Pub Date : 2013-03-05DOI: 10.17764/JIET.56.1.T755M81670245652
R. Morrison, L. Racz, D. J. Carter
For 25 years, Draper Laboratory has been active in the areas of microelectromechanical systems (MEMS) and multichip modules (MCM), using two separate laboratories. When these laboratories were constructed, cleanroom technology was in its mid-life cycle. To meet evolving R&D needs, the cleanroom facilities recently underwent a major renovation as described in this article.
{"title":"Case Study: Design and Construction of the Draper Laboratory Microfabrication Center","authors":"R. Morrison, L. Racz, D. J. Carter","doi":"10.17764/JIET.56.1.T755M81670245652","DOIUrl":"https://doi.org/10.17764/JIET.56.1.T755M81670245652","url":null,"abstract":"For 25 years, Draper Laboratory has been active in the areas of microelectromechanical systems (MEMS) and multichip modules (MCM), using two separate laboratories. When these laboratories were constructed, cleanroom technology was in its mid-life cycle. To meet evolving R&D needs, the cleanroom facilities recently underwent a major renovation as described in this article.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67807980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-10-29DOI: 10.17764/JIET.55.1.2N44576W61240722
G. White
This paper uses experimental vibration data to evaluate the relationship between strain and velocity on a ground vehicle platform. The data also are used to compare the acceleration and the strain. Comparisons are made in the time, frequency, and damage domains. The results clearly show the strain data are more closely related to the vibratory velocity than to the acceleration, but the analysis is complicated somewhat by characteristics of the experimental data set.
{"title":"Relationship between Strain and Velocity for Ground Vehicle Vibration","authors":"G. White","doi":"10.17764/JIET.55.1.2N44576W61240722","DOIUrl":"https://doi.org/10.17764/JIET.55.1.2N44576W61240722","url":null,"abstract":"This paper uses experimental vibration data to evaluate the relationship between strain and velocity on a ground vehicle platform. The data also are used to compare the acceleration and the strain. Comparisons are made in the time, frequency, and damage domains. The results clearly show the strain data are more closely related to the vibratory velocity than to the acceleration, but the analysis is complicated somewhat by characteristics of the experimental data set.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67806532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-10-29DOI: 10.17764/JIET.55.1.27662M34H12V32P6
M. Hale, J. Porter
Multiple Degree of Freedom (MDOF) excitation systems and MDOF vibration control systems continue to improve, and are now standard equipment in many dynamic test laboratories. Determination of an input specification for such MDOF systems is critically dependent on properly acquired field data. Validation of field data will be discussed and demonstrated employing the same transformation tools used in both transformation-based 6-degree-of-freedom (6-DOF) vibration control and generalized MDOF vibration specification development (VSD).
{"title":"Validation Techniques for 6-DOF Vibration Data Acquisition","authors":"M. Hale, J. Porter","doi":"10.17764/JIET.55.1.27662M34H12V32P6","DOIUrl":"https://doi.org/10.17764/JIET.55.1.27662M34H12V32P6","url":null,"abstract":"Multiple Degree of Freedom (MDOF) excitation systems and MDOF vibration control systems continue to improve, and are now standard equipment in many dynamic test laboratories. Determination of an input specification for such MDOF systems is critically dependent on properly acquired field data. Validation of field data will be discussed and demonstrated employing the same transformation tools used in both transformation-based 6-degree-of-freedom (6-DOF) vibration control and generalized MDOF vibration specification development (VSD).","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67806408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-10-29DOI: 10.17764/JIET.55.1.2441H544M128474K
Dinesh Kumar Parasuraman, A. Arnoldus, Maria Kemps
Particle fallout in cleanrooms is a primary concern for industries manufacturing super critical products with surfaces highly susceptible to particulate contamination. Limited research has been conducted to predict the contribution of particulate contamination by production activities in cleanrooms. This paper describes a prediction model that utilizes the relationship between airborne particulate contamination and particle fallout, and the relationship between particle fallout and spatial variations, to predict the level of particle fallout on product surfaces in the cleanroom. Experimental modeling and statistical process control techniques were employed in establishing the above relationships and validation was performed by comparing the predictions from the model with actual observations at production cleanrooms.
