Aggregate Planning Implementation for Planning And Controlling The Materials in The Beverage Packaging Industry

The Beverage Packaging Industry in Indonesia is currently experiencing very rapid development and has resulted in intense competition in the industrial market (Tannady & Pratama, 2019). The Ministry of Industry noted that the contribution of the food and beverage industry to the Produk Domestik Bruto (PDB) of the non-oil and gas industry reached 34.95 percent in the third quarter of 2017. This performance result makes the sector the largest contributor to industrial PDB compared to other subsectors. Companies need to compete to be able to achieve consumer loyalty that is superior to their competitors (Kirana, 2020). For every industry, demand fulfillment, loyalty, and customer satisfaction are important aspects to compete in the global market (Ning et al., 2019). Every industry to be able to achieve this aspect needs to increase productivity and efficiency in its production process (Dahlia & Andri, 2021). Increasing productivity in this industry is more directed at optimizing the production process, ART ICLE INFO ABSTRACT


INTRODUCTION
The Beverage Packaging Industry in Indonesia is currently experiencing very rapid development and has resulted in intense competition in the industrial market (Tannady & Pratama, 2019). The Ministry of Industry noted that the contribution of the food and beverage industry to the Produk Domestik Bruto (PDB) of the non-oil and gas industry reached 34.95 percent in the third quarter of 2017. This performance result makes the sector the largest contributor to industrial PDB compared to other subsectors. Companies need to compete to be able to achieve consumer loyalty that is superior to their competitors (Kirana, 2020). For every industry, demand fulfillment, loyalty, and customer satisfaction are important aspects to compete in the global market (Ning et al., 2019). Every industry to be able to achieve this aspect needs to increase productivity and efficiency in its production process (Dahlia & Andri, 2021). Increasing productivity in this industry is more directed at optimizing the production process, especially in production planning for meet consumer demand and produce optimal production output (Gulsun et al., 2009). In addition, the efficiency applied is more directed at minimizing costs in each production process that takes place for generate maximum profits by utilizing available resources (Magdalena, 2020).
Currently, one of the competing industries in the market is more focused on the food and beverage sector. Beverage Packaging Industry is a soft drink industry that provides ready-to-drink products for packaged tea products. This industry is a company that produces the first packaged tea in Indonesia with one of its leading products being Box Bottle Tea (BBT) 250 Slim. Based on initial observations, production demand continues to increase and the amount fluctuates (can be seen Figure 1). However, with fluctuating and dynamic consumer demand, the Beverage Packaging Industry is faced with the problem of not optimally planning its production to produce an accurate product quantity that is close to the actual number of each distributor. This had an impact on production in 2019, the company was unable to produce according to customer demand. High demand while the resulting low production. The continuity of the production process to meet consumer demand requires good production planning (Fairuzzahira et al., 2020). Where production planning is planning about the products produced and the number of products that will be produced in the coming period (Jamalnia et al., 2019). Based on the problems above, it seems that improvements need to be made (Yuliastuti et al., 2019). Therefore, it is necessary to have an improved solution with an approach that can control production so the company can meet customer demands (Atikno et al., 2021). This research will integrate the aggregate planning approach with a statistical approach. Linear regression is needed to complete the data analysis method.

