Design and development of aloe vera peeling and dicing system

INTRODUCTION

WHAT IS ALOE VERA

Aloe vera is a tropical plant known for its distinctive green, lace-shaped leaves with jagged edges, belonging to the lily family (Liliaceae) rather than the cactus family With over 300 species primarily found in Africa, Asia, and parts of America and Europe, Aloe vera L stands out as the most recognized variety due to its extensive use and reputed healing properties The plant produces two types of juice: a yellow latex extracted from the vascular bundles and a clear, mucilaginous gel from the inner pulp.

Aloe vera is widely cultivated across Vietnam, particularly thriving in the central and southern regions This versatile plant is primarily grown for its medicinal and cosmetic properties, flourishing best in full sunlight conditions.

Figure 1.1: The shape of Aloe vera (Internet)

Aloe vera can grow up to 100 cm height, although most specimens are from 30 to

The plant reaches a height of 60 cm and features thick, fleshy leaves that grow in a rosette formation These leaves, measuring 30-60 cm in length and 10 cm in width at the base, possess serrated edges and originate from a central base The parenchyma cells within the leaves are rich in pulp, contributing to their robust structure.

Aloe vera plants can be harvested every 6 to 8 weeks by carefully removing 3 to 4 leaves per plant These leaves are sensitive to subfreezing temperatures, so weather conditions significantly impact the harvesting schedule To harvest, gently pull back the green leaf and cut it at the white base, ensuring that the rind remains intact to avoid damage to the mother plant.

In biblical times, the Egyptains hailed Aloe vera as a plant of immortality Ancient Egyptain papyrus and Mesopotamian clay tablets described Aloe as useful in curing

Aloe vera is widely recognized for its medicinal properties, including its effectiveness in treating infections, skin issues, and serving as a laxative In various contemporary cultures, it remains a significant component of traditional medicine The Chinese refer to aloe vera as their "elixir of youth," describing its skin and inner leaf lining as a cold, bitter remedy that helps alleviate constipation caused by heat accumulation.

Aloe vera has gained recognition for its significant contributions to human health, particularly in nutrition, pharmaceuticals, and cosmetics Known for its remarkable benefits, Aloe vera is considered a natural cosmetic powerhouse Consequently, products derived from Aloe vera, including Aloe juice, yogurt, health drinks, and desserts, are increasingly popular among consumers.

Figure 1.2: Some products from Aloe vera ( Internet)

2 Structure of Aloe vera leaf

2.1 Physical structure of Aloe vera leaf

The Aloe vera leaf consists of three layers: (i) the outer thick layer of 15-

The plant features 20 protective cells known as the rind, which play a crucial role in synthesizing carbohydrates and proteins Within the rind, vascular bundles facilitate the transportation of essential substances, including water through the xylem and starch via the phloem Additionally, there is a viscous, jelly-like mucilage layer that houses these vascular bundles, which extend into it from the inner surface of the rind Finally, the fillet proper, characterized by its hexagonal structures, provides structural integrity and serves as the primary water storage area for the plant.

Figure1.3: Physical structure of Aloe vera leaf [3]

2.2 Chemical composition of Aloe vera leaf

Aloe vera leaves primarily consist of several key components, including Aloin, which is an irritant laxative found in the yellow sap and is part of the Anthraquinone complex Additionally, Methanol-Precipitable Solids (MPS) form when alcohols are added to Aloe solutions, resulting in approximately 20-25% of total solids precipitating out The chemical makeup of Aloe vera mainly includes polysaccharides, glycoproteins, and organic acid salts, with polysaccharides accounting for 50-75% of the MPS, translating to about 10-15% of the total solids Notably, there are over 200 different types of polysaccharides present in Aloe vera.

2.3 Biologically active chemical constituents of Aloe veraleaves

Aloe vera gel, composed of 98.5% water with a pH of 4.5, is rich in active polysaccharides like Glucomannan and Acemannan Glucomannan serves as an effective moisturizer commonly found in various cosmetic products Acemannan, the primary carbohydrate in the gel, is a water-soluble long-chain mannose polymer known for its ability to accelerate wound healing, enhance immune function, and exhibit antiviral properties.

Table 1.1: Major medical compositions of Aloe vera [3]

PRACTICAL SIGNIFICANCE OF PROJECT

This project focuses on researching Aloe vera peeling machines both in Vietnam and globally As the output of this system serves the food industry, ensuring food safety is paramount.

We have conducted a thorough analysis of real processing methods, gathered insights from employees experienced in peeling Aloe vera leaves, and researched various Aloe peeling machines on the market Our goal is to manufacture a more efficient and cost-effective Aloe vera peeling machine that outperforms existing options.

