Total Productive Maintenance Analysis Using OEE and FMEA Method at PT. XYZ Phosphoric Acid Factory

The smooth production process in the company is influenced by several factors, one of which is the machine. Machine maintenance is something that needs to be done by the company because it has an important role in the smooth production process. PT XYZ is a company engaged in the manufacture of fertilizers and chemicals. Phosphoric Acid Plant, production department III A, PT XYZ, in its production process, has 193 machines that are used to process phosphate rock. Based on a survey related to problems that often occur at the Phosphoric Acid Plant, it can be seen that three machines have the highest breakdown time, namely 1st Filter (Fil-2321), 1st Vacuum Pump (C-2323), and Digester (R-2302 B). From these problems, machine maintenance analysis was carried out using Total Productive Maintenance with Overall Equipment Effectiveness and Failure Mode Effect and Analysis methods.


Introduction
The production process is the most important thing in the company that needs to be considered.The smooth production process in the company is influenced by several factors, one of which is the machine (Nurjaman & Haryadi, 2018).The production floor consists of several machines that are integrated and used by the company to produce goods.Machines have a great influence on the smooth running of the production process because when the machine is damaged it will certainly hamper the production process so that the production process can be stopped (Islam, 2020).
Machine maintenance is something that needs to be done by the company because it has an important role in the smooth production process.The machine maintenance process needs to be carried out according to the target so that there is no delay in the machine (Arsyad & Sultan, 2018).Things that can happen when the maintenance process is not carried out by the target will cause losses for the company such as stop time, breakdown time, and decreased production speed so the output produced by the company will decrease.By routinely carrying out machine maintenance according to the target, the production process at the company will run well and productivity will increase.
XYZ is a company engaged in the manufacture of fertilizers and chemicals.The products produced by XYZ company include phosphate fertilizer, urea fertilizer, sulfuric acid, phosphoric acid, and so on.Phosphoric Acid Plant, production department III A, PT XYZ, in its production process, has 193 machines that are used to process phosphate rock.In this study, a survey was conducted related to the problems that often occur in the Phosphoric Acid Plant.From the survey results, it can be seen that there are three machines that have the highest breakdown time, namely 1st Filter (Fil-2321), 1st Vacuum Pump (C-2323), and Digester (R-2302 B).Breakdown occurred due to damage to several machines which varied, including cracked bearings, dirty impellers, jammed oil pumps, and leaky shell inside.Based on these problems, it is necessary to analyze machine maintenance using Total Productive Maintenance with Overall Equipment Effectiveness and Failure Mode Effect and Analysis methods.With this research, it is hoped that the company will be able to make machine repairs properly so that productivity increases.

Maintenance
Maintenance is the activity to maintain facilities according to their functions so that they can be used in good condition.Maintenance activities in a production process are carried out on several machines so that production facilities can run well and smoothly (Majid et al., 2014).The purpose of machine maintenance is to keep machines in good condition and reduce machine failures in the production process.Machine failure can occur due to poor planning, weak installation, and incorrect machine application (Ansori, 2016).

OEE
OEE is one of the methods used to measure engine efficiency.This method is generally used in the manufacturing industry.OEE focuses on how effectively operations in the manufacturing process take place where the results are expressed in a generic form that allows comparisons of manufacturing units between departments (Or, 2010).The purpose of OEE is to determine the performance of equipment and as a material consideration in the procurement of new equipment at the company (Oktaria, 2011).To calculate the OEE value, it is necessary to know several things such as the value of availability, performance rate, and quality rate.

FMEA
FMEA is a tool used to analyze the reliability and causes of failure of a system.This method is used to identify three things, namely the cause of system failure, the effect of the failure, and the criticality level of the failure effect (Gaspersz, 2002).The benefits that can be obtained from the application of the FMEA method are improving product quality and safety, increasing customer satisfaction, reducing product development costs, and setting priorities in the improvement process.

Material and Methods
This research consists of several steps.The first step is to conduct field observations at the Phosphoric Acid Plant, production department III A, XYZ company to find out the existing problems, then proceed with determining the research objectives.The data used in this study are primary data consisting of observations and interviews and secondary data consisting of machine data at the factory, running time, planned downtime, downtime, machine breakdown, set up, stop time, operating time, processed amount, and defects.amount.The next step is to calculate availability, performance rate, and quality rate, and then calculate OEE.After obtaining the OEE value, six big losses are calculated and make Pareto diagrams and fishbone diagrams.The final step in this research is to analyze FMEA and provide suggestions for improvement for the company.