Figure 1.
Total of demand (units) 2018-2020 One of the production planning is aggregate planning. Aggregate planning is in the form of the quantity planning process and certain timing through adjustment of factors production level, employees, inventory and other controllable factors (Bagchi & Paul, 2018). Aggregate planning is a method to estimate the amount of output that will be produced to meet demand during the planning period and adjusted to the company's production capacity (Cheraghalikhani et al., 2019). Aggregate planning allows the company to develop a strategy to use company resources well, to achieve effective and efficient capacity based on forecasts of future demand . Effective means alignment between planning and the results obtained (Rosyidi & Zabadi, 2019). While efficient means being able to produce a certain output with existing resources as well as possible (Nivasanon et al., 2021).
The development of aggregate planning methods is often implemented in large manufacturing industries to plan and control their production (Jayakumar et al., 2017). The application of aggregate planning not only controls production in large industries but can be applied in small and medium industries (Oey et al., 2020). Several sources of previous research also noted that this method can be integrated with other methods to obtain complex research results (Schroeder & Larson, 1986). Aggregate planning is often combined with algorithms to get a good model that can efficiently and effectively solve all types of aggregate production planning (Biazzi, 2018). This method can suppress the occurrence of product shortages in the manufacturing supply by using two-level particle swarm optimization (Oktavianty & Sukmono, 2020) (Jang & Chung, 2020). There are many advantages to the company if implementing aggregate planning (Nisa & Kusuma, 2017). Aggregate planning is a method for planning and controlling production in the medium term so that companies can minimize their production costs (Juliantara & Mandala, 2020). The purpose of this research is to plan and control production to help smooth the production process so that the company can meet consumer demand. Based on previous research references which state that aggregate planning can carry out production planning and control, this study will implement an aggregate planning method that is integrated with the linear regression method to determine the capacity of the raw materials so that it becomes novelty in this study .

RESEARCH METHOD
This research focuses on planning and controlling production in the Beverage Packaging Industry to expedite the production process to create products on time. The method used is Linear Regression and Aggregate Planning. The choice of linear regression method as a predictive method in this study is based on its advantages in estimating the parameters of a simple model and the data used are time series based. Linear regression is one of the methods used in production to forecast or predict quality and quantity characteristics. This is because by estimating various product combinations, companies can maximize profits and estimate the right amount of production. This research is included in descriptive research using a quantitative approach. The descriptive technique describes or explains the forecasting process up to aggregate production planning. This research was conducted in the Beverage Packaging Industry which produces bottled tea located in Bekasi, Indonesia. This company was chosen because of fluctuating demand for products from customers and less than optimal production planning, so there is often a problem of excess product inventory when demand is low, on the contrary, there is a shortage of product inventory when demand increases. This has a negative impact on the company's operations where production costs are high, materials are not controlled and targets are not achieved. In addition, strategically the company is unable to compete in the global market because it does not meet customer demands. The product that is the focus of this research is the Box Bottle Tea 250 Slim. The primary data used comes from observations and interviews, while the secondary data comes from company documentation, such as data on the number of requests last year, raw materials, production capacity, production time, articles in journals and institutional annual reports.
This study uses a conceptual framework to determine problems, improvement planning objectives and expected improvement results. The following conceptual framework of this research can be seen in Figure 2. Conceptual framework The first step is to define the problems that occur in the production of BBT 250 slim. Once the problem is found, then determine the target for improvement. Forecasting is done using Linear Regression. Furthermore, planning and controlling with Aggregate Planning includes making a Master Production Schedule (MPS) with a hybrid strategy and determining raw material requirements with lot for lot. This equation is determined by a = intercept is the point of intersection between the X and Y axes when the value X = 0, while b = the slope of the trendline, which is the rate of change in demand and the value of t = time index (t = 1,2, 3, ,,,, etc.) is the number of time periods. The X and Y equations are used to explain the demand variable and a certain time period in the regression equation so that the best model is obtained. Equation (1)-(4) are used to forecast with linear regression.
UPRT is a unit of calculation to determine the number of products produced according to the company's regular schedule.

