Surface Engineering and Finishing for Automotive and Motorsport Applications
The automotive and motorsports industry is a constantly evolving field, demanding the highest standards of engineering and manufacturing. A vehicle comprises numerous components that work together seamlessly to ensure its smooth functioning. Each part of the system has its own role to play, and any flaw in the functioning of a single component can cause a catastrophic failure of the entire assembly. The engineering work in the automotive industry requires meticulous design and machining work. The smallest components are combined to create a final assembly, and each part plays its own role in running the whole system. The engine, transmission, braking, suspension, and steering systems all work together to ensure a vehicle runs smoothly on the road. The complexity of the engine itself highlights the attention to detail required in the industry. For instance, the opening of the valve, working of the fuel injector, movement of the piston, crankshaft, camshaft, and ignition of the air-fuel mixture, are all variables that need to be calculated and ensured within the calculated values for the engine to function perfectly.
The functionality of different components adds different requirements to a part. Some components require airtight contact between two parts, such as intake valves, exhaust valves, piston, and cylinder walls. In contrast, many other components can accept a little roughness, such as the housing of different components. However, microscopic finishing levels, if not cared for, can be the cause of failure of the assembly. Therefore, high finishing standards are essential to ensure the longevity and functionality of each component.
In motorsports, the demand for high-performance components is even more crucial. Different components must perform well at high torque levels and extreme speeds. The interaction of different metal surfaces in such circumstances can cause overheating, power loss, and eventually, catastrophic failure if different standards are not adhered to. Kemet, a world leader in surface engineering and finishing, has been a trusted partner in the motorsports industry for decades. Applying proper manufacturing techniques and adhering to the strict standards of the motorsports industry, Kemet has enabled racers to achieve outstanding results. The company provides confidence and trust to motorsports teams by ensuring their components are finished to the absolute maximum, ready for racing events such as Formula 1 and NASCAR.
Critical Components that Require High Finishing Standards:
- The following are some of the critical components in a vehicle that require high finishing standards to ensure optimal performance:
- Engine: Camshaft, crankshaft, tappets, valves, piston, and rocker arms
- Braking System: Disc, disc pads, drums
- Transmission Component: Clutch, gears, differential, pressure plate
- Steering System
When any type of machining operations are performed on components, some irregularities or non-uniformity are left behind, which can be referred to as peaks and valleys. The peaks and valleys are microscopic and cannot be seen or felt. However, in mechanical operations where two different components are in close contact with each other, this can be detrimental. Therefore, components that require an extremely high finish undergo a process known as lapping. Lapping is a machining process used to achieve extremely high flatness and surface finish. This process involves using an abrasive compound and a rotating lap to remove material from the surface of a component. The result is a perfectly flat and smooth surface that ensures optimal performance and longevity of the component.
Enhance Automotive Performance with Precision Finishing of Parts
Precision finishing of automotive parts is a crucial process that ensures the optimal performance and longevity of a vehicle. In the highly competitive automotive industry, even the slightest difference in the quality of the components can make a significant impact on the performance of the vehicle. Therefore, it is imperative to ensure that all the components meet the required standards of finish. The transmission system of a vehicle is an integral part that requires a high degree of finish. The flywheel, which has a clutch plate and pressure plate mounted on it, is responsible for transferring power from the engine to the transmission. The surface finish between these components is crucial to ensure smooth power transfer. Therefore, the lapping process is employed to achieve the required degree of finish. Similarly, the brake disc is also required to have a good finished surface for optimal braking performance.
The engine of a vehicle is made up of various smaller components that require precise machining and finishing. For instance, the seat ring and wedge of the valve must be lapped to ensure a perfect seal with no leakage. The camshaft, which operates the intake and exhaust valves, is lubricated during engine operation and also requires a high surface finish. The pistons and piston pins are integral parts of an engine and require a high degree of finish to ensure a smooth conversion of power from linear to rotational. If any roughness is present in these components, the engine will not run smoothly, and there would be hesitation in the conversion of power.
Other components, such as spray nozzles, injectors, hydraulic pumps, and impellers, also require a high degree of finishing process like lapping for optimal performance. The microscopic irregularities or non-uniformity on the surface of the components can cause peaks and valleys, which can be detrimental to the performance of the vehicle. Therefore, a high degree of flatness and surface finish is required to ensure the optimal performance of the vehicle.
To achieve the required degree of finish, precision finishing techniques are employed, such as lapping, polishing, and grinding. These techniques are employed to remove any peaks and valleys on the surface of the components, resulting in a smooth and flat surface finish. This process not only improves the performance of the components but also improves their durability and longevity.