The loss of biological activity in the gel is primarily caused by microbial decay, which begins when the leaves are harvested If the base of the leaves is not properly sealed, it can lead to a significant increase in microbial counts, thereby greatly diminishing the product's biological activity Additionally, the rind of the leaf serves as another major source of microbial contamination.

Aloe vera leaves, upon harvesting, often contain dirt and impurities It is essential to thoroughly remove the yellow fluid secretion from the leaves to access the valuable prolage layer beneath the green rind Using a cutter, the top rind must be carefully removed while avoiding the vascular bundles, and the bottom rind should be treated in the same manner.

Once peeled, Aloe vera is diced to facilitate various applications, including Aloe yogurt, health drinks, and juices This method not only saves time but also simplifies preservation and transportation.

The project addresses real market demand, ensuring broad practical applications By implementing this project, the time-consuming peeling process will be significantly streamlined With a capacity of 5,000 kg/h, the peeling efficiency will be greatly enhanced, enabling a continuous operation.

To solve this problem, “Aloe vera peeling and dicing system” is done with the objective of 5000(kg/h).

PROJECT OBJECTIVES

This project aims to create an "Aloe Vera Peeling and Dicing System" to address the demands of the food industry in Vietnam and enhance international export opportunities Additionally, it offers valuable experience for researchers by applying mechanical knowledge to design and develop a versatile machine with broad applications.

The "Aloe Vera Peeling and Dicing System" is designed to process 5,000 kg/h, efficiently peeling Aloe vera leaves before moving them to the dicing stage, where they are cut into 3-5mm pieces The system is constructed using stainless steel for durability and hygiene.

5 to fabricate the the main components of the “Aloe vera peeling and dicing system to meet the safety food product standard.

The project aims to design and develop an efficient loading, peeling, and dicing mechanism for Aloe leaves It features a simple mechanical system that processes Aloe leaves of varying sizes, utilizing a conveyor and leaf-leading roller to guide the leaves into the peeling mechanism, which effectively removes the fillets and rind Following this, the Aloe is transferred to a dicing mechanism equipped with horizontal and vertical cutting rollers, allowing for adjustable cutter sizes and easy cutter replacement Additionally, the design prioritizes ease of assembly and cleaning, ensuring food safety standards are met The control system includes a control board and panel for streamlined operation.

The scopes of “Aloe vera peeling and dicing system” are loading mechanism,peeling mechanism, Aloe dicing mechanism and some elecctrical equipments.

SOMES PEELING PROCESSES OF ALOE MACHINE

Aloe leave after being trimmed top and bot

Automatic top and bot rind peeling

Figure 1.4: Some Aloe peeling processes flowchart

THE RESEARCHES RELATING TO THE PROJECT

This project is designed to develop a machine with all automatic steps from loading, filleting, peeling rind to dicing.

Aloe vera leaf after being trimmed top and bot

Automatic top and bot rind peeling

Figure 1.5: Flowchart of Aloe vera peeling and dicing system of this project VI THE RESEARCHES RELATING TO THE PROJECT

The products from the Aloe vera is very famous in Europe, India and China. There are some Aloe vera peeling machines which is used in the market.

The Aloe vera peeling machine from TecnoTrans-Sa, a German company, utilizes a conveyor-belt and roller system to efficiently peel both sides of Aloe vera leaves After trimming the butts and tips, the leaves are fed into the machine for peeling, with the first side processed followed by the second in subsequent steps The peeling process is supported by employees, highlighting the importance of human involvement in ensuring optimal performance.

Figure 1.6: Aloe peeling machine of TecnoTrans-Sa company (Germany)

The Aloe peeling machine from Mexico operates on a rolling principle, where employees support the Aloe vera leaves After trimming the butts, tips, and fillets, the leaves are fed into the machine The rotation of two rollers guides the Aloe leaf into the peeling mechanism, allowing the inner gel to be separated from the outer rind The machine efficiently processes approximately 500 kg of Aloe per hour, with the rind collected in a container beneath it.

Figure 1.7: Aloe peeling machine of Mexico

The Aloe vera peeling machine from Xingtai City Judu Commercial in China efficiently processes trimmed Aloe leaves by placing them on a conveyor belt This conveyor system moves the leaves forward, positioning them between the conveyor and the cutter for optimal peeling.

8 cutter, the Aloe rind will be peeled The Aloe leaves is supported by employees and the effect is about 1-1,5 ton/hr (according to the information of the Producer).

