IMPLANTS REPAIR IRREGULAR HEARTBEATS

R&R Tool is 15,000ft2 with 25 employees that offers CNC turning, CNC milling, some punch press work, wire EDM and a full tool room, which adds to the company's self-sufficiency. Roughly 90% of their work is in stainless and the other 10% is steel castings and cold rolled tool steel. Their primary customer is the medical industry, but they do some work for the foundry industry – valving work, machining parts for valves ranging from 1" to 4" in diameter.

"At one point, recently, we found ourselves without the capacity to keep up – especially as the family of one part in particular continued to grow – so we started looking," says R&R Owner Dan Reed. "Technology-wise, GBI Cincinnati had the right machines for our needs." R&R's oldest Feeler is about a year, and in all they have four Feelers – two VM-40SAs and two QM-22Aapcs with twin pallets and automatic pallet changers. Other nameplates in the shop include Fadal, Cincinnati and more, but the Feelers are the ones doing much of the really complex medical work.

Reed explains that of the many parts he runs through the Feelers, there is one part both models of Feelers work together to produce. "There are seven different sizes and configurations of this part, and then there are right- and left-side versions, so together there are 14 different variations of this part in a family. It is made of stainless, and it is used in the ablation of heart tissue for arrhythmia problems. It goes into the body cavity to help repair irregular heartbeats."

Reed explains that this part starts out on the VM-40SA as a stainless steel block, 0.750" x 3.250", and when finished on the QM-22AAPC, it's about 0.1875" x 2.500" (or 3" on some). It's 100% profiled and looks like a banana: it goes from thick to thin and is a continuous curve. On the VM-40SA, machining the part involves true 3D milling. The feedrate is 75ipm, and in first operation they use a 0.625" roughing tool and mill to a depth of 1". In some cases, they have milled one-third of the way into the starting block. At the other extreme is milling the profile: 0.004" to 0.006" per step at a rate of 55ipm. So the first major operation, creating the perfect profile, is the VM-40SA's job.

Next, Reed says they take the part to the QM-22AAPC and fixture it on the first pallet, radius side up and turn it upside-down. They machine the bottom flat with grooves and holes and slots. Then the part is moved to the second pallet where a third operation machines angles and slots at 90° to the first axis. This completes the part from beginning to end.

"The tolerances are 0.002" overall, and in the 10ths on hole positioning," Reed says. "Two thousandths does not sound like much, but on this part, with all that we do relative to its size, 0.002" is very tight. The surface finish is around 32Ra. We grit and bead blast the part for stress relief and to achieve consistent finishes. We have to work very closely with the machines on a part of this complexity to ensure we get good parts, one after another. It may look like it is not particularly complex, but it is too complex to finish grind. Our customers check these parts under microscopes, that is how consistently accurate we have to be."

A GLANCE AT R&R'S FEELERS

The two Feeler VM-40SAs have axis travels of 40" x 20.5" x 19.9", and rapids of 1.417ipm (X/Y) and 1.260ipm (Z). Positioning accuracy is ±0.0003" while repeatability is ±0.00012". Way systems are linear (X/Y) and boxed (Z).

The spindle is 40 taper, 10,000rpm, driven by a 25hp GE Fanuc direct drive motor. ATC is a swing arm-type with 24 tools and a 1.9 second tool-totool change time. Control is a Fanuc 0i-MC.

The dual-pallet Feeler QM-22AAPCs have axis travels of 22" x 16.5" x 17.7" (Z), and rapids of 1.890ipm (X/Y/Z).

Positioning accuracy is ± 0.0004" while repeatability is ±0.0004". Way systems are linear in all axes. The spindle is 30 taper, 12,000rpm, driven by a 5hp GE Fanuc direct drive motor. ATC is a swing arm-type with 20 tools and a 0.8 second tool-to-tool change time.

GETTING DOWN TO BASICS

Reed says there are a number of reasons they chose Feeler: dual pallets, chip conveyor systems, and that the VM- 40SA is a good profiling machine. "Then they had something else that is really hard to find," Reed says, "great service and training. GBI offered training, not at our site – they would have done that had we wanted – but at their facility." And while talking training, one of the things in the industry that frustrates Reed is that good machinists are hard to find. "General mechanics is actually problem-solving techniques, and the basics for manufacturing are in the engineering. And that is what is lost on kids these days. They do not have a grasp of the simple stuff, yet they immediately want to program the CNCs and run the machines," Reed explains. "What they do not understand is that this is only 25% of part making.

The other 75% – understanding tool deflection, the use of proper coolant, using the right machine for the job – this is the big part that sets us apart from most other companies. This is the 'knowing the engineering' part."

A PHILOSOPHY OF CLARITY

"What we st r ive for, a kind of motto at R&R, is 'Clearly Defined Requirements,'" Reed explains. "That word, 'clearly,' stops a lot of things from starting. When we focus on Clearly Defined Requirements, we tend to do pretty well. Assuming something, or thinking we know what a customer was saying – this is how we get into trouble.

If it is clearly defined, 99% of the time it is written down." And Reed says that this philosophy applies across the board, from defining employees' jobs and functions to the acquisition of machine tools. "We have a large number of machines from a variety of sources," he says. "Each was purchased for a specific, clearly defined purpose, and the four Feelers are doing precisely what we purchased them to do. Clearly Defined Requirements... when you keep your focus fixed there, you will usually get what you expect. And sometimes even more."

GBI Cincinnati
Cincinnati, OH
gbicincinnati.com

R&R Tool
Blanchester, OH
rrtool@excite.com