|
|
|
|||||
|
|
|
|
|
|
|
|
| Projects Improvements in Calibrations and Uncertainty Evaluation MicroFeature Calibration Development Optical Comb and Refractometry Complex Geometry Instrumentation and Standards Micrometer level surface finish metrology
Date created:
|
Precision Engineering Division Program
Dimensional Metrology Program Program Manager: Steve Phillips Annual FTEs: 16 NIST staff 4 Guest Researchers/Contractors 20 total FTEs Challenge: To promote innovation and enhance U. S. productivity by optimizing MEL’s dimensional metrology portfolio to take advantage of advances in information, computational, and optoelectronic measurement technology for high accuracy dimensional metrology. Overview The Dimensional Metrology Program (DMP) addresses selected needs in dimensional metrology over length scales ranging from micrometers to kilometers. This includes calibrations of measuring instruments such as laser interferometers and laser trackers, a wide array of engineering gauges, standard reference materials, and specialized measurements, e.g., from high accuracy coordinate measuring machines (CMMs). The program also provides expertise and representation of U. S. interests in national and international standards committees. The DMP focuses on developing dimensional measurement infrastructure to support significant improvements in U.S. productivity. In particular, the DMP targets building new measurement capability for enabling technologies and high value products in which the U.S. has a significant industrial presence. Selected national and international standards, particularly in emerging technologies, are aggressively supported to promote international trade, foster innovation, and reduce manufacturing costs. The program also strives to increase the leverage of NIST’s measurements through deep penetration of its measurements into the U.S. metrology chain. Strategically, the DMP will develop unique measurement capabilities – typically a combination of extremely low uncertainty and difficult measurands. By strategically positioning the program and exploiting economies of experience and scope, the program generates capabilities that are difficult for other laboratories to replicate; this differentiates the DMP from other top tier calibration laboratories and from universities. The DMP implements its strategy through a series of objectives, each containing a set of time staggered projects. The objectives are forward looking that will create and deliver solutions to significant dimensional metrology problems, typically leading to new measurement services. In addition, the work defined within this program addresses, in one way or another, several of the identified and validated U. S. Measurement System Measurement Needs (MN). The specific MNs and page numbers from Appendix B of the Report are found at the end of this document. Why NIST? NIST has the unique mission to work with industry to foster innovation and trade that promotes U. S. competitiveness. NIST’s position is distinct from that of industry and universities. The DMP selects projects that target NIST’s mission and cannot effectively be addressed by other constituency. The selection of a metrology project balances several competing forces. Our measurement problems involve measurands of extreme technical difficulty and accuracy where the cost of measurement excludes the domain of profitable industrial enterprises. Simultaneously, the program creates positive return on investment by targeting projects with significant leverage and value with net positive aggregate benefits to the nation. Additionally, the program recognizes the lower cost structure of universities and avoids projects that could be addressed more economically and efficiently by these institutions. In particular, the DMP exploits economies of experience and scope from NIST’s unique long term institutional knowledge and capability which is unavailable to academia. NIST’s specific role as a neutral third party with technical excellence provides NIST a unique role for national and international standards that foster trade, create a level playing field, and promote emerging or high value technologies where the US has a significant presence. Standards have significant leverage by formulating how an entire industry specifies and tests its products. Well written standards have positive externalities to industry by: avoiding costs of individualized (i.e. idiosyncratic) testing, optimizing capital purchases by allowing meaningful comparisons between different products, and lowering barriers to adopting new technology through the increased confidence and information imparted to industrial users enhances early adoption of technology. Ongoing Measurement Services Measurement Services provide industry with accurate and timely dimensional calibrations to enhance U.S. productivity and quality. The cornerstone of the DMP is to realize and disseminate the meter by providing industry with accurate and timely measurement services including calibrations, special tests, and standard reference materials and data. One focus of the DMP is emphasizing measurement services with highly leveraged penetration into the US traceability chain. For example, each gauge block calibrated at NIST provides explicit metrological traceability for over 1000 blocks in industry use. The other focus is on providing unique high accuracy metrology for high value components; recent examples include NASA satellite flight hardware and nuclear weapons gauges. The program periodically re-examines the portfolio of services for current applicability and also continuously improves service metrics including on-time delivery and days-turn-around time for its calibrations. To accomplish this objective the program has a carefully selected array of ongoing calibrations and a series of scheduled improvements for maintaining state-of-the-art dimensional metrology. Dimensional Metrology Program DMP Ongoing Reimbursable Dimensional Calibrations Measurement Services Overview DMP measurement Service delivers, on an ongoing basis, high accuracy calibrations that focus on either high value components or high leverage calibrations. The program culls out measurement services in technologically declining areas. For example, level rod calibrations (used in civil engineering) have been eliminated since GPS offers higher accuracy over large distances. The calibration of mechanical sieves will be eliminated in FY-08 as sieves are a relatively low-value calibration that can be performed by secondary calibration laboratories. Quality assurance metrics have been implemented and have continuously improved over the past three years. On time delivery is now over 95%, a significant increase from less than 60% only four years ago. Turnaround time has remained stubbornly fixed at roughly 65 days; additional emphasis is being focused on reducing this value. Deliverables and Intermediate Milestones
