Shall we consider why a differential is needed for an automobile? A traditional differential is a gear train with three shafts that has the property that the angular velocity of one shaft is the average of the angular velocities of the others. In automobiles, the differential allows the outer drive wheel to rotate faster than the inner drive wheel during a turn. This is necessary when the vehicle takes turns, making the wheel that is travelling around the outside of the turning curve roll farther and faster than the other.

Classification of differential in automobile applications

Automobile manufacturers have developed several types of differential in the world to achieve various tasks such as improving traction between tire and road and stability control. The following types are the most common types of differential in day automobile applications.

Open differential

Locking differential

Limited-slip differential

Torsen Differential

Open differential

The open differential is a type of differential that supplies the same amount of torque to each of the wheels of a vehicle. The differential splits Engine torque into two output shafts. The output shaft can be rotated at different speeds.

Shortcomings of open differentials

Traction is determining the amount of torque that is supplied for the wheels. The engine can limit the amount of traction needed on hard. In slippery, wet or unstable surfaces, torque is applied so that traction can be achieved without risking slippage. When one wheel has steady traction and another is at risk of slipping, the differential divides the torque between both wheels, reducing the torque for the stable wheel to that of the slipping one. This has the disadvantage of reducing revolutions per minute (rpm) to zero.

Advantages

1. Great on roads
2. Predictable power distribution on the dry surface
3. Easy to drive and handle simplicity of design
4. Lower maintenance cost

Disadvantages

1. Poor off-road handling
2. Unpredictable power distribution on lower friction surfaces

Locking differential

The locking differential is an improvement of the open-type differential. A locking differential provides increased traction than an open differential by restricting each of the two wheels on an axle to the same rotational speed without regard to available traction or differences in resistance seen at each wheel. There are two types of lockers

1. Automatic locker
2. Selectable locker

Automatic locker

Automatic lockers lock and unlock automatically with no direct input from the driver. During ordinary conditions, when the vehicle is driving a straight road, the differential at “lock” state and if the difference between the speeds of the two rear wheels is minimal to the specified limit no signal will be generated by the electronic circuit. They will never allow either wheel to spin slower than the differential carrier.

Selectable locker

Selectable lockers allow the driver to lock and unlock the differential at will from the driver's seat. This can be accomplished in many ways. 

1. Compressed air (pneumatics).
2. A cable cable-operated mechanism is employed.

The shortcoming of locking differential

Locking the differential on a high-grip surface such as dry pavement makes it difficult to turn the vehicle. Increased tire wear and noticeable impact on driving behaviour. During cornering, which half-axle is uncoupled is dependent on the torque direction applied by the driveline. In selectable locker Mechanically complex with more parts to fail. Needs human interaction and forward-thinking regarding upcoming terrain.

Advantages

1. Traction is maximum due to both wheels providing high force with the same speed

2. Simple

3. Robust

4. No electronic controllers

Disadvantages

1. More expensive

2. Limited slip during engagement

3. Driver needs to manually engage

4. Some systems may be complex

Limited slip differential

Limited slip differentials (LSD) are used in vehicles to overcome the traction difference problem of drive wheels. Two types of limited slip differential are commonly used in automobiles.

1. Clutch Plate Limited Slip Differentials
2. Viscous Limited Slip Differential

Clutch Plate Limited Slip Differentials

Apart from basic components in open differential, there are a few special components: steel plates (orange), friction plates (blue), and casing, as shown in the figure. Friction plates are locked with side gears. Side gears and friction plats are always moved together.

Viscous Limited Slip differential

In this kind of differentials hydrodynamic friction from fluids with high viscosity is used to transfer engine power to drive wheels. Silicon base fluids are normally used as fluid. Here, a cylindrical chamber of fluid filled with a stack of perforated discs rotates with the normal motion of the output shafts.

Viscous limited slip differentials are less efficient than clutch limited slip differentials types because in this case lose some power.in case fluid is heated up very high temperature viscosity will reduce then the differential effect will stop temporarily or permanently.

There is an exponential relationship between torque transfer and speed difference. Therefore, it transfers a little torque at the initial stage of slip. To mitigate this issue, manufacturers adjust the final drive ratio by introducing pre-load the VC.

