02 Jan 2013
January 2, 2013

How to make brakes

0 Comment

Brakes consist of numerous elements and usually include a brake caliper which applies pressure onto the brake pad which in turn clamps on to each side of a brake rotor made usually of cast iron or stainless steel and causes deceleration.

Automotive brakes which employ the cast iron brake rotor technology in 99% of cases usually use brake pads made of semi metallic or organic materials impregnated for durability and performance demands with metals and fibres. These brake pads are produced by blending the fibres, with the other ingredients and binding them with a petroleum based resin into a preform cake or puck that resembles the actual shape of the pad required. These friction material cakes or pucks are then placed onto a pressed steel backing plate and under heat and pressure in a press the plate and friction material are fused together.

Many brake pad manufacturers apply glue to the steel backing plate to enhance the bonding of the two parts but in recent years mechanical inter locks have been devised which remove the need for glue. After the initial molding process which produces a green or semi cured product many brake pads require baking for 3-5 hours in an oven to finally cure the brake pads and remove volatile elements which would cause the brakes to fade under aggressive use. The brake pads are then painted or powder coated to prevent corrosion and surface ground sometimes adding edge chamfers or expansion slots to enchance various performance aspects of the brakes.

Many motorcycle brakes also use semi metallic or organic brakes but recent advances in technology have brought sintered metal brake pads into the world of brakes. The advantage of the sintered metal pads are that a more compact brake pad in size can be made which also has considerable durability advantages over its earlier stablemates. This allows the brake caliper to be smaller and reduces the all important unsprung weight of a motorcycle. Sintered brakes are usually made from a copper alloy blend although sintered iron was tried with little success for cost reasons in the 90’s.

Sintered brakes are made still employing a steel backing plate which is always copper coated and it is this copper coating to the steel backing plates which forms the adhesive layer. Much in the same way as with organic and semi metallic brakes, the puck or friction material compact is pre formed and positioned of the copper coated steel backing plate and the two married together are placed in one of two different kinds of furnaces where under applied pressure the copper between the puck and the copper coated plate fuse together and effectively brake the two components together. Bonds strengths obtained in the production of sintered brakes are many times higher than with simple glue bonded brake pads and as such are a safety enhancement.

Unlike organic or semi metallic brakes sintered disc pads do not require any curing after the furnace braking. It is normal however to coin or grind the surface of the friction material to produce a perfectly flat surface to the components and speed up the bedding in time. Some manufaturers coat the surface of their brake pads with special materials to help bed-in.