Rice Mill Machine: Paddy Rice Huller and Husk Separator

Rice Mill Machine: Paddy Rice Huller and Husk Separator - Rice milling is one of the post-harvest handling technology that is quite popular in agriculture (rice farmers). This machine has helped many farmers in terms of processing paddy to rice. In the aspect of business, these machines are also able to increase the marketability of agricultural products as opposed to selling in the form of paddy directly. On the other hand, demand for rice continues to increase, because the rice has been a staple food for most countries in the world. Hence the development of rice mill machine is more effective, more efficient and more quality is promising.

In the processing of un-hulled rice, in order to produce high-quality rice, we have to use some machines like paddy rice huller machine, husk separator, rice polisher and rice sifter.

(1) Paddy rice huller machine is used to break and release bran (husk). Input materials of this machine is a un-hulled rice with a moisture content of about 14% and output in the form of brown rice (pure white).

(2) Husk separator is used to separate grain of rice and husk using a blower system. The system utilizes the difference in specific gravity between rice and husk. Husk which has a smaller specific gravity to be sucked by the blower, while rice tend not to be affected by the air blower and straight out through the rice outlet.

(3) Rice polisher is used to remove the epidermis (aleuron) on brown rice to produce white rice that is ready to be marketed or cooked. This machine uses the screw extruder system in the cylinder which has the inner surface uneven. When brown rice fed into the cylinder it will jostle and rub against the cylinder surface which causes the epidermis to be eroded.

(4) Rice shifter is used to separate the rice based group quality such as whole rice (best quality) and broken rice (second quality). This machine uses a filter screen plate or cylinder shaped. Rice with some sort of quality level will be mixed again with a certain ratio to determine the selling price before the rice is packaged to be marketed.

This article will explain in more detail on the description of the machine, but it is limited to brown rice huller and separator machine. Both machines will be combined into one machine as the title of this article, namely Rice Mill Machine: Paddy Rice Huller and Husk Separator. Description of these machines include machine construction, main part of machine, basic concept of brown rice huller and separator, machine  principle and machine operation.

Construction of Rice Mill Machine

Construction designed for rice mill machine refers to the incorporation of brown rice huller and husk separator. Brown rice huller system uses the speed difference on the rubber roll, so the construction will put on top two pieces of rubber roll just below the hopper. Husk separator using air blower system, so the construction will accommodate air flow toward a brown rice and husk are out of rubber roll. Machine construction along with its main parts are complete can be seen in the picture below.

Constructions of rice mill machine in the image above showing some of the main parts of the machine are:
1) Shutter, as the main valve controls the expenditure of grain in hopper.
2) Feeding roll, a roll leveler serves to regulate the importation and spread the rice on the rubber roll.
3) Rubber roll, serves as a breaker of rice
4) Roll gap adjuster, serves as spacer rubber rollers.
5) Distribution, serves to divide the flow of brown rice out of a rubber roll.
6) Wind adjuster controls the air entering the blower.
7) Blower, suction air function is the air flow from inlet to brown rice husk and then brought out through husk outlet.
8) Husk outlet, serves as the drain husk
9) Rice outlet, serves as a channel that has a separate brown rice with husk

The basic concept of huller rubber rolls

Paddy rice huller uses two pieces of rubber roll as a means of breaking the un-hulled rice. Both roll is mounted adjacent (parallel) with a certain distance and rotated at different speeds in opposite directions. Roller that rotates at high speed is called main rollers or fixed roll, while the other roll is called auxiliary rollers or moveable roll. The main roll is mounted on a stationary shaft while the auxiliary roller mounted on a shaft whose position can be shifted to adjust the distance (gap) between the two roll. Auxiliary roll speed should be slower for about 24% of the main roll.

The basic concept of 'huller rubber roll' is the process of peel bran (husk) using frictional forces that occur between rice and rubber roll. When un-hulled rice through the gap between the rubber roll, on the one hand will be restrained due to friction with the auxiliary roll and on the other hand will be pushed due to friction with the main roll. Because the distance between the two rollers arranged around 0.5-0.8 mm or smaller than the thickness of the un-hulled rice grain, then the friction that occurs will be stronger than the resilience husk itself. The condition causes the husk to be separated from brown rice.