Advantages

1. Smooth torque transfer
2. Easy to drive
3. More proportional response due to slip
4. Limited "wind up" at low speed

Disadvantages

1. Fluid can break down with time
2. Less efficient than a conventional differential
3. Higher associated maintenance
4. Delay response due to viscous fluid is a flexible medium.

Torsen Differential

The Torsen differential is a generous method that provides differential effects and overcomes traction difference problems. There are some components other than traditional open differential. There are six warm and wheel sets as shown figure.

When one wheel is a slippery surface that wheel tries to rotate at high speed. The wheel connected to a slippery wheel shaft trying to rotate the other warm wheel. But that warm wheel cannot rotate the wheel mesh with it. Finally, the whole system will lock. Then whole system rotates as one solid part. That means good wheels also get equal power same as slippery wheels. One drawback of the original differential was 50:50 torque distribution.

Advantages

1. Mechanical Simplicity
2. Less maintenance
3. Continuous Torque Transfer
4. No need for driver input

Disadvantages

1. High manufacturing cost
2. Limited slip but not locking
3. More complexity

Automotive

November 29, 2023

What is Total Quality Management (TQM)?

Total quality management (TQM) is a continuous management process to improve an organization's processes to give customers the best service. Continuously, TQM detects and reduces errors in manufacturing. Today, customers are astute and aware of how to behave with modern technologies. They always expect organizations to provide their best quality product and services to them. The ultimate target of TQM is customer satisfaction and giving such benefits to organizational members.

All members of the organization represent the total quality management process to build long-term success by focusing on improvements in quality. Organization approaches to streamline supply chain management to identify and minimize errors. There are a few important aspects of TQM, such as communication, collaboration and continuous learning within an organization.

Total Quality Management (TQM) is a collaborative process among the various sections within an organization, which plays different roles including design, engineering, marketing, and more. In TQM, management gives all facilities and manages the right person in the right place providing comprehensive training, and setting clear, achievable objectives.

History of TQM

In the 1920s, the principles of scientific management swept the U.S. industry and the initialization of quality management in an industrial setting by applying the science of statistics. Also, the process of planning and executing the plan was separated by the business, and the organization used the Hawthorne experiments in the late 1920s to show the impact of participation on worker productivity.

Walter A. Shewhart created a statistical control chart and developed methods for statistical analysis and control of quality in the 1930s.Furthermore, in the 1950s, W. Edwards Deming developed Shewhart’s ideas, and he taught quality control and statistical analysis to Japanese engineers and executives, it can be identified as the origin of TQM. Also, Joseph M. Juran taught quality control methods and published his book, Juran’s Quality Control Handbook. Armand V. Feigenbaum has published his book regarding Total Quality control. Philip B. Crosby promoted zero defects quality improvements for companies at the same time. Therefore, the TQM concept was initiated during the 1950s and 1960s.

Total quality management exhibited its success to organizations worldwide and U.S. companies adopted TQM to increase productivity. Japanese named their approach to enhancing total quality companywide quality control in 1968.

Currently, TQM is the systematic approach to improve customer satisfaction and many businesses apply TQM to give better service to customers. Today organizations follow quality standards and quality management systems.

The 8 fundamental principles of TQM explored

Organizations follow the eight principles of TQM to enhance quality. Those principles are the straight points of TQM to have continuous improvement.

Customer focus: -

The customer is the key person for the business and customer feedback is very important to understand customer needs. Therefore, the company needs good customer care service to respond to customer's feedback.

Employee involvement: -

Employee involvement is the key parameter to the success of the TQM. Because All employees should attend to this program with proper training. For that, organizations should increase the training programs and give facilities to enhance their knowledge.

Focus on process: -

Every worker should attend to the TQM process with proper education and knowledge. TQM is a continuous improvement process which analyzed frequently to identify its weaknesses.

Integrated business systems: -

Organizations must integrate all TQM processes to convey important information among the employees to give a better understanding of the process.

Systematic approach: -

TQM activities must be planned and managed well to get better results.

Continual improvement: -

TQM is the continuous improvement process. This improves the quality of the products or services to achieve competitive advantages according to market changes.

Fact-based decision-making: -

The company should analyze the data to accuracy of the decision-making. Also, the collected data should be documented for future reference.

