Adaptive Control for Intelligent Open Die Forging

2004 ◽  
Author(s):  
Wensheng Liu ◽  
T. J. Nye
Keyword(s):  
Adaptive Control ◽  
Manufacturing Process ◽  
Flexible Manufacturing ◽  
A Priori ◽  
Raw Material ◽  
Cross Sectional ◽  
Geometry Model ◽  
Die Forging ◽  
Process Feedback ◽  
Open Die Forging

Open die forging is a manufacturing process with a number of advantages; in particular it is an inherently flexible manufacturing process that makes efficient use of raw material. A fundamental drawback of this process, however, is the difficulty found in creating forging programs to control part manipulation and forming steps. A-priori approaches to creating these programs, such as by using FEM simulations or using modeling materials, are slow and have a strong tendency for errors to accumulate when predicting the results of consecutive forming steps. In this paper we present a new approach in which process feedback is used between forming steps to update a part geometry model that allows the forming sequence to be adjusted adaptively. This approach has been implemented in a simulated forging cell that uses non-linear FEM analyses to predict the effects of each forming step. A fully adaptive control scheme has been implemented that efficiently forges bars of one cross sectional shape into another shape, such as square to round or hexagonal. Programming the forging system with this scheme has proved particularly simple; the shape of the raw material is measured, and a desired shape is specified. Physical experiments have confirmed the simulation results.

scholarly journals An analytical cost estimation model for the design of axisymmetric components with open-die forging technology

2020 ◽  
Vol 110 (7-8) ◽  
pp. 1869-1892
Author(s):  
Federico Campi ◽  
Marco Mandolini ◽  
Claudio Favi ◽  
Emanuele Checcacci ◽  
Michele Germani
Keyword(s):  
Analytical Model ◽  
Cost Estimation ◽  
Manufacturing Process ◽  
Cost Model ◽  
Raw Material ◽  
Average Deviation ◽  
Die Forging ◽  
Geometrical Features ◽  
The Cost ◽  
Open Die Forging

Abstract Open-die forging is a manufacturing process commonly used for realising simple shaped components with high mechanical performances and limited capability in terms of production volume. To date, an analytical model for estimating the costs of components manufactured with this technology is still an open issue. The paper aims to define an analytical model for cost estimation of axisymmetric components manufactured by open-die forging technology. The model is grounded on the analysis of geometrical features available at the design stage providing a detailed cost breakdown in relation to all the process phases and the raw material. The model allows predicting product cost, linking geometrical features and cost items, to carry out design-to-cost actions oriented to the reduction of manufacturing cost. The model is mainly conceived for design engineers, cost engineers and buyers, respectively, for improving the product design, the manufacturing process and the supply chain. Cost model and related schemas for collecting equations and data are presented, including the approach for sizing the raw material and a set of rules for modelling the related cost. Finally, analytic equations for modelling the cost of the whole forging process (i.e. billet cutting, heating, pre-smoothing, smoothing, upsetting, max-shoulder cogging, necking and shoulders cogging) are reported. The cost model has been tested on eight cylindrical parts such as discs and shafts with different shapes, dimensions and materials. Two forge masters have been involved in the testing phase. The absolute average deviation between the actual and estimated costs is approximately 4% for raw material and 21% for the process. The absolute average deviation on the total cost (raw material and manufacturing process) is approximately 5%.

Real-Time Process Characterization of Open Die Forging for Adaptive Control

2000 ◽  
Author(s):  
T. J. Nye ◽  
A. M. Elbadan ◽  
G. M. Bone
Keyword(s):  
Adaptive Control ◽  
Real Time ◽  
Program Control ◽  
Time Process ◽  
Forming Process ◽  
Plastic Deformations ◽  
Die Forging ◽  
Process Characterization ◽  
Open Die Forging

Abstract Open die forging is a process in which products are made through repeated, incremental plastic deformations of a workpiece. Typically, the workpiece is held by a manipulator, which can position the workpiece through program control between the dies of a press. The part programs are generated with an empirically derived parameter, called the spread coefficient, whose value is subject to some contention. In this work, we demonstrate how process information can be used in real time to derive the actual spread coefficient for a given workpiece as it is being formed. These measurements and calculations occur in real time, and can be used to regenerate part programs to optimize the forming process, or can be used to adaptively control each incremental deformation of the workpiece.