Figure 1.8: Aloe peeling machine of Xingtai City Judu Commercial (China)

In Vietnam, there is a lack of research and application regarding Aloe peeling and dicing machines in manufacturing processes Although some Aloe peeling machines are imported from China, their limited usage is primarily due to a high wastage rate.

THE NECESSARY OF PROJECT

The manufacturing potential of Aloe products is significant; however, the complex process involves multiple steps that require a substantial workforce and machinery, posing challenges for ensuring food safety.

The hand filleting method for processing Aloe leaves was created to prevent contamination of the internal fillet with yellow sap This technique involves using a sharp knife to carefully remove the rind, which helps maintain low levels of anthraquinones, although it results in most of the mucilage being left on the working table During the process, specific parts of the leaf are discarded, including the lower 25 mm of the leaf base, the tapering point of the leaf top (50-100 mm), and the sharp spines along the leaf margin The knife is then used to access the mucilage layer beneath the green rind, allowing for the removal of both the top and bottom rinds effectively.

Figure 1.9: Peeling Aloe vera by hand

The demand for Aloe products is rapidly increasing, leading to a growing supply of raw materials to support continuous manufacturing While there are Aloe peeling machines available from China, their high wastage rates limit their usage Currently, employees are responsible for peeling the Aloe leaves, and the inner gel must be transferred to separate machines for dicing Additionally, the efficiency of Aloe peeling machines from India, China, and Europe remains low due to the reliance on manual labor for filleting Aloe vera leaves.

In Vietnam, there is a lack of research and implementation of Aloe peeling and dicing machines in the manufacturing sector As a result, numerous businesses, including Viet Nam Dairy Products Joint Stock Company and Nutifood Joint Stock Company, are compelled to allocate many employees to this labor-intensive process.

There are over 300 species of Aloe [1], but Aloe vera L (Aloe vera) is called the

“real Aloe vera” planted in Viet Nam – Figure 1.10.

Figure 1.10: Aloe vera which is planted in Ninh Thuan Province

Accoding to the demand of manufacturing Aloe peeing system, the project is researched to design and develop a Aloe peeling and dicing system.

MECHANICAL DESIGNING

ENERGY THEORY OF FRACTURE FOR AN LASTIC FILM-KENDALL’S MODEL 12 I DESIGNING THE PEEING MECHANISIM

In 1975, Dr Kendall introduced a model in his article "Thin-film peeling-the elastic term" that analyzes how various factors affect the peeling strength of a thin elastic film adhered to a rigid substrate, utilizing energy balance principles The experimental setup includes parameters such as film thickness (d), width (b), displacement (Δl), elastic modulus (E), peeling angle (θ), and applied force (F), as illustrated in Figure 2.5.

Figure 2.5: Schematic of the peeling-off system

B Elastice adhesive thin film, modul G

Dr K Kendall's research categorizes the energy changes in the peeling process into three types, with the first being related to surface energy changes This energy change corresponds to the energy needed to create new surfaces To facilitate analysis, a new variable called adhesive energy (R) is introduced, representing the energy required to create new surfaces per unit area Consequently, the surface energy term can be expressed using Equation (2.1).

It should be noted that R is the dependent on peeling rate.

The second term refers to a change in potential energy, which is influenced by the work performed by the peeling force We assume that the adhesive film is inextensible, enabling the potential energy change to be calculated as the peeling force multiplied by its displacement in the direction of that force.

So the potential energy change can be expressed in Equation (2.2)

In the peeling process, the adhesive layer exhibits elastic properties, gradually extending as the separation occurs Consequently, there is an additional energy change component related to this elasticity For ease of calculation, we consider the region AB to extend in length.

The change in elastic energy is influenced by the peeling force, which can be divided into two components The first component corresponds to the work performed by the peeling force during the stretching phase, represented mathematically in Equation (2.3).

When region AB is stretched, it stores energy, which we can liken to a spring According to Hooke’s Law, the energy stored in the extended region AB can be mathematically expressed by Equation (2.4).

So the overall value of the elastic energy change is:

Elastic modulus is the ratio of stress and strain Accding to this defination, we can conclude the relation ship between elastic modulus G andl

Equation (2.6) and (2.7) can be conbined, so the elastic energy change can be expressed in Equation (2.8)

II DESIGNING THE PEEING MECHANISIM

Aloe vera leaves are first cleaned and trimmed before being placed on a conveyor belt, which directs them into a filleting mechanism The leaves then pass through a peeling mechanism consisting of two parallel rollers that rotate in opposite directions at the same speed These rollers have adjustable apertures to accommodate the varying widths and thicknesses of the Aloe vera leaves The elasticity of the inner gel and the downforce of the flexible roller create a rectangular cross-section of the Aloe leaf before it reaches the cutter The weight of the flexible roller is carefully calculated to ensure proper contact with the cutter; if it is too light, the leaves won't be fully peeled, while if it is too heavy, they may become deformed To optimize efficiency and minimize machine size, a three-mechanism roller rotary system is employed.