The basic concept of husk separator

Husk separator using air blower system with the capacity to suck husk but unable to suck brown rice. The condition can occur because of differences in density between brown rice and husk, brown rice which have the higher density. When brown rice that has been separated by the rubber roll out of the husk and fell through the air flow, then the husk will be pushed into the airways and out through the husk outlet, while brown rice will keep falling towards the rice outlet.

The machine is equipped with two air ducts. The first ducts as the main separator which serves to suck out husk of the rubber roll. The second ducts serves as a second separator. If there are brown rice that is carried along with the husk on the main separator or if there are husk that is carried along with paddy rice on the main separator, it will be separated again by the second separator.

Principle of Rice Mill Machine

Rice milling principle is to use electricity on continuous moving parts and uses a manual system the regulator components. Components are driven by electricity like rubber rolls and air blower. Components are driven by manually like shutter, feed adjuster, roll gap adjuster and wind adjuster.

Its mechanism of action begins with un-hulled rice entering into the hopper. Power comes from an electric power (electro motors or diesel engines) rotating rubber roll through the transmission system with a certain ratio. When shutter is opened, un-hulled rice will go down and get into the gap between rubber roll. At that time, there is a huller process (husk peeled and separated from paddy rice). Huller processing speed can be set through the shutter, the feed adjuster and roll gap adjuster. Then rice descending through two distribution channels arranged by the distribution handle. The two channels will pass through the air suction area. In this area husk will be attracted or sucked out through the husk outlet, while paddy rice remains down towards the rice outlets. The speed and power of the suction blower can be adjusted by the wind adjuster handle.

Operation of Rice Mill Machine

How to operate rice mill machine is as follows:

1. Make sure the 'shutter' in a closed condition, prior to un-hulled rice (paddy) is inserted.
2. Put paddy rice into hopper.
3. Turn on drive system (electric motors or diesel engine), make sure the rubber roll and air blower has been active.
4. Open the 'shutter' slowly, so that paddy can be entered to rubber roll.
5. Set velocity flow of the paddy with a twist 'feed adjuster'.
6. Set distance between roll by turning the ‘roll gap adjusters' to match thickness of paddy. If distance between roll is too large will cause a lot of paddy were not peeled, while distance between roll that is too small will cause a lot of paddy broken (brown rice is not intact)
7. Adjust speed of wind by turning the 'wind adjuster'. Wind speed that is too large will cause a lot of brown rice sucked, whereas if the wind speed is too small will cause a lot of husk were not sucked (with brown rice together).
8. Place the rice container under 'rice outlets' and the husk container under 'husk outlet'.
9. If there husk still united with paddy rice which are not broken, then input back into the hopper.
10. Repeat the process steps start point 1.
11. If all the processes are finished, turn off the machine.

That is a description about Rice Mill Machine: Paddy Rice Huller and Husk Separator. If you find misconceptions in this post, please provide the correction in the comment box.

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What is a Timing Belt and How to Select Its Type?

What is a Timing Belt and How to Select Its Type? - Timing belt is one type of transmission belt that is already known the general public, especially in automotive, because timing belt is one of the automobile parts. Timing belt selected based on standard type, width and length. This post will explain how to choose the timing belt type in accordance with rotation speed and power are transmitted, how to determine the timing belt width corresponding to power capacity that is transmitted and how to determine the timing belt length corresponding to the distance between shaft and the diameter of timing pulley. But before selecting timing belt, we need to know in advance what is a timing belt.

What is a timing belt?

Timing belt is a belt transmission which has a tooth profile and paired with the timing pulley-shaped gear as well. Therefore, timing belt hook can perform transmission like gears and chains so it can be used for motion with a fixed ratio of rotation (without slippage).

Timing belt is made of neoprene rubber or polyurethane plastics as raw material with a core made of glass fiber or steel wires as well as teeth are carefully molded inner surface of belt. Timing belt has a maximum speed limit of approximately 35 m/s which is higher than v-belt and power transmitted can be reach 60 kW up to 100kW.

Generally, belt transmission has advantages such as low cost, simple construction and easy to get a speed ratio needed. Timing belt has another advantage is that it avoids the occurrence of slippage between belt and pulley.

