Big Gear Inspection is Booming

A recent expansion and investment in a precision gear inspection system is helping this Wisconsin company meet customer needs for high quality, fast delivery, and quality control.

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Northern Wisconsin’s Merit Gear is bagging more big gear business from surging energy, mining, construction and transportation industries with the help of its Gleason 3000GMM Series Analytical Gear Inspection System.

If you think rural north central Wisconsin is an unlikely place to find a world-class gear production facility then guess again. The 116,000 sq. ft. factory and 123 employees of Antigo, Wisconsin’s Merit Gear have never been busier, running around the clock, six days a week to keep pace with the demand for spur and helical gearing as large as 3,500 mm in diameter, with quality levels as high as AGMA 15. Figure 1

Big gear business is booming, despite a location more conducive to trophy sized deer and Muskie, says Merit Gear’s President and CEO Thomas Rouse. “Back in 1951 our two founders came here looking for good hunting and fishing,” says Rouse.

“They put down roots and soon found that the north woods can be fertile ground for gear production too. Sixty years later, we’ve recently completed investment in a precision large gear plant expansion that’s helping us land new customers requiring production of the highest quality gears and gearboxes for everything from wind turbines to oil well drilling rigs; rail cars to electric mining shovels.”

One Stop Shop
Merit Gear’s investment in turnkey production facilities – everything from cutting to heat treat, gear grinding and inspection are on site – gives the company an important strategic advantage, according to Merit Gear Vice President of Operations Friedrich Neuhoff. “Lot sizes can range from one piece to several thousand, but most orders today are in the range of just 25 to 200 parts,” Neuhoff explains. “These parts are as diverse as a 3,000 mm internal ring gear for a planetary gear system for a wind turbine, to a complex eight-gear assembly for an offshore oil rig gearbox, to the gearbox housing itself. Yet all these parts have at least two things in common: the need for high quality and faster throughput. The investments we’ve made to put resources like the Gleason 3000GMM gear inspection system all under one roof are critical to achieving both.”

Trust, but Verify
While Merit Gear’s large gear production expansion included two new large profile grinding machines with on-board inspection, it was clear to Merit Gear Quality Manager, Carl Kakes, that this alone would not be sufficient to meet the quality verification standards of many, if not all, of Merit Gear’s fast expanding large gear customer base. This was particularly true of Merit Gear’s fast-growing wind turbine gear business, where 100 percent part inspection is the rule, not the exception. Nor could Merit Gear afford to take the days, even weeks of extra time required to outsource finished gears for inspection elsewhere.

So Kakes and his team went shopping. “We looked at five inspection systems and the other four didn’t even come close to the Gleason 3000GMM’s capabilities,” says Kakes. “In fact, it was the only one with a 3,000 mm workpiece diameter capacity that could meet the inspection criteria of an important wind turbine gear and pinion assembly, where that assembly had to be precisely timed to an apex point in space. This was a deal-breaker for the other systems.” Figure 2

Making Life Easy in the QC Lab
A recent visit to Merit Gear’s QC Lab found Merit Gear Lab Technician Marshall Williams hard at work setting up, programming and conducting an inspection on a typical Merit Gear workpiece: an important gear assembly used on an offshore oil rig platform of one of North America’s largest platform drilling contractors.

Or maybe not so hard at work, explains Williams. “Despite the complexities of this particular assembly and the inspection requirements – two dual helicals, the need to verify a precise timing relationship between the two, and so on – the Gleason system does all of the ‘heavy lifting’,” says Williams.  “In fact, programming is so intuitive, and setup and operation so fully automated, that almost anyone could become a reasonably competent operator of this system in a matter of hours.”

With 14 years’ experience, Williams makes set up of this particular part seem simple, single-handedly lowering the part onto a universal chuck, and zeroing it in to a pre-established starting point with the help of the GMM’s unique Journal Reference software. All an operator has to do is position the part anywhere to within 10 mm of the desired location and then the Journal Reference software takes over from there. It automatically probes to determine the actual location of a datum such as the O.D., takes a radial and axial measurement, and corrects for the new zero location so that no additional painstakingly slow manual ‘truing up’ of the part is required. Figure 3

Then Williams uses the GMM’s GAMA™ (Gleason Automated Measurement and Analysis) operating software to simplify programming and completely automate the inspection process. GAMA is a powerful Windows® based application that puts a host of features right at the fingertips of the operator in a simple, highly intuitive graphical user interface (GUI).

Here’s How it Works:

    1) A typical GAMA screen has “quick buttons” across the top giving the operator immediate access to the most common system operations. All important gear and specific test information is shown down the left side of the screen, with tabs and forms making it easy for the operator to quickly and accurately establish gear parameters. The majority of the screen is used to chart the inspection results of, say, lead and involute tests, which appear in real time as the tests are performed. (Williams particularly likes the fact that a digital image of the part being inspected is also shown on-screen for visual confirmation).

    2) The operator starts the process by either recalling, loading and activating existing part programs with the click of a mouse, or by creating a completely new part program, which can be done in just minutes in a few easy steps. The operator simply selects from a list of typical machine configurations, enters a part number, and clicks a “create” button. A series of tabs then appears across the top of the screen. The operator clicks on these tabs one by one, filling out the necessary fields with pertinent gear data, special tests required for highly modified gear profiles and geometry, and the type of analysis required.

    3) Depending on the requirements of the customer, GAMA can provide test results to meet any global industrial standard, including DIN, AGMA, JIS, ISO, GB, GOST, UNI, etc. The operator can also select a variety of options for how a permanent record of the inspection is stored, whether in PDF format, Scalable Vector Graphics, or even HTML for easy emailing.

Brains – and Brawn
If the Gleason 3000GMM is the ‘smartest’ gear inspection system Williams has ever operated, it’s also the most physically capable as well. It’s equipped, for example, with a series of Renishaw SP80H 3-D scanning probes, with various stylus sizes and configurations, all interchangeable from an automatic probe changer. The Renishaw probe is reputed to be ‘light years’ ahead of older proprietary model 2-D and 3-D scanning probes; it can acquire data much faster and more accurately on even the most complex gear tooth profiles.

In addition, the 3000GMM features a solid granite base, providing considerably more stability for, gears weighing as much as 19,500 kg (42,900 lbs.), as compared to competitive models with cast-iron bases. Its Meehanite® cast iron slide assemblies provide vastly better damping characteristics as well. Figure 4

GMM – as CMM
According to Vice President of Operations, Friedrich Neuhoff, Merit Gear is now embarking on a new program calling for the use of the 3000GMM as a true Coordinate Measuring Machine (CMM). “One of the unique advantages of the Gleason system is that it can also be used for inspection of non-gear related features found on a prismatic part,” says Neuhoff. “We will soon be producing a gearbox housing and cover where we will need to use the Gleason system as if it were a CMM, to inspect features on the housing such as center distances, perpendicularities and so on. It is yet another example of the critical versatility the Gleason system gives us, as we produce new products and enter new markets.”