In this, the first instalment of our regular ‘Dr Friction’ column, Comline’s resident friction expert, Dr Keith Ellis, answers our questions relating to brake disc manufacturing and quality testing.
Dr Keith Elllis – Comline’s resident friction expert.
Q. With safety-critical components such as brake discs, quality materials are essential. How should materials be selected to ensure quality and performance?
A. The correct raw material is crucial to the resulting performance of a disc, and the specification must be carefully selected to meet the demands of the required application. At Comline, we combine our materials and engineering expertise with stringent prototype testing, both on-vehicle and with a brake dynamometer, to ensure we have the right material for each application. Selecting the appropriate material is only part of the puzzle; we must then ensure consistent material specification for each production batch, time after time.
Q. Can you give us a bit of an insight into the manufacturing process that goes into producing a brake disc?
A. Control of the manufacturing process is critical in achieving product consistency. Comline implements ISO9001 controlled quality systems to ensure each brake disc is manufactured to consistently high standards and the right specification.
The key components of the process are the casting of the disc from the molten metal, followed by a machining process. Traditional machining techniques could be used but our approved foundries now use state-of-the-art CNC machines which are quicker, while offering unparalleled levels of specification consistency.
Comline brake discs are now offered with a specialised, anti- corrosion coating which has seen a new stage added to the production process. Each disc is sprayed with its coating to micron levels of consistency to deliver rust protection and improved aesthetics.
Q. What does the quality testing process involve?
A. In addition to the checks made by the engineers at our approved foundries, Comline has its own engineer who checks all brake disc product before it leaves the factory. Both processes are designed to ensure discs are dimensionally accurate and that they meet all functional checks like runout, disc thickness variation and hardness. Other factors like coating thickness and packaging integrity are also checked and re-checked.
The last step in the process is a final inspection in our purpose built Comline Quality Lab, located at our UK headquarters.