Communication: -

Communication is the way to identify issues and weaknesses of the process. Also, communication improves the relationship between employees and employees feel better when they know the strategies, and methodologies of the process.

Not only that, better communication with customers gives more opportunity to increase the quality. This leads to retaining customers long time.

Importance of TQM

TQM is the systematic process that can lead to organizational success. TQM directly impact customer satisfaction, operational efficiency, employee morale, and the reputation of the organization.

As discussed earlier, customer satisfaction is the most important parameter to the success of the business. The customer is the key person who plays a crucial role in the Centre of the activities. TQM always focus on improving the quality of product or service to meet or surpass customer expectation. TQM is involved in manufacturing, marketing, or customer service to deliver better customer service. Therefore, it leads to a stronger relationship with customers, loyalty and the reputation of the business. TQM enhances customer satisfaction.

The special thing of TQM is the continuous improvement of the process.  In this case, the company regularly evaluate their process to identify the weak areas and TQM encourages it to make the necessary changes. These improvements lead the company to a competitive market. Therefore, TQM drives for continuous improvement.

TQM is the process which is carried out by all employees in the organization. All employees are valuable persons for this process and all have a major responsibility to the success of this program. Given such things, employees feel comfortable and satisfied with their roles. Also, they have been given proper training and guides. Therefore, TQM is important to enhance the employee's morale.

In addition to that, TQM helps to build the company's reputation by giving high-quality service and products to customers. Organizations can directly enter into competitive markets with reputed and branded products and services. Also, TQM manages better resource utilization and high efficiency. Therefore, businesses can achieve higher profits with existing resources.

How to implement TQM

1. It takes time to plan, develop, and implement TQM, and the amount of time required varies depending on the organization.

2. The organization identify their potential values by reviewing its current culture and quality control systems.

3. The management team makes the decision to embrace Total Quality Management (TQM) and creates a TQM master plan.

4. The company lists and ranks the needs of its clients.

5. Management lays out the procedures required to satisfy client demands.

6. To supervise efforts to enhance procedures, management assembles a team.

7. Management begins to add to the process by giving more training and planning.

8. To standardize day-to-day process management, management develops a procedure.

9. The management is always asking the staff for their opinions.

Benefits of TQM

Enhance Customer Satisfaction:

Purpose of the TQM is to increase product or service quality. Good quality products mean higher customer satisfaction, because TQM identifies customer needs through customer's feedback. Therefore, organization can improve product quality continuously.

Improve efficiency: 

TQM is the systematic process that can reduce errors, reworks by utilizing current resources and process effectively. Therefore, it increases overall efficiency.

Fewer cost:

High quality product and service means less defects, less customer return. Therefore, organization can reduce the rework, scrap cost, service cost. This leads to saving more money and increases profit as well.

Enhance employee's morale:

All employees involve for TQM process. They are always updated about process news and provided more training and facilities. Employees feel the ownership and they work hardly to achieve the goal. This collaborative culture enhances the employee's morale.

Better reputation:

Better quality products means higher customer satisfaction. Therefore, TQM helps to get the better reputation from customers and stakeholders.

High quality product and service:

TQM is the continuous improvements process to identify the weakness of the process. Implementing TQM, manufactures can produce high quality product and services.

Grater market share:

Customers are keen to buy high quality products and services. Therefore, TQM increases market share rapidly.

Disadvantages of TQM

Time-Consuming:

TQM is the process that is implemented with continuous training, changing organizational culture. Therefore, it takes a significant time to implement TQM.

Resistance to Change:

Employee resistant to major organization culture change. They feel their jobs insecurity. Therefore, it slows the process and employees should be informed clearly to avoid this.

High Planning and resources time:

Time consuming is significantly higher to planning and resource.

Added costs for implementation:

TQM needs training and infrastructure. Therefore, it adds the significant cost

Dependance on employees:

TQM is the process to involve all employees in organization. Therefore, success of the process depends on the commitment and participation of the employees.

Examples of TQM

Toyota:
Toyota adapt to TQM and Kaizen to achieve higher product and work quality. In 1994, Toyota established the "Toyota Group Executive TQM Training Course" to providing TQM training for new executives.