How to choose the timing belt type

Selection of timing belt types based on small pulley rotation speed and power transmitted. If the higher speed of small pulleys and the greater power transmitted so the greater timing belt size is selected. Selection of timing belt size refers to the diagram supplied by the manufacturer of the timing belt. Each type of timing belt has a different diagram. For security timing belt, the power transmitted is motor power multiplied by some factor correction with the following formula:

Note:

Pd = Power transmitted (kW)

P = Motor electric power (kW)

fc = Load factor

f’c = Velocity ratio factor

Based on tooth shape, timing belt has several types like inch timing belt, metric timing belt and high torsion timing belt. For each type of tooth has a size variation determined based on the distance between the teeth timing belt (pitch). How to choose the timing belt size? Here we will explain how to choose the timing belt size for each type.

Inch type of timing belt (XL, L, H, XH)

Inch type of timing belt also called classical timing belt has a teeth trapezoidal shape with the distance between teeth (pitch) in inches units. Classical timing belts offer a maintenance free and economical alternative to conventional drives like chains and gears. This timing belt is capable of transmitting up to 100 kW and speeds of 10.000 rpm. This timing belt can be used in a wide range of applications from light duty office machinery to heavy duty industrial drives. 

To select a drive it is necessary to know the driver and driven shaft speeds, the demand power, proposed centre distance and duty cycle. This timing belt has a variation size with codes are XL, L, H and XH. We can be use the diagram below to select a timing belt size with regard to small pulley speed and power transmitted.

Metric type of timing belt (T2.5, T5, T10, AT5, AT10)

Metric type of timing belt has a teeth trapezoidal shape with the distance between teeth (pitch) in metric units. The metric timing belt series was created to meet industries need for polyurethane belts with a high quality ratio. They provide maximum power transmission combined with perfect tooth meshing. This timing belt is capable of transmitting up to 60 kW and speeds of 10.000 rpm.

To select a drive it is necessary to know the driver and driven shaft speeds, the demand power, proposed centre distance and duty cycle. This timing belt has a variation size with codes are T2.5, T5, T10, AT5 and AT10. We can be use the diagram below to select a timing belt size with regard to small pulley speed and power transmitted.

High torsion type of timing belt (3M, 5M, 8M, 14M)

High torsion timing belts or HTD timing belt offer optimized load distribution through the rounded tooth form, guaranteeing high power transmission in low speed and high torque applications. HTD timing belt is capable of transmitting up to 300 kW and speeds of 14.000 rpm. HTD timing belts can be used in a wide range of applications from minimum drives like electronic power tools to heavy duty machinery where durability and low maintenance is required. 

To select a drive it is necessary to know the driver and driven shaft speeds, the demand power, proposed centre distance and duty cycle. This timing belt has a variation size with codes are 3M, 5M, 8M and 14M. HTD timing belt made by certain manufacturers such as Japanese Misumi is usually to use the code of SM likes S3M, S5M, S8M, and S14M. We can be use the diagram below to select a timing belt size with regard to small pulley speed and power transmitted.

That is a description about What is a Timing Belt and How to Select Its Type?. If you find misconceptions in this post, please provide the correction in the comment box.

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Specification of Paper Shredder Machine

Specification of Paper Shredder Machine - Paper shredder used to cut the paper until it reaches a certain size according to the capacity and type of blade. More detailed explanation of the importance of this machine, the basic concept of machine, the working principle, machine construction and operation can be found in the article on the paper shredder description. (Read more: description of the paper shredder machine) In this article are described in greater detail about the specifications of the machine and its main components such as the functions of components, the material used, the working principle and position on the machine. The machine specification especially with regard to material and dimensions is obtained based on the calculation and design of machine through the existing formulas in an article on the paper shredder design. (Read more: design of paper shredder machine)

General specifications of the paper shredder machine

Paper shredder machine is driven by electric motors powered 200 Watt, 1 phase, 220 Volt and 1450 rpm. This machine is able to cut the paper in the vertical direction with a width of 5 mm and cut the paper in the horizontal direction with a length of 30 mm, in other words the output of this machine is the size of the shredded paper 30 x 5 mm. Paper specifications are able to be cut by this machine is a sheet of A4 size paper with HVS, a maximum of 80 gms and a maximum of 10 sheets per cycle. Transmission ratio between an electric motor with a shredder blade is 1/96 means maximum rotation reaches 15 rpm shredder blade or cutting the rate of 1,5 m/min (24 mm/s). With these speeds, the machine is able to work at 300 cycles/hour of speed, so that the maximum capacity of this machine is 3000 sheets/hour.