{"title":"Prediction Model for Particle Fallout in Cleanrooms","authors":"Dinesh Kumar Parasuraman, A. Arnoldus, Maria Kemps","doi":"10.17764/JIET.55.1.2441H544M128474K","DOIUrl":"https://doi.org/10.17764/JIET.55.1.2441H544M128474K","url":null,"abstract":"Particle fallout in cleanrooms is a primary concern for industries manufacturing super critical products with surfaces highly susceptible to particulate contamination. Limited research has been conducted to predict the contribution of particulate contamination by production activities in cleanrooms. This paper describes a prediction model that utilizes the relationship between airborne particulate contamination and particle fallout, and the relationship between particle fallout and spatial variations, to predict the level of particle fallout on product surfaces in the cleanroom. Experimental modeling and statistical process control techniques were employed in establishing the above relationships and validation was performed by comparing the predictions from the model with actual observations at production cleanrooms.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67806782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-10-29DOI: 10.17764/JIET.55.1.2678772445383675
D. Aldridge
Vibration test time-compression methods have existed for decades and are well-documented. However, not all practitioners are aware of how these methods were developed and the proper utilization of the developed theory. While many sources have attempted to clarify the methodology, there is confusion on many points. The objective of this paper is to help new vibration test engineers understand accelerated testing theory and practice. The lab is a valuable training ground, but sometimes the subtleties are not communicated. A more complete understanding of the theory and practice of vibration test time-compression methods is needed when translating contract requirements into test procedures used in product development and validation.
{"title":"Do You Know that Your Accelerated Vibration Test Requirement Is Correct","authors":"D. Aldridge","doi":"10.17764/JIET.55.1.2678772445383675","DOIUrl":"https://doi.org/10.17764/JIET.55.1.2678772445383675","url":null,"abstract":"Vibration test time-compression methods have existed for decades and are well-documented. However, not all practitioners are aware of how these methods were developed and the proper utilization of the developed theory. While many sources have attempted to clarify the methodology, there is confusion on many points. The objective of this paper is to help new vibration test engineers understand accelerated testing theory and practice. The lab is a valuable training ground, but sometimes the subtleties are not communicated. A more complete understanding of the theory and practice of vibration test time-compression methods is needed when translating contract requirements into test procedures used in product development and validation.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67806891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-10-29DOI: 10.17764/JIET.55.1.2Q4650XQT7J0K506
V. Bateman, Ronald Merritt
This paper presents a comprehensive description of pyroshock, the interpretation of pyroshock data, and the validation of pyroshock data. Recent events in the pyroshock testing community show that corrupted pyroshock data are still being acquired at government agencies and private companies. A large part of this paper is devoted to acquisition and analysis of pyroshock data because proper time-history data acquisition and, consequently, test specification development are common industry problems. To avoid corrupted pyroshock data and thus corrupted pyroshock specifications, recommended practices for instrumentation and data acquisition systems as well as data analyses are provided. Causes of corrupted pyroshock data are explored and recommendations for avoiding corrupted pyroshock data are presented.