Customers: Collaborators:
Projects Dimensional Metrology Program DMP Program ObjectiveObjective 1. Provide industry with accurate and timely dimensional calibrations to enhance U.S. productivity and quality. Effective measurement services require that ongoing research into improvements to high accuracy calibrations be continually done. This research focuses on improving either high value components or high leverage calibrations to ultimately achieve the highest accuracy for the customer base. Project 1.1: Improvements in Calibrations and Uncertainty Evaluation Project Overview Improving dimensional calibrations through reduced uncertainty, greater throughput, and new measurands is a core mission of the DMP. This project develops these new capabilities through acquiring new equipment, characterizing measurement processes, and developing documentation and quality assurance activities for improved measurement services. Additionally, the project advances the theory and practice of measurement uncertainty evaluation, for both DMP calibrations and industrial practice. Specific calibration improvements include upgrading contact surface roughness capability through new instrumentation, improving survey tape accuracy, characterizing gauge penetration effects, and increasing throughput of flatness measurements. Activities in measurement uncertainty characterization include advancing the state of the art in uncertainty evaluation theory, providing practical access to measurement traceability, and developing new evaluation procedures compliant with the international Guide to the Expression of Uncertainty in Measurement (GUM). Deliverables (D) and Intermediate Milestones (IM): Surface Roughness Metrology
Large Scale Metrology
Engineering Metrology
Advancing Uncertainty Evaluation
Customers: Collaborators:
Dimensional Metrology Program Objective 2: Provide accurate microfeature metrology with 100 nm or less uncertainty. The DMP will develop and provide high accuracy metrology for an array of high value products in medical, aerospace, automotive, energy, and biotechnology fields that include small features ranging from 10 mm to 1000 mm in size. While two-dimensional metrology in this domain has long been available, three-dimensional coordinate metrology is not currently capable of the levels of accuracy required. Specific challenges include measuring the full geometry of 100 mm bores with aspect ratios of 20:1, as found in next generation fuel injectors. In addition, to access many of these small features, DMP will develop methods for sub-microNewton probing forces to avoid damage to the part. Additionally, the DMP will study the physical issues such as electrostatic forces, meniscus forces, and physisorbed films that represent phenomena that can bias high precision measurements. This effort will provide microfeature measurement services with 100 nm or less uncertainty within the next three years. Project 2.1: MicroFeature Calibration Development Project Overview The primary goal of the microfeature calibration development effort is the deployment of a second Moore M48 high accuracy CMM dedicated to microfeature calibrations. DMP will install the new M48, develop metrological capabilities similar to the current M48, and then adapt the new M48 with the recently developed fiber optic microprobe and a vision system (as described below). DMP will have this new CMM characterized and approved by the PED quality system for both microprobing and vision calibrations by Q1/2012. A secondary goal of the effort is the continuous measurement improvement of the current UMAP microfeature CMM and its use in measuring fuel cell microchannel plates. Deliverables (D) and Intermediate Milestones (IM):
Customers: Collaborators:
Dimensional Metrology Program Objective 3: Lower the barriers to innovation by advancing the next generation realization of the meter. The DMP will advance the realization of the meter through the use of absolute refractometry to achieve below one part in 108 accuracy. This will reduce a major uncertainty source in high precision length measurements. The meter is currently realized by using a small set of frequency calibration optical sources, and corrected for the index of refraction using measurements of temperature, pressure, and humidity via the Edlén equation. This technique is limited to several parts in 108. This effort will halve this uncertainty within the next three years. Furthermore, by using an optical comb, a near continuous set of calibrated frequency sources will be available from the infrared to the visible, allowing advances in multi-frequency interferometry needed to reduce the measurement ambiguity interval. The comb will also lower the barrier to innovation by allowing common telecommunication lasers to be easily calibrated by receiving GPS satellites frequencies as the reference oscillator for the comb. Additionally, it could allow frequency dissemination via an all-optical fiber telecommunication network. Realization of practical frequency standards from the comb are expected within two years, while industrial in situ availability will be available some years following. Project 3.1: Optical Comb and Refractometry Project Overview The second goal of this project is the practical realization of calibrated optical wavelengths using the optical comb. In this arrangement, the meter is realized by using the atomic clock aboard GPS satellites, accessed via their broadcast frequencies, and used as a reference frequency for the comb. This effort will demonstrate that an extremely high accuracy optical reference source can be created in a manner that can be realized in industry. Additionally, the comb has the potential to serve as a multiple wavelength source for multicolor interferometry. Deliverables (D) and Intermediate Milestones (IM): Refractometry
Comb