This paper shredder machine consists of three main parts: the machine construction, transmission systems and cutting system with the specifications described below.

Construction of the paper shredder machine

The machine construction is the main part of the paper shredder machine that serves as the base or foundation for other machine components, especially moving parts. Construction machine consists of machine frame, left base, right base, shredder support and gear support. Machine frame is used to support all components of the paper shredder machine. The machine frame is made of steel angle-shaped profile with a size of 25 x 25 x 3 mm which is connected through welding process. The material used for the machine frame is ASTM A36 so that the welding process can use arc welding with electrodes E 6013 specification means having a maximum tensile strength of 60,000 lb/in2 or 42 kg/mm2.

Left base serves as anchoring the left side of main shaft while the right base serves as anchoring the right side of main shaft, the holder of gear transmission and an electric motor mounting. Left base and right base made of ASTM A36 steel plate with a thickness of 3 mm formed by laser cutting process. Left base and right base mounted on the machine frame by using a standard M4 bolt connection size. On the left base and right base is also fitted deep groove ball bearing code 6000 have reached 10220 hours life time on the reliability factor of 99%. (Read more: ball bearings selection guide). The main shaft will be installed on the both bearing with the aim that the main shaft can rotate stably with a low level of friction.

Shredder support mounted between the left and right base. Shredder support serves to hold the base on top side and the static blade holder. Gear support is mounted on the front of the right base. Gear support serves to hold the transmission gears. Shredder support and support gear is made of ASTM A36 steel plate with a thickness of 2 mm formed by laser cutting and bending processes.

Transmission of the paper shredder machine

The transmission system is one of the main parts of the paper shredder machine that serve to forward rotation or power from the electric motor to the cutting system. Transmission system uses a series of gears with a certain ratio to reduce the rotation (gear reducer). The transmission system consists of helical gears and spur gear. Helical gears serve to forward and reduce direct rotation of the electric motor. Why is selected helical gear? The helical gear is more secure and able to withstand axial and radial force at high speed. (Read more: calculation of helical gear). Helical gear transmission uses gear ratio of 1/6 with 1,5 module and helix angle of 10 degree.

The next transmission is spur gears. Why is selected spur gear? Spur gears appropriate for low rotation and high torque. Spur gear transmission on the paper shredder machine is made of two stages with different modules according to the results of calculation. Spur gear transmissions are forward and decrease the rotation of helical gears to the main gear. (Read more: calculation of spur gear) Spur gear 1st stage transmission uses gear ratio of 1/4 with 1,5 module while the spur gear 2nd stage transmission uses gear ratio of 1/4 with 2 module.

Cutting system of the paper shredder machine

Cutting system is one of the main parts of the paper shredder machine that serves as the cutting tool on the vertical and horizontal direction. The system consists of the main shaft, dynamic cutting blades, static cutting blades and main gear. The main shaft serves as the cutting blade holder. The main shaft has a square shape in the position of cutting blade holder and has a round shape at both ends in the position of the holder main bearings and gears. (Read more: shaft calculation). The main shaft is made of VCN 150 or AISI 4340 materials with a minimum diameter of 20 mm.

Dynamic cutting blade is round-shaped blade with 4 (four) the cutting edge, given a square-shaped hole in the middle, mounted on the main shaft and main shaft move together. This blade is used to cut the paper in vertical and horizontal directions. Static cutting blade is square-shaped knife, a hole is round, loosely mounted on the main shaft and the part is not rotating (static). This blade is used to cut the paper in the horizontal direction and is used as a spacer or barrier between the dynamic cutting blades. Cutting blades are designed with tool steel material (HSS-High Speed Steel) with the specification are 112 pieces of blade, 2 mm of blade thickness and 60-degree of cutting angle.

The main gear consists of two spur gears paired with the size (number of teeth and modules) the same. One spur gear mounted on the rear main shaft and direct contact with the transmission spur gears previous. Another spur gear mounted on the front main shaft. The spur gears are drive two main shaft with a rotation in the opposite direction.

That is a description about Specification of Paper Shredder Machine. If you find misconceptions in this post, please provide the correction in the comment box.