Amazon:
Amazon implemented TQM to improve the quality of their service because it is customer-centric business e-commerce model. They applied to improve the order processing, website interface and customer care services.

TATA Steel:
TATA steel applied TQM in the 1980s also it was awarded the Deming Application Prize in 2008. TATA steel follows the TQM to identify the customer variation and their requirements. TATA Steel formed the committee " Performance Improvement Committee" to improve continuously.

Apple:
Apple is the biggest high quality electronic items manufacturing company. I phone, I pad, Mac book are the main products of the Apple company. Apple follows TQM process to design, testing, response to customer feedback. They continuously improve the their products to gain the market share and improve the customer satisfaction.

Manufacturing Quality

November 14, 2023

What is an Electric Vehicle

People use gasoline and diesel vehicles for their transportation. Traditional fossil fuel cars have internal combustion engines which are spark-ignited internal combustion engines for gasoline and compression-ignited combustion engines for diesel vehicles. In these types, the generated energy transfers to wheels through a mechanical transmission system. Mainly, fossil vehicles exhaust gases from the engine into the environment, which directly influences environmental pollution, and it has become a burning issue in the world. Also, there is a risk of the end of crude oil stock. Therefore, inventors were doing many activities to find alternative propulsion systems.

Electric vehicles are one of the best solutions recently and many car manufacturers are designing and manufacturing electric vehicles. Electric vehicles are commonly referred to as battery electric vehicles (BEVs), have low running costs and are environmentally friendly. Electric vehicle has electric motor instead of combustion engine, and large battery pack to power the electric motor. Due to the use of electric power, emissions are zero. Also, it does not contain the typical liquid fuel components of a normal combustion vehicle, such as a fuel tank, fuel pump, fuel pipes and exhaust system. The electric vehicle industry is still growing around the world.

Also, Plug-in Hybrid Electric Vehicles (PHEVs) and Hybrid Electric Vehicles (HEVs) are semi-electric vehicle types. However, those types are equipped with internal combustion engines. Semi-electric vehicles are the most popular versions in the current vehicle market.

Key components of EV

Battery pack

The battery pack is the most important, and heart of an electric vehicle. Electric vehicles use battery packs to store electrical energy to propel the vehicle. The battery pack contains a series of battery cells that are grouped together as modules. After the battery is charged sufficiently, it provides the required power to the relevant components. Lead acid or metal hydride batteries are used for some EVs. However, battery technology improves day by day, modern EVs use Lithium-ion batteries, because they have a very low self-discharge rate for a few days, even weeks.

Electric Motor

Electric motors convert battery energy to mechanical energy to power the vehicle. EVs have one or more motors which are highly efficient and minimum maintenance. Also, there are motor generators to propel the vehicle and to regenerate the power back.

Power Inverter

The inverter converts the direct current (DC) battery power to alternating current (AC) to drive the elective vehicle. Also, inverters manage the speed of the motor by changing the frequency of the alternating current. In addition, it can maintain the flow of power between the motor and the battery, including regenerative braking.

Onboard Charger

The onboard charger maintains the external AC electricity power to charge the batteries by converting them into DC electricity power. It monitors the characterization of the battery, such as temperature, voltage, current and charging status.

Thermal Management System

A thermal management system maintains the temperature of the battery pack and critical components during the operation. This system contains coolants which circulate through pipes and pump across the battery pack, electric motor, power electronics, and other components. This helps to maintain the right temperature for high battery performance and the life of the battery.

Electric Power Control Unit (PCU)

The power electronics controller helps to manage and control the flow of electrical energy between the battery, electric motor, and other components to control the speed of the motors. Furthermore, it functions to control the rate of charge using information from the battery. Simply, it changes the speed and performance of the vehicle.

Transmission

EVs use a single-speed transmission to transfer mechanical power from the electric motor to propel the vehicle. Some EVs have multi-speed transmissions. Electric motors can provide a wide range of torque.

Regenerative Braking System

Regenerative brake converts some of the kinetic energy during deceleration and braking into electrical energy to recharge the battery.

Electronic Vehicle Controller

The electronic control unit manages various parameters of the vehicle including acceleration, braking and energy management. This is also called the brain of the vehicle. It is operated by software.