Data collection
Data processing can be done when the data has been collected both primary data and secondary data.Primary data is obtained from direct interviews with field supervisors in the form of qualitative and quantitative data, while secondary data is data that is data that has been collected in advance by someone and becomes company history data.The data needed include machine data at the boiler station, machine running time, planned machine downtime, machine downtime, machine setup time, machine breakdown, machine stop time, total production, and defect amount (Table 1).

Calculation of the Overall Equipment Effectiveness (OEE) and six big losses machine
Data processing is carried out using the Overall Equipment Effectiveness (OEE) method which is based on three factors, namely availability, performance efficiency, and quality rate (Rusman et al., 2019).Availability calculation describes the utilization of machine time at the boiler station available to carry out operations (Jaqin et al., 2020), Performance rate describes the actual ability of the machine to operate at an ideal speed based on capacity, and the quality rate is carried out using data on the amount of bagasse that was successfully processed and the amount that was not successfully processed.
After obtaining the value of availability, performance efficiency, and quality rate, the measurement of the OEE value can be carried out on each machine at the boiler station.The results of the OEE calculation can be seen in Table 3.  3 above, it can be seen that the calculation of the engine OEE value at the PA factory at PT. XYZ period January-August 2021 is still below the standard, which is around 79%, such as 1st Filter 79.85; 1st Vacuum Pump 79.80; Digester 78.60 where according to the OEE Classification in Japan Institute of Plan Maintenance the value is in the normal category, is that production is considered reasonable but still shows there is a large room for the company to develop, and the company's competitiveness is low.
The second stage after getting the OEE value from each machine at the PA factory is to measure the six big losses.Six big losses are six factors that affect the OEE value.The value of six big losses for each machine at the PA factory that is not ideal is calculated to determine the most dominant and influential factors on the OEE value 1st Filter, 1st Vacuum Pump, and Digester.Six big losses are represented by downtime losses (breakdown losses, set up, and adjustment losses), speed losses (idling and minor stoppages losses and reduced speed losses), and defect losses (rework losses and scrap losses) (Dewi et al., 2020).

Root cause analysis
The benefits of this fishbone diagram can help us to find the root of the problem in a userfriendly manner that shows the relationship factors as a result that affect the level of machine productivity in the PA plant.The influencing factors are man, method, material, machine, and environment (Saifuddin et al., 2021).

Failure Mode and Effect Analysis (FMEA)
Failure Mode and Effect Analysis (FMEA) was performed as a follow-up to the fishbone diagram analysis.Root Cause Analysis diagram will be a potential cause in FMEA.In addition to potential causes, identification of potential effects is also carried out, namely what is the result of the failure.
Determination of the value of the Risk Priority Number (RPN) is the result of the multiplication of the values of severity, occurrence, and detection (Saifuddin et al., 2022).Furthermore, the severity, occurrence and detection values used have been adjusted to the company's existing conditions by conducting discussions with related parties (Qothrunnada et al., 2022).The criteria used to determine each value from 1 to 10 on severity, occurrence, and 67 detection are obtained from discussions with the company so that the criteria used can represent the company's condition well.

To be continued…
Plant Maintenance, which is 85%.This condition shows that there are still big opportunities for the company to improve.The delay that causes the lack of effectiveness of the 1st Filter, 1st Vacuum Pump, and Digester machines is idling and minor stoppage losses.The delay was caused by several factors, including humans, methods, machines, materials, and the environment, and the main priority problem in repairing the 1st Filter machine was the machine experiencing downtime with the largest RPN value (216) the cause of the failure was the roller coaster was damaged and the handling was done correctly.check the damage to the roll coaster component, if there is severe damage, a part replacement will immediately be carried out, for the 1st Vacuum Pump machine, the machine experienced downtime with the largest RPN value (216) the cause of the failure was the motor fault and the handler balancing the rotor and modifying the safety using electronic over current relay so that it can easily monitor the condition of the motor, including wide ampere range, quick reset, ampere meter, alerting, manipulation of amperage range, and for the Digester machine, the machine experiences downtime with the largest RPN value (210) the cause of the failure is acidic material concentrated (H3PO4) with the handler needs to do neutralization and cleaning so as not to damage the machine.

From
the calculation of the percentage of the six big losses factor above, the highest factor percentage for the 1st Filter machine is Idlling and Minor Stoppages Losses of 21.293%, for the machine 1st Vacuum Pump are Idling and Minor Stoppages Losses of 21.244%, and for Digester are Idling and Minor Stoppages Losses of 22.233%.

Table 1 .
Company machine data collection

Table 3 .
Calculation of Machine OEE at PA factory and OEE classification according to JIPM

Table 4 .
Calculation of the machine six big losses factors