clean the impurities and stages of natural oxidation of the crude product or also because the conditions of transport of the coils, which can occur due to wetting from rain. The final product is called coils pickled hot rolled steel in the width specified as customer's request. After the pickling process (the surplus can be sold directly) steel coils are sent to the reversible cold rolling mill (2 - SRT) at this stage the objective is the reduction of plate thickness. In this case the cops come to be called the cops "Full Hard" (BFH) and his translation is closer to the Portuguese would be "high hardness" due to physical characteristic of the steel after the rolling process. These coils are annealed in the electroplating process for obtaining hardness standards as requested by customers. Following the coils BFH pass to the next process (the surplus can be sold directly) called electroplating in Continuous Galvanizing Line (3 - LGC), considered the heart of the products with coatings that ensure the integrity and longer life to steel . This process transforms the BFH's in galvanized steel coils that can be either galvanized steel coils Galvanized (BZN) or galvanized steel coil Galvalume  (BGL) whose rank and operating license is granted by BIEC International CO.
After dip galvanizing process, the products can be sold to both national and international market and / or forwarded to the Line of Continuous Pre-Painting (4 - LPC1) or the Steel Service Center (5 - CS) where will be cut according to customer requests.
The pre-painting is characterized by the application of paint film in one or both sides of the steel coil. This production line is recognized for excellence and high technology used in its production process. The point of entry of these products is the object of this study. The pre-painted coils can be sold domestically and internationally, or even sent to the steel service center (5 - CS) where they run the various court systems currently on the market for steel. The cutting process serves precisely to a more direct application to key major customers of this unit, as a segment of white goods, construction and automotive.
Changes in the entry line, object of this study is done by a crane PR # 07 with a load capacity of up to 15 tons. The percentage of utilization of PR # 07 is unknown, it therefore becomes the primary resource for supply LPC # 1. Due to the various movements necessary to attend both the withdrawal of products from the production of Galvalume (LGC # 1), regarding the effective loading of goods wagons for shipment to customers, internal drives and transfer coils of a shed to another.
Following the methodology of simulation, started the study constitutes the abstract model of the process of moving coils, in order to visualize how the physical system is constituted. After this step we move to the conceptual model, also known as Activity Cycle Diagrams - ACD (translated into Portuguese: diagram of the activity cycle) where it was possible to know the flow of the system that are represented in computational form.
Also considered were the time of other surveys, such as stopping to crane maintenance, exchange, shift operators, lunch operators, downtime and replacement of handling equipment.
After the process of data collection and integration of these spreadsheets has begun observing the statistical results of each process to implement them in the computer model (simulator). The initial check was in scouting for finding out if there were no points of the curve in statistical distributions, called Outliers.
For each Work Center (work) was necessary to add a "resource", which are considered as secondary activities of the ACD and, before each activity, it was necessary to add the storages bins (rows), for in them is that they focus the rows of each activity. Each item was checked before being added to the system in an orderly manner to avoid false results when the simulation. Several "checks" (checks) are required for finding the correct link and application of all resources and queues. Another feature implemented was the "poolled resources" due to the object of study, has two cranes, where they share some activities.
After implementing the system, one way to verify the computational model was consistent with the physical situation has been through the experience of staff involved in the process. Another way to check was the number of daily production of steel coils that simulation time multiplied by the average weight of coils generated a volume very close to reality, stating that the computer system was in line with reality. Another situation was to compare the amount of coils loaded on wagons, which already struggling with the volume disposed above, reflects much closer to reality. The review carried out with the working group who knew the activities of the study site was an important technique for verification and validation.
Whole model is based on minutes. As the simulation period (results collection period), subgroups were 129,600 minutes, or three months, and as warm-up period (warm-up), took up 14,400 minutes in a 24 hour operation, 7 days a week ie, uninterrupted.
