Driving forward

Investment in multi-spindle technology has allowed DJJ Precision Engineering of Pontypool to resume production of an automotive job lost to India. Machined from high tensile steel bar (606M36), the component is a vehicle braking system shaft for a tier one UK automotive supplier and the machine in question a German-built Index MS32C six-spindle multi (Geo Kingsbury Machine Tools). Image: A multi-spindle wins work back from India Operations mainly involve turning outside diameters, thread-cutting and a small amount of prismatic machining to produce a hexagon on one end. Cycle time on the Index MS32C is 14 seconds, which allows the company to manufacture the part for 29 pence, plus the cost of the material and finishing. The previous cycle time on a single-spindle, sliding-head lathe at Pontypool was over four times longer. Coventry-based Expert Tooling & Automation has invested in WorkNC CADCAM software from Sescoi to help ensure trouble-free machining of its 3D tooling for the automotive sector. The company has been successful in developing interior trim panels for low volume luxury vehicle manufacturers. Complex 3D tooling is required for accurate location of veneer laminates prior to bonding to a substrate, and to hold the component during the trimming of apertures and excess material. All the tools it produces include 3D shapes that need to match exactly the surface forms of the panels its customers have designed. WorkNC accepts native CAD data and translates car line designs to the desired machine datum, ready for machining. Just one seat of WorkNC keeps Expert Tooling & Automation's six Hurco machines running 24 hours per day. "Our previous CAM system was too cumbersome. WorkNC was recommended to us and, in fact, Rolls-Royce asked us to use it, so we could share native CAM files," says Simon Doleman, manufacturing manager. "Furthermore, we have noticed that WorkNC produces smooth cutting trajectories, with very little wasted movement, and its graphical toolpath editing is fast and ensures that we are always climb-milling, to produce a superior surface finish." The inherent complexity of many automotive parts, particularly engine components, ensures that measurement is as challenging as machining in many cases. For example, despite their significant influence on engine efficiency and exhaust emissions, the measurement of valve seats and guides has traditionally been so challenging and time consuming that methods used are often a compromise and do not allow for responsive process feedback. VAST AMOUNTS OF DATA But now, a new solution based on the Revo 5-axis measurement system from Renishaw is changing this situation, enabling very fast collection of large amounts of data, from which the analysis parameters for both the valve seat and the valve guide features can be calculated. The method performs exceptionally well in both repeatability and reproducibility tests, and takes as little as 20 seconds per valve, says Renishaw. The new measurement process involves two helical scans, one on the valve guide bore and the second over the valve seat area. On the guide, a single helical scan is used with a typical pitch of 0.5 mm, at a scanning speed of 150 mm/s, while for the seat a single helical scan is carried out at a finer pitch of 0.1 mm and a faster scanning speed of 500 mm/s. The latter scan utilises Revo's adaptive scanning capability, which allows a single scan command to cover the areas above and below the critical valve seat surfaces. The two measurement routines capture all necessary data about the valve seat and valve guide surfaces, which is then analysed within a utility embedded in Renishaw's new Modus metrology software. A report is generated automatically that includes analysis of valve seat form error, run-out of the seat to the guide bore axis, circularity of the seat at any specified height, form error of the cones, and circularity profile of the guide cylinder at any specified height. Image: Renishaw's valve seat innovation Having identified a need to improve the in-process measurements of critical bores located on the company's boosted master brake cylinders, automotive supplier Carlisle Brake Products of Pontypool has invested heavily in quality control equipment from Bowers Metrology. Quality manager David William investigated the available alternative bore gauges. "As we wanted to purchase a robust range of internal gauges with a common operating system that could be used on all of our many bore sizes across the site, by both production operatives and quality control personnel, we needed to find a flexible, easy-to-use range of internal micrometers," he says. "I found the answer to our internal gauging needs in Bowers' XT Analogue range." XT Analogue bore gauges are the fourth generation of analogue internal micrometers. With the ability to measure bores from 2 to 300 mm, length extensions also enable the gauges to perform precise deep-hole measurement. The gauges boast hard wearing, tungsten carbide measuring faces on all 3-point measuring heads larger than 12.5 mm. Box Item 1 Cutting edge style Performing both milling and turning operations on several special automotive projects is Germany-based Technop, where a number of recently installed Haas machine tools are being used to make parts for vehicles such as the Street Ray (designed by Luigi Colani – "the unabashed agent provocateur of the design world"), which, with its streamlined fenders and fighter jet nose, is reminiscent of the futuristic concept cars shown at the auto salons of the 1950s and 60s. The company is using its Haas VF-6 CNC machining centre to make many of the model prototypes and moulds required to produce the bodywork, along with several of the Street Ray's other prismatic parts. In fact, the same machine is used to machine a number of the parts for another special automotive project, the T-Rod, which fuses the front end of a race car with the rear end of a high performance motorcycle. Parts machined include complex aluminium alloy wheel parts and hardened-steel mudguard moulds. In total, the company sells around 25 specialist vehicles a year. Image: Haas machines help produce stunning vehicles Box Item 2 Casting off inefficiency Diamond electroplated grinding wheels from superabrasives specialist Engis are providing automotive foundries with a competitive edge. Engis electroplated grinding wheels are used in the cleaning of a wide variety of cast components for the automotive sector, including power steering pumps, brake rotors and engine parts. Because of their construction, Engis says that its diamond electroplated grinding wheels can be operated safely at significantly higher speeds than conventional wheels, enhancing the efficiency of the grinding process by reducing the 'chip load' on each abrasive grain, thus reducing wear and extending wheel life. Furthermore, they do not need to be dressed or reconditioned during use, increasing up-time and throughput. One company benefiting from these advantages is US-based Grede Foundries Inc, where Gary Dalgaard, director of manufacturing engineering, says: "Engis has been a valued partner with Grede in the development of diamond wheels for robotic grinding, and we continue to work with them to expand the use of these products to many other applications throughout the foundry." First published in Machinery, November 2009