Fall Technical Meeting to highlight 26 compelling presentations

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With more than three decades of technical conferences, AGMA is no longer a name just synonymous with gear standards. It has become the association to provide members with the latest information in gearing research from industry experts around the world. The AGMA Fall Technical Meeting (FTM) is the premier technical forum in the United States to hear and discuss the latest emerging technology as it relates to gear design, manufacture, operation, and processes.

This year we are on track to have 26 presentations in five sessions: Application, Design, and Rating; Optimization and Performance; Gear Wear and Failure; Manufacturing, Inspection, and Quality Control; and Materials and Heat Treatment. We solicited more than 50 peer reviewers from across the globe to assist us in evaluating all papers in a double-blind review process. All technical papers are published by AGMA and are later indexed in Scopus, the largest abstract and citation database of peer-reviewed literature: scientific journals, books, and conference proceedings. FTM attendees will receive PDF copies of all technical papers from the sessions for which they registered.

Some highlights for this year’s compelling research include a presentation by Sandeep Thube from Sumitomo Drive Technologies on “The Deliberate Application of Theoretical Quantitative Analysis Techniques to Improve Gearbox Development for the Food and Beverage Industry.” His paper explores the ability to design and construct a gearbox that stays in compliance with applicable general standards while optimized to fit the specific requirements of the application. In addition, we have a presentation from Georg Mies of Klingelnberg, who will be discussing the “Full Automated Roughness Measurement on Gears, Even on the Shop Floor.” Through his paper, we will learn about the capabilities of machining technologies that can create extremely smooth surfaces at a more cost-effective rate. The research shared at this year’s FTM will help bring the latest emerging technologies such as 3D printing and automation to the manufacturing floor. Attendees will be able to hear new processes and methods that they could employ to fine tune their manufacturing operations and lower their overall operating costs.

In addition to an information-packed three days, we are inviting FTM attendees to unwind and network in an evening of conversation and games at Pinstripes in Oak Brook. It is important to take a break from the presentations and meet new people or reconnect with peers from across the gear industry. What better way to do that than with great food, bowling, and bocce? This new event combined with luncheons and the welcome reception will make this FTM the event of the year.

As always, the integrity and quality of our conference would not be possible without the help of our reviewers. Therefore, I would like to take this opportunity to thank each and every one of our volunteer experts who helped as peer reviewers as well as the members of the AGMA Technical Executive Committee, chaired by Todd Praneis from Cotta Transmission Company, for their time and valuable assistance over the last several months to help bring you the high-caliber presentations that you have come to expect of the AGMA FTM. I encourage all gear industry engineers and technical experts to attend this year to engage with the researchers and presenters.

This year’s FTM is September 24-26 in Oakbrook, Illinois. Early bird registration ends August 24, so make sure to get your spot as soon as possible. A full list of presentations is available in this AGMA section of Gear Solutions, and presenter bios can be found on the AGMA website at www.agma.org. I look forward to seeing you this September.

Industry experts gather for the 2017 Fall Technical Meeting. (Courtesy: AGMA)

Fall Technical Meeting schedule

MONDAY AFTERNOON

SESSION 1: Application, Design, and Rating

Moderator: Jason Daubert, FLSmidth, Inc.

Filling Some Gaps in Spline Design Guidelines: Centering, Friction, and Misalignment | Stephen McKenny, General Motors Co.

International spline standards and other widely used published documents have detailed definitions of two-dimensional spline geometry, and while they cover basic axial effects and stresses, more can be provided for design engineers. Results from an analytical study of misalignment factors and an experimental study of centering forces will be presented to provide information to help refine calculation methods. These include: how to calculate the effective pressure angle of straight-sided splines that must be used to accurately determine normal and radial loads; how to calculate the effective centering force of a spline pair; how to calculate the centering moment of a spline with “topping”; an update to current publications; and an update to the calculation of the maximum axial force that a spline can transmit via friction.

Methods to Determine Form Diameter on Hobbed External Involute Gears | Shuo Zhang, Oerlikon Fairfield

Two mathematical methods have been developed to be used for the calculation of true involute form diameter when specialized software or original gear designer information is not easily accessible. These methods are designed for external involute gears produced by the hobbing process, possibly followed by a finishing operation. Method A is a more precise match, but it requires special inputs that may be time consuming without special software. Method B, although not as accurate, still has relative error of TIF diameter below 0.1 percent over wide ranges of gear design parameters. Method B is also easy to apply and can be integrated into most existing gear design programs.

