Hands-off Production: Understanding Rotary Transfer

A new vertical rotary transfer machine was designed for complex components that need to be turned but have many intricate milling and deburring operations.

CIM: How does rotary transfer differ from traditional machining? 

Meehan: A 16-station rotary transfer machine can simultaneously put 20 or more tools in the cut (16 stations plus four or more stations with vertical units). It really is the mother of all multitasking machine tools.  Sixteen stations allow great flexibility in laying out your job and performing all of the operations in one setup. 

Rotary transfer machines can perform all or most of the operations in one chucking or one presentation to the machine, thus maintaining relational tolerances and consistent quality in the finished part. 

Sixteen stations also allow you to break up longer operations over multiple stations and even perform increasingly critical and demanding deburring operations with high-speed spindles. 

CIM: What are some of the operational benefits?

Meehan: One of the hallmarks of the rotary transfer machine is its ability to complete a part requiring many operations in one setup.  You can also use multiple stations to break up your longest operation, further reducing cycle time.

The small footprint, energy efficiency, and ease of maintenance are other obvious benefits of transfer technology.

If a machining system is proven and capable, scrap rates can be driven very low with things like gauging that feed back offsets to the machine tool or with seat sensors in the chucks that detect misloads.

CIM: How does this fit with the theory of turnkey production?

Meehan:  Once a machining process is debugged, proven out, and has achieved process capability, the efficiency and quality of the part will be much more consistent, especially over weeks and months. 

Robots don’t get sick, tired, or take breaks, much less get carpal tunnel syndrome.

CIM: Is automation possible?

Meehan: Rotary transfer machines have always been easily and effectively bar-fed because of their basic nature -- that is, high-production turning in which the material is stationary and the tools rotate. 

This also makes a rotary machine especially well-suited to machine profiled stock and extrusions, both of which are very challenging to spin at high RPMs in traditional CNC turning.

Today about half of all the systems we produce utilize automatic loaders and robots to perform the loading and unloading of the equipment.  Not only do the robots lend themselves well to loading blanks, but they are the only means to get the machine loaded and unloaded safely, and with no compromise to the low cycle times associated with rotary transfer machines. 

CIM: Are rotary transfer machines limited to large part volumes? 

Meehan: Not at all.  Many of our customers perform three to four quick changeovers a week.

CIM: How has this technology recently changed to keep up with machining trends?

Meehan: A good example of this is the development of a vertical rotary turning transfer machine. 

Hydromat calls its machine the AT platform. It was specifically designed for complex components that need to be turned but have many intricate milling and deburring operations, as often seen on medical components and devices.  To satisfy these needs, we developed a multistation turning machine that utilizes standard tooling, tool changers, gang tooling, and high-speed spindles that can complete these parts, including precision deburring, in one chucking.

Another example is our development of a CNC tool station that can be easily and retrofitted economically onto the many first- and second-generation Hydromat machines.  Customers with our older technology can now add one to six stations of CNC to their existing machine.  For example, they might add a station to perform three-axis milling/deburring, eliminating a costly manual secondary operation.

CIM: How does this technology make manufacturers more competitive?

Meehan: It is a common scenario in the U.S. and Canada to see two or three technicians running six or more rotary transfer machines.  Each one can have up to 20 independent axes of movement. That’s as many as 120 independent spindles performing operations simultaneously in a fairly small footprint. 

Compare that to, say, two rows of 25 lathes in Asia to machine the same parts at the same quantities, along with the 25 operators, and probably four times as much floor space.  It is this scenario and others like it that have many companies moving their work back to North America.

CIM: What is the future of lights-out production?

Meehan: Lights-out production or limited manned production is the only way North America can compete with China and other emerging markets in production-oriented manufacturing. 

Lights-out production is not a determining factor for competitiveness when a company produces a lot of short- to medium-lot runs in a lean environment.  The U.S. is quite competitive on this type of work. 

Lights-out production on CNC transfer machines and CNC multispindle lathes is the great equalizer in competing with China and India when you’re running higher-volume automotive and industrial components. 

That is why we are seeing work return to the U.S. and Canada. Costs are rising rapidly in Asia, and the advantages they enjoyed just three or four years ago are shrinking rapidly.

For more information, visit www.hydromat.com.