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Chicken Plucker Machine by Vertical Retraction System

Chicken Plucker Machine by Vertical Retraction System - Chicken plucker machine is a machine whose function is to pull out the feathers of the chicken skin. This machine is used for conditions of a chicken that has been boiled in hot water first. This machine is designed easy to use and easily removable. Why is this important and necessary as one of the appropriate tech machine? This is one of the questions that will be described at the beginning of this article.

This machine is important because the demand for chicken meat continues to increase every year. These conditions impact on increasing demand for businesses based chicken from a chicken farm, slaughter chickens, broilers seller, chicken restaurants and chicken-based company. On the other hand, people also began to care about the hygiene and quality of the chicken so chicken processing should be supported with adequate facilities and equipment both in terms of efficiency, quantity, quality and technology.

Simply put, the processing of chicken consists of several stages including slaughtering, boiling (inserted into the hot water, in order to easy the process of plucking chickens), plucking chickens and lastly further processing as needed. The processing is very easy and common practice. However, this process would be very inconvenient if we have to process chicken in large quantities. This condition will be experienced by the sellers of chicken, meat distributor who supplies the restaurant and hotel, food companies made chicken and chicken meat traders in the market.

Chicken processing in large quantities will also make it difficult to control the level of hygiene and quality of chicken meat, if processing is done manually. Therefore the use of appropriate technology is needed, especially in the chicken slaughter and plucking chickens. In the current technological developments have been found many type of chicken processing such as the chicken slaughtering machines and the chicken plucker machine. They are using manual, electric motor or the power-assisted automation systems. But in this post will be limited to the chicken plucker machine using an electric motor.

Selection of these topics based on the consideration that the segmentation of chicken meat traders in traditional markets. This type of machine is expected to help plucking a chicken in large quantities at a more effective and efficient than manual chicken plucker. In terms of investment, this machine is much more affordable when compared with chicken plucker machine automatically. But of course, these machines are still able to maintain the quantity, quality and level of hygiene of chicken meat produced.

Many types of chicken plucker machines are often used by the producers of chicken. Based on its principle, there are two systems were used that chicken plucker machine with vertical and horizontal retraction system. In the vertical retraction system, the chicken is rotated on a vertical axis direction inside the drum, while the horizontal retraction system, the chicken is rotated in the direction of the horizontal axis through the spindle. In this post will be limited to the topic of the chicken plucker machine uses vertical retraction system.

The construction of chicken plucker machine

In general, construction of chicken plucker machine and the main parts of the machine can be seen in the image below.

The concept of vertical retraction system

Basically chicken plucker machine is using the same principles in a way manual or traditional revocation ie chicken that was killed and soaked in hot water and then plucked one by one. The difference if the traditional process, quill removed manually by hand or manual equipment while on this machine quill lifted through the lifting of a system using multiple finger (see machine construction). Finger serves to hold the quill when the revocation process.

The basic concept also resembles the traditional way. The concept is a chicken held by the left hand or using a tool holder while the right hand moves plucking chickens. On this machine chicken feather held by some of the finger is placed in the static part and dynamic part. When the dynamic part is driven and static part remains silent, then the quill held by finger would be interested to release it.

The principle of chicken plucker machine

Chicken plucker machine is a machine designed by using an electric motor. Electric motor drives the dynamic finger mounted on the finger plate at a certain speed. Transmission power from the electric motor to the finger plate is using v-belt transmission. Driver pulley mounted on the electric motor and the driven pulley mounted on the main shaft. Main shaft rotating on a vertical axis direction and moving the finger plate directly. This principle distinguishes between vertical and horizontal retraction system.

Chicken will be processed placed on a finger plate. In the finger plate has been installed dynamic finger made of rubber with a screw shape that serves to bind the chicken feathers. When the finger plate rotates at a certain speed, the chickens will come round and is likely to be thrown into the drum wall due to centrifugal force. Chicken feathers tied in dynamic finger will be regardless of chickens when the chickens thrown into the drum wall. In the drum wall mounted static finger that will bind chicken feathers when chicken thrown into the drum wall. Chickens will fall back to dynamic finger due to gravitational forces. Chicken feathers tied in static finger will be regardless of chickens when the chickens fell into finger plate.

The operation of chicken plucker machine

The operation of the chicken plucker machine easy enough:

1. Put chicken that has been boiled into the tube
2. Turn on the electric motor, so that the finger plate (dynamic finger) rotates.
3. Chicken feathers would come loose and fall to the bottom of the finger plate.
4. Chicken feathers that have been separated driven by upside down finger out through the output chute
5. Prepare a container of chicken feathers just below the output chute
6. Turn off the electric motor, if all the feathers had been removed.
7. Remove the chickens that have been processed.