Optimization of a Rack and Pinion Design for Offshore Jack-Up Applications | Adrian Nowoisky, Oerlikon Fairfield

The presenter will walk you through his concept for best practice of designing a rack and pinion for offshore jacking applications. They will demonstrate the impact of major gear parameters for a pinion design and their impact on the life expectation. They will also show the benefit of a custom pinion design and how much improvement can be achieved with emphasizing the design process properly.

The Deliberate Application of Theoretical Quantitative Analysis Techniques to Improve Gearbox Development for the Food and Beverage Processing Industry | Sandeep Thube, Sumitomo Drive Technologies

The food-and-beverage industry has a variety of gearbox applications that are regulated by governmental industry standards, such as the NSF and the FDA. What if we were to design and construct a gearbox that stays within compliance standards, but may be substantially different from typical industrial requirements? Details of this new gearbox design, developed for food-and-beverage applications, will be discussed. Designers used specific tools to minimize the number of needed prototypes. These tools included: Quality Function Deployment (QFD), Failure Mode Evaluation Analysis (FMEA), and computational ‘Finite Element Analysis’ (FEA). 3D printing was used to find design defects at early stages and validate the gearbox assembly procedure.

TUESDAY MORNING

SESSION 2: Optimization and Performance

Moderator: Mike D’Arduini, The Gleason Works

Increasing Static Friction with Laser | Gerhard Flores, Gehring Technologies GmbH (Germany)

Flat and curved surfaces with the functionality of high static friction are increasingly needed for force-fitted nonslip power transmissions. This is especially true for con rod and cam structuring for high-torque resistance or front-face connections of sprockets, gears, or cam-shaft adjustments. Expensive solutions such as diamond layers, diamond coatings, or form-fitting design are increasingly being substituted. A modified laser process with defined exposed micro structures is the alternative for innovative manufacturing. Exposed micro melting burrs of smaller micrometer height with martensitic material structures are the precondition for the required high friction. So, such high static friction surfaces can be produced economically with repeatability of small tolerances in high-volume productions.

Design and Optimization of a Hybrid Vehicle Transmission | Massimiliano Turci, Studio Tecnico Turci (Italy)

Hybrid vehicles seem to be the fastest solution for the containment of consumption and of pollution for personal transport. The designer of a hybrid transmission has to address additional issues with respect to the classical cases, in particular the high speed of the electric unit and the bidirectional motor/generator operation. In this case, a lot of attention should be paid to how to consider the four combinations of signs for torque and speed in the load spectrum. Come and learn several approaches for the alternating bending factor, the effects of the asymmetric crowning (especially the helix modification tapered or parallel) and how to consider the housing stiffness in the TCA. You will also learn about an interesting solution from the kinematic point of view, the compound planetary, relatively well-known in the automotive, but much less so in industrial gearbox design.

Influence of Thermal Distortion on Spur Gear Tooth Contact | Jon Larrañaga, Mondragon University (Spain)

The reduction of component size and oil volume of current automotive and aeronautical transmissions, along with the increasing input speeds, are pushing gear teeth bulk temperatures to their scuffing limit. Even with development of new lubricant additives and coatings, high temperatures may produce other issues. In this paper, the author will analyze the effects of thermal distortion on the profile geometry and tooth contact parameters in the transverse plane of a spur gear by calculating the steady-state temperature distribution relevant to immersion depth, sump temperature, and lubrication regime in the contact area. Then, thermally distorted geometry and tooth contact analysis is computed by means of a 2D finite element model where load distribution, transmission error, backlash, and other parameters will be analyzed. The results of the study will allow one to set the limits of design backlash to avoid gear jamming and to size the initial profile shift or tooth modifications to reach the desired contact behavior.

