Value Optimization among Process Parameters of Mungbean Sheller using Response Surface Methodology


Academic Paper, 2019

5 Pages


Value Optimization among Process Parameters of Mungbean Sheller

Christian Malacapo Mortel

#Mechanical Engineering Department, Romblon State University, Philippines

Liwanag, Odiongan, Romblon, Philippines

Abstract - This paper investigated the significant effects of the identified variables (input capacity, blower air velocity and the shelling cylinder shaft rotation) on the shelling recovery process of mungbeans to lessen the impurities and mechanical damages of kernels. This study utilized response surface methodology through Box-Behnken design as a tool to identify the effect of the identified variables to the response variable using the Minitab 17 software. It also aimed to establish the optimum values of the identified variables and the response variable. Based on the assessment from the fifteen (15) experimental runs, it was identified that the three identified variables are considerably significant to the shelling recovery of the mungbeans. Moreover, the optimal conditions of the independent variables, input capacity, blower air velocity and shelling cylinder shaft rotation are 40 kg/hr, 3.3536 m/seconds and 343 revolution pe r minute, respectively. These optimum values could predict an optimum shelling recovery of 96.9691%. This means an increase of the weight of cleaned kernels, decrease in impurities and the total losses (blower loss, scattering loss, unshelled loss and the separation loss) as well. The computed optimum values for input capacity and shelling cylinder shaft rotation are the medium level values and only the blower air velocity values are to be changed to produce optimum shelling recovery. It is lesser than the medium level (4 m/sec) therefore it is recommended redesign of the blower’s shaft rotation to decrease its air velocity. The study is delimited in the verification of those values in the actual set-up.

Keywords shelling recovery, Box-Behnken Design, input capacity, blower air velocity, shelling cylinder shaft rotation


One of the tedious jobs in the mungbean postharvest is the shelling and cleaning of the seeds. The shelling is accomplished through the concept of threshing where there were engaging teeth to break the mungbean pod. These spike teeth are attached to a rotating shaft that is driven by an electric motor. The kernels were separated and cleaned by means of a blower and an oscillating screen to separate the impurities from the kernels. But due to the unavailable values for blower speed and shaft rotation for this purpose, many designers used the values from the thresher of rice and sheller for peanuts. This resulted to different losses accounted during the preliminary testin g of the machine. The losses were blower loss, scattering loss, separation loss and some were unshelled pods. Aside from these, there were mechanically damaged kernels due to the high level rotation of the shaft that contacted with the pods. Thus, it decreases the recovery the shelling process due to the increased impurities that were not separated from the kernels during the process.

Mechanization in the mungbean industry is still considered low. Planting is still done manually, either by broadcasting or drilling. Harvesting is a tedious job wherein farmers selectively pick the matured pods and leave the others to mature. Pods are sun-dried before shelling is performed. Shelling is done by manual threading or beating and seeds are cleaned by winnowing (Pinoy Farmer, 2009).

From the study of Vejasit and Salokhe (2004), it was observed that the moisture content of the crop, the speed of the cylinder shaft assembly and the feed rate significantly affect the quality of the seeds, capacity of the machine and the efficiency as well. Moreover , losses were also observed and an increase in the power consumption of the prime mover. However, the study did not mention the optimum values of those variables that affect the performance of the machine.

The interaction effects of impact velocity and moisture content influenced the percentage physical damage in mungbean seeds ( Shabazi, Valizadeh, and Ali Dolatshaie, 2011).

The researcher wanted to know the significant effect of the blower speed (m/sec), rate of input capacity (kg/hour) and the shaft rotation (rev/min) to the shelling recovery rate of the machine. Based on the Philippine Agricultural Engineering Standards (PAES) of 220:2004 definitions, shelling recovery is the weight of the shelled kernels collected at the main kernel outlet, to the total kernel input of the sheller. Below is the formula to get the following parameters:

Abbildung in dieser Leseprobe nicht enthalten


Wc is the weight of cleaned shelled kernels (kg);

Bl is the blower loss (kg);

Sl is the separation loss (kg);

Scl is the scattering loss (kg);

Usl is the unshelled loss (kg);

Lt is the weight of total losses (kg);

Wic is the initial weight of cleaned kernels;

Wim is the weight of impurities; and

Sr is the shelling recovery (kg/hour).

The study delimits to 3 operating factors with 3 levels, and a constant parameters of moisture content (10.7%) and the species of the monggo (Vignata radiata). The researcher already identified different values for the independent variables: Input capacity, blower speed and shaft rotation. The medium levels were 40 kg/hr, 4.0 m/sec and 434 rpm for the input capacity, blower air velocity and shelling cylinder shaft rotation respectively based on the existing values of the existing machine.

One of the optimization techniques available is the Response Surface Methodology (RSM). It is a set of mathematical and statistical technique used by the researchers to aid in the solution of certain types of problems.

The most extensive applications of RSM are particularly in situations where several inp ut variables have potentially influence on some performance measures or quality characteristics of the product or process. RSM initiates from design of experiments (DOE) to determine the factors’ values for conducting experiments and collecting data. The data are then used to develop an empirical model that relates the process response to the factors.

Based on the study conducted by Pishgar – Komleh, S.H., et. al., (2012), response surface methodology was used to analyze the relationship between cylinder and travel speed and the corresponding model was designed. The results recommended that the 2F1 model as the highest model with significant term can describe the harvesting losses in relationship between cylinder and travel speed .

RSM was also used in the study of Singh, D. & Vinay, D. (2014) to evaluate the machine performance for optimal design parameters viz, height 755 mm, time 5.1 minutes and crop load 1.5 kg. The responses selected were production, total cardiac cost of work (TCC W), musculoskeletal disorder (MSD) and the rate of perceived exertion (RPE). Optimization experiments were designed using the RSM with the help of design expert 8.06 software and surfur software 9.0 was employed for the geographical optimization of the multiple responses. The Box Behenken design was used and in that each numeric factor (Independent variable) was varied over 3 levels.

The researcher used the response surface methodology through Box-Behnken design using Minitab 17 Software.


The researcher used the Response surface methodology through Box-Behnken design using the Minitab 17. The shelling recovery was determined through testing the combination of the 3 independent variables in table 1.

Table 1. The Identified Independent Variables

Abbildung in dieser Leseprobe nicht enthalten

The researcher wanted to evaluate the effects of every independent parameter to the dependent variable, shelling recovery including the optimum values of the variables. The Analysis of variance was used to determine the effects of significant parameters or factors and interaction among them. Under the design of experiment, the researcher used the optimizer to know the optimized values of the identified variables and the optimized response.


The Minitab 17 Software generated a total of fifteen (15) experimental runs for the experimental design consisting of three center points. It was treated as one block and randomized. After completing the test and experiment of each run, the shelling recoveries were computed and tabulated (Table 2) based on the equations (1), (2) and (3).

Table 2. Matrix of experiments in terms of chosen factors with computed response values.

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Excerpt out of 5 pages


Value Optimization among Process Parameters of Mungbean Sheller using Response Surface Methodology
Mechanical Engineering
Catalog Number
ISBN (eBook)
Registered Mechanical Engineer with international presentations.
value, optimization, process, parameters, mungbean, sheller, response, surface, methodology
Quote paper
Christian Mortel (Author), 2019, Value Optimization among Process Parameters of Mungbean Sheller using Response Surface Methodology, Munich, GRIN Verlag,


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