Investigation on Influences by Adapting Additives to Electrolytic In-Process Dressing (ELID) Grinding

2010 ◽  
Vol 447-448 ◽  
pp. 169-173
Author(s):  
Ning Lou ◽  
Ioan D. Marinescu ◽  
Michael C. Weismiller
Keyword(s):  
Manufacturing Industry ◽  
Grinding Process ◽  
Mirror Surface ◽  
Chemical Additives ◽  
Efficient Technology ◽  
Metallic Oxide ◽  
High Quality ◽  
Elid Grinding ◽  
Before And After ◽  
Hard And Brittle Materials

As demand for high-quality machined tools considerably grows, ELID, a new and efficient technology, has been successfully brought into the precise manufacturing industry of hard and brittle materials with mirror surface finish. Hence, besides conventional functions like lubrication, fluid solutions in this grinding process are required to serve more functions, especially as electrolyte. Writers of this paper mainly work on the methodology to optimize this kind of fluid by adding various related chemical additives. By varying the pH, the accretion of additives is controlled and consequential effects are studied which is the metallic oxide layer variation before and after each test. Corresponding experiments have been carried out with procedures and results analysis included in the paper.

Study on Material Removal Mechanism of Silicon Nitride during ELID Ultraprecision Grinding

2011 ◽  
Vol 314-316 ◽  
pp. 1740-1745
Author(s):  
Wei Dong Jin
Keyword(s):  
Silicon Nitride ◽  
Material Removal ◽  
Dynamic Balance ◽  
Grinding Process ◽  
Silicon Nitride Ceramic ◽  
Elid Grinding ◽  
Hard And Brittle Materials ◽  
Plastic Shearing ◽  
Material Removal Mode ◽  
Passivating Films

Based on the analyzing ultraprecision grinding process of hard and brittle materials, taking ELID grinding of silicon nitride ceramic as an example, active control technology of passivating films state was introduced in this paper. ELID ultraprecision grinding process respectively at adaptive dynamic balance mode, discontinuous electrolyzing mode and discontinuous grinding mode had been comparatively studied. By means of AFM used for analyzing surface topography of parts, studies show that material removal method for ELID grinding is always a combination of micro brittle fracture, plastic shearing, lapping and polishing action, and which is the main material removal mode depends on the actual grinding contact state. Finally, finishing surface generating mechanism for silicon nitride in ELID ultraprecision grinding was summed up.

scholarly journals ELID Mirror Surface Grinding for Concave Molds by Conductive Elastic Wheel Containing Carbon Black

2022 ◽  
Vol 16 (1) ◽  
pp. 21-31
Author(s):  
Atsushi Ezura ◽  
Katsufumi Inazawa ◽  
Kazuhiro Omori ◽  
Yoshihiro Uehara ◽  
Nobuhide Itoh ◽  
...  
Keyword(s):  
Carbon Black ◽  
Removal Rate ◽  
Surface Finishing ◽  
Grinding Wheel ◽  
Butadiene Rubber ◽  
Mirror Surface ◽  
Grinding Wheels ◽  
High Quality ◽  
Shape Accuracy ◽  
Elid Grinding

Elastic grinding wheels have previously been adopted for the development of the mirror surface finishing method for concave spheres. In this study, new conductive elastic grinding wheels, to which electrolytic in-process dressing (ELID) can be applied, are developed; the aim of the study is to address the challenge of maintaining a constant removal rate for rubber bond wheels. When ELID grinding is performed using a non-diene (isobutane isoprene rubber, IIR)-based wheel, a larger removal amount is achieved, and a higher-quality surface is also achieved compared to a diene (acrylonitrile-butadiene rubber, NBR)-based wheel. In addition, to investigate the effect of grinding wheel bond hardness on the removal amount and ground shape accuracy, grinding wheels with various levels of hardness are prepared by controlling the amount of carbon black contained in them, and grinding experiments are conducted. Thus, a larger removal amount is achieved using a harder grinding wheel, but the roughness of the ground surfaces deteriorates. Therefore, in practice, it is necessary to select an appropriate grinding wheel that can achieve both productivity and surface quality. Finally, to obtain a high-quality mirror finish on a concave spherical surface, ELID grinding is performed on the workpieces as is done for spherical lens molds. Thus, high-quality mirror surfaces with roughness Ra < 10 nm were generated. When the work pieces are ground using a grinding wheel of the same radius, excessive removal occurs at the edge of the concave spherical profile, decreasing the form accuracy. Numerical simulation demonstrates that chamfering of the grinding wheel is effective for improving the shape accuracy. The results of this study are expected to contribute to automation and cost reduction in the mirror-finishing process for concave molds.