{"title":"Validation of Pyroshock Data","authors":"V. Bateman, Ronald Merritt","doi":"10.17764/JIET.55.1.2Q4650XQT7J0K506","DOIUrl":"https://doi.org/10.17764/JIET.55.1.2Q4650XQT7J0K506","url":null,"abstract":"This paper presents a comprehensive description of pyroshock, the interpretation of pyroshock data, and the validation of pyroshock data. Recent events in the pyroshock testing community show that corrupted pyroshock data are still being acquired at government agencies and private companies. A large part of this paper is devoted to acquisition and analysis of pyroshock data because proper time-history data acquisition and, consequently, test specification development are common industry problems. To avoid corrupted pyroshock data and thus corrupted pyroshock specifications, recommended practices for instrumentation and data acquisition systems as well as data analyses are provided. Causes of corrupted pyroshock data are explored and recommendations for avoiding corrupted pyroshock data are presented.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67807867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-10-01DOI: 10.17764/JIET.55.1.2171387035102W27
D. Smallwood
As multiple axis vibration testing has become more widespread, it has become increasingly important to ensure the instrumentation is accurately portrayed in the instrumentation table. However, errors do occur. The method used in this paper to help uncover these errors is based on the condition that at low frequencies (below any resonant frequencies of the object being studied) the response is essentially rigid body. The spectral density matrix (SDM) at a low frequency, of many more than six response measurements, is decomposed using singular value decomposition (SVD). Under the assumption of rigid body response, it is assumed that the first six singular vectors are linear combinations of the six rigid body modes. The best linear fit is then calculated for this fit. The measurements are then removed one at a time, and the reduction in the fit error is calculated. It is assumed that if the removal of a measurement reduces the error significantly, that measurement is likely in error.
{"title":"Validation of Measured Dynamic Data Using Rigid Body Response","authors":"D. Smallwood","doi":"10.17764/JIET.55.1.2171387035102W27","DOIUrl":"https://doi.org/10.17764/JIET.55.1.2171387035102W27","url":null,"abstract":"As multiple axis vibration testing has become more widespread, it has become increasingly important to ensure the instrumentation is accurately portrayed in the instrumentation table. However, errors do occur. The method used in this paper to help uncover these errors is based on the condition that at low frequencies (below any resonant frequencies of the object being studied) the response is essentially rigid body. The spectral density matrix (SDM) at a low frequency, of many more than six response measurements, is decomposed using singular value decomposition (SVD). Under the assumption of rigid body response, it is assumed that the first six singular vectors are linear combinations of the six rigid body modes. The best linear fit is then calculated for this fit. The measurements are then removed one at a time, and the reduction in the fit error is calculated. It is assumed that if the removal of a measurement reduces the error significantly, that measurement is likely in error.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67806495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-10-24DOI: 10.17764/JIET.54.2.J6367818507386L7
S. Kalelkar, J. Postlewaite
Cleanroom wipers have long played an indispensable role in managing contamination in controlled environments. From wiping residues on hard surfaces to applying cleaning solutions, wipers perform a variety of tasks that help maintain the cleanliness levels desired in a given cleanroom environment. This makes the selection of cleanroom wipers a critical decision in any controlled environment. One common way to distinguish between cleanroom wipers of similar structural design is to compare test results across a variety of criteria, according to recommended practices by organizations such as the IEST. However, these results are typically listed as single data points for a given test and are meant to indicate either “typical values,” or even target specifications, in some instances. This approach is inherently limited and ineffective in assessing the true levels of cleanliness of a given wiper product. In this study, we review the test methods that are used to evaluate cleanroom wipers and present a new and improved approach by which users can evaluate their cleanliness. We provide a framework by which the consistency of the cleanliness of cleanroom wipers can be assessed in a statistically relevant manner. Finally, we demonstrate the value of using consistency of test results rather than a singular test result as the true measure of wiper quality.