Figure 2.7: Crossing section of Aloe after passing the rollers

The design calculations for each machine component are based on a capacity of 5000 kg/h and the dimensions of Aloe vera leaves, with average measurements of 495 mm for length, width, and thickness.

80 and 28 mm, respectively, after measurement Wang and strong (1993) had reported that the average weight of the individual leaves, varied from 390 to

700 g, length 480 to 600mm, width 89 to 115 mm and optical density 1.020 to 1.437 (abs) [4]

Three flexible rollers are used separately for three peeling mechanism. The diameter of the flexible roller is decided on the basis of length of leaf.

To maintain a continuous flow without obstruction from excessive foliage, the average length of an Aloe vera leaf used for design calculations is 495 mm, derived from the average measurement of 50 leaves.

Considering the 10 mm margin and 495 mm leaf length, the diameter of movable roller is calculated on the basis of length as periphery of roller [4]

Figure 2.9: The gap of two rollers

The periphery of the flexible roller: P G    D G

= diameter of flexible roller and the average weight of Aloe vera

The calculated diameter of flexible roller will be taken as D  150( mm)

To reduce the weight of the roller but still have enough force, choose:

To ensure a continuous flow without obstruction from excess Aloe vera leaves, the flexible roller's length was determined to be twice the width of an average Aloe vera leaf, which measures 80mm This design choice effectively prevents leaf blockage during operation.

According to [4], the length of the roller is:

The calculated length of flexible roller will be taken as L c 160( mm)

Figure 2.10: The distance of two rollers

The gap between two rollers will be taken as 25% less than the thickness of the Aloe vera leaf (28mm) to keep Aloe vera leaf passing easily through two rollers [4]

The clearance between rollers is  28 75

The calculated gap between two rollers will be taken as 20 mm.

Figure 2.11: The structure of flexible roller

The dimensions of roller is determined as follows: d  0, 20 0,5 D  0, 20 0,5150 30 75 (mm)

The dimensions of the flexible roller are shown in Fig.2.11.

Figure 2.12: The dimensions of flexible roller

The power of the motor is determined as follow:

P ct : The necessary power of motor (kW)

P t : Calculated power of working (kW)

Where:  d ol =0.95: The effect of belt drive

=0.99: The effect of a pair of gearings (table 2.3 [7])

The necessary power is given according to the calculated power P t

The calculated power is given by:

The working power is given by:

Calculating the flexible roller power:

The dimensions of the keyway: ( L  W  H ) : 0.015  0.006  0.003( m)

Specific weight of 304 stainless stell:

The necessary power is given by:

There are three peeling mechanism to meet the need of 5000 kg/hr, so the effect of each peeling mechanism is determined as follows:

The average weight of an Aloe vera leaf is approximately 0.5 kg, allowing for quick peeling within a second With a roller diameter of 150 mm, the periphery measures around 471.2 mm, which corresponds to the average length of an Aloe vera leaf Consequently, the formula for determining the number of leaves processed per minute is n = 60(v / p).

Based on the real condition and the environment, the calculated speed of roller will be taken as n  150( rpm)

Perameter: P motor  0.12 (kW ) n motor 1380 rpm  cos   0.66

150 9.2 n motor n working u chain u gear motor

So the transmission of geae motor will be taken as u

4.2 The parameters of chain transmission

The number of teeth of smaller gear will be taken as:

The number of teeth of bigger gear is varified by the relationship: z

Straind roller chain with pitch of chain: p 12.7( mm)

(table 5.5 [7]) is choosen to satisfy:

The number of chain link: x x

The calculated number of chain link will be taken as

9,3 s   s : The chain drive is satisfied.

The coordinate system is considered as below: z x y

Figure 2.14: The coordinate system for calculating flexible roller

Figure 2.15: Load diagram of flexible roller

Using moment equation and vector projection in ZOX and ZOY plane:

The moment diagram for the roller:

Figure 2.16: The moment diagram of flexible roller

Base on the the toughness, fit and technology, the roller diameters are taken as: d 10  20

5.3 Safety factor at roller sections

According to the structure of roller and moment diagram, the dangerous sections need to be tested are:

The dimensions of keyway, value of moments is shown in the below table:

Table 2.2:Dimensions of keyway, value of moments at dangerous sections

10 11 12 The rollers are manufactured on the turning machine, so the dangerous sections must satisfy:

K d , are shown on the table below:

Table 2.3:The parameters at dangerous sections

2,5 so the roller hardness testing is not necessary s 

The bearing load is determined as follows:

So single row ball bearings is choosen

Basic static radial load rating

6.2 Basic dynamic radial load rating

Dynamic load is given by:

1: the factor affected by temperature

 Basic dynamic radial load rating is satisfied.