Real Earnings Management before and after Reporting SOX 404 Material Weaknesses

2015 ◽  
Vol 30 (1) ◽  
pp. 119-141 ◽  
Author(s):  
Tuukka Järvinen ◽  
Emma-Riikka Myllymäki
Keyword(s):  
Earnings Management ◽  
Internal Control ◽  
Internal Controls ◽  
Real Earnings Management ◽  
Public Disclosure ◽  
High Quality ◽  
The Public ◽  
Material Weaknesses ◽  
Internal Control System ◽  
Before And After

SYNOPSIS The purpose of this study is to investigate whether SOX Section 404 material weaknesses manifest in real earnings management behavior. The empirical findings indicate that, compared to companies with effective internal controls, companies with existing material weaknesses in their internal controls engage in more manipulation of real activities (particularly inventory overproduction). This implies that the weak commitment by management to provide effective internal control system and high-quality financial information relates to a tendency to use real earnings management methods. Moreover, we find evidence suggesting that companies employ real earnings management (overproduction and reduction of discretionary expenses) after disclosing previous year's material weaknesses. We conjecture that the public disclosure of material weaknesses induces management to strive to mitigate the expected negative reactions of stakeholders to the disclosure by engaging in real earnings management, which is not easily detected or constrained by outsiders. Overall, this study suggests that material weaknesses in internal controls signal an environment where management is more inclined to employ real earnings management.

The behavior of managers handling digital business transformations: theoretical issues and preliminary evidence from firms in the manufacturing industry

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Diego Matricano ◽  
Laura Castaldi ◽  
Mario Sorrentino ◽  
Elena Candelo
Keyword(s):  
Organizational Culture ◽  
Case Studies ◽  
Manufacturing Industry ◽  
Qualitative Content Analysis ◽  
Preliminary Evidence ◽  
Digital Innovation ◽  
Content Type ◽  
Textual Data ◽  
Before And After ◽  
Theoretical Issues

PurposeOrganizational culture plays a central role when dealing with the issue of digital business transformation (DBT). Managers handling a DBT and involved in digital strateging are expected to modify the organizational culture of firms to make it more fitting with the paradigm of digital economy and having more chance of success. Thus, it is noteworthy to inspect the role they can have over DBTs. Accordingly, the purpose of this paper is to investigate the behavior that managers assume when they approach DBTs by investigating whether they act as mentors/facilitators or entrepreneurs/innovators, as coordinators or decision makers.Design/methodology/approachTo achieve the above purpose, ten case studies about manufacturing firms have been selected. Case studies, retrieved by the Digital Innovation Observatories of the School of Management of the Politecnico di Milano, are studied and analyzed by means of a qualitative content analysis on textual data. This allows getting specific insights into organizational culture before and after DBT and about the role played by managers.FindingsAchieved results disclose that managers need to modify the organizational culture of their firms to handle a successful DBT. However, firms can assume different organizational culture and thus the role assumed by managers handling a DBT can change as well.Originality/valueTo the authors knowledge, this paper is among the first that aim to investigate the role that mangers assume when handling DBTs. In particular, originality lies in the fact that assumed roles are rebuilt in reference to their ability to modify organizational culture.

