Design of Onion Epidermis Peeling and Onion Smoothing Machine with Rubber Friction Method Application

Onions are the main ingredients for all types of cuisine so the level of demand is quite high. In the industrial world, a great number of processes of onion epidermis peeling are still using either manual and simple low capacity methods or high capacity machines with expensive components. Therefore, it is necessary to make a high capacity machine to peel the onion epidermis in a short time by using inexpensive and durable components that are designed with the help of Solidworks software. The onion epidermis peeling and smoothing machine uses a 0.5 HP electric motor power as a bond drive and a rubber friction method for the process of peeling the onion epidermis. Besides, this machine is also designed to be compatible with peeling by connecting the rotation of the motor that is directly connected to the electric motor so that its design is simpler and does not require a long cycle of time. This peeling process is able to peel 2 kg of onion in 3 minutes and 0.5 kg for the refinement process in 5 minutes.


Introduction
Onions are a type of plant that is widely used as a cooking spice in various countries in the world. Apart from being able to make the taste of food delicious, onion is also rich in nutritional value. Therefore, onions continue to be used and even become one of the main needs in seasonings until now.
Judging from the current needs, it is clear that the use of onions is high in the daily lives of Indonesian people. In its processing, most of the stripping of the onion epidermis is still a problem for the majority of foodstuff producers whose main ingredient is onion. In addition, peeling the epidermis makes their eyes runny. So, it is deemed necessary to have an innovation similar to an onion epidermis peeling machine using a different system from the previous design. The motor power used on the previous machine is also large so that in terms of cost it is certainly expensive and requires considerable electrical power.
From the problems, this research will make a design of onion epidermis peeling and smoothing machine that has clean green epidermis with a different design using rubber friction and is easier to maintain and replace its components by utilizing centrifugal force and friction to peel onion epidermis. Thus, it is more efficient and effective because it can minimize cycle time.
Whereas the previous machine used a mounting system on all walls in the tube so that if it was calculated in terms of cost it would cost more.

Literature Review
Lydia 2017, made a redesign of garlic peeler machine that uses a spiral-shaped rubber which in its work process uses a blender tube media which is placed in the middle of the tube and can only accommodate the capacity of 0.25 onions in each process [1].

Figure 1. Prototype Design Results
The onion peeler machine has also been made by Sahrudin et al. 2018. This machine was named "Portable Onion Peeler Machine". This machine consists of a plate that is directly in contact with the onion so it can make the epidermis of the onion peel off with a rough surface. The epidermis of the onion will be more easily peeled off with a large enough capacity [2]. Effendi, R, et al. 2018, also made the design of a multipurpose onion chopper machine driven by an electric motor with a capacity of 55 kg/hour. This machine uses an electric motor with a speed of 1400 rpm, power of 0.25 HP, and a voltage of 220 V, and the diameter of the drive shaft used is 9.586 mm [3].

Figure 2. Peeler Machine Design
Modification of Onion Peelers is also made by Ikram et al, 2018. The specification of the machines used are frame size 600x550x3mm, stripping tubes 400x350x2 mm and electric motor 1400 rpm. The test results of the machine designed to be able to peel 1500g of 2kg capacity of onions in 300 seconds. Where stripping reaches 79% [4]. Preliminary studies on the design of onion peeling machines have been carried out by Saputro, et al 2017. The onion peeling machine design aims to help onion sellers in markets to meet consumer needs and to help food entrepreneurs or other entrepreneurs to speed up the peeling process. The design is made of a rotating system of onions using a stirring shaft connected to a 1 HP calling motor so that friction occurs between the onion and the designed wall so that the epidermis of the onion can be peeled off without damaging the onion [5].
Then a further study was carried out namely modification of the Shallot Peeler Machine by Ikram, et al 2018. The electric motor used has a power of 0.5 HP with a maximum rotation of 1400 rpm. This machine is also supported by the existence of a peeling plate which is designed to peel the shallots by rotating at a certain speed and utilizing the rubbing of the rubber found on the part around the tube. It also has a container with a large enough capacity in order to keep the test material (onion) from being thrown out while the peeling process is in progress. In the testing process, there are two stages carried out. The first testing phase, the device is tested using a mass of red onions of 1 kg with a motor speed of 1400 rpm whose power is passed on to the peeling disk rotation through a belt and pulleys and using water inserted in a stripping tube. In this first test, the peeling process is carried out 3 times using the same mass of onion that is 1 kg for 5 minutes. The tool is able to produce an average of 767 grams of peeled onions. In this first test, the percentage of success of the tool was 79.8%. Furthermore, in the second test phase, the length of time and the rotational speed of the tool is still the same as in the first test phase which is still using a working time of 5 minutes and a rotational speed of 1400 rpm. However, the mass of onions added to the paring machine was added to 2 kg. So, an average yield of 1533 grams of chopped onions was obtained. With this result, the second experiment achieved a success rate of 79% [4,6].

Research Objectives
This research aims to create an innovative machine design that is different from existing designs and mobile. This system is made simple and easily understood by users by using all materials that are safe for food (food grade) with stainless steel and non-rubber materials and using hollow metal S403 as a construction that is not in direct contact with food ingredients It also designs transmissions such as the use of small motor power, appropriate shaft and pivot dimensions, pulleys that can operate at the same time two functions, namely reducing the rotation of the peeling hoper and onion smoothing blender and have mechanical vibration attenuation below the safety and noise threshold and have a value depreciation of the machine so that it still has a sale value when it is used in the next few years.

