There are several important aspects to look at when it comes to inspecting different parts of vehicles and equipment in the automotive industry. Similar to how different parts play their own role in how the final machine operates and functions, various types of quality control are needed depending on what needs to be checked.


Regardless of the quality resulting from skilled work, there are things such as operating safety, lifetime, and overall cost that can be observed and improved during the manufacturing process. 


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Common Parts Passing Through Quality Assurance in the Automotive Industry 



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Shafts & Bearings


A car shaft, also known as a drive shaft or propeller shaft, is a mechanical component that transmits torque and rotation from the engine to the wheels of a car. It is a cylindrical rod that connects the transmission output shaft to the differential input shaft, allowing the power from the engine to be transferred to the wheels. Typically made of steel, it is designed to withstand the high amount of force generated by the engine, thus making quality control extremely important.


Supporting the rotating shafts and axles in a car, bearings reduce the amount of friction and allow smooth movement of the parts. It is a type of rolling or sliding element that is designed to withstand the weight and forces it encounters when in contact with these rotating parts. Overall, these components play a critical role in the smooth and efficient operation of a car’s mechanical systems, helping to reduce friction and wear. To perform optimally, advanced measurement and analysis are required during each step of the production process.



Quality Control Techniques

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Dimensional Measurement

During the manufacturing process of automobiles, dimensional measurement is carried out at various stages to ensure the parts are being manufactured to the correct specifications. For example, during the machining process, coordinate measuring machines (CMMs) and other precision measuring tools are used to measure the dimensions of the parts and ensure they are within the allowable tolerance limits..

Roughness, Roundness, and Form Analysis

These three subjects are constantly under observation when concerning shafts and bearings during the manufacturing process as these are critical components inside any vehicle. Each component has an optimal specification requirement that needs to be met and can only be tested with devices such as a profilometer, roundness tester, and in some cases even a CMM.

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Hardness Testing for bearings

The property of a material that allows it to withstand plastic deformation, typically through penetration, is referred to as hardness. One common way to measure hardness is through the Rockwell hardness test method. This involves using a diamond cone or hardened steel ball indenter to make an indentation in the test material. Once the indentation has reached equilibrium, a measuring device is used to track the movements of the indenter and monitor changes in its depth of penetration.




In an automotive system, gears are typically used in transmissions, differentials, and transfer cases. As each of these plays a key role in transferring the force of the engine to the wheels, detailed inspection and testing are required to ensure that they perform their job correctly. Automotive gears come in a variety of shapes and sizes, depending on their intended use. The most common types of gears used in automotive systems are spur gears, helical gears, and bevel gears.


Quality Control Techniques

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Dimensional Measurement

To ensure that the size and shape of gears are up to specification, there is no better machine than a CMM. For the most precise and accurate measurements, touch and scanning probes are regularly used for this purpose. The typical measurements performed during this part of quality control usually consist of tooth profile, pitch diameter, backlash, and runout measurement.

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Surface Inspection

Gear surfaces must have a smooth and uniform finish to ensure proper operation and minimize wear. Surface inspection techniques such as visual inspection or surface roughness analysis are used to detect defects or other surface imperfections that could harm the durability and cause a failure in its lifetime. Following parameters set by the design engineers, surface roughness measurement can be performed to ensure that they meet the design values set before production.

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Hardness Testing

Gears must have sufficient hardness to withstand the loads and stresses they encounter during operation. Hardness testing techniques such as Rockwell, Brinell, Vickers, or Micro-Vickers hardness testing are used to verify the gear's hardness which varies based on location and material.

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Car Body


More than what you just see on the outside of a car, the car body is the outer shell that encloses the internal components of a vehicle. Typically made of steel, aluminum, or composite materials, it serves several functions like protecting the occupants from external elements, providing a rigid structure for the vehicle, and housing various mechanical, and electrical components. Making it one of the most important parts of every vehicle you find on the road today.



Quality Control Techniques

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Dimensional Measurement

Car bodies must be manufactured to precise dimensions to ensure they fit correctly with other components. As car bodies are generally quite large, quality control practices require measurement from large CMMs or even non-contact devices such as laser scanners.

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Surface Inspection

Car bodies must have a smooth and uniform surface, and surface inspection techniques such as visual inspection or 3D scanning are used to detect defects such as dents, scratches, or other paint or sealer defects.




Gaskets are commonly used throughout various industries as a device to prevent fluid or gas leakage between two or more mating surfaces. They are typically made of a compressible material such as rubber or silicone and are placed between the coupled surfaces to create a tight seal.


In regards to use in automotive vehicles, they are often located in the construction of engine blocks, cylinder heads, exhaust systems, and transmission systems. They are critical components that help ensure the proper functioning of the engine and other systems by maintaining proper pressure through the prevention of leaks.