Oil-Off Characterization Method Using In-Situ Friction Measurement for Gears Operating Under Loss-of-Lubrication Conditions | Aaron Isaacson, Gear Research Institute, Applied Research Laboratory – Penn State University

The oil-off performance evaluation of gears is of significant interest to the Department of Defense and various rotorcraft manufacturers so the aircraft can safely land in an accidental loss-of-lubricant situation. However, unlike typical gear failure modes, gear failure in an oil-off situation is very rapid and likely catastrophic. This presentation describes the procedure and instrumentation used for an oil-off test to measure the frictional loss in the test gear mesh and the “air” temperature just out of mesh. Sound and vibration data was also recorded during testing. Data from typical failures showing the detection of scuffing onset and its progression to catastrophic failure for gears made from several aerospace alloy steels is presented.

Application of Finite Element Analysis for the Strain Wave Gear Tooth Surfaces Design and Modifications | Zhiyuan Yu, Penn State University

This presentation is on a rigorous definition and parametric study of tooth surface modification of the strain wave gear. You will see that optimal modification for a sample strain wave gear is found from FEA and tested by contact pattern, transmission error, and life cycling experiments. The resulting innovative design with modified fully conjugate tooth surface improves accuracy, backlash, and the life of the existing design.

TUESDAY AFTERNOON

SESSION 3: Gear Wear and Failure

Moderator: Todd Schatzka, Rexnord Innovation Center

Experimental Study on the Pitting Detection Capabilities for Spur Gears Using Acoustic Emission and Vibration Analysis Methods | Mateusz Grzeszkowski, Technical University Berlin, Chair of Electronic Measurement and Diagnostic Technology

During this presentation, you will learn about an experimental investigation on spur gears to characterize the pitting degradation process using monitoring features. Previous investigations have revealed that pitting has an impact on the gear vibration behavior. But is it possible to detect pitting at an early stage using acceleration sensors and acoustic emissions (AE) sensors to avoid consequential damages and subsequent correction activities? Come learn of this experimental investigation on spur gears to characterize the pitting degradation process using monitoring features. You will hear about the results of the investigation, including how the results show a detection of pitting is possible several hours before complete gear failure and more.

Optimization of Power Density by Local Gear Failure Modeling | Marco Kampka, Fraunhofer USA

Power density is a key factor in gear design. Increasing the power density enables engineers to use smaller gears for their applications, which leads to smaller and lighter gear boxes. The most common way to design gears is using industry standards in which material strength can be obtained either from fatigue limit tables or by means of empirical formulae. Due to limited empirical data, a lot of averaging and approximations are used to make the available standards applicable to a wide range of applications. To design the gear closer to the power density limit, a high level of information is necessary. The presenter will show how local FEA-based calculation approaches can be used to design gears closer to their power density limits for pitting, tooth root breakage, and flank fracture. The calculation results will be validated in running tests on different test rigs.

Load Intensity Distribution Factor Evaluation from Strain Gauges at the Gear Root | José Calvo Irisarri and Unai Gutierrez, Gamesa Energy Transmission (Spain)

Strain gauges are commonly used to obtain the load intensity distribution on the flank of a gear mesh. To get the load distribution on the flank, the strain data must be processed and changed into load intensity distribution on the tooth flank. Research has been conducted on the best methodology to place strain gauges when calculating load intensity distribution on the flanks of a gear. The presenter will discuss these research methods that use FEM models and his analysis of how to deal with the effect of strain gauge positioning errors, in order to find the optimal placement.

Impact of Root Geometry Manufacturing Deviations from a Theoretical Hob Rack on Gear Bending Stress | Rahul Nigade, Eaton Technologies Pvt. Ltd. (India)

Gear reliability is a key requirement of any automotive transmission. Two common failure modes of gears are pitting and bending fatigue. So, the total gearing reliability depends upon the bending and pitting reliability. Come and listen to a comparison of a theoretical root fillet geometry generated by the hob racks of gear drawings to an actual measured tooth fillet geometry of manufactured gears, which determines the impact of the different root fillet geometries on tooth bending stresses. An emphasis will be placed on the importance of using a root fillet geometry truly representative of the actual gears in production for the bending stress calculation so the required bending reliability can be achieved in the field.