Optimization of open-die forging process design to ensure homogeneous grain size refinement of cast structures by three-dimensional rigid-plastic finite element analysis

2004 ◽  
Vol 218 (9) ◽  
pp. 931-946 ◽  
Author(s):  
K Tamura ◽  
J Tajima
Keyword(s):  
Strain Distribution ◽  
Three Dimensional ◽  
Rigid Plastic ◽  
Cross Sectional ◽  
Forging Process ◽  
Size Refinement ◽  
Die Forging ◽  
Pass Schedule ◽  
Sectional Shape ◽  
Open Die Forging

Focusing on the rough-forging stage of the hot open-die forging process, the influence of pass schedule on the equivalent plastic strain distribution at the surface of a forged billet has been numerically analysed using a three-dimensional rigid-plastic finite element method. By analysing the circumferential distribution of the strain obtained by one forging pass, it has been clarified that the distribution is strongly influenced by the cross-sectional shape of a workpiece. By utilizing the analytical results, a new method has been developed to predict the cross-sectional shape and the strain distribution without numerically analysing all passes. As a result, a new pass schedule has been proposed to ensure homogeneous grain size refinement of cast structures and the effect of the pass schedule was verified by a real hot open-die forging experiment.

Real-Time Process Characterization of Open Die Forging for Adaptive Control

2000 ◽  
Vol 123 (4) ◽  
pp. 511-516 ◽  
Author(s):  
T. J. Nye ◽  
A. M. Elbadan ◽  
G. M. Bone
Keyword(s):  
Adaptive Control ◽  
Real Time ◽  
Program Control ◽  
Time Process ◽  
Forming Process ◽  
Plastic Deformations ◽  
Die Forging ◽  
Process Characterization ◽  
Open Die Forging

Open die forging is a process in which products are made through repeated, incremental plastic deformations of a workpiece. Typically, the workpiece is held by a manipulator, which can position the workpiece through program control between the dies of a press. The part programs are generated with an empirically derived parameter, called the spread coefficient, whose value is subject to some contention. In this work, we demonstrate how process information can be used in real time to derive the actual spread coefficient for a given workpiece as it is being formed. These measurements and calculations occur in real time, and can be used to regenerate part programs to optimize the forming process, or can be used to adaptively control each incremental deformation of the workpiece.

scholarly journals Stillbirth outcome capture and classification in population-based surveys: EN-INDEPTH study

2021 ◽  
Vol 19 (S1) ◽  
Author(s):  
Hannah Blencowe ◽  
◽  
Matteo Bottecchia ◽  
Doris Kwesiga ◽  
Joseph Akuze ◽  
...  
Keyword(s):  
Gestational Age ◽  
A Priori ◽  
Healthcare Providers ◽  
Population Based ◽  
Reproductive Age ◽  
Group Discussions ◽  
Cross Sectional ◽  
Vital Status ◽  
Neonatal Deaths ◽  
Adverse Pregnancy