6.3 Basic static radial load rating

The value design basic static radial load rating should sastify:

Where: C 0 : Basic static radial load rating

 Basic static radial load rating is satisfied.

DESIGNING THE FILLET MECHANISM

2 Designing the fillet mechanism 2.1 Designing fixed roller

Fixed roller is used for three peeling mechanisms Dimensions of the fixed roller is follow the flexible roller, except the length.

The length of the fixed roller is calculated to be double that of three flexible rollers, with an additional 25% margin included to prevent any blockage of the leaf.

L  23 60 25% 3 1601200 (mm) The dimension of the fixed roller will be taken as L  1310( mm)

Figure 2.18: Dimensions of fixed roller 2.2 Designing the leaf-leading roller

The structure and dimensions ofleaf-leading roller is the same as the fixed rooler

3 Motor and transmisson ratio 3.1 Motor

: the necessary power of motor (kW)

: calculated power of working (kW)

= 0.95: the effect of chain transmission

 ol =0.99: the effect of a pair of gearings (table 2.3 [7]) The necessary power is given according to the calculated power P t The calculated power is given by:

Where : P 1 : Power of fixed roller

: Power of leaf-leading roller : Power of conveyor

3.1.1 Calculating the power of fixed roller:

The number of fixed roller : 1

Figure 2.19 : Dimensions of fixed roller

Specific weight of 304 stainless steel:

The total weight : m  V total total

The force is considerd as:

3.1.2 Calculating the power of leaf-leading roller

The number of fixed roller : 1 The dimensions and structure of leaf-leading roller are the same as fixed roller so:

3.1.3 Calculating the power of conveyor v conveyor   v roller  1.18(m)

The diameter of conveyor roller: d  75( mm) :

Figure 2.20: The dimensions of conveyor roller

Specific weight of 304 stainless steel:  sta inless steel = 7930 (kg/m 3 )

The total weight : m total  V total  stainless steel  1.15 10 3  7930 9.12 kg 

The force is considerd as:

F 1   F Aloe   F roller   F drag   m Aloe   a   m total   a   F drag

The design value of system trassission ratio is given by: u

Where: n motor : the number of revolutions of motor n lv : the number of revolutions of working roller

3.2.2 Parameters of chain transmission a Rotation n motor n n n

Table 2.4: Parameters of chain transmission of fillet mechanism

The number of revolutions n (rpm)

The number of teeth of bigger gear is varified by the relationship: z

Straind roller chain with pitch of chain: p  12.7( mm) (table 5.5 [7]) is choosen to satisfy:

The number of chain link:

5 Fixed roller and leaf-leading roller test

Figure 2.21: The coordinate system for calculating fixed roller

Figure 2.22:Load diagram of fixed roller

Using moment diagram and vector in ZOX and ZOY plane for calculating:

Moment diagram for the roller:

Figure 2.23:Moment diagram of fixed roller

Base on the the toughness, fit and technology, the roller diameters are taken as: d 10 20d 11 30 d 13  40

5.3 Safety sections in some sections

Base on the roller structure and moment diagram, the sections need to be tested are:

The demensions of keyway, the value of moments is in the below table: Table

2.5: The dimensions of keyway, the value of moments at dangerous sections

The rollers are manufured on the turning machine, so the dangerous sections must satisfy: R a  2.50.63 ( m) , stress concentration factor to surface states:

The value of   ,   , K     , K     , K  d , are shown on the table below:

Table 2.6: The parameters at dangerous sections

S 2.5 so the roller hardness testing is not necessary.

Choose 206-R series single row angular contact ball bearings

Inside diameter d 30 mm , basic dynamic radial load rating: basic static radial load rating:

 Basic dynamic radial load rating is satisfied

Basic static radial load rating should satisfy:

Where: C 0 :Basic static radial load rating

ALOE VERA DICING MECHANISM

Aloe dicing mechanism includes 2 rollers: vertical cutting roller and horizontal cutting roller as as Fig 2.16:

Disk-shaped cutters are mounted on the vertical cutter, allowing for adjustable Aloe dice sizes by varying the dimensions of the rings positioned between the disk-shaped cutters (δ), as illustrated in Fig 2.17.

