Optimizing the grinding process: R&D project aims to change grinding from an art to a science

Modern Machine Shop, Dec, 2003 by Leo Rakowski

The grinding process involves more variables--type of grinding wheel, wheel speed, infeed rate, wheel dressing frequency, dressing method, type of coolant and so forth--than most other metalworking processes. There are so many variables, in fact, that controlling the grinding process has come to be viewed as an art more than an exact science--a task best handled by a skilled grinding machine operator with years of experience.

That may change, however, as a result of a research and development program intended to provide "intelligent optimization and control of grinding processes." The R&D project is a joint venture involving several companies involved with grinding. It was chosen by the National Institute of Standards and Technology (NIST) as a recipient of its 2002 Advanced Technology Program (ATP) competition award. The award, announced a few months ago, provides $6 million in funding for the 3-year term of the program.

Here's a quick rundown of what is involved. Participants in the project will develop analytical models of each of the major grinding processes--surface grinding, cylindrical grinding, centerless grinding and so forth based on extensive studies using highly instrumented test beds. Each model will represent an extensive knowledge base for optimizing a particular grinding process. When the details of a specific grinding task--workpiece material, type of grinding wheel, dimensional tolerances, surface finish requirements and so forth--are loaded into the model, the system will determine the machine settings, wheel speed, depth of cut, dressing frequency and other parameters required to optimize the operation.

The system will be somewhat flexible: The end user will be able to ask for the settings that provide the fastest cycle time or those that provide the lowest production costs. Either way, the user starts out with the optimal parameters, eliminating the need for trial and error.

Benefits expected to result from optimized grinding processes include increased productivity; reduced expenditures on consumables; scrap and rework reduction; and improved quality. The joint venture partners conservatively estimate that optimized grinding will provide a 10 percent cost savings for U.S. grinding operations, about $1 billion annually. Perhaps more importantly, optimized grinding represents a step toward competing in a global economy using intelligent tools and proprietary processes.

The Players

* Purdue University, Lafayette, Indiana, is the technology provider for the project. Studies of the grinding process during the last 10 years by Dr. Yung C. Shin, a professor at Purdue's School of Mechanical Engineering, provide the core technology that the joint venture partners will use to generate the knowledge base and optimize grinding processes. Dr. Shin's work on the grinding process will continue, and results will be made available to the other joint venture partners during the term of the project.

* TechSolve, Cincinnati, Ohio, is a participant in NIST'S Manufacturing Extension Partnership (MEP), a nationwide network of technical and business assistance centers developed to help small and medium-sized manufacturers improve performance and competitiveness. The network is dedicated to improving the competitiveness of manufacturing and related businesses, particularly through improvements of their machining operations.

TechSolve explains that it will be responsible for the overall management of the research and development effort. As part of the team, it will develop the knowledge base for the surface grinding portion of the intelligent grinding project in its own laboratory. It will also assist the other partners in the development of the databases by conducting tests on different grinding test beds created at partner sites. These databases will be further used to develop the various grinding models.

* Landis Gardner, Waynesboro, Pennsylvania, a UNOVA company, is a producer of grinding machines and systems, primarily for the automotive industry. The company's areas of expertise include advanced computer-based machine control systems, machine/sensor integration, and software tools for monitoring and controlling grinding processes all of which are essential elements of an intelligent grinding process.

Landis will be responsible for testing of the centerless grinding process. In addition, the firm will continue its work on sensor technology--particularly force, power and acoustic emissions sensors--which is needed to provide adequate process monitoring. The firm reports that it has already done quite a bit of work in those areas independently, but that the results of its studies have not been consolidated.

* Delphi Corp., Troy, Michigan, a major manufacturer of automotive components with 48 manufacturing facilities in the U.S. and 169 worldwide, will provide real-world testing of the intelligent grinding technology and will be one of its first beneficiaries. The firm uses grinding extensively for such components as bearings, fuel injectors and valve train components, and it has very specific ideas about where it will employ the intelligent grinding technology to achieve immediate benefits. The firm expects to optimize its grinding operations to reduce costs, create more stable processes and lower scrap rates.