Quality Control Techniques

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Dimensional measurement

Gaskets must be manufactured to precise dimensions to ensure they fit correctly with the surfaces they are in contact with. For this, non-contact optical measuring devices are regularly used due to their high speed and accuracy.

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Material testing

Gasket materials have a specific requirement unlike other materials found inside automotive components, this is compressibility. To find this out, a hardness tester is often used to determine the resistance that these materials have during and after the manufacturing process.

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Visual Inspection

To prevent defects that might affect the gasket’s sealing ability such as cracks or scratches, optical systems with artificial intelligence can be used to automatically perform an inspection.


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Electric Motor Housing


Electric motor housing is an extremely important part found in both hybrid and electric vehicles. The motor housing serves as a protective casing for the motor's internal components and helps dissipate heat generated during its operation.


Typically made of aluminum or other lightweight materials they are designed to be compact and efficient. The importance of its manufacturing and quality control methods is that it fits correctly with the internal and external components to prevent mechanical failure.


Quality Control Techniques

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Dimensional Measurement

The most obvious of measurements when it comes to a housing of any kind, is dimensional measurement. In order to ensure that the housing fits with its corresponding components correctly, the dimensions need to be spot on.

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Surface inspection

Surface inspection is a quality control technique used to detect any defects or imperfections on the surface of electric motor housings in the automotive industry. The housing's surface needs to be free from any scratches, dents, or other types of damage that could affect the motor's performance or durability during its life cycle.

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Roughness Measurement

The roughness of the housing surface can affect the motor's performance, noise level, and overall quality. Particularly important where the housing makes contact with another component, the surface roughness must be in line with the parameters set by the engineer.

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Geometries and Profile Feature Measurement

With key features including sealing surfaces, flanges, boreholes, cooling holes or coolant channels, wall thickness, and several others. Form and dimensional measurement machines are required to confirm if these features will affect the component’s ability to perform once assembled.




Hairpins, also known as hairpin stators, consist of copper or aluminum wires that are bent into a U-shape, creating two parallel branches with a common base. The wires are then inserted into slots in the stator core, creating a loop that carries current and produces the magnetic field necessary for the motor to operate.


These hairpins are a type of winding configuration for the stator, which is the stationary part of the motor that surrounds the rotor. Hairpin stators are used in permanent magnet synchronous motors (PMSMs) and induction motors for both electric and hybrid vehicles.

Quality Control Techniques

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Optical Measurement

Being such a precision part, the shape and alignment can significantly affect motor performance. The use of optical measurement involves the use of specialized instruments such as 3D optical scanners to capture high-resolution images of the hairpins. These images are then analyzed using specialized software to obtain measurements of the hairpins' dimensions, shape, and position.

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Form Measurement

Form measurement involves using specialized instruments such as coordinate measuring machines (CMMs) or optical measurement systems to measure the hairpins' dimensions, shape, and position. The measurements are compared to the required specifications to ensure the hairpins meet the desired tolerances.

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Battery Foil


Battery foil, also known as electrode foil, is a thin metal sheet found inside battery cells. It serves as the current collector for the electrode material, which is coated onto the foil's surface. The foil is typically made from materials such as aluminum, copper, or nickel, and its thickness can vary depending on the type of battery and its intended use.


Quality Control Techniques

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Dimensional measurement

Battery foil thickness is critical in ensuring the correct amount of electrode material is applied for optimal battery performance. Quality control personnel can use thickness measurement techniques such as optical or mechanical gauging to ensure the foil thickness is within specifications in a way that doesn’t harm the material.

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Visual inspection

Inspecting the surface of the foil for any defects such as scratches, dents, or tears can help detect any imperfections that may cause problems down the line. Visual inspection can be done manually by inspectors or can be easily automated with systems incorporating the TAGLENS.




The least often thought of part of a car is wire, used in various applications such as electrical systems, sensors, and communication networks, its role is just as important as the motor. Automotive wire is designed to withstand harsh conditions such as high temperatures, vibrations, and exposure to chemicals and moisture, and thus it makes sense that rigorous quality control must be performed on it.


Quality Control Techniques

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Dimensional Measurement

This technique involves measuring the diameter, length, and thickness of the wire to ensure it meets the required specifications. Often performed with non-contact gauges, such as the Laser Scan Micrometer, diameter and thickness can be done extremely quickly and effectively during production.

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Material Testing

Since the durability of wires in a car matter so much, hardness testing is performed on the material to guarantee a long lifetime without any issues.



Our advanced CMM systems, laser-optical scanning technology and software analysis techniques are ideal for the 3D measurement necessary for complex automotive applications.


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