Figure 2.25: Aloe vertical cutting priciple

Rectangle cutters mounted on a horizontal roller allow for adjustable Aloe dice sizes by modifying the cutter distance or roller revolutions This horizontal cutting principle is illustrated in Fig 2.16.

Figure 2.26: Aloe horizontal cutting principle

2 Design the vertical cutting roller

The roller's width is determined by the combined width of three Aloe vera leaves, with an additional 25% allowance to ensure smooth passage through two rollers To prevent leaf blockage, the vertical cutting roller's revolutions are synchronized with those of the flexible roller.

Figure 2.28:Dimensions of vertical cutting roller

3 Design the horizontal cutting roller

The length of the horizontal cutting roller is equivalent to that of the vertical cutting roller; however, the number of revolutions for the horizontal cutting roller is calculated to be five times greater than that of the vertical cutting roller, based on the roller's structure.

Figure 2.30: Dimensions of horizontal cutting roller

P ct : The necessary power of motor (kW)

: Calculated power of working (kW)

 ol =0.99: the effect of a pair of gearings (table 2.3 [7]) The necessary power is given according to the calculated power P t

The calculated power is given by:

: Power of vertical cutting roller

: Power of horizontal cutting roller

To reach the effect 5000(kg/hr), the number of revolutions of vertical cutting roller is as the number of revolutions of flexible n  150( rpm)

The number of revolutions after being calculated base on the structure of 2 roller is taken 5 times as the number of revolutions of vertical cutting rolller n  750( rpm)

The total weight: m total  V total  stainless steel  4.52 10 4  7930 3.59 kg 

Working force is determined as follows:

F 3 F Aloe  F roller  F drag  m aloe  a m roller  a m F drag

The design value of system trassission ratio is given by: u 

Where: n motor : the number of revolutions of motor n n : the number of revolutions of horizontal cutting roller n lv : the number of revolutions of vertical cutting roller Where: u chain2 =1

4.2.2 Parameters of chain transmission a Rotation n 1365( motor n gear motor n  n gear motor d n n  gear motor n u b Power

5 Designing chain transmissions 5.1 Chain type

Table 2.7: The parameters of chain transmission of dicing mechanism

P (kW) The number of revolutions n (rpm) Moment

The number of teeth of bigger gear is varified by the relationship: z 21 u x  z 11 5 21 105 z max 120 z 22 u x  z 12 1 28 28 z max 120

Straind roller chain with pitch of chain: p  12.7

( mm) (table 5.5 [7]) is choosen to satisfy:

The number of chain link: x  2 a  z 1  z 2  (z 2  z 1 ) 2  p p24 2 a x 

 10.2  s   s : The chain drive is satisfied.

Figure 2.37:The coordinate system for calculating vertical cutting roller

Figure 2.38:Load diagram vertical cutting roller

Figure 2.39:Moment diagram of vertical cutting roller

Base on the the toughness, fit and technology, the roller diameters are taken as: d 10 20d 11 30 d 13  40

- Belt-assembly section (10) in Table 2.8

- Bearings-assembly section (11) in Table 2.8

The demensions of keyway, the value of moments is in the below table:

Table 2.8: The dimensions of keyway, the value of moments

The rollers are manufured on the turning machine, so the dangerous sections must satisfy: R a  2.50.63 (m) , stress concentration factor to surface states:

Table 2.9: The parameters of some dangerous sections

S  2,5 so the roller hardness testing is not necessary.

Inside diameter d 30 mm , basic dynamic radial load rating: C  15.3 (kN ) , basic static radial load rating: C o

Basic dynamic radial load rating is satisfied

Where: C 0 :Basic static radial load rating t

Figure 2.40:The coordinate system for calculating horizontal cutting roller

Figure 2.41: Load diagram of horizontal cutting roller

Figure 2.42:Moment diagram of horizontal cutting roller

Base on the the toughness, fit and technology, the roller diameters are taken as: d  20

The demensions of keyway, the value of moments is in the below table:

Table 2.10: The dimensions of keyway, the value of moments at dangerous section

10 11 12 The rollers are manufured on the turning machine, so the dangerous sections must satisfy:

S  2,5 so the roller hardness testing is not necessary.