The table below outlines the finish standards for engine and vehicle-driven components. While the listed values serve as a benchmark for various components, it is important to note that different companies may have slightly different specifications.
| Component | Acceptable Roughness (Micro inches) | Manufacturing process |
|---|---|---|
| Cylinder bore | 16-20 | Honing |
| Tappet bore | 60-75 | Reaming |
| Main bearing bore | 60-80 | Boring |
| Head surface | 40-50 | Milling |
| Piston skirt | 45-55 | Lapping |
| Piston bore | 30-38 | Lapping |
| Piston pin | 9-12 | Lapping |
| Crankshaft Main Journal Bearing | 4-6 | Lapping |
| Crankshaft Connecting Rod Journal Bearing | 4-6 | Lapping |
| Camshaft Journal Bearing | 4-6 | Lapping |
| Camshaft | 15-20 | Lapping |
| Rocker Arm | 14-20 | Lapping |
| Intake valve stem | 34-38 | Lapping |
| Intake valve seat | 25-40 | Lapping |
| Exhaust valve stem | 18-20 | Lapping |
| Exhaust valve seat | 34-45 | Lapping |
| Tappet Face | 4-5 | Lapping |
| Hydraulic lifter | 22-25 | Lapping |
In the automotive industry, stringent standards are imposed on high-performance cars. The following table outlines the requirements for automatic transmission, clutch, and braking systems. If any of the moving parts fail before the expected lifespan, surface inspection is often to blame. The appropriate standards vary depending on the engine's specifications. For instance, a recent case indicated that diesel engine piston pins with surface roughnesses of 6 and 5 micro inches failed rapidly, whereas a smoother finish of 4 micro inches proved effective. Conversely, petrol engines require a surface roughness of 9 micro inches.
| Automobile Driven Components | Acceptable Roughness (Micro inches) | Manufacturing Process |
|---|---|---|
| Front Pump Journal Shaft | 18-22 | Lapping |
| Front Pump Shaft Thrust surface | 11-14 | Lapping |
| Reverse Gear Drum – Braking surface | 150-170 | Turning |
| Intermediate Shaft Journal no1 | 6-7 | Lapping |
| Intermediate Shaft Journal no2 | 50-60 | Lapping |
| Central main shaft journal | 23-27 | Lapping |
| Central Main Shaft Thrust Surface | 20-30 | Lapping |
| Output Shaft Journal no1 | 14-16 | Lapping |
| Output Shaft Journal no2 | 10-15 | Lapping |
| Output Shaft Journal no3 | 27-32 | Lapping |
| Front Drum – Braking Surface | 90-110 | Turning |
| Clutch Plate | 16-24 | Turning |
| Main shaft Journal No1 | 20-25 | Lapping |
| Main Shaft Journal No2 | 25-30 | Lapping |
| Low Range Reaction Member – Thrust surface 1 | 35-40 | Lapping |
| Low Range Reaction Member – Thrust surface 2 | 65-75 | Lapping |
| Front Drum – Braking surface | 90-110 | Turning |
| Brake Drum – Front | 65-75 | Turning |
| Rear | 75-85 | Turning |
| Clutch Pressure plate | 40-50 | Turning/Lapping |
| Kingpin | 6-8 | Grind |
| Universal Spider Race | 14-16 | Grind |
Ensuring Quality and Reliability of Automotive Parts through Non-Destructive Testing
To ensure quality components in the automotive industry, Non-Destructive Testing techniques (NDTs) are performed before assembly to detect defects without damaging the workpiece. PT, ECT, MPI, UT, and Laser Holographic Inspection are commonly used NDTs. Penetration Testing (PT) uses ultrasonic cleaning and a colored penetrating liquid to identify surface defects in non-porous workpieces like rims, suspension, and steering components.
Maintaining High Cleanliness Standards in the Automotive Industry
With the precise calculations involved in manufacturing an automobile, the presence of any foreign particle will impede the system from functioning smoothly and will have an adverse effect on the assembly. Foreign particles and residues as a result of different machining processes can weaken their structural strength and eventually the life of the component. Therefore, after performing different machining operations, it becomes extremely important to clean the component to ensure that there is no unwanted contamination in the assembled part. This is especially important in components such as crankshafts, camshafts, cylinder walls, pistons, injectors, valves, and hydraulic systems, which require very high finish and cleaning standards.
To ensure the cleanliness of different parts in the engine, transmission, suspension, steering system, and many other components, two standards were introduced in the 2000s: ISO 16232 and VDA 19. These standards were intended to assist the automotive industry in ensuring the cleanliness of components. ISO 16232 specifies methods for the assessment of the cleanliness of components and systems used in the automotive industry. It covers sampling techniques, extraction methods, and particle counting methods. The standard specifies cleanliness classes based on the number and size of particles present in the component. VDA 19 is a German standard that specifies cleanliness requirements for automotive components. It defines cleanliness classes based on the size and number of particles present in the component. The standard also specifies testing methods, cleaning processes, and inspection procedures.
Components are cleaned using an ultrasonic cleaning method with the assistance of a cleaning fluid. Ultrasonic cleaning is a process that uses high-frequency sound waves to remove dirt, grease, and other contaminants from the surface of components. It is a highly effective cleaning method that is widely used in the automotive industry.
