In automotive manufacturing, the connecting rod remains a key component in ensuring engines maximise fuel efficiency and service life. Con rods require the correct alignment with perfect surface finish to optimise performance, and as with most components in the automotive industry, precise tolerances are essential.
The case was no different for this industry leading automotive manufacturer, with production of connecting rod components upwards of 2,000,000 per year. Such a mass-production component meant significant pressure was placed on the manufacturer to optimise productivity and meet critical lead times from customers.
Whilst the need to increase output was paramount, the manufacturer was also experiencing a number of issues with varying component quality, due to tool wear during the manufacturing process.
To provide a solution for these manufacturing issues, Rigibore’s Zenith solution was enlisted to finish machine crankshaft and pin bores, automatically compensating the cutting edge for tool wear.
Zenith provided micron accurate compensation of finish boring bars to hold size on two connecting rod bores.
- ∅ 150 ± 0.008mm steel crankshaft bore
- ∅ 83 ± 0.015mm steel pin bore
Rigibore’s Zenith Solution
The Zenith system integrates ActiveEdge tools with in-process gauging to enable a machine controller to automatically compensate for insert wear, temperature changes and material inconsistency without manual intervention and without stopping the manufacturing process.
Using years of experience and knowledge in automated boring, Rigibore worked closely with the manufacturer to implement a closed loop manufacturing process.
An ABB Robot IRB 6640 unloaded the con rods from the Stama 536 machine and placed parts into a intra gauge where critical bore sizes were measured.
The gauge software automatically calculated any required finish tool compensation and stored the value.
The value was then relayed to the machine’s Fanuc control through the PLC. The CNC program recognises a compensation requirement to adjust the cutting edge, it adjusts in the machine carousel while the tool remains idle, meaning no spindle downtime.
Advantage Through Automation — Zenith Benefits
With productivity targets outlined as the primary concern, the manufacturer was looking to shave valuable seconds per component off through a more efficient and streamlined manufacturing process.
The Zenith’s automated cutting-edge compensation in the machine carousel allowed maximised spindle utilisation, significantly reducing cycle time and increasing part throughput by 40%.
- Process Control
Automated compensation of the tool's cutting edge allowed the manufacturer to improve process control, specifically Cpk.
Customisable Rigibore macros allow organisations to set an upper and lower warning limit on bore sizes, if these bore sizes stray outside of the tolerance, a compensation request is sent to the tool via wireless technology, automatically adjusting to the required tolerance.
This capability led to a standard deviation of just 0.001mm from nominal tolerance, and a Cpk statistic of 3.04.
- Part Accuracy
Another key performance objective was to uniform the quality of components. Implementation of an automated solution removed the need for operator intervention, and subsequently risk of human error.
Since being implemented, Zenith has achieved over 90% of the first setup parts correctly, certifying part quality whilst ensuring critical lead times are met.
More about Zenith and ActiveEdge technology below, including more case studies.