High-voltage wiring and Connectors

Electricity flows through high-voltage wires and connectors from the battery to the motor and other components.

Vehicle Charging Port

Charging port allows to connect with external power source at stations or home.

How EVs works

Electric vehicles have forward and reverse modes according to transmission selection. When putting the vehicle into gear position and pressing the accelerator pedal, the vehicle moves. So, the power inverter converts DC power from batteries to AC power for the electric motor. Electronic Vehicle Controller adjusts the vehicle speed by changing the frequency of the AC power according to the accelerator pedal. When pressing the brake, the car decelerates, and the motor starts to operate as an alternator to charge the batteries.

Advantages

Noise is very low

Zero emission

No additional mechanical components, such as exhaust, IC engines, gears

Lower operating cost due to fever mechanical components

High energy efficient

Limitations

Rechargeable time is higher

Low driving range

Lack of charging stations

Higher battery replaces the cost

Future trends

As per technology development, many manufacturers try to resolve the issues daily. The battery industry grows rapidly around the world. Many of the world's leading car manufacturers invest more money to invent new technologies to make electric vehicles an increasingly popular and practical choice for many consumers. 

Another big news is the Hydrogen Fuel Cell based vehicle industry. In this type, hydrogen is used to power the motors. This is also still an upcoming technology, and few car models were manufactured for testing purposes. The Honda car manufacturing company has developed and produced the world's first government-certified commercial hydrogen fuel cell vehicle.

Automotive

November 09, 2023

 

What is an Anti-lock braking system?

Anti-lock braking system, commonly known as ABS is a safety feature in modern vehicles. It helps drivers control their vehicles during hard braking or emergency stops. ABS works with a regular brake system to prevent the wheels from locking up and skidding which involves to loss of steering control and accidents.

Anti-lock brake systems were initially tested for railway cars and aircraft in the 1950s. The world’s first Formula car was incorporated with the ABS system in the 1960s. After that, Mercedes-Benz began to install the ABS system into commercial vehicles. After a few years back, they revealed technology. Then the ABS system was included in many cars.  Therefore, ABS is a standard feature of modern vehicles to enhance vehicle stability and control.

ABS is mainly effective in slippery conditions, such as rain, ice or snow which needs traction control. During the sudden stopping, there is a possibility to loss of traction between the tires and the road surface. It increases risks of skid and loss the control of steering. This leads to accidents. When such kind of situation, the ABS comes to the rescue.

Anti-lock braking system includes four main parts,

Speed sensors

Pump

Valves

Controller

Speed Sensors

Speed sensors provide wheel speed in an Anti-lock braking system. These sensors are located at each wheel or differential. It takes action to provide speed when the wheels are going to lock up.

Pump

Pumps restore pressure back to the system when the valve releases the pressure from the brakes.

Valves

The valve in the system allows three positions to allow, block and release pressure on the brakes. In the first position, the valve passes pressure from the master cylinder to break through the valve opening. Secondly, the valve isolates the master cylinder and brake to prevent pressure from rising. Finally, the valve releases some of the pressure from the brake.

Controller

The electronic control unit (ECU) takes data and processes the data. Then it gives real-time commands to control the braking pressure according to the wheel-speed sensor data. This is known as the computer in the car.

How it works

In this system, the ECU always monitors the wheel speed through wheel-speed sensors for rapid deceleration. In this kind of situation, the wheels lock up. ECU knows that wheels cannot have such a kind of deceleration. Before the locking wheels, Wheels need to be stopped quickly to prevent accidents. The ABS controller gives commands to reduce pressure to the brakes until the wheel acceleration again and then increase the pressure until the wheels decelerate again. This is done very quickly before reducing wheel speed suddenly. This is happening to slow down the wheel speed at the same rate as the car.

Modulation of Brake Pressure: The special thing is that the electronic control unit can maintain the brake pressure of each wheel independently. This allows the maximum braking power to the car. The system rapidly increased and decreased brake pressure when necessary to prevent skidding.

Pulsating Brakes:  while operating ABS, the driver feels a pulsating or vibrating sensation through the brake pedal. This is a normal condition that indicates the ABS works correctly to prevent the wheel from locking up.