Before running the system, some assumptions were adopted to complete the construction of the computational model, namely:
1. Creating poolled resources, ie the aid of the crane PR # 08, in only two activities primarily allocated to PR # 2007 crane, removal of materials from the birthplace of LGC for the area of packaging and handling of coils in the inner area packaging or the stock;
2. Percentage of availability ("availability") crane PR # 07 is 86.25% and the crane PR # 08 is 30% (percentage based on information from the experience of professionals, counting the times of shift change , snacks and dinner operators);
3. Output rate of the stock material A04, for the supply of LPC1 was considered the sum of production times the final daughters of the coils, the time to find the reel "mother" of supply;
4. Considered fixed exchange bucket twice a day, or once every turn;
5. Unloading of vehicles from the gate 111, even given the low volume receiving at this location was not possible to collect sufficient time for the basis for calculating statistics. Assumption based on historical discharge of the gate.
6. For this study, due to system limitations, were considered the mix of production of construction and white goods, construction of which has an average production of 400 500 tonnes per day and the white line has a volume from 190 to 220 t / day;
7. The speed of the crane was based on information passed by the person responsible for maintenance of bridges, with a constant of 90m/min.
8. It was also considered a priority order (priority) to meet the cranes for each activity on a scale of 0 to 100, where 100 are the activities that must be met first;
Importantly, the data collection was done in a period of low volume, high-volume stocks, and halted two weeks of the crane PR # 07 for maintenance. Data which may influence the result. If the situation is reversed, the ideal would be to conduct a new collection from time to again make the simulation.
Three scenarios were elected from among the many current simulations, to present the results and possible improvements to be suggested for the decision:
Current Scenario: Model of the current operation, knowing the potential bottlenecks and points of improvement, or rather, "where we operate. "
Completion of Current Scenario: The current percentage use of the crane PR # 07 indicated a 71.48% average availability of 86.25%, since the crane PR # 2008 represented an average use of 78.63% availability 30% of which was premised. This result is exactly what was expected, since this equipment is used to perform all activities of the warehouse, with the aid of the crane PR # 08. The data were validated through the volumes disposed of, produced and aid professionals.
We can also conclude according to table 03, that the activities car "transfer " and "out of the BZN A04 to A02, totaling 89.2% of the attendance LPC1, being respectively 10% and 79.2%. That is, the time dedicated resource PR # 07, LPC1, and would be carrying out other activities, like loading a wagon that indicates waiting for attendance of 96.9%. Another issue to be addressed is the potential for charging through the gate PE111, which according to table 03, identifies low utilization. As a suggestion for improvement, make shipments through the gate PE111, increasing runoff.
Scenario 1: In this situation, was simulated by a 30% increase in the supply line painting, or that the line would have to be filled on average every 36 minutes (data confirmed by the engineers at these LPC # 1). Also considering a 30% increase in shipping materials to the tank A04 A02, drive through the transfer, an increase of 30% of the production equipment of galvanizing LGC # 1 and unloading of vehicles.
Completion of Scenario 1: In this scenario we can see that the percentage of the crane had a small increase in use, rising to 74% of the crane PR # 07 and 79.9% of the crane PR # 08. But according to table 04, due to the increase, the expected attendance for review of all activities, significantly reduced, as shown in table 04, waiting in the description. Note that the result of a scenario, according to table 03, was very similar to the current scenario, it is not justifiable to purchase over a crane to perform the same activities, plus 30%. Finally, it remains a suggestion for improving the loading opening through the gate PE111, as suggested in the conclusion of the current scenario.
Scenario 2: In this scenario, he maintained the percentage increase of 30% of activities, including also the same percentage increase for loading wagon. Deleted the transfer operation between the A04 and A02 deposits, 100% of the simulated discharge the gate PE111. Was removed from the current restriction of this activity receiving only during daytime, making it 24 hours, with scheduling discharge every two hours. As this situation is planning to increase the warehouse at 900m ², the speed of the crane PR # 07 was reduced to 90m/min, 67.8 m / min, according to information engineering techniques responsible for the cranes. Another assumption adopted for increasing the shed is that PR # 07, having a significant increase in the discharge, should be assisted in their activities by PR # 08 in at least three jobs: the withdrawal of coils for stock, moving stock and a small percentage of loading wagon.