Energy and Resources Recovery from Gasified Screenings and Toxic Sludge

2021 ◽  
Vol 1045 ◽  
pp. 194-202
Author(s):  
Siviwe H. Bunge ◽  
James L. Topkin ◽  
Joshua Gorimbo ◽  
Diakanua B. Nkazi
Keyword(s):  
Liquid Fuel ◽  
Energy Content ◽  
Chemical Species ◽  
Adsorption Properties ◽  
Fuel Production ◽  
Management Options ◽  
High Quality ◽  
Oil Resources ◽  
Bio Oil ◽  
Before And After

Sludge and screenings management is increasingly becoming a dilemma due its accumulating and tightening environmental regulations that limit its disposal methods. Various sludge management options have been researched, ranging from incineration, thermochemical liquefaction, to pyrolysis and gasification. This work proposes syngas, bio-oil, chemical resources and bio-char production for beneficiation through gasification of a mixture of sludge and screenings at different ratios of 25/75, 50/50 and 75/25. It also studies mass loss and toxins possible destruction by gasification temperatures and reactions. Toxicity and CHNS analysis before and after gasification were aimed at finding sludge energy content, while thermogravimetric analysis (TGA), was to find sampling and stopping temperatures during gasification. The overall best results of high syngas quality (high LHV, H2, CO and CH4 contents) and high quality bio-oil (i.e. cleanest, with high crude oil equivalent bonds such as C1 up to C36 and higher applicable bio-oil resources and chemical species obtained) was achieved by a 75/25 ratio, followed by a 50/50 ratio. The results also showed some possibility of biological and chlorinated hydrocarbon toxins (PCBs and PAHs) break down as well as the reduction of sludge and screenings to about 32% of the initial mass. These results can be further investigated for syngas application in power generation and liquid fuel production. Char toxicity can be analysed for its application in agriculture and for its adsorption properties. Char can be analysed for the presence of metals in it.

INVESTIGATION ON HIGH-TEMPERATURE OXIDIZATION OF MIRROR-QUALITY GROUND STAINLESS STEEL

2010 ◽  
Vol 24 (15n16) ◽  
pp. 3005-3010 ◽  
Author(s):  
KAZUTOSHI KATAHIRA ◽  
HITOSHI OHMORI ◽  
MASAYOSHI MIZUTANI ◽  
JUN KOMOTORI
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
High Temperature ◽  
High Quality ◽  
Spinel Type ◽  
Combined Process ◽  
Elid Grinding ◽  
Modification Method ◽  
Quality Surface ◽  
High Quality Surface

To investigate the possibility of developing a new surface modification method by the combined process of ELID grinding and high-temperature oxidization, we treated ELID finished specimens and polished specimens by high-temperature oxidization in the atmosphere and performed detailed analysis to determine how the treatment would change the specimen surfaces. The ELID-series showed high quality surface roughness and excellent tribological characteristics as compared with the polished-series. The improved surface properties of the ELID-series seem to result from formation of fine, uniform structures of spinel-type multiple oxides FeCr 2 O 4 and Cr 2 O 3 on the surface by high-temperature oxidization.

Surface Behaviors of ELID Ground Engineering Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 1469-1472 ◽  
Author(s):  
Jian Yun Shen ◽  
Wei Min Lin ◽  
Hitoshi Ohmori ◽  
Xi Peng Xu
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Material Removal ◽  
Grinding Process ◽  
Removal Mechanism ◽  
Material Removal Mechanism ◽  
Silicon Nitride Ceramic ◽  
Engineering Ceramics ◽  
Elid Grinding ◽  
Engineering Ceramic

In this study, grinding of Si3N4, SiC, and Al2O3 ceramics under the condition of electrolytic in-process dressing (ELID) system was investigated. The surface appearances of these engineering ceramics during the ELID grinding process were attentively observed to describe the formation of finely finished surfaces. Based on the analysis of material properties and detailed micro-observation of ground surfaces, it can be concluded that the material removal mechanism of engineering ceramic is closely related to its mechanical properties. The silicon nitride ceramic was most easily machined to precision surface among these three engineering ceramics.

Sign in / Sign up

Export Citation Format

Share Document