Steering Control: ABS helps to maintain the stability of the vehicle during the rapid braking through the ABS system. This allows steering control by preventing wheel lock-up.

Anti-Lock Brake Types

Four channel, four sensor

This system has four individual sensors and four valves for each four wheels. System monitor all wheels separately. This is the best system and it gives maximum braking force to the vehicle. Also, Four-channel ABS system gives better traction control.

Three channel, three sensor

This system consists three sensors and three valves. Two front wheels have individual sensors and valves while both rear wheels have one sensor and valve. For rear wheels, it is positioned in the rear axle to monitor both wheels together. This system commonly can be seen on pickup trucks with four-wheel ABS. The front wheels can achieve maximum brake force due to sensors monitor front wheel individually. However, rear wheel are monitored together. Therefore, there is a possibility to only one wheel before lockup.

One channel, one sensor

This system only has one sensor and one valve for rear wheels. This is commonly seen in pickup trucks with rear ABS. The sensor is located in the rear axle. One-channel ABS system works same as the rear end of three-channel ABS. There is a possibility to only one wheel before lockup by reducing the braking effectiveness.

Advantages and Disadvantages of ABS

Advantages	Disadvantages
Low wearing brake pads and brake discs	maintainance cost is high
Vehical can be controlled at heavy braking	high complexity of the system
avoid uneven tyre wear due avoiding lockup wheels	braking distance may vary on different surface conditions
Due to smooth braking conditions, vehicle is running smoothly
Enhanced Traction

Automotive

November 07, 2023

 

The impact of manufacturing activities on the global environment is becoming noteworthy, and effective waste reduction and energy conservation technologies are urgently needed in manufacturing processes to achieve sustainable development. The majority of manufacturing processes involve welding processes ranging from traditional to recent manufacturing technologies.

Nowadays, laser welding is the most popular method in the manufacturing industry, and it is used on a wide range of materials and products. Laser welding is the most advanced process. Very low heat input to the weld, low distortion and the ability to weld heat-sensitive components are the advantages of laser welding. The selection of input parameters is critical for obtaining good weld bead geometry.

Laser Beam Welding

The joining technique is one of the vital manufacturing techniques that may be utilized to enhance product design and reduce production costs. Laser beam welding uses gas tungsten arc welding (GTAW). Welding is the process the accurate, reliable, and economical process of joining the two work-pieces together. Also, it has below  characterizations,

Excellent quality

High performance

High precision

High speed

Good flexibility

Minimal distortion

The power density of the laser beam is shown below,

There are many principal characteristics related to the laser beam welding process (LBW),

Characteristic	Note
The high density of energy	Minimum distortion
Speedy processing	Economical (if fully utilized)
Sudden start/stop	Because this process is operated by a CNC programme
Atmospheric pressure welds	Compared to arc procedures and electron beam welding
No X-rays are produced	Versus welding with an electron beam
No need for filling (Autogenous weld)	Failing to remove the flow
Confined weld	Minimal distortion
Zone with very little Heat Affected	Weld is performed near heat-sensitive materials
It is possible to weld quite precisely	Weld can be done from low to high workpiece
Excellent weld bead profile	There is no need to clean up
In a magnetic field, a beam cannot stray	As opposed to electron beam welding
Without contamination	Relying on gas obscuration
Rarely can difficult materials be welded	General benefit

Laser Welding Types

CO2 Laser

The process has little heat input and excessive density of energy which is generated using the continuous wave of CO2. This type of laser welding produces a tiny heat-affected zone (HAZ), which cools more speedily with less disfigurement and has a high depth/width ratio for the fusion area.

The primary outcome of the procedure is the CO2 laser strengthens the plume of the welding above the joint by diffusing the power density of the beam, reducing the weld depth and enhancing the weld joint’s surface breadth. Traditionally, CO2 lasers have been used for applications related to automobiles.

There are a number of benefits, 

Quick
Repeatable
Long weld with high-quality
Straight seams
Can weld axisymmetric components

Neodymium yttrium aluminium garnet (Nd:YAG) Laser

The solid-state laser crystal known as neodymium-doped yttrium aluminium garnet, or Nd: YAG, is extensively employed in a variety of applications. This laser gets its name from the dopant (neodymium) and the host crystal (YAG). Recent developments in Nd: YAG laser technology have made it possible to transmit beam energies of at least 2 kW across fibre optic cables. Particularly beneficial for robotic operations where the laser beam must be manipulated around a stationary part.