Customers: The optical comb will serve internal needs as the top of the traceability chain in PED. There are both internal and external (DOD) needs for calibration at 543 nm, and the multicolor capabilities of the comb will fulfill this need. For refractive index, our most pressing needs are internal, where state-of-art refractive index measurements will be needed to meet future industrial needs, particular for the semiconductor industry where refractive index corrections limit our ability to deliver measurements of the highest accuracy. Measurement of refractive index also has potential applications to other types of NIST and industry measurements; for example, there is a clear potential to use refractive index for pressure measurements, of interest both to the NIST pressure group and to DOD. Finally, Boeing is already requesting that we provide traceability for their iodine stabilized laser used as a primary length standard. Collaborators:
Dimensional Metrology Program Objective 4: Promote innovation and reduce time to market through the development of rapid complex geometry metrology. The DMP will promote innovation and a reduction of time to market by developing calibration capabilities and standards for measuring geometrically complex surfaces. Complex surfaces are increasingly employed in advanced manufacturing, especially for large components. Such structures are found in dynamic structures such as airframes, turbine blades, propellers, and ship hulls where these surfaces are responsible must minimize drag. Small deviations in manufacturing quality or mechanical alignment can significantly disturb their function and cause inefficiencies that consume large quantities of energy. Traditional metrology instruments used to measure these structures, such as large CMMs are immobile, represent a large fixed capital investment, and are slow at collecting the large number of data points needed to fully characterize these complex surfaces. Recent developments in electro-optical instrumentation eliminate these drawbacks and greatly increase throughput with lower labor costs. This objective targets advancing this technology by providing access to high accuracy calibrations and standards within three years. Project 4.1: Complex Geometry Instrumentation and Standards Project Overview The principal goal of this project is to create a calibration facility that can accommodate a wide range of scanning instrumentation. The activity bifurcates into a calibration of the instrument’s ranging technology (i.e. the instrument’s metric of length) and a calibration of the full 3D measuring capability. The ranging calibration facility is under construction in the NIST tape tunnel and includes a range for cooperative targets (e.g. retroreflectors) and spherical noncooperative targets. The 3D geometry calibration facility will include both fixed ‘monument” artifacts, and repositionable portable artifacts (e.g. large bars). The project will also develop new standards for scanning instruments through the newly formed ASTM E57 committee. Deliverables (D) and Intermediate Milestones (IM):
Customers: The target customers of this project are instrumentation companies that are developing new scanning technology and need access to calibration facilities to determine their actual measurement errors and thus enable improvements in the technology. A secondary customer base is the high end users of this technology who seek independent calibration documentation of their instruments. This group would include a wide array of industries including aerospace, heavy equipment, construction, and precision manufacturing. The broadest customer base is the general metrology community that will benefit from documentary standards to improve their capital equipment decisions. Collaborators:
Dimensional Metrology Program Objective 5: Provide optical three-dimensional surface topography measurement at the micrometer level. Conventional surface topography involves contact stylus instruments ( e.g., as used in Objective 1.1) and are considered the “gold standard” in surface metrology. Advances in optical instrumentation for surface topography allows rapid three dimensional characterization of surfaces. Characterization of these instruments and establishing their traceability at the micrometer scale is imperative to many industries and government agencies. Applications include the traceable measurement of hardness, where the shape of the indenter strongly affects results and the measurement of topography of bullets and casings in crime labs, where the fine individual characteristics that produce positive identification of individual weapons need to be separated from longer scale characteristics that characterize overall shape. this project is a microscale analog of the Complex Form Metrology found with Objective 4. Project 5.1: Micrometer level surface finish metrologyProject Overview This project will establish the limits of validity for surface texture measurement obtainable by optical methods and developing standards for measurement of surface texture and topography derived from optical measurements. The research directions include: 1) the measurement of surfaces using optical techniques and the comparison of the results with stylus methods, 2) leadership in the development of documentary standards for optical techniques, and 3) the development of physical standards and measurement parameters for optical microscopes used in crime labs to examine bullets and casings. Specifically, the project will investigate the large errors arising with the use of coherence scanning interferometry for measurement of roughness average in the 50 nm to 300 nm range. This technique will be compared with that of confocal microscopy and the more fundamental stylus techniques. Additionally, documentary standards for phase shifting interferometric microscopy, coherence scanning microscopy, and confocal chromatic probing, will be developed. As a specific application of optical techniques, the project will continue to evolve the physical standard, SRM 2460, for optical examination of bullets and an analogous standard, SRM 2461, for examination of the casings. This work has application to the infrastructural work on optical techniques, discussed above, because the similarity between surface topography as measured by stylus and optical techniques is of crucial importance to establishing the validity of optical techniques. Deliverables and Intermediate Milestones: Optical Surface Metrology
Customers:
Collaborators:
|
