Special fasteners are crucial components in the automotive industry and are used right across the production process, from engines and brakes, drive technology and chassis, locking mechanisms and roof systems to hinge mechanisms and control systems. Such fasteners require intricate geometries and close tolerances that must be consistently maintained.
Historically, many such parts have been turned, a process involving a metal blank being cut to produce the finished part. This process produces a significant amount of waste material, a factor that adds dramatically to the final cost of the finished part. Keeping down part costs is crucial in the automotive industry and this is where the precision process of cold forming proves itself as an attractive alternative.
With cold forming, wire is cut to pre-determined lengths and then formed at ambient temperature into the finished part, using high-pressure punches and dies. The major benefit of cold forming over turning is the fact that no waste material is produced, as all of the starting material is converted into a finished part. This elimination of waste material alone can provide savings of up to 70%, it is calculated.
HIGH-SPEED PARTS
Cold forming is a high-speed manufacturing process that can produce up to 400 parts per minute, again reducing costs against slower turning and casting processes, and making product delivery faster.
The process also produces parts that are stronger than cast or machined alternatives. As the metal is compressed, the grains deform, following the shape of the part. This means the grains are unbroken throughout the finished part, increasing its tensile strength and fatigue performance.
“As well as material savings, the compressing of the material during the cold-forming process ensures a high quality of surface finish and close dimensional tolerances, with repeatability consistently maintained during the production process,” according to HEICO Fasteners, part of the international HEICO Group. “More intricate contours and shapes can be delivered and dimensional accuracy maintained, without the need for secondary operations.”
At this years’ Automechanika show (June, NEC Birmingham), HEICO Fasteners extolled the virtues of this specialist metal-forming process to visitors from the automotive supply chain. The HEICO Group itself is an ISO/TS16949 accredited cold-forming specialist, with a long heritage in automotive fasteners, having formed long-standing partnerships with a number of automotive companies, including Audi, BMW, Seat, Skoda, Jaguar Land Rover and Volkswagen.
75M PARTS A MONTH
The group’s modern press plant, which is located in Ense, Germany, has the capacity to make 75 million parts per month, producing complex geometries up to 100mm long, with diameters from 3mm to 16mm and head diameters up to 30mm.
Paul Windsor, national sales manager at Heico, makes the following point for cold forming: “The cold-forming process offers cost savings to customers of up to 60% against machined fasteners, and the high-volume capacity at our press plant, combined with our UK based warehouse, sales and technical support, means we can offer unrivalled service to the UK automotive industry.”
THE COLD FACTS.....
Cold forming, or cold heading, is the process of shaping metal in a closed die using pressure; a process that does not involve heat or metal cutting. It is said to offer the following benefits:
- Raw material savings – there is no material cut away, as there is with machining, so there is little or no waste.
- Superior component strength – reforms the material grain to flow with the shape, resulting in significant increases of strength and hardness
- High production rates – parts are produced at a rate of one per second, or faster, considerably quicker than most machining, casting and forging.
- Superior surface finish – results in a smooth surface finish requiring no further finishing
- Close tolerances – allows parts to be made more consistently reducing non-conforming products and minimizing secondary processes
- Part consolidation – allows individual parts to be formed as one component for greater cost efficiency and improved part strength
- Lower piece prices – longer tool life and low energy use, with material savings and high production rates, results in lower component prices.
Heico Fasteners UK
http://www.heico-fasteners.co.uk