Nd: YAG laser beam welding is a high energy density and low heat input process that causes a small heat-affected zone (HAZ), which has a high ratio between depth and width for the fusion zone and cools more quickly with minimum distortion.

Fibre Laser Welding

The fibre laser welding process is a modern efficient, versatile and precise method to use to join material together. Fibre laser welding produces a smaller heat-affected zone, therefore, fibre laser welding can reduce the risk of distortion and damage to the surrounding material. This process has a few benefits, such as

High weld quality

Non-contact welding process

Automation capability

Low maintenance

Diode Lasers

Diode lasers have a wavelength that is near to the spectrum of infrared. As an example, it is about 808 nm. On the other hand, the relevant equipment size is quite compact. It is about a box of shoes for laser heads with kW capacities. Diode lasers have a significant advantage over traditional CO2 and Nd: YAG lasers in terms of weight and compact size; in addition to that, diode lasers are mounted to equipment with robot to move easily. Less cooling and higher life are the most important parameters.

Weld defects

Weld pool pores

This happens due to falling down the keyhole quickly. preventing molten metal from flowing into the centre of the keyhole before solidification. They are most common at the weld's root. In some Al alloys, macro-porosity (holes greater than 0.2 mm in diameter) is mostly caused by keyhole formation instability. This weld defect increases when increasing the power density and duration between pulses while performing the weld.

Undercutting

Undercutting is a major defect and it happens when the weld edge is below the weld center. The difference between the maximum and minimum points of the weld surface is considered the undercutting. Undercutting may occur irregularly while increasing the speed of the weld using the pulsed laser.

Humping

This is a longitudinal weld defect and can be identified as Consistent bumping and limitation of the face of the weld. The metal from the weld develops humps above the workpiece's surface. This defect may occur at high velocities and the weld pool shape is important in the formation of the lift of the weld.

Blow-holes

Keyhole instabilities can cause blow-holes to emerge in the top weld bead, most at very high welding speeds.

Cracks

Welding cracks can be seen in the top part of the weld and it forms primarily.

Non-uniformity and surface roughness

The surface roughness of the weld surface depends on the speed of welding, power of the laser beam, duration of pulse, and average peak power density. The optimum speed of the weld helps to obtain the lowest roughness on the surface. Furthermore, roughness rises dramatically while having the very low power of the laser beam.

Limitation of Laser Welding Process

Only applicable to metals and alloys

Less effective on highly reflective materials

Commonly used for materials with moderate thickness

Gaps or misalignment affect negatively weld quality

Cost is high

Require regular maintenance

Need skill operators

safety concerns

Application of Laser Welding Process

Automotive Industry for body, chassis, exhaust system, powertrain components weld

Aerospace Industry for turbine blades and aircraft components weld

Laser diode assembly

surgical instruments and implantable devices manufacturing

Jewelry manufacturing

shipbuilding

consumer electronic manufacturing

Load cell manufacturing process

Manufacturing

November 04, 2023

 

The 3D printing process is also called additive manufacturing. This process is used to create three-dimensional objects from a digital design or model. In this process, the material is added thin layer by layer where necessary. However, it involves the cutting and shaping material to create a final product. Due to the flexible characterizations, such as technology's adaptability and ease of use in creating intricate, customized, and complex designs, it is becoming more popular day by day in a variety of industries. Here's how the typical 3D printing process works,

Design:

The design of the desired object is created as a digital 3D model using 3D modelling software or by scanning an existing object using 3D scanners. This file is saved in STL file format.

Slicing:

This process is done to divide the digital model into thin, horizontal layers. A set of instructions (G-code) which is used to guide the 3D printer is created by this software.

Printing:

The 3D printer uses the G-code to add material layer by layer. There are plenty of popular materials for the 3D printing process, such as plastics (like PLA and ABS), metals, ceramics, and even organic materials like living tissue in bioprinting. Depending on the kind of material, the printer's print head or nozzle will either heat or cool it before depositing it onto the build platform or earlier layers.