Inside diameter d 30 mm , basic dynamic radial load rating: basic static radial load rating:

Basic dynamic radial load rating

 Basic dynamic radial load rating is satisfied

Where: C 0 :Basic static radial load rating

DESIGNING THE CUTTER

The thickness of Aloe vera leaf: h = 2,8     0, 05  0, 08 h

Material of tool: 304 stainless steel

The angle of calculation will be taken as

The calculated angle will be taken as   5

Cutting force is determined as follows:

DESIGNING THE LEAF-FEEDING CONVEYOR-BELT

= 0.61: specific weight of material (ton/m 3 ) s =0.15 [9]

60 Minimum rotation of conveyor-belt is given by: n 

The calculated ratation will be taken as n  300( rpm)

The conveyor speed is given by: v       d      n       75     300    1.18 m / s 

The necessary power is determined as follows:

Base on the the size of the machine and type of material, the width of the conveyor-belt will be taken as B = 1000 mm (table 1 [9])

Figure 2.47 : The forces on conveyor [9]

  0.03 : friction factor between belt và pulley (table 16 [9])

TECHNOLOGY PROCEDURE

DESIGNING THE TECHNOLOGY PROCEDURE FOR MANUFACTURING

The manufacturing steps are shown in the below table:

Table: 3.1 Technology procedure of flexible roller

1 st manufacturing step: facing and center drill

2 nd manufacturing step: facing and center drill

3 rd manufacturing step: straight turning  40

4 th manufacturing step: straight turning  20,  30

5 th manufacturing step: straight turning  30

6 th manufacturing step: keyway milling

8 th manufacturing step: straight turning 150

DESIGNING THE TECHNOLOGY PROCEDURE FOR MANUFACTURING THE

FOR MANUFACTURING THE FIXED ROLLER

The manufacturing steps are shown in table below:

Table 3.2: Technology procedure of fixed roller

1 st manufacturing step: facing and centre drilling

2 nd manufacturing step: facing and centre drilling

3 rd manufacturing step: straight turning  40

8 th manufacturing step: straight turning  150

DESIGING THE TECHNOLOGY PROCEDURE FOR MANUFACTURING THE

The manufacturing steps are shown in table below

Table 3.3: Technology procedure of vertical cutting roller

1 st manufacturing step: facing and drill milling

2 nd manufacturing step: facing and drill milling

6 th manufacturing step: external threading M 24

7 th manufacturing step: face milling

DESIGING THE TECHNOLOGY PROCEDURE FOR MANUFACTURING THE

MANUFACTURING THE HORIZONTAL CUTTING ROLLER

The manufacturing steps are shown in table below:

Table 3.4: Technology procedure of horizontal cutting roller

1 st manufacturing step: facing and centre drilling

2 nd manufacturing step: facing and centre drilling

4 th manufacturing step: straight turning  26,   20

7 th manufacturing step:external threading M24x3

8 th manufacturing step: facing milling

DESIGN OF ELECTRICAL RECRUIT

CONTROLL SYSTEM

Figure 4.1: Block diagram of controll system

ELECTRICAL RECRUIT

0 K 2I nv er te r 2 R 1I nv er te r 1 R U V W U V W 5 3 1 5 3 1 5 3 1 5 3 1 5 3 1 M M M M M

Figure 4.2: Aloe vera electrical recruit

ELECTRIC DEVICES

PRINCIPLE OF OPERATION CONTROLL CIRCUIT

Pressing S1 activates K0, Inverter 1 and 2, and H0 The motors turn on when S3, S5, S7, S9, or S11 are pressed, while pressing S4, S6, S8, S10, or S12 will turn the motors off To stop the entire system, press S2 Adjust the motor speed using R1 and R2.

RESULT AND DISCUSSION

PARTS

Figure 5.1: Aloe vera vertical cutting roller

Figure 5.2: Aloe vera horizontal cutting roller

Figure 5.3: Aloe vera dicing mechanism

RESULT

Figure 5.9: Aloe vera peeling and dicing system

The Aloe peeling and dicing system has been successfully designed and developed, achieving 99% of its objectives It effectively removes the Aloe rind with a capacity exceeding 5000 kg/hr, demonstrating its efficiency and reliability in processing.

Figure 5.10: Aloe vera after being peeled

Figure 5.11: Results after being diced

After researching three peeling mechanisms, we found that 56 Aloe vera leaves can be processed in just 20 seconds, resulting in a capacity of 5040 kg/h (calculated as 0.5 x 56 x 3 x 60) The average weight of an Aloe vera leaf is 500 grams, and experiments conducted on 50 kg of Aloe vera revealed that the average weight of the inner gel is 432 grams The target dimensions for Aloe vera processing are 8x8x8, and our design and development efforts have yielded promising results.