Abstract Background Household surveys remain important sources of stillbirth data, but omission and misclassification are common. Classifying adverse pregnancy outcomes as stillbirths requires accurate reporting of vital status at birth and gestational age or birthweight for every pregnancy. Further categorisation, e.g. by sex, or timing (intrapartum/antepartum) improves data to understand and prevent stillbirth. Methods We undertook a cross-sectional population-based survey of women of reproductive age in five health and demographic surveillance system sites in Bangladesh, Ethiopia, Ghana, Guinea-Bissau and Uganda (2017–2018). All women answered a full birth history with pregnancy loss questions (FBH+) or a full pregnancy history (FPH). A sub-sample across both groups were asked additional stillbirth questions. Questions were evaluated using descriptive measures. Using an interpretative paradigm and phenomenology methodology, focus group discussions with women exploring barriers to reporting birthweight for stillbirths were conducted. Thematic analysis was guided by an a priori codebook. Results Overall 69,176 women reported 98,483 livebirths (FBH+) and 102,873 pregnancies (FPH). Additional questions were asked for 1453 stillbirths, 1528 neonatal deaths and 12,620 surviving children born in the 5 years prior to the survey. Completeness was high (> 99%) for existing FBH+/FPH questions on signs of life at birth and gestational age (months). Discordant responses in signs of life at birth between different questions were common; nearly one-quarter classified as stillbirths on FBH+/FPH were reported born alive on additional questions. Availability of information on gestational age (weeks) (58.1%) and birthweight (13.2%) was low amongst stillbirths, and heaping was common. Most women (93.9%) were able to report the sex of their stillborn baby. Response completeness for stillbirth timing (18.3–95.1%) and estimated proportion intrapartum (15.6–90.0%) varied by question and site. Congenital malformations were reported in 3.1% stillbirths. Perceived value in weighing a stillborn baby varied and barriers to weighing at birth a nd knowing birthweight were common. Conclusions Improving stillbirth data in surveys will require investment in improving the measurement of vital status, gestational age and birthweight by healthcare providers, communication of these with women, and overcoming reporting barriers. Given the large burden and effect on families, improved data must be made available to end preventable stillbirths.

Should Weights and Risk Categories Be Used for Inspection Scores To Evaluate Food Safety in Restaurants?

2016 ◽  
Vol 79 (3) ◽  
pp. 501-506 ◽  
Author(s):  
DIOGO THIMOTEO da CUNHA ◽  
VERIDIANA VERA de ROSSO ◽  
ELKE STEDEFELDT
Keyword(s):  
Food Safety ◽  
Food Service ◽  
Safety Evaluation ◽  
Cross Sectional Study ◽  
Raw Material ◽  
Risk Category ◽  
Cross Sectional ◽  
Evaluation Bias ◽  
Risk Categories ◽  
Food Safety Evaluation

ABSTRACT The objective of this study was to verify the characteristics of food safety inspections, considering risk categories and binary scores. A cross-sectional study was performed with 439 restaurants in 43 Brazilian cities. A food safety checklist with 177 items was applied to the food service establishments. These items were classified into four groups (R1 to R4) according to the main factors that can cause outbreaks involving food: R1, time and temperature aspects; R2, direct contamination; R3, water conditions and raw material; and R4, indirect contamination (i.e., structures and buildings). A score adjusted for 100 was calculated for the overall violation score and the violation score for each risk category. The average violation score (standard deviation) was 18.9% (16.0), with an amplitude of 0.0 to 76.7%. Restaurants with a low overall violation score (approximately 20%) presented a high number of violations from the R1 and R2 groups, representing the most risky violations. Practical solutions to minimize this evaluation bias were discussed. Food safety evaluation should use weighted scores and be risk-based. However, some precautions must be taken by researchers, health inspectors, and health surveillance departments to develop an adequate and reliable instrument.

scholarly journals Methodological quality of systematic reviews on treatments for depression: a cross-sectional study

2017 ◽  
Vol 27 (6) ◽  
pp. 619-627 ◽  
Author(s):  
V. C. H. Chung ◽  
X. Y. Wu ◽  
Y. Feng ◽  
R. S. T. Ho ◽  
S. Y. S. Wong ◽  
...  
Keyword(s):  
Systematic Reviews ◽  
Methodological Quality ◽  
A Priori ◽  
Cross Sectional Study ◽  
Risk Of Bias ◽  
Sectional Study ◽  
Pharmacological Treatments ◽  
Cross Sectional ◽  
Depression Treatments