RESULTS AND DISCUSSION
In this section, analysis is carried out for planning and controlling production with aggregate planning. Data analysis begins with defining the problems experienced by the Beverage Packaging Industry. Production planning in the Beverage Packaging Industry is based on the previous year's demand and production planning. The following is data on demand for BBT 250 slim products in 2020 which can be seen in Table 1.  Table 1 shows that production demand and realization do not match. This is a problem in the Beverage Packaging Industry that needs good planning and control. Planning is done by considering the available production capacity. The following production capacity available during 2020 can be seen in Table 2. After last year's demand data is known, the next step is forecasting.
Based on Table 1 and Table 2, forecasting is carried out using the Linear Regression method. This data processing is done by using Ms. Excel 2016. The following is the calculation of the constants and their variable coefficients. The regression equation above is interpreted if the independent variable increases by 107,851 it will reduce product demand by 1.956 units or rounding up to 2 units. Forecasting calculations for next year can be seen in Table 3.
Calculating constant according to equation (   Based on Table 3, it can be seen that the forecast for the 2021 period is calculated. Then the calculation using a hybrid strategy can be carried out with production capacity. The calculation of UPRT uses formula (4) and the recapitulation of the results can be seen in Table 4.  Based on the results of the calculations in Table 4, we can know the total value of production per period. The results of the above calculations include the production of BBT 250 slim. The total production in Table 4 will be used as the Master Production Schedule (MPS). UPRT is used because it refers to regular production that is often run by the company so it is assumed that it can be used as MPS. MPS data is taken from the total production recapitulation data on the hybrid strategy. The following is the total production requirement per period as can be seen in Table 5. Based on the MPS data in Table 5, the planned raw material requirements of the BBT 250 slim component are calculated using the lot for lot method in order to obtain optimal raw material requirements. Lot for lot was chosen because it is able to provide inventory in accordance with the required material so that the amount of inventory available is as minimal as possible. The number of orders is adjusted to the actual number of requests and results in no inventory being stored. So that the costs incurred are only in the form of ordering costs. The lot for lot method is a process to determine the optimal order size for each product item based on the calculation of net needs. The lot for lot method is closely related to determining the number of components or items that must be ordered or provided. This product is composed of several components that make up the Bill of Materials for the BBT 250 slim product which can be seen in Table 6. The following is the calculation of each raw material needed in the manufacture of the BBT 250 slim product sample in January.
Dry Tea A = 330,000 carton x 24 pack = 7,920,000 pack 7,920,000 pack x 250 ml = 1,980,000 Liter : 6000 (per batch) = 330 batch 330 batch x 36 Kg (per batch) = 11,880 Kg Sugar B = 330,000 carton x 24 pack = 7,920,000 pack 7,920,000 pack x 250 ml = 1,980,000 Liter : 6000 (per batch) = 330 batch 330 batch x 2,950 Kg (per batch) = 1,120,079.6 Kg Water C = 330,000 carton x 24 pack = 7,920,000 pack 7,920,000 pack x 250 ml = 1,980,000 Liter : 6000 (per batch) = 330 batch 330 batch x 9500 liter (TCP and Sugar Syrup) = 3,135,000 Liter Straw D = 330,000 carton x 24 pack = 7,920,000 pack 7,920,000 x 1 pc = 7,920,000 pc Carton E = 330,000 x 1 pc = 330,000 pc Paper F = 330,000 carton x 24 pack = 7,920,000 pack 7,920,000 pack : 15000 pack (per roll) = 528 Roll Based on the results of the calculation of raw materials above, the company can determine and manage the inventory of raw materials every month. After the calculations are done, the data recapitulation is carried out. The following is a recapitulation of the calculation of raw material requirements for the 2021 period using the lot for lot method which can be seen in Table 7. Calculation of raw material requirements in 2021 using the Hybrid and Lot for Lot methods is much smaller than the company's calculations based on 2020 data. This interprets that calculations using aggregate planning are more efficient. The comparison of the average material requirements in 2020 and the 2021 plan can be seen in Table 8.

CONCLUSION
The results showed that to support the smooth production can do planning and control on the material. Controlled materials can reduce high production costs, determine production capacity and meet customer needs so as to support smooth production. Production planning with forecasting calculations using the Linear Regression method produces a model Y = 107,851 -1.956X. Based on the analysis of aggregate production planning, the calculation of the main raw material needs in 2021 using the Hybrid and Lot for Lot method is much smaller than the company's calculation based on the data in 2020. Based on the calculation with the hybrid strategy, it can be seen that the production plan for the next period is 12 months. Calculation data for forecasting is used for one year only. This research can be continued in further research by planning and controlling production using the time series forecasting method, so that more accurate forecasting calculations will be obtained and in the long term.