Disc Brakes are an essential part of any vehicle, be it IC Engine or EV’s , as they are responsible for stopping the vehicle and must provide an efficient braking mechanism. This braking assembly mainly consists of Brake discs, generally made up of Grey Cast Iron and brake pads.
Grey Cast Iron has a disadvantage that it wears out over a period of operation which not only reduces its working life, but also poses another serious issue. The Disc Brake, subject to friction with brake pads generates heat and also, it wears out releasing fine dust particles as fine as PM10 that is, 10 micrometres diameter or even less. These fine particles generated due to disc brakes are one of the significant contributors to air pollution along with CO2 emissions and they can have adverse effects on respiratory systems and cause dangerous diseases. To cope up with this, Euro 7 norms have been made more stringent which gives rise to demand for a new solution for mitigating the fine dust emissions.
So, what could be the solution to this ?? Let’s explore.
Analysing the root cause of the problem and stepping towards the solution-
Root cause of the problem is that Grey Cast Iron, used in disc brakes due to its cost effectiveness and damping properties, has a huge disadvantage, that is, it wears out over a period of time. One of possible solutions might be giving it a coating of a material with higher abrasion, wear and corrosion resistance. However, methods like electroplating and thermal spraying cannot be applied to this situation because in these processes, the bond between the coating and base material is not metallurgical, but a mechanical bond, which will chip off due to friction. So, the best solution is giving the Disc Brake a coating of a suitable material which will form a metallurgical bond with the base material. This reduces wear, and thus reducing the fine dust pollution and enhancing life of the disc as well.
Extreme High Speed Laser Cladding as a solution to Fine Dust Emission in Disc Brakes:
The coating given by Laser Cladding forms a metallurgical bond with the base material which is more durable than mechanical bonds. However, not even conventional laser Cladding is enough for this process because along with the powder, some amount of heat is also transferred to the Grey Cast iron, which may cause a reaction and some of the Carbon content from the Base Material may accumulate into the coating and make it brittle.
This may cause problems like cracking. That’s why an advanced method called “ Extreme High Speed Cladding” is being used for this application. In this method, the powder is melted by the laser beam on the fly, that is, before it falls on the part.
Liquid drops fall on the designated areas of the part and solidify to form a metallurgical bond. In this process, very less heat is transferred to base Grey cast iron. This increases the durability of the coating.
How the process works?
The Brake Disc of Grey Cast Iron is given a coating of highly wear and abrasion resistant materials, generally carbides. But, these materials are very brittle, so there might be crack formation.
Moisture may seep through these cracks and corrode the Grey Cast Iron. That is why, a buffer layer of corrosion resistant Stainless Steel is first applied to the Grey Cast Iron Brake Disc, and then the Carbide Layer is applied over it. This makes our disc brake wear resistant. It not only reduces the Fine Dust Emission to a significant extent, but also enhances the durability of the Brake Disc.
Conclusion
With more advancements in technology and urbanisation, the need to take precautionary measures to preserve the environment will give rise to more stringent norms. This makes advanced processes more important. Extreme High Speed Laser Cladding will be in higher demands in future due to the Euro 7 norms, and environmental norms, which are going to get more stringent in future.
With growing EV trends, this is going to be in demand as EV’s also use Disc Brake mechanisms.
We, at Laser Automation, provide custom Laser Cladding Machines according to customer requirements. With our 14 years of experience in Laser Cladding and our Application lab where we carry out application trials on customer components, either Robotic Laser Cladding machine or CNC Based Laser Cladding, customised according to Customer requirement can be provided.
