Shop Solutions: Machining a Superhard Variety of Energy Metals
Seeley Machine (Queensbury, NY) is a small business, family-owned by Barb, Charlie, and Craig Seeley. Begun in the Seeley garage, today the shop occupies a split-level facility where large-part machining takes place on the lower level and smaller parts and machines are on the upper level. Material often moves from one level to the other—roughing on one level, finishing on the other, by some 20 employees. Manufacturing space occupies 20,000 ft2 (1858 m2).
"We are pretty much the definition of a job shop," said Ed Leonard, shop supervisor. "We process a wide range of materials, including exotics, Inconel, Hastelloy, Waspaloy, 300–400 series stainless steel and some aluminum. Over the past 10 years, the energy segment, specifically power generation, has been our bread-and-butter focus. For example, we produce several sizes of labyrinthine bearing seals, which redirect coolant or lubrication around a shaft. Many of these seals are larger than we technically should be doing on our new Hyundai WIA F-M Series vertical machining center. Many of the seals coming off the F750B are up to 32" [812 mm] in diameter and 3–8" [76–203-mm] thick. These typically are machined from aluminum, exotics and different grades of stainless and involve significant stock removal, tight tolerances and fine surface finishes," Leonard said.
The typical seal starts as rough aluminum stock, which is placed on a subplate setup with locating pins. They run "OP1" and machine the part to a certain stage, hitting all the features on the part in one setup. If they have a batch of 40, they will run all 40 parts through OP1. Next, they set up OP2 where they flip the part and come back through and hit the remaining features. In OP1, they locate off rough surfaces and locating pins, and once OP1 is done they have machine-known surfaces for locating during OP2. They continue then with the same subplate, locating against pins and known surfaces until they get through all the features on the seal.
"The surface finishes on the bearing seals are very critical," said Leonard. "On some we get to a 32 Ra, but the majority of our surface finishes are around 63 Ra. Tolerances are typically ±0.001" [0.03 mm], but we can hold much tighter with the Hyundai F750B. The seal is probably 3' [0.9 m] in diameter, and while in this case the part is aluminum and not very heavy, we run parts on the same machine that weigh more than 2000 lb [907 kg]. Part programming is done off-line via solid modeling on SolidWorks. The program is loaded to a data card, which is then transferred to the Fanuc control, and it’s as simple as touching the part, locating it, and running. SolidWorks displays the subplate, so they know where the material is at all times," said Leonard.
"The Hyundai WIA machines are able to handle light and delicate materials as well as very heavy, tough and rough-cutting materials. A good example is our machining of Stellite, which is as tough and rough-cutting as you can get. Stellite has been a big part of our business for probably 15 years. We got into it because of increasing demand for superhard finishes. We made the equipment investment, sent personnel to Houston for Stellite training, and now we offer a wide range of coating materials—cobalt and nickel-based alloys, superalloys and alloy steels—that meet all requirements of the power generation industry for protection against heat, corrosion, erosion and wear. Our clients include most of the significant players in power generation, and we apply Stellite on all of their parts, specifically after the part has been roughed and prior to finish machining."
Seeley Machine applies Stellite 6 powder to rough-machined round and/or flat metal surfaces using the plasma transferred arc (PTA) method of welding, which melts the powder and creates a slurry or plasma overlay on the surface. When the Stellite surface becomes very hard, it is corrosion resistant, wear resistant and has high resistance to galling, making it able to survive severe environments. "It’s really a magic bullet for industries that require these hard surfaces, and we have a real competitive advantage being able to supply customers with the surface they need because there are so few shops willing to make the investment, learn the process and then supply it."
"We take heavy cuts in Stellite, and the Hyundai WIA machines are so rigid the material doesn’t phase them at all," said Leonard. Seeley Machine has four Hyundai WIA machines, all purchased within a three-year timeframe, the F750B, a VX950, a VX650-50 vertical machining center and an L400LC turning center. "To be perfectly honest," Leonard said, "what drove us to the Hyundai WIA machines was value. We needed to expand capacity to create a niche where we were in between the big guys and the small guys. I started shopping around for machines, and Hyundai WIA kept catching my eye. The price-to-value ratio was that compelling. When I compared them to competitive German and Japanese machines, some were nearly twice the price of the Hyundai WIAs with seemingly no real advantage. I’m not taking anything away from Hyundai WIA’s competition, but why should I pay more to get the same capability?" Leonard asked.
"So, we bought our first VMC from Hyundai WIA and absolutely loved it. Then we bought another, then another, and then another. Bang for the buck, you can’t beat them. Excel Machine Technology (Rochester, NY), is the Hyundai WIA distributor that handles all of our service, and it has been fantastic. We’re very happy. I call it a very good marriage. This investment has really helped us in terms of productivity, throughput and competitiveness. The Hyundai WIA machines have played a key role in achieving the quality required by the energy industry, making it is easier to machine great finishes on certain materials, thus consuming less time. Runtimes have gone down because the machines are beefier and are able to handle bigger parts faster. So we have increased cycle time, throughput and quality. For the investment, these machines keep us a step or two ahead of the competition, which is enormously important in today’s marketplace," said Leonard. ME
For more information from Hyundai WIA go to www.hyundai-wiamachine.com , or phone 201-636-5601; from Seeley Machine, go to www.seeleymachine.com or phone 518-798-9510.
This article was first published in the May 2013 edition of Manufacturing Engineering magazine. Click here for PDF.