That is a description about Chicken Plucker Machine by Vertical Retraction System. If you find misconceptions in this post, please provide the correction in the comment box.

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Design of Cassava Chips Machine

Design of Cassava Chips Machine - This machine is used for slicing cassava with a certain thickness as needed. Sliced cassava is a feedstock or raw material from cassava chips. This machine uses some cutting blade mounted an angle on the blade holder (disc). Slicing process occurs when the spinning blades and cassava move straight towards the knife. Slicing process produces cassava piece shape with a thickness that can be adjusted through the depth of the blade. A more complete description and specifications of this machine can be seen in a previous article titled Cassava Chips Machine by Planer Cutting System.

Read more: Description of Cassava Chips Machine

In this article I will explain how to design of cassava chips machine. Design process begins by calculating the power requirement for cassava cutting process. The power will be a reference in choosing an electric motor. Having chosen the type of electric motor, the next process is to calculate the strength of the machine parts according the machine construction. In this post, the calculation of the strength and dimensions of the machine parts are limited only to the calculation of cutting blade strength.

Power requirement for cassava cutting process 

The electric motor is a power supply to drive the entire system dynamic of cassava chips machine. Advantages of electric motors compared to other types of resources for electrical energy easily available and practical for small-capacity machine. Selection of the electric motor based on the calculation of the cutting load.

The cutting process occurs when the cutting force is greater than the cutting load requirement. Cutting load derived from the cassava ruptures strength. Cassava ruptures strength is ability of cassava to withstand the cutting forces provided by the cutting blades. The greater ruptures strength of cassava, the cutting load will be even greater. So that the force required by the cutting blade becomes larger in order to cut the cassava.

Besides cassava ruptures strength, there are other factors that affect of the cutting load such as the cassava diameter and number of cutting blades. So that the cutting load of cassava can be calculated with the following formula:

Note:

F = Cassava cutting load (Kg)

σ = Cassava ruptures strength (mN/mm2)

i = Blade number

d = Cassava diameter (mm)

g = Gravity (m/s2)

The total forces requirement in the cutting process consists of cutting forces and frictional forces. The cutting forces which received cassava force of blade movement during cutting process. The frictional force is the force that inhibits the movement of the blade when the cutting process due to the thrust of cassava to feed. Friction is occurs between cassava with blades spinning disc.

Cutting force is influenced by the angle blade and the cutting load. Angle blade will also affect the sharpness of blade, the sharp cutting blades will cut the smaller force is needed, but the life time blade becomes lower. Therefore, it is necessary to design the right angle of blade so that the required cutting force as small as possible with a higher life time.

Based on many references of the blade, blade angle ideal range is 20 degree. If the cutting load already known on the previous formula, then the blade cutting forces can be calculated with the formula;

Note:

F_C = Blade Cutting Force (Kg)

F = Cutting Load (Kg)

α = Blade Angle (20 degree)

Frictional force caused by the thrust that form the normal force perpendicular to the friction area of cassava. The driving force comes from pressure given to cassava in order to move towards a spinning cutter blade. On cassava chips machine, the pressure cassava assigned manually by hand, so the pressure tend to be constant. The pressure must not be less than the blade axial force, because it will cause unstable slice thickness. The pressure must not be greater than the cassava ruptures strength, because it will cause a rupture.

If the coefficient of kinetic friction between the cassava with a disc blade is µ, the friction forces that occur are:

Note:

F_F = Friction force (Kg)

P = Cassava driving force (Kg)

µ = coefficient of kinetic friction

The total force requirement to the cassava cutting process is a tangential force consisting of a cutting forces and friction forces, formulated as follows:

Note:

F_T = Total force requirement (Kg)

F_C = Blade Cutting Force (Kg)

F_F = Friction force (Kg)

Having in mind the total force required for the cutting process of cassava, the force requirement can be converted into units of power because the force is the tangential force generated from the electric motor rotation. In general, the power requirement for the cutting process of cassava chips machine can be calculated using the formula:

Note:

P = Power Requirement (Kw)

T = Torque (kgmm)

n = Blade speed (rpm)

The torque on the blades can be calculated using the formula:

Note:

T = Torque (kgmm)

F_T = Total force requirement (Kg)

R = Radius of blade position (mm)

Design of the cutting blade strength

The cutting blade strength of the cassava chips machine is located at the tip of blade, so that the blade tip must always be sharp in order to retain the ability to cut cassava well. Cutting ability will decrease if the blade tip experiencing torpor due to frictional forces and cutting forces. Bluntness caused the blade tip isn’t able to withstand the frictional forces and cutting forces. So that the blade does not experience the bluntness, the tip of blade should be made radius.

