\A Renishaw RMP600 touch probe on a 5-axis machining center measures axle housings at Tridan Engineering.

UK-based Tridan Engineering traditionally takes 8 to 10 weeks to go through design, testing, and proveout of custom parts. However, when racing car parts supplier Ricardo Performance Products was having trouble with the rear axle on a racing car, it needed new parts in 17 days.

Two complex castings make up the rear axle assembly – a cover and a main case. For the main case, the first two operations are performed on a Mazak horizontal machining center (HMC). The part is then transferred to a 5-axis machining center for a single operation before returning to the HMC for finishing. The cover is machined complete on a 5-axis machining center in three operations. Parts are then separated in pairs, before tooling holes are machined as the final operation on a HMC.

“With every batch of castings machined for Ricardo, we have to supply a first article inspection report (FAIR) detailing all critical dimensions on the part,” says Paul Coupland, machine shop manager at Tridan. “For this we use our coordinate measuring machine (CMM) with Renishaw PH10MQ probe head to deliver complete peace of mind for both ourselves and the customer. We use various attachments with the PH10MQ, including the Renishaw TP20 kinematic touch trigger probe.”

Machining challenge

“Ricardo Performance Products was having problems in the testing of a rear axle for a rally car that we had manufactured on previous occasions,” Coupland explains. “The issue was one of design/strength, so they needed a new beefed-up axle to test. A project like this would normally take 8 to 10 weeks as we would arrange meetings with the customer, offer design-for manufacture recommendations to help remove cost, prepare tooling, and so on. However, we were given just 17 days in order to meet a date slot that had already been booked at the test house.”

The quick turnaround time forced Tridan’s team to focus on speed without sacrificing quality. Coupland says Renishaw’s technology made that possible.

“On our 5-axis machines, we use Renishaw RMP600 high-precision probes, which enable us to balance the cover castings accurately on the first operation,” Coupland says. “That way, we can guarantee to Ricardo that the holes and features are where they need them to be. Similarly, on the horizontals we use Renishaw OMP60 probes, which are again used for balancing the main-case castings on the first operation to ensure we supply good parts to the customer. This proved vital for the first batch as Ricardo had precious little time between assembly and delivery to the test facility. There was no margin for problems or delays at the assembly stage – the parts had to fit, first time.”

When machining a casting, it is imperative to create a datum or some other point from which to work. By setting the position and alignment of the casting using Renishaw machine tool probe technology, Tridan engineers ensure the machining process automatically adapts to any variation in stock condition. The work coordinate system is automatically aligned to each part. Optimal part setup guarantees that no shortage of material (undercut) will occur during machining.

“The meat of the casting has to be in the right place,” Coupland says.

The process requires a measurement data set of the blank casting to be aligned to the position and orientation of datum and machined features, which is where the Renishaw probes come into play. Probing can maximize the efficiency, quality, capability, and accuracy of machine tools. Standard routines built into modern CNC controls simplify the integration of probing cycles into machining operations.

After separate machining of the cover and main case components, the two parts are bolted together and machined as an assembly on Tridan’s HMCs. The Renishaw probe on the CMM allows Tridan to access the internal recesses and awkward features on the castings. This CMM is also used to perform first-off inspection for machined castings, although some features are checked with Tridan’s manual CMM, using a Renishaw MH20i probe head with various attachments.

“Accuracy is the main reason we use Renishaw technology,” Coupland states. “I don’t think we could do half of what we do without their probes. Furthermore, as a company Renishaw is very supportive, although to be honest, we’ve never had to call on their service department – the products simply don’t go wrong.”

Tridan Engineering machine shop manager Paul Coupland shows a finished Ricardo rear axle housing.

Meeting deadlines

The ability to align the castings accurately and efficiently meant that Tridan could give its customer a quality product in the short timeframe specified.

“Without doubt, speed and efficiency is the major benefit,” Coupland notes. “Considering the complexity of the parts, we would probably have been looking at 2 to 3 days if we had to measure them manually due to the amount of features to be checked. Furthermore, the tolerances involved would make manual measurement almost impossible.”

Tridan employees collaborated with Ricardo’s team and worked overtime to machine and test axle parts, delivering the updated rear axle to the customer at 10 a.m. the day before the scheduled test.

Mazak Corp.
www.mazakusa.com

Renishaw Plc
www.renishaw.com

Ricardo Performance Products
http://motorsport.ricardo.com

Tridan Engineering
www.tridan.co.uk