Aims.Depression is one of the most common mental disorders and identifying effective treatment strategies is crucial for the control of depression. Well-conducted systematic reviews (SRs) and meta-analyses can provide the best evidence for supporting treatment decision-making. Nevertheless, the trustworthiness of conclusions can be limited by lack of methodological rigour. This study aims to assess the methodological quality of a representative sample of SRs on depression treatments.Methods.A cross-sectional study on the bibliographical and methodological characteristics of SRs published on depression treatments trials was conducted. Two electronic databases (the Cochrane Database of Systematic Reviews and the Database of Abstracts of Reviews of Effects) were searched for potential SRs. SRs with at least one meta-analysis on the effects of depression treatments were considered eligible. The methodological quality of included SRs was assessed using the validated AMSTAR (Assessing the Methodological Quality of Systematic Reviews) tool. The associations between bibliographical characteristics and scoring on AMSTAR items were analysed using logistic regression analysis.Results.A total of 358 SRs were included and appraised. Over half of included SRs (n = 195) focused on non-pharmacological treatments and harms were reported in 45.5% (n = 163) of all studies. Studies varied in methods and reporting practices: only 112 (31.3%) took the risk of bias among primary studies into account when formulating conclusions; 245 (68.4%) did not fully declare conflict of interests; 93 (26.0%) reported an ‘a priori’ design and 104 (29.1%) provided lists of both included and excluded studies. Results from regression analyses showed: more recent publications were more likely to report ‘a priori’ designs [adjusted odds ratio (AOR) 1.31, 95% confidence interval (CI) 1.09–1.57], to describe study characteristics fully (AOR 1.16, 95% CI 1.06–1.28), and to assess presence of publication bias (AOR 1.13, 95% CI 1.06–1.19), but were less likely to list both included and excluded studies (AOR 0.86, 95% CI 0.81–0.92). SRs published in journals with higher impact factor (AOR 1.14, 95% CI 1.04–1.25), completed by more review authors (AOR 1.12, 95% CI 1.01–1.24) and SRs on non-pharmacological treatments (AOR 1.62, 95% CI 1.01–2.59) were associated with better performance in publication bias assessment.Conclusion.The methodological quality of included SRs is disappointing. Future SRs should strive to improve rigour by considering of risk of bias when formulating conclusions, reporting conflict of interests and authors should explicitly describe harms. SR authors should also use appropriate methods to combine the results, prevent language and publication biases, and ensure timely updates.

28 Assessment of Pain and Provision of Non-Pharmacologic Analgesia to Children by Prehospital Providers in Southwestern Ontario: A Cross-Sectional Study

2021 ◽  
Vol 26 (Supplement_1) ◽  
pp. e21-e21
Author(s):  
Karina Burke ◽  
Branka Vujcic ◽  
Jonathan Hamilton ◽  
Charlotte Mace ◽  
John Teefy ◽  
...  
Keyword(s):  
Primary Outcome ◽  
Rating Scale ◽  
A Priori ◽  
Numeric Rating Scale ◽  
Cross Sectional Study ◽  
Subject Area ◽  
Stepwise Logistic Regression ◽  
Tertiary Referral Centre ◽  
Cross Sectional ◽  
Pain Scores