Frictional forces and the cutting forces are working continuously on the cutting blade will cause the stress at the blade tip. Cutting blade strength is the ability of cutting blades to withstand the stress so as not to cause wear and tear. Cutting blade has a good strength if the allowed stress for the blade material is greater than the maximum stress. The maximum stress of cutting blades can be calculated using the formula:

Note:

σ = Maximum stress (Kg/mm2)

F_C = Blade Cutting Force (Kg)

F_F = Friction force (Kg)

A = Area of the blade tip (mm2)

Area of the blade tip can be calculated using the formula:

A=2.r.l

Note:

A = Area of the blade tip (mm2)

r = Radius of the blade tip (mm)

l = Length of the blade tip (mm)

Cutting blades on the disc is clamped by the clamp fastened with two screws. Disc and clamp gets a load in the direction of the x-axis and y-axis of the cutting forces and frictional forces. The load was detained by two bolts. Force on the x-axis direction resulting tensile force on the bolt. Force on the x-axis direction is equal to the normal force of blade.

F_x = N

Force on the y-axis direction resulting in shear forces on the bolt. Force on the y-axis direction of the same with a blade cutting forces and frictional forces together.

F_y = F_C + F_F

Once known force on the x-axis direction and forces on the y-axis direction, then we can calculate the strength of bolt which binds cutter knife.

That is a description about the Design of Cassava Chips Machine. If you find misconceptions in this post, please provide the correction in the comment box. If you want to know more details about cassava chips machine can be seen in a previous article titled Cassava Chips Machine by Planer Cutting System.

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Welding Design: How to Choose the Appropriate Type of Welding

Welding Design: How to Choose the Appropriate Type of Welding - In the design of construction, welding plays an important role in connecting two or more construction materials that can be formed construction components as needed. The material used in the construction design is usually derived from the steel plate, steel profile (angle, UNP, IWF, H-Beam), strip, plate, square hollow, steel pipe etc. Most of the manufacturing process from material derived construction is done through the connection process and certainly in this post will only be explained about the welding joint.

Welding is one of the types of construction joints. According to the definition of Deutsche Industrie Normen (DIN), welding is a metallurgical bond at the metal or metal alloy joint which is carried out in a molten or liquid state. In other words, welding is a local joint of several pieces of metal by using thermal energy.

There are so many types of welding that can be used in the connection process. Harsono and Toshi in the handbook of welding engineering welding classify based on the principle of work into gas welding, arc welding, electric welding slag, electric welding gas, thermite welding, electron beam welding and plasma arc welding. However, the most commonly used in the construction industry and manufacturing are gas welding and arc welding. In this post, gas welding is limited in oxyacetylene welding, arc welding is limited in Shielded Metal Arc Welding (SMAW), and a combination of both gas welding and arc welding is limited to Gas Tungsten Arc Welding (GTAW) and Gas Metal Arc Welding (GMAW). How to select or specify the type of welding that, in this post will be explained in more detail based on the form of the base material, type of filler, weld strength, thermal energy source and welding cost.

Before choosing the type of welding that according to the construction design, we must first understand the characteristics of each type of welding. Here will be explained one by one characteristic of some types of welding used in the construction design.

(1) Oxy-Acetylene Welding

Oxy-acetylene welding is one type of welding that uses a heat source coming from the gas. The gas obtained from the combustion of fuel gas mixed with oxygen (O2). The combustion process produces flame with high temperature (3000 Celsius degree), which can melt the base metal and filler metal. The type of fuel gas used is acetylene, propane or hydrogen, so this welding method is often called oxy-acetylene welding. This welding can also be done directly or by using a filler metal depending on the connection type and thickness of the metal base.