Fatigue Life Predictions of Spherical Gear Couplings | Ibai Ulaci, Mondragon University (Spain)

Spherical gear couplings are mechanical components that allow transmitting torque by means of equally spaced teeth. Modern roll-leveling machines are characterized to level high-strength steels by using small rolls under high torque requirements. The small size of the rolls decreases the space between the spline couplings, causing misalignments up to 7 degrees. The presenter will discuss a geometry-generating procedure that has been developed for both the hub with internal teeth and the crowned teeth shaft in spherical gear couplings. A finite element model has been developed to study the effect of backlash and misalignment on the number of teeth in contact and root stresses. Finally, fatigue tests are performed, and numerical predictions are correlated with experimental results.

Potentials of Free Root Fillets in Planetary Gearbox Applications | Jonas Pollaschek, Laboratory of Machine Tools and Production Engineering (WZL) of RWTH Aachen University

Planetary gear stages are commonly used in many different fields of application, including wind turbine and automotive gearboxes. In this presentation, you will hear about a potential for increased root load carrying capacity at the planet gear of a planetary gear application. The approach considers local material characteristics such as hardness, fatigue strength, and mean stress sensitivity, as well as residual stresses and different stress rations that result from the mesh with the sun and ring gear. It offers a detailed tooth contact analysis based on the Finite Element Method. The result of this work allows for the possibility of changes in the gear design.

WEDNESDAY MORNING

SESSION 4: Manufacturing, Inspection, and Quality Control

Moderator: Terry Klaves, Milwaukee Gear/Regal

Microgear Measurement Standards: Comparing Tactile, Optical and Computed Tomography Measurements | Stephan Jantzen, The National Metrology Institute of Germany

Microgears are widely used in industry, as they are essential components of gearboxes used in precision engineering, medical technology, and robotics. The presenter will discuss the development of a new internal involute microgear measurement standard for research and industry. A comparison between the tactile calibration performed using a micro coordinate measuring machine (µCMM) and the measurement results obtained by means of a computer tomography (CT) system and optical CMM will be presented. The new results, compared with the results of the comparison measurements of the external microgear measurement standard, will be discussed. The results and discussion will provide an overview of the state of the art in microgear metrology.

Generative Gear Milling — Kinematics, Applications, and Benefits | Yefim Kotlyar, Machine Tool Builders

During this session, you will learn about Generative Gear Milling, an innovative software feature for gear cutting. The involute generative principle is based on an incremental positioning of a simple and inexpensive milling “disk” cutter with trapezoidal or parallel sides on the “line of action.” The presentation will outline the needs for this procedure and the applications of generative milling. And, the presenter will discuss the benefits of Generative Gear Milling, including improved efficiency, reduced cutter cost and delivery time, and expanded pitch range capability.

Reducing Tool Wear in Spiral Bevel Gear Machining with the Finite Element Method | Fang Hou, Third Wave Systems

Due to the complexity of spiral bevel gear machining, the cutting tools can be a significant cost of gear manufacturing. Unlike the price of material, which is fixed by the market, the cost of tooling and subsequent re-grinding can be lowered through reducing tool wear and increasing tool life. The presenter will discuss an alternative approach to physical testing for predicting and reducing tool wear using the finite element method. This virtual design approach uses real-world cutting tool geometry, automatically generated gear blanks, and known process kinematics to simulate the cutting process. Additionally, lessons learned, potential benefits and pitfalls of this approach to tool wear reduction and future work will be discussed.

Method for High Accuracy Cutting Blade Inspection | Haris Ligata, Gleason Corporation

Inspection of the cutting blade is a crucial step in the manufacturing of bevel gears. The proper blade geometry ensures the desired gear tooth form can be achieved. The accuracy of the process can be compromised when the blade consists of several small sections, or when dust particles, surface roughness, or floor vibration during the data acquisition occurs. Come and hear about a new method for improving the robustness of the inspection process in such cases. A proposal for using larger portions of the blades to evaluate the properties of the small features will be discussed. The presenter will discuss the methods developed and provide several examples of gears made using these methods.

Fully Automated Roughness Measurement on Gears, Even on the Shop Floor | Georg Mies, Klingelnberg (Germany)

For many years, the focus of the design of precision components for transmissions has been on optimizing gear geometry. The work in this area has come so far that we are now seeing a shift from design to a concentration on surface quality of the functional surfaces. The roughness of highly stressed gear flanks has significant influences on noise, wear, and power loss. Thanks to new or improved machining technologies, extremely smooth surfaces can now be produced cost-effectively. The need now arises for reliable measurement of roughness of gears. Come and discover the newest solution that enables fully automatic measurements of gear geometry and roughness in one clamping.

