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Dear Colleague:

2011 is shaping up to be a very exciting year at ASPE.

Building on our momentum from two sold out topical meetings in 2010, ASPE has teamed up with euspen to organize a joint topical meeting in the spring of 2011 on Structured and Freeform Surfaces. Over 40 submissions have been received for what promises to be our third consecutive sold out topical meeting. We are also working on a second topical meeting for this coming summer.

Our Annual Meeting is being held this year in Denver, CO from November 13 to November 18, 2011. Coincidentally, ASME is also holding its annual meeting in Denver a few city blocks from ASPE's Annual Meeting. We are exploring ways to build on this confluence of precision and mechanical engineers. When we first considered starting a new society in 1986, one of our options was to start a new division in ASME. While we did not go that route, there are some areas of common interest and I am interested in any ideas you may have to interact with them in Denver.

2011 will be a year of changes. The website will be updated very shortly for easier navigation and access to past conference papers. The website offers an updated look signifying the move into our second quarter century of service to the precision engineering community.

The ASPE Board of Directors is also looking for ways to improve and grow ASPE's influence in American manufacturing. Your ideas are invaluable to mold ASPE to fit your evolving interests and needs and to attract a broader membership base into ASPE.

I look forward to hearing from you and seeing you at an ASPE Meeting in 2011.

Best wishes and a Happy New Year.

Tom Dow, Executive Director ASPE

Precision Tips


Precision manufacturing requires precise motions. Rigid body motion has six degrees of freedom, XYZ and rotation about these axes. Therefore when motion is required, the non-motion degrees of freedom, six-minus-n motion degrees, must be fixed. If a machine/instrument is constrained in more than six-minus-n ways, stresses and strains will occur, decreasing performance. Mounts that are constrained to six-minus-n motion degrees are called Kinematic Mounts.

When loads are high, robustness and stability demand more constraint and loss of precision can occur. The loss of precision can be minimized through manufacture of over-constrained degrees of freedom to exceptional tolerances minimizing stresses and inter-connecting the over-constrained degrees of freedom elastically. But this is usually obtained at the expense of increased cost.

PATTERN #3: Connect mating elements of a machine/instrument such that the number of constraints is equal and only equal to six minus the number of degrees of freedom required. If load conditions, robustness or stability cannot be met with kinematic design, employ elastically inter-connected, over-constrained mounts.


*Based on "Patterns for Precision Instrument Design", a classic ASPE tutorial by C. Teague, C. Evans and later D. Swyt. It uniquely identifies 12 foundational mechanical concepts or patterns driving precision in fabrication, assembly and metrology.

The American Society for Precision Engineering promotes the future of manufacturing in America by advancing precision engineering; though supporting education; and encouraging the development and application of precision principles.

ASPE, founded in 1986, is a non-profit organization.

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July 2010 Newsletter
September 2010 Newsletter