Brian Kateley 06.04.2014
I’m told my last blog post called “Hobb-It!” is one of the most-read Okuma blog posts of all time, well so far anyway (wow!). So I thought I’d continue my tradition and talk today about “Cam-It!” I’m a huge gearhead, and in my career I’ve gotten to spend time working as a machinist for race teams like Chip Ganassi Racing and Robby Gordon Motorsports. In my younger days I got to do some road racing on motorcycles, which was a blast, literally! This means when I see something here at Okuma that’s a great fit for automotive manufacturers, I really pay attention. Right now I’m fascinated with the cam options for our LU3000 EX CNC lathes, which are uniquely suited for cutting automotive pistons.
CNC Lathes for Piston Manufacturing
Okuma introduced our cam turning lathes at IMTS in 1990. They’re designed for the specific purpose of non-concentric cutting as well as concentric cutting, and can handle non-round parts such as ellipse, eccentric circular and cam. Today these CNC lathes go by the name LU3000 EX, and are available in either V1 or V8 cam options. They can perform high-speed cam turning and improve productivity through greater spindle speeds along with the advantage of heavy-duty cutting, which the majority of hard cam/cam follower machines cannot do. Turret specifications are chosen based on the types of workpieces you’re making and the production quantity you need to achieve:
- V1Cam: Turning at high-speed with light turret; specialized for mass production
- V8Cam: Capable of loading up to eight tools; specialized to produce a variety of products
Inspection Reading: 0
In these lathes the X-axis is driven by a double slide system, composed of slides specifically designed for cam turning at high speed with quick response. The double slide system allows the machinist to turn quite a bit of RPM while maintaining a high level of accuracy. Interesting story: one shop I heard of cut a part using one of our lathes, and when it was done they measured it with their inspection equipment. It read “0”, so immediately they scrambled around, trying to figure out why their equipment was “broken”! Turns out the reading of 0 was accurate. They were just surprised, because they’d never made that good of a part using their old machine.
The Devil’s in the Thermals
Managing thermal growth in piston manufacturing is really a science. That’s why our LU3000 EX CNC lathes come standard with our Thermo-Friendly Concept technology. Typically, machining accuracy varies significantly due to ambient temperatures around the machine, heat generated by the machine, and heat generated during machining. Thermo-Friendly Concept automatically compensates for temperature changes, so high accuracy can be achieved without interventions from the machine tool operator.
Another thing that helps manage thermal growth is the machine build itself. An Okuma has a sturdy cast iron base that does not have the coolant tank built into it. This tank is separate, so as you run the machine throughout the day and your coolant starts to warm up, the thermal environment inside the machine remains more stable.
Popular for Pistons and Rope Threading
So we try and cover all the unique needs that arise with high-speed cam turning of non-round parts. You can see why our cam lathes are popular with the major piston manufacturers. Plus, they’re used for rope threading in the oil industry as well.
As for myself, I just need to expand my personal Man Cave (garage, not TV room!) so I can bring one of these home with me. Speaking of which, my current “free-time” project is putting a V8 into a Chevy Astro van. I’m kinda crazy like that. Any gearheads out there have any advice for me? Please comment below and share your wisdom. And feel free to contact your Okuma distributor, or contact us directly, if you want to learn more about cam lathes.
Brian Kateley is Applications Engineer, Okuma America Corporation.