Integrating Non-Contact Metrology in the Process of Analysis and Simulation of Gear Drives | Alfonso Fuentes, Rochester Institute of Technology

Non-contact metrology allows for a very fast collection of points on the measured gear tooth surfaces, with data rates that can be as high as millions per second. It is a wealth of information about the gears. The presenter will discuss using this data for reverse engineering, noise root cause analysis, or as a baseline for stress information for further gear design optimization. You will be presented with an approach on integration of non-contact metrology to enhance current methodology of analysis and simulation of gear drives.

WEDNESDAY AFTERNOON

SESSION 5: Materials
and Heat Treatment

Moderator: Michael He, Scot Forge Company

Integrated Approach for Gear Testing of High-Performance Clean Steels | Dieter Mevissen, Machine Tool Laboratory of WZL RWTH Aachen University Chair of Machine Tools — Group Gear Technology

The power density of gearboxes is continuously increased by different research activities. Besides new material developments, the cleanliness of steels comes to the forefront in order to meet future requirements regarding load carrying capacity of gears. Come and learn an integrated approach for gear testing of steels. In order to determine the differences between steels of different cleanliness levels, the testing approach has to be improved as a whole.

Lean Heat Treatment for Distortion Control | Volker Heuer, ALD Vacuum Technologies GmbH

Controlling distortion is of key importance during the case hardening process in the production of gear components. By effective control of distortion and the variation of distortion, significant costs in post-heat treatment machining processes can be avoided. The presenter will be focusing in on new vacuum furnace designs that allow the treatment of small batches in a single layer of parts (2D treatment), which allows for easy automated loading and unloading of the fixture-trays. When performing case hardening, the components are Low Pressure Carburized (LPC) at high temperatures, followed by gas quenching. The treatment in single layers offers an optimum quality with temperature homogeneity, quench homogeneity, and distortion control.

Residual Stress Measurement of Case Hardened Steel Gears | David Easton, Advanced Forming Research Centre (AFRC) – University of Strathclyde

Aerospace gear components are required to demonstrate excellent load carrying and endurance characteristics. Case hardened steels are often used for these parts, but often residual stresses are developed. These residual stresses are known to have a significant effect on distortion during the heat treatment and machining processes. The speaker will present research conducted on gears manufactured from two different starting points: as-received bar material and hot-forged billet. The presenter will discuss the results of the work and compare the two sets of spur gears.

Combining Ultra-High-Strength and Toughness for Affordable Power Densification in Steel Gears | Buddy Damm, TimkenSteel

In the last few years, improvements in clean steel technology have been coupled with development of new ultra-high-strength, high-toughness steels. These technologies provide affordable solutions for critical, power-dense components. The presentation will review and compare steel cleanness metrics between re-melted steels and steels that meet AGMA grade 3 cleanness. The new steels provide yield strengths ranging from 175-210 KSI, ultimate tensile strengths ranging from 230-250 KSI, and Charpy impact energies ranging from 35 to 50 foot-pounds, allowing these grades to provide longer life, more power, and/or lighter weight. The higher fatigue strength of these steels is compared to more commonly used gear steels, and an analysis is presented that illustrates a potential for either a 30-percent reduction in gear set mass or a 45-percent increase in gear set torque capacity.

Reliability of Gears — Determination of Statistically Validated Material Strength Numbers | Michael Hein, Gear Research Center (FZG) – Technical University of Munich

This presentation is intended to provide a review on the statistical reliability behavior of cylindrical gears with regard to pitting and tooth root breakage failures. A mathematical reliability approach was developed and drafted to expand standardized load capacity calculation methods. The deduced models and procedures allow the consideration and conversion of different reliability levels in the design process of cylindrical gears. Practical examples of the research will be provided.

Calendar of Events

Whether you’re looking for technical education, networking opportunities, or a way for your voice to be heard in the standards process, AGMA has something to offer you. Visit www.agma.org for a complete list of upcoming events.