The automotive industry is fiercely competitive. Tier-one car manufacturers are constantly looking for breakthroughs in areas such as performance, safety and design, all of which place ever stricter requirements on the processing of metal components. SuperAlloy Industrial (SAI) is a supplier of lightweight forged metal products. The forged wheel and car chassis components SAI produce are used by several car manufacturers. Renishaw machine tool probe systems, including the OLP40, RMP60, OMP60 and the NC4, are used for SAI.
SAI came to Renishaw because it needed to enhance product quality and reduce the amount of rework and corrections during processing to achieve high-quality levels.
The production of aluminium forged wheel rims
The forged wheel production process is complex, particularly for low-volume, high-diversity production. Strict standards are applied to workpiece setting, reference measurements and key dimension detection during metal processing, as the precision requirements for machining wheel mounting surfaces exceed the requirements of even the aerospace industry. SAI currently has 600 CNC machine tools working on wheel rim production, including 150 Victor Taichung lathes and 450 YCM milling machines. So how does SAI ensure that the precision and stability of 600 machine tools remains consistent?
To increase production precision and reduce scrap, SAI equipped the relevant lathes with Renishaw OLP40 touch probes, which use optical signal transmission and are adapted for turning processes. The CNC milling machines were equipped with RMP60 machine tool probes, which use wireless radio transmission to measure workpiece position and reference height, as well as providing in-line key dimension detection, thereby increasing production performance.
Y. C. Kao, senior manager of SAI’s Wheel Production Dept., said: “The automated workpiece setup, enabled by Renishaw machine tool probes, allows us to ensure that the cutting dimensions remain stable and consistent when we are producing wheel rims, as well as effectively reducing human error. For example, the air valve hole cutting thickness Process Capability Index (CPK) rose from 0.71-1.13 to 1.35-1.43 when using Renishaw machine tool probes.”
3D appearance modelling for forged wheel
Wheel styling design has moved from flatter surfaces toward more 3D effects in recent years, causing wheel rims to become even larger, and placing increasingly stringent demands on processing precision. Until 2011, SAI’s acceptable tolerances for wheel rim production (with the flatter designs used at the time) were 0.05 to 0.10 mm. However, the tighter tolerance requirements of the current 3D designs has gradually increased cutting times and processing; wheel rim appearance processing takes as long as 180 to 240 minutes, with the result that any rework imposes considerable pressures in terms of both production time and cost.
OLP40 probes carry out in-process measurement control to achieve tolerance of less than 0.02 mm, and can replace human measurements and updates to workpiece coordinates. This greatly improves cutting and efficiency for surface precision processing after coating. Even more importantly, it reduces rework by 80%, as before the introduction of in-line measurement systems wheel production generally had to be processed twice to achieve the necessary precision.
Precision processing for car chassis
The safety and stability of lighter vehicles moving at high speed is closely connected to the manufacturing of the car chassis. The higher the precision of chassis produced with aluminium alloys, the safer and more stable the car is when travelling at speeds as high as 200 km/h.
SAI now has 38 Tongtai high-end, five-axis CNC machine tools, all of which are equipped with OMP60 optical machine tool probes and NC4 non-contact laser tool setters.
Unlike wheel rim production, chassis production tends to involve high volume and lower diversity, but nevertheless still requires high-precision metal cutting and processing. OMP60 optical machine tool touch probes use modulated optical transmission to provide 360° signal transmission. The probe simplifies measurement and calibration processes, thereby achieving high-precision measurement for workpieces with complex profiles. The NC4 uses laser technology to perform high-speed, high-precision measurement of cutting tools as small as 0.2 mm, and to perform tool breakage detection on cutting tools as small as 0.1 mm. Its non-contact method avoids the potential for causing wear or damage of cutting tools.
Production times for car chassis are relatively short, and can generally be kept within 20 to 25 minutes. The machine tool probe systems provide the operator with turnkey solutions for real-time positioning and measurement and in-process control measurement.
The company now has 10 CMMs fitted with Renishaw probes. For machine tool performance checks, SAI has also fitted its machining centers with QC20-W telescopic ballbar measuring instruments for the most comprehensive diagnostic testing and verification functions.
Filed Under: TECHNOLOGIES + PRODUCTS, Automotive, ALL INDUSTRIES, Machine tool industry + subtractive manufacturing