Cooling and Solidification:

The printed 3D model cools and solidifies after each layer is deposited. Some materials solidify instantly, while other materials may need post-processing operations, such as oven baking or UV curing.

Support Structures:

Sometimes, support structures may be used to prevent sagging or collapsing during the printing process for some model which has an overhang or complex geometries. These supports are usually removed after printing is complete.

Finishing:

Once the object is fully printed, it may require post-processing steps like sanding, painting, or assembly. This is done according to the desired final product.

Types of 3D Printing Technologies

There are few 3D printing technologies. In this section, these technologies are described briefly.

Fused Deposition Modeling (FDM)

Fused Deposition Modeling is one of the most popular 3D printing methods and is widely used in 3D printing technology.  This is referred to as Fused Filament Fabrication (FFF). It is used for melting and extruding thermoplastic materials through a nozzle to build the object layer by layer. FDM is a cost-effective, simple, accessible, and versatile process. However, it has a few limitations, such as layer lines and visible print lines on the surface of the printed object, which may require post-processing to achieve a smoother finish. Mainly it is used for prototyping, hobbyists, and small-scale production.

Stereolithography (SLA)

Stereolithography is also an additive manufacturing process which is used to build high-precision, detailed, and complex three-dimensional objects with smooth surfaces using liquid photopolymer resin layer by layer. Mainly it is used for prototypes, dental models, jewellery, and custom medical devices. However, SLA 3D printers and the associated resins tend to be more expensive than some other 3D printing technologies like Fused Deposition Modeling (FDM).

Selective Laser Sintering (SLS)

Selective Laser Sintering (SLS) is an advanced additive manufacturing process. It uses a high-powered laser to sinter or fuse fine powdered materials to create strong, durable and complex 3D objects using plastics or metals. SLS is known for its ability to produce parts with high strength and heat resistance for aerospace, automotive, and healthcare industries. 

Digital Light Processing (DLP)

The Digital Light Processing method is similar to Stereolithography (SLA) but uses digital micro-mirror devices (DMDs) and a light source to create highly detailed three-dimensional objects with smooth surfaces. DLP is a speed and precision process for projection displays and 3D printing resin-based objects. It is used for crucial applications, such as dental, jewellery, and custom manufacturing industries.

PolyJet

Polyjet uses liquid photopolymer resin to build highly detailed, multi-material, and multi-colour parts. This machine cures layers using UV light. It can create products with aesthetics, high levels of visual and functional realism and fine details, such as product design, automotive design, architecture, and the production of consumer goods. However, it may not be the ideal choice for parts requiring high heat resistance or extreme durability.

Binder Jetting

Binder jetting is a method of layer-by-layer construction in which a liquid binder is selectively injected into a powder bed to bind particles together. This method is frequently used to create full-colour items that resemble sandstone.

Material for 3D Printing

Plastics: PLA (Polylactic Acid) and ABS (Acrylonitrile Butadiene Styrene), commonly used for FDM printers.

Metals: 3D printing with metals like stainless steel, titanium, and aluminium, mainly used for SLS.

Resins: Photopolymer resins, are mainly used for SLA and DLP printers.

Ceramics

Composites

Biocompatible Materials: Carbon fiber-reinforced plastics

Advantages of the 3D Printing Process

Rapid Prototyping
Cost-effective
Highly customization

Can create complex geometries

Low waste

Limitations of the 3D Printing Process

Less availability of material

Post-processing activities

Less speed for large or highly detailed objects.

Applications of 3D Printing Process

Aerospace: Producing lightweight components for aircraft and spacecraft.

Medical: Creating custom implants, prosthetics, and anatomical models.

Automotive: Rapid prototyping and manufacturing of custom parts.

Dental: Fabricating dental crowns, bridges, and orthodontic devices.

Art and Jewelry: Artists and jewellers use 3D printing to create intricate designs.

Education: 3D printing is used for educational purposes, teaching STEM concepts, and promoting creativity.

Architecture: Architects use it for creating detailed scale models and prototypes.

3D Printing Software

Autodesk Fusion 360

Tinkercad

Blender

Ultimaker Cura

PrusaSlicer

Manufacturing

November 03, 2023