{"title":"Consistency as the True Measure of Cleanroom Wiper Quality","authors":"S. Kalelkar, J. Postlewaite","doi":"10.17764/JIET.54.2.J6367818507386L7","DOIUrl":"https://doi.org/10.17764/JIET.54.2.J6367818507386L7","url":null,"abstract":"Cleanroom wipers have long played an indispensable role in managing contamination in controlled environments. From wiping residues on hard surfaces to applying cleaning solutions, wipers perform a variety of tasks that help maintain the cleanliness levels desired in a given cleanroom environment. This makes the selection of cleanroom wipers a critical decision in any controlled environment. One common way to distinguish between cleanroom wipers of similar structural design is to compare test results across a variety of criteria, according to recommended practices by organizations such as the IEST. However, these results are typically listed as single data points for a given test and are meant to indicate either “typical values,” or even target specifications, in some instances. This approach is inherently limited and ineffective in assessing the true levels of cleanliness of a given wiper product. In this study, we review the test methods that are used to evaluate cleanroom wipers and present a new and improved approach by which users can evaluate their cleanliness. We provide a framework by which the consistency of the cleanliness of cleanroom wipers can be assessed in a statistically relevant manner. Finally, we demonstrate the value of using consistency of test results rather than a singular test result as the true measure of wiper quality.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67805246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-10-24DOI: 10.17764/JIET.54.2.J3761476322338W1
M. Paulus
This paper presents a set of experimental data comparing repetitive shock (RS) vibration, single-axis electrodynamic (ED) vibration, and multi-axis ED vibration. It was found that multi-axis testing is more severe than single-axis testing at the same level. In addition, weaknesses were found in the RS system at low frequency. Smoothing of the data or poor line resolution was also shown to change the overall severity of a test. A poor correlation was shown between the power spectral density (PSD) and the rate of natural frequency change (RFC) over a wide frequency shift. The change in natural frequency caused the initial PSD to be an ineffective indicator of test severity. Quantification of the severity of the test profile can be accomplished through characterization of the RFC.
{"title":"Limitations of the Power Spectral Density as an Indicator of Test Severity","authors":"M. Paulus","doi":"10.17764/JIET.54.2.J3761476322338W1","DOIUrl":"https://doi.org/10.17764/JIET.54.2.J3761476322338W1","url":null,"abstract":"This paper presents a set of experimental data comparing repetitive shock (RS) vibration, single-axis electrodynamic (ED) vibration, and multi-axis ED vibration. It was found that multi-axis testing is more severe than single-axis testing at the same level. In addition, weaknesses were found in the RS system at low frequency. Smoothing of the data or poor line resolution was also shown to change the overall severity of a test. A poor correlation was shown between the power spectral density (PSD) and the rate of natural frequency change (RFC) over a wide frequency shift. The change in natural frequency caused the initial PSD to be an ineffective indicator of test severity. Quantification of the severity of the test profile can be accomplished through characterization of the RFC.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67805649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-10-24DOI: 10.17764/JIET.54.2.J7502N53R4305HJ7
M. Dyke, Portia Peters
A significant amount of acoustic spatial variability is characteristic of direct field acoustic testing using a single random signal to drive the loudspeaker sources. This has raised concerns about the potential for under- and over-testing of hardware, particularly because of the consequential high sensitivity of the test environment upon the configuration of the test equipment and test hardware. Meanwhile, little is known about the specific spatial characteristics of the test acoustic field. A recent demonstration single-drive direct field acoustic test afforded the opportunity to map various planes of the acoustic field with a 36 microphone grid, offering unprecedented physical insight into the field characteristics. Analysis of the data reveals that the field is predominantly characterized by wave interference patterns at any given frequency. These data correlate well with 3-dimensional numerical models. The presence of wave interference patterns created by the fully correlated array of sources also ex...
{"title":"Spatial Variability Caused by Acoustic Wave Interference in Single-Drive Direct Field Acoustic Testing","authors":"M. Dyke, Portia Peters","doi":"10.17764/JIET.54.2.J7502N53R4305HJ7","DOIUrl":"https://doi.org/10.17764/JIET.54.2.J7502N53R4305HJ7","url":null,"abstract":"A significant amount of acoustic spatial variability is characteristic of direct field acoustic testing using a single random signal to drive the loudspeaker sources. This has raised concerns about the potential for under- and over-testing of hardware, particularly because of the consequential high sensitivity of the test environment upon the configuration of the test equipment and test hardware. Meanwhile, little is known about the specific spatial characteristics of the test acoustic field. A recent demonstration single-drive direct field acoustic test afforded the opportunity to map various planes of the acoustic field with a 36 microphone grid, offering unprecedented physical insight into the field characteristics. Analysis of the data reveals that the field is predominantly characterized by wave interference patterns at any given frequency. These data correlate well with 3-dimensional numerical models. The presence of wave interference patterns created by the fully correlated array of sources also ex...","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67806389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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