Abstract Primary Subject area Emergency Medicine - Paediatric Background There is abundant evidence that provision of pharmacologic analgesia by prehospital providers to children is suboptimal. Most paediatric calls are performed by primary care paramedics (PCPs) who are unable to administer pharmacologic analgesia to children but can administer non-pharmacologic therapies. Objectives Our objective was to describe the provision of non-pharmacologic analgesia to children by prehospital providers. Design/Methods We reviewed all ambulance call reports (ACRs) of children 0-17 years with acutely painful conditions (headache, abdominal pain, injury, head/ears/eyes/nose/throat pain, and back pain) who were transported to a paediatric tertiary referral centre serving a catchment of > 1 million from 2017-2019. Data collection was recorded by two blinded assessors using a study-specific Excel™ sheet. The primary outcome was the proportion of children offered non-pharmacologic analgesia. We performed a stepwise logistic regression on the primary outcome using covariates defined a priori: age, sex, visible deformity, type of crew, complaint, pain score, call time, and prior analgesia. Results All 11,084 ACRs from January 1, 2017 to December 31, 2019 were reviewed. The sample included 5887/11084 (53.1%) males, ranging from 1 month to 17 years, with a mean (SD) age of 10.5 (5.6) years. Calls involved mainly PCPs [8576/11084 (77.4%)]. Non-trauma-related musculoskeletal injuries were most common, comprising 2743/11,084 (24.7%) of calls. Pain scores were documented in 6947/11084 (62.7%) of calls. The verbal numeric rating scale (0-10) was used in 5022/6947 (72.3%) of calls, with a mean (SD) score of 5.2 (3.2). Non-pharmacologic analgesia was provided in 2926/11084 (26.4%) of calls, most commonly splint (1115/2926, 38.1%) and ice (931/2926, 31.8%). Pharmacologic analgesia was provided in 458/11084 (4.1%) of calls. In the multivariate model, mild (OR: 3.2; 95% CI 2.3-4.4; p < 0 .001) and moderate pain (OR: 1.7; 95% CI 1.3-2.2) (versus no pain) were significant predictors of non-pharmacologic analgesia, whereas visible deformity (OR: 0.5; 95% CI 0.3-0.6; p < 0 .001) was a significant negative predictor. Conclusion The provision of non-pharmacologic analgesia to children in Southwestern Ontario by prehospital providers is suboptimal, despite moderate to severe pain. There is a clear need for education surrounding approaches to non-pharmacologic analgesia in children among prehospital providers.

A - 28 Mastering Concussion Reporting: Does Previous Injury and Education Play a Role in Reporting Skill?

2021 ◽  
Vol 36 (4) ◽  
pp. 668-668
Author(s):  
Tomczyk CP ◽  
Covassin T
Keyword(s):  
Linear Regression ◽  
A Priori ◽  
Collegiate Athletes ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Previous Injury ◽  
Demographic Questionnaire ◽  
Predictor Model ◽  
Study Participants ◽  
Score Range

Abstract Objective The purpose of this study was to determine whether previous injury (PI) and/or concussion education (ce) significantly predicted collegiate athlete reporting skill (RS). It was hypothesized that both PI and ce would be significant predictors of RS. Methods A cross-sectional study design was implemented, and collegiate athletes (n = 105; age = 19.77 ± 1.23; sex = 53% female) from two institutions were included in the study. Participants were administered a demographic questionnaire to determine PI and ce prior to enrollment, and the Reporting Skill Scale (5-items) was administered to measure RS. A composite score (range: 1–5) was calculated where higher values indicated greater RS. A stepwise multivariable linear regression was used to determine the predictive value of PI and ce on RS (a priori p < 0.05). Results A high percentage of the sample reported PI (n = 52, 49%), received ce (n = 83, 78%), and had high levels of RS (4.27 ± 0.68). The stepwise multivariable linear regression generated a one predictor model where ce significantly predicted RS (F(1,105) = 4.804, p = 0.03, R2 = 0.05, β = 0.35, 90% CI [0.33, 0.67]), whereas PI did not significantly predict RS (p = 0.83, β = −0.22). Conclusions The study revealed that ce partially predicts RS in collegiate athletes. Although the predicted variance was small, this highlights that educating athletes on the steps needed to report an injury is better suited for influencing the psychomotor domain of concussion reporting than simply experiencing a PI. Determining an athlete’s RS, including the factors that influence it, can aid clinicians in identifying athletes that may not fully understand how to report a concussion following injury.

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