Research Methods
The method used in this research is to design machine construction using Solidworks, where the frame dimensions are planned for length x width x height, 110 cm high, 60 cm long and 40 cm wide.

Figure 4. Design Results
The tube volume is for 17.6 liters or equivalent to 2 kg of onions while for the onion refiners after peeling are 2.2 liters or 0.5 kg equivalent.
The assembly process is the final stage of the process of designing and manufacturing the machine. In this process, each part or machine is put together to form a mechanical assembly that is ready for use in accordance with the planned function. Of course, before these parts are assembled, each section has gone through the measurement and calculation stages of the planning so that no part of the wrong size is found again.
The steps for assembling Onion Peeling and Smoothing Machines with a capacity of 2 kgis as follows. It begins with the installation of a 2-inch pulley to an electric motor and then the installation of a belt to the motor pulley (so that the frame is not later pinched) and the mounting of the motor against the frame. After that, the installation of the onion smoothing rotator, tube, and cap smoothing. The installation of pillow bearings to the upper frame is also carried out when mounting the stirring shaft to the pillow bearings. Then, the installation of 10-inch pulleys to the stirrer shaft followed by the installation of belts on both pulleys, Pillow bearings 2 on the lower frame and ending with the installation of a peeler tube, onion stirrer and the lid of the tube. After the components have been combined or assembled, the machine can be used in accordance with its function.

Material for Making Peelers and Smoothing Onions
The materials needed in the design or manufacture of onion peeler and smoothing machines can be seen in the table 1:

Calculation of Onion Peeler and Smoothing
Tube  Onion Peeler Tubes Based on the size of the onion which has an average diameter of 2 cm and it is planned to meet 2 kg of onions in one peelingprocess, we need to calculate the required tube dimensions and volume, which in this design uses a tube shape with a diameter of 30 cm and a height of 25 cm. To calculate the capacity of the tube the following volume formula is used [3,9]: (1) = 3,14 x (15cm) 2 x 25cm = 17.662,5 cm 3 = 17,6 dm = 17,6 Liter With a 17.6 liter result, it can be said to be ideal for loading 2 kg of onions which in the process requires more space so that the onion does not come out of the container during the process.

 Onion Smoothing Tube
In this design, the onion smoothing tube is planned to hold 0.5 kg, so the tube for onion refiners uses a blender jar that is already on the market that has a dimension of 20 cm high and 12 cm in diameter, then it can be calculated:

Motor Calculations
It is known that the motor power is 0.5 HP = 0.37 kW and the correction factor is 1.3. Taken based on the use of machines 8-10 hours per day [8].

Onion Peeler Shaft Round Planning
The planned rotation of the onion peeler shaft is 250 rpm where the motor used has 1330 rpm. The type of pulleys used are type-A pulleys where the motor pulleys have a diameter of 2 inch and a diameter of peeling pulleys of 10 inch. So, to find out the resulting rpm, it can be calculated by using the following formula [7,9,10]: With the result n2 = 266 rpm, it can be said to be ideal if you look at the planned rpm before 250 because the pulley ratio is the closest to the planned rpm when compared to other pulley size comparisons [8,9].

V-Belt Calculation
The distance between pulley centers is known to be 250 mm, so the required V-belt length can be calculated by using the following formula [9][10][11][12]:  Calculating the V-Belt Length L = 2C+1,57 + (d1 + d2) + (9) = 1340 mm = 134 cm So, if counted through the outside diameter of the belt, a belt length of 134 cm is needed. Because the pulleys used are type-A pulleys, the Vbelt used also uses type-A V-belts. From the results, which is 13 mm to find the safety factor of this machine design using a 25 mm diameter shaft.

Calculation of Mechanical Vibrations
 To find the vibration value (ωn), we first look for the k value as follows [11][12]:

Tool Frame Calculation
In the construction of the framework, it is necessary to calculate the load analysis that will be used for the construction to be made so that it can determine the feasibility of the frame construction that will be used. The type of iron used in making the frame is 4x4 cm galvanized hollow iron. The strength of the support experienced by the frame can be calculated as follows: If the use of this machine is carried out continuously without stopping then the bearing life reaches 17968 hours = 750 days, planned use of the machine is 8 hours per day, so that the life of the machine can reach 2250 days or 6 years.

Calculation of Machine Depreciation
To find the price of engine depreciation based on bearing life that has been calculated which is 6 years, it is neededto know the overall cost of making the machine and also the life of the machine. The following table details the costs required in making a onion peeler and smoothing machine:

Test Results
The final stage of the Calculation and Design of Onion Epidermis Peeling and Smoothing Machine is to do a test to find out whether the machine runs with its function. This test has performed a total of 6 times,3 times stripping test and 3 times onion crushing test. While the stripping test was carried out 3 times with a capacity of 2 kg of onion for 3 minutes, 5 minutes and 8 minutes. The onion smoothing test was also carried out with a capacity of 0.5 kg in 3 minutes, 5 minutes and 7 minutes. Where will be known the effective time needed for the maximum percentage of success of this machine. Based on the percentage of the results of the stripping process in table 6, it can be said to have a high effectiveness compared to stripping the onion epidermis manually, and the machine design can be said to be successful. From the results obtained, it takes 5 minutes only to smooth the onions to achieve maximum results.

Conclusions
Based on the results of the tests conducted, it can be concluded that the results of onion epidermis peeling have increased significantly compared to the previous design of the tool The time required for the previous tool is 5 minutes with 79% results, while the results of this latest machine is 5 minutes with a result of 85%. So, there is a difference in yield of 6% increase, while the results of refinement itself reached 100% in the five minutes.