Completion of Scenario 2: We can clearly conclude that keeping the production increase, and changing the layout of receipt (that would be ideal), the percentage of the crane PR # 07 increases to 81% for service activities, can become bottleneck entire operation. Also important to note that the crane works in PR # 08 100% 30% availability in assisting the activities of PR # 07, and thus become the bottleneck process, especially as performing other important activities. An alternative to minimize the bottleneck would increase the availability of PR # 2007, through new hiring or relocation of those, only at times of break and lunch, so it does not stop so long. Another alternative would be to enhance the loading PE111 road through the gate and the gate of the rail access, would increase the loading capacity and especially the company's sales. Investment in the shed, removed from the car transfer and expansion of the asphalt to dock rail access is approximately R $ 2,900,000.00. Remembering that the simulation works only when the ceilings of the processes, which not only indicates that these changes are made, the process stops, but the PR # 07, this simulation scenario 2 indicates that on a full time operation, the bridge will operate at full capacity.
Scenario 3: This situation was maintained at the base of the second scenario, changing the loading capacity of 5,000 t in car / month (which is the maximum possible departure) and the procurement of LPC1 considering an average time of 33min / coil to increase the mix galvanized steel products for construction, information given by the head of the line. Thus was simulated by the crane PR # 08 would assist the crane PR # 07 only in relation to withdrawal from the galvanizing and materials handling in the packaging area. Another modification was to add a new crane to service the dump truck, supply LPC # 1, load the wagons and stock movements, with the need to create another "poll resources" for the cranes and new PR # 07 . The speed of the bridges was considered for all of 90m/min.
Completion of Scenario 3: The percentage of all the bridges becomes fully acceptable and in accordance with a very high volume production and shipment of the wagon. Importantly, acquiring the new bridge rail loading capacity becomes greater than or equal to 5,000 tons per month, even with the current situation of noise-loading wagons on trade issues, but may become a new option of charging road through PE111 gate (in addition to discharge). Another potential road charging would be through the loading gate rail, but demand for investment in highway access to the site. So in this scenario is no possibility of increasing the flow of runoff and two gates. There is also a study of building a new paint line (LPC # 2) and through this simulation, note that it is fully possible to meet the whole operation with the expansion of the shed and the LPC # 1. The investment for implementation of scenario 3 would be beyond the values used in scenario 2, £ 2.900.00,00, and also buying a new crane, totaling approximately R $ 4,000,000.00, totaling R $ 6,900,000.00. The figures are impressive, however justifiable, considering that occurs maximum loading capacity of wagon / truck, increase productivity and the percentage of lines for any of the bridges will be idle, ideal for the expansion of LPC # 1 and # 2 construction of the LPC.
The current situation represents a very low turnover through the railroad, due to high modal transit time of this, that this restriction prevents an increase in the use of the railroad. But regardless of whether the shipment will be via rail or highway, a dock would be provided more outlets by increasing the speed in loading and possible daily revenue of the company.
We conclude that the third scenario, would bring a considerable increase in speed and loading capacity daily, increasing the level of service and billing. The increase in production volume of 130 thousand to 100mil tonnes per year of LPC # 1, would be fully supported and investment would be justified by the new potential of rail and road loading. It is also concluded that the expansion of the painting line and the shed to meet only with the crane PR # 07, this would place the bottleneck for the operation, so the need for investment in a new crane. Other assumptions have been suggested for PR # 07 alone meet the second scenario, such as reducing the loading of wagon, but would generate less revenue for the company and difficulty in disposing of products, since they lose a point of disposal. Remember that you need to sell produce, and sell you need to sell, so increasing the loading capacity, we would be improving the level of service. A reduction in the current bottleneck in shipping products that location would meet the growing market for steel and successfully attain the goals of increased production. In the near future the construction of a new line of exclusive attention to painting the white line could also be confirmed from these investments.

FINAL

This study was initiated by the growth of the current market pre-painted steel to meet the construction, appliance and automotive industry. To service this growth, a study was conducted in inner-PR CSN, concluding that only by enhancing the production equipment of the paint line at CSN - PR would be possible to meet the rising market. From there began a new project studying the design of logistics resources to enable this growth in production to meet that market. As the basis of the whole process, which was established from the current scenario, which would create possible scenarios for the simulation and identify opportunities for improvement.
Given this estimate of growth, especially the preparations for the 2012 Olympics and World Cup 2014, we project a growth in sales and justify new investments in plant CSN-PR as shown in scenario 3, however, increasing its production capacity and loading, to enable increased production processes and company revenues.
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