1st 2nd 3rd 4th 5th 6th 7th 8th 9th

Figure 5.12 : Size and weight of Aloe vera dice per a leaf

Aloe vera dice exhibit nearly equal length and width, but their height varies significantly This unique shape results in a deeper bottom compared to the top, causing the weight of the dice to differ from bottom to top The heaviest Aloe vera dice, measuring 8x8x8, weigh 3.25 grams, with the weight decreasing as one moves towards the top.

With 50 kg Aloe Vera we have:

ALOE VERA DICE SIZE other 6x7x8

Figure 5.13 : Size of Aloe vera dice per a leaf

THE STRENGTHS OF THE PROJECT

The Aloe peeling and cutting system is a highly efficient solution designed for versatile applications, allowing processed Aloe vera to be used in various products like yogurt and drinks This system not only saves time but also ensures easy preservation and transportation while maintaining food safety standards Additionally, it is cost-effective, offering a price reduction of up to 75% compared to similar products on the market The design includes hinges on the casing for easy observation of the process, further enhancing its usability and functionality.

The system operates at a capacity of 5000 kg/hr, utilizing three peeling mechanisms powered by individual motors This design allows for flexible operation, enabling each mechanism to be activated or deactivated based on the material volume Additionally, the project incorporates simple mechanisms, ensuring ease of assembly, maintenance, and repair.

THE WEAKNESSES OF THE PROJECT

While the system boasts several strengths, it also has minor weaknesses The project is developed and produced quickly, which can lead to a product that occasionally falls short of expectations Additionally, the high operational speed generates noticeable noise during functioning.

CONCLUSION AND FURTHER RESEARCH

CONCLUSION

The innovative Aloe vera peeling and dicing system effectively addresses key challenges such as high costs, time consumption, and food safety concerns By eliminating manual labor in the processing of Aloe vera, this system ensures enhanced food safety while minimizing the use of chemical compounds in the mixing gel Experimental results demonstrate that the peeling and dicing mechanisms are both efficient and effective, with a working speed suitable for practical online applications Future research could explore the integration of this system with existing and subsequent processing technologies.

FURRTHER RESEARCH

The Aloe Vera peeling and cutting system has reached completion, yet further enhancements are necessary to optimize production efficiency Key improvements include the integration of automatic loading, utilizing image analysis to assess the orientation of Aloe Vera leaves, correct their positioning, and eliminate damaged foliage Currently, the process requires two or three workers to place cut leaves onto conveyor lines, but automation could significantly streamline this operation and enhance stability Additionally, the project aims to refine the system for mass production by upgrading the dicing mechanism to lower costs while maintaining high efficiency, despite the constraints of a graduation project that limit it to single production runs.

SUGGESTION

The project “Designing the Aloe vera peeling system applying to international standard ” is a highly practical one The effect of reducing workers in the initial

92 process is so positive that prosperously, this topic will be carried out a large amount of products to sell in market.

With the inevitable limitations of the objective and subjective reasons of a thesis, the sincere feedbacks from teachers will be valuable lessons for us in future work

[1] Chemical characterization of the immunomodulation polysaccharide of Aloe L

[2] V K Chandegara, A K Varshney, Aloe vera L processing and products:

A review Researchgate-Vol 3, No 4, pp 492-506, December 2013.

[3] Pinghuai Liu, Deli chen and Je shi, Chemical Constituents, Biological

Activity ans Agricultural Cultivation of Aloe vera, 16 May 2013.

[4] Dr Vallabh Chandegara and Anil Kumar Varshney, Design and Development of Leaf Splitting Unit for Aloe Vera Gel Expulsion Machine - Article in Journal of Food

[5] Launa Natalia Gonzalez Bustacara, Study of The Effect of The

Environment Realtive Huminity on The Angle Dependent Peeling Strength of Pressure Sensitive Adhesives (PSA), August 2015

[6] Trường Đại Học Bách Khoa Đà Nẵng, Giáo trình thiết bị cán

[7] Trịnh Chất- Lê Văn Uyển, Tính toán thiết kế hệ dẫn động cơ khí

[8] ĐH Sư phạm Kỹ Thuật TP.HCM, Nguyên Lý Chi Tiết Máy

[9] Nguyễn Văn Dự, Hướng Dẫn Tính Toán Băng Tải, 2011

[10] Hồ Viết Bình, Phan Minh Thanh, Hướng Dẫn Thiết Kế Đồ Án Công Nghệ

[11] Nguyễn Đắc Lộc, Lê Văn Tiến, Ninh Đức Tôn, Trần Xuân Việt, Sổ Tay

Công Nghệ Chế Tạo Máy – Tập 1, 2001

[14] Nguyễn Ngọc Đào, Trần Thế San, Hồ Viết Bình, Chế Độ Cắt Gia Công Cơ

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