Oxy-acetylene welding principle is not very complicated, that only by setting the acetylene gas and oxygen, then the tip is brought near to the fire will arise the flame. But the amount of acetylene gas and oxygen must be arranged by turning the pressure regulator slowly. If acetylene gas is turned on it will issue ordinary flames with soot, whereas if the acetylene gas is too little then there would be no flame.

Oxy-acetylene welding advantages include:

• The equipment is relatively inexpensive and requires low maintenance
• How to use a very simple does not require a high welding technique so easy to learn
• The welding equipment is small and simple, so easy to carry and can be used in the field, factory or workshop.
• Almost all types of metals can be welded, through proper welding technique
• Welding can be used for the process of cutting and splicing

(2) Shielded Metal Arc Welding (SMAW)

Shielded Metal Arc Welding (SMAW) is one type of welding that uses a heat source that comes from an electric arc. Electric arc occurs when the electrode has been electrified positive contact with the base metal wing negative electric current. The heat from the electric arc formed between the base metal and the electrode is capable of causing the base metal and electrode tip melts and then freezes simultaneously.

Shielded Metal Arc Welding (SMAW) is also quite simple principle that only by raising or lowering the electrical current (ampere) we can adjust the size of the generated electric arc. The larger the electric arc occurs, the faster the process of melting the base metal and the electrode.

The advantages of Shielded Metal Arc Welding (SMAW):

• Welding equipment price is lower, so the initial cost of investment is low
• Operationally reliable and simple
• Cost of filler material (electrode) is quite low
• Can use various types of filler material (electrode)
• Can use the same equipment for different types of base metal
• Can be done at any thickness
• Can be done in all welding positions

Further explanation of the Shielded Metal Arc Welding and how to design it, you can see the post about Shielded Metal Arc Welding Design.

(3) Gas Tungsten Arc Welding (GTAW)

Gas Tungsten Arc Welding (GTAW) or better known as Tungsten Inert Gas (TIG) welding is the kind of gas arc welding with electrodes are not fed means electrode does not function as a filler material. Welding uses tungsten rods as electrodes that can generate an electric arc but the electrodes remain intact (not melted). As fillers used welding wire which is included separately with the electrode. TIG welding is using noble gas as a protective gas which generally uses pure argon gas.

The use of TIG welding has the advantage of;

• Filler metal feeding speed can be set themselves without being affected by electrical current so that the penetration of filler metal into the base metal can be set directly as required (easy setup for thin or thick plate).
• Better quality in the welding area.

(4) Gas Metal Arc Welding (GMAW)

Gas Metal Arc Welding (GMAW) or better known as Metal Inert Gas (MIG) Welding is the kind of gas arc welding with electrodes fed directly. MIG welding using a wire electrode welding as well as filler wire. MIG welding using noble gases as a shielding gas generally use gas Ar and CO2.

The use of MIG welding has the advantage of;

• The welding operation is easy because of the high concentration of the arc with a little splash
• The efficiency is excellent because it can use the high current at high speed
• Weld metal formed quite a lot
• The nature of toughness, elasticity, airtight and insensitivity to the slag is very good.

Considerations in choosing Type of Welding

Once we know the type of welding used in the manufacture of construction, we can then choose the appropriate type of welding we need to consider several things, among others:

1. Metal base, what type of material to be welded and how the thickness of the material. This information is very important because there are some types of welding are not suitable for the particular material or very difficult process to a certain thickness.
2. Filler, we must determine in accordance with the type of filler metal base material. Filler can be selected based on the material and type. Examples of filler materials such as carbon steel, stainless steel, aluminum, brass etc. Examples of types of filler such as filler rods, filler wire, electrodes encased etc. After the material and the type of filler selected, we can determine the appropriate type of welding.
3. Welding strength, is related to the cross-sectional thickness of the weld. To obtain the appropriate thickness of the weld cross section, we must determine the type of connection and seam welding are used.
4. Thermal energy source, an energy source that we have in accordance with the type of welding.
5. Welding cost, this consideration is crucial in business. Welding costs including the initial investment, the cost of equipment, operating costs, the cost of the filler rod or electrode and man cost.

Having in mind some of the considerations above, then we can determine the type of welding that is appropriate to the characteristics and advantages of each type of welding.

That is a description of Welding Design with the topic about How to Choose the Appropriate Type of Welding. If you find misconceptions in the welding design, please provide the correction in the comment box.

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