The brakes are the most important safety feature of any vehicle, and the calipers are one of the most important components of the braking system. They apply the force necessary to slow and stop the vehicle. Producing quality calipers that stand the test of time, wear & tear and is essential to safe operation. If the calipers aren’t working, the car will just keep on going—even when one doesn’t want it to.
Disc brakes came on the commercial vehicle market in the 1950s. They represented an improvement over older drum brakes, which were prone to overheating and deteriorating performance over a short amount of time. Nearly all cars and trucks known have front-end disc brakes; some less expensive models still use drum brakes on the rear axle.
The standard brake caliper contains metal plates on both the outside and inside face of the rotor. The plates are faced with brake pads, which are the point of contact between the calipers and the rotors. When you depress the brake pedal, brake fluid flows through a master cylinder, which is linked to a piston housed within the calipers. The piston presses against the pads and forces them against the rotors. The action of friction slows down the rotor and the wheel.
Floating and Fixed
Floating calipers have their hydraulic pistons on the inboard side of the rotor; they move in and out as the brake pedal is depressed. Fixed calipers have their pistons set up on both sides of the rotor and apply pressure directly from both sides, allowing them smoother operation and more braking power; the floaters, however, are less tolerant of any defects or warping of the rotors.
Brake calipers can be one or two pieces and contain pistons or cylinders made of aluminum or steel. Two-piece designs are less expensive to manufacture, but have some disadvantages, which includes flex, less present in one-piece designs. Brake calipers hold the brake pads and have channels that accept the hydraulic brake fluid that activates the piston to push the brake pad against the rotor.
Most brake calipers consist of aluminum, as aluminum is very strong, but a light material that can handle the constant wear that exists in the braking system. Minimizing weight is crucial to the design of any vehicle and using forged or cast aluminum brake calipers helps accomplish this goal. Sometimes magnesium alloy is used, but it is expensive and often reserved for race cars. The brake rotors are made of a harder metal, as the friction against the rotor face during braking can bend or warp lighter metals.
The InterTech Solution for Testing Brake Calipers
Here’s one example of a turnkey system designed and built by InterTech Development Company in the USA. Do bear in mind that this technology is now available in India to best ensure that your products are tested with a robust and reliable system while ensuring that your parts meet the standard and quality requirements of your Customers.
Components are leak tested to a 3 sccm. limit at 5 psig.
Piston retraction is gaged within a 0.010˝ window after venting down from 200 psig.
An InterTech M-1075 Mass Flow Leak Detector controls the leak test cycle.
Reliability: System operates in a fail-safe mode with self-check features.
SPC Capabilities: Test results may be transmitted via RS232 interface or stored on disk.
Measurement Capabilities: Test R&R meets QS9000 requirements.
The Brake Caliper Functional Test Cell automatically tests and marks r.h. and l.h. calipers at a rate of 211 pph.
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Source: eHow.co.uk & eHow.com