scholarly journals Evaluation of dimensional accuracy of dental bridges manufactured with conventional casting technique and CAD/CAM system with Ceramill Sintron blocks using CMM

2018 ◽  
Vol 12 (4) ◽  
pp. 264-271 ◽  
Author(s):  
Alireza Izadi ◽  
Fariborz Vafaee ◽  
Arash Shishehian ◽  
Ghodratollah Roshanaei ◽  
Behzad Fathi Afkari
Keyword(s):  
Reference Model ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Three Dimensions ◽  
Casting Technique ◽  
Dimensional Changes ◽  
Conventional Casting ◽  
Cad Cam ◽  
Milling Method ◽  
Measuring Machine

Background. Recently, non-presintered chromium-cobalt (Cr-Co) blocks with the commercial name of Ceramill Sintron were introduced to the market. However, comprehensive studies on the dimensional accuracy and fit of multi-unit frameworks made of these blocks using the coordinate measuring machine (CMM) are lacking. This study aimed to assess and compare the dimensional changes and fit of conventional casting and milled frameworks using Ceramill Sintron. Methods. A metal model was designed and scanned and 5-unit frameworks were fabricated using two techniques: (I) the conventional casting method (n=20): the wax model was designed, milled in the CAD/CAM machine, flasked and invested; (II) the milling method using Ceramill Sintron blocks (n=20): the wax patterns of group 1 were used; Ceramill Sintron blocks were milled and sintered. Measurements were made on the original reference model and the fabricated frameworks using the CMM in all the three spatial dimensions, and dimensional changes were recorded in a checklist. Data were analyzed with descriptive statistics, and the two groups were compared using one-way ANOVA and Tukey test (α=0.05). Results. The fabricated frameworks in both groups showed significant dimensional changes in all the three dimensions. Comparison of dimensional changes between the two groups revealed no significant differences (P>0.05) except for transverse changes (arch) that were significantly greater in Ceramill Sintron frameworks (P<0.05). Conclusion. The two manufacturing processes were the same regarding dimensional changes and the magnitude of marginal gaps and both processes resulted in significant dimensional changes in frameworks. Ceramill Sintron frameworks showed significantly greater transverse changes than the conventional frameworks.

scholarly journals In Vitro Comparative Evaluation of Different Types of Impression Trays and Impression Materials on the Accuracy of Open Tray Implant Impressions: A Pilot Study

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Sonam Gupta ◽  
Aparna Ichalangod Narayan ◽  
Dhanasekar Balakrishnan
Keyword(s):  
Reference Model ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Impression Material ◽  
Impression Materials ◽  
Significant Difference ◽  
Different Types ◽  
Measuring Machine ◽  
The Difference

Purpose. For a precise fit of multiple implant framework, having an accurate definitive cast is imperative. The present study evaluated dimensional accuracy of master casts obtained using different impression trays and materials with open tray impression technique.Materials and Methods. A machined aluminum reference model with four parallel implant analogues was fabricated. Forty implant level impressions were made. Eight groups (n=5) were tested using impression materials (polyether and vinylsiloxanether) and four types of impression trays, two being custom (self-cure acrylic and light cure acrylic) and two being stock (plastic and metal). The interimplant distances were measured on master casts using a coordinate measuring machine. The collected data was compared with a standard reference model and was statistically analyzed using two-way ANOVA.Results. Statistically significant difference (p<0.05) was found between the two impression materials. However, the difference seen was small (36 μm) irrespective of the tray type used. No significant difference (p>0.05) was observed between varied stock and custom trays.Conclusions. The polyether impression material proved to be more accurate than vinylsiloxanether impression material. The rigid nonperforated stock trays, both plastic and metal, could be an alternative for custom trays for multi-implant impressions when used with medium viscosity impression materials.

scholarly journals Computer-aided preparation of detail production on numerically controlled lathes

Mechanik ◽  
2019 ◽  
Vol 92 (8-9) ◽  
pp. 594-596
Author(s):  
Marcin Sobiegraj ◽  
Piotr Sikora ◽  
Andrzej Zaborski
Keyword(s):  
Computer Simulation ◽  
Production Process ◽  
Coordinate Measuring Machine ◽  
Control Software ◽  
Computer Aided ◽  
Cad Cam ◽  
Measuring Machine ◽  
Cam Systems

The study presents the possibility of using modern CAD/CAM systems for computer simulation of the process of making the detail on a numerically controlled lathe MIYANO BNA 42GTY. The Alkard CNC Wizard software was used. To verify the correctness of the implemented production process, a coordinate measuring machine Zeiss Prismo 5 with a Renishaw PH-20 head was used. The measurements were carried out using the Modus control software.

Experimental Investigations for Rapid Moulding Solution of Plastics Using Polyjet Printing

2011 ◽  
Vol 701 ◽  
pp. 15-20 ◽  
Author(s):  
Rupinder Singh ◽  
Varinderjit Singh
Keyword(s):  
Plastic Material ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Point Of View ◽  
Experimental Investigations ◽  
Support Material ◽  
Economic Point ◽  
Measuring Machine ◽  
Plastic Components ◽  
Polyjet Printing

Rapid prototyping (RP) has been in evidence for the past twenty years and is being widely used in diverse areas, from the building of aesthetic and functional prototypes to the production of tools and moulds for technological prototypes. The purpose of the present study is to experimentally investigate the rapid moulding (RM) solutions for plastic components using polyjet printing (PP) technique. Starting from the identification of component/benchmark, prototypes with three different type of plastic material were produced, at different orientation and support material. Measurements on the coordinate measuring machine helped in calculating the dimensional tolerances of the plastic components produced. Some important mechanical properties were also compared to verify the suitability of the components. The study highlighted the best orientation, support material quantity and type of plastic material for the selected component from dimensional accuracy and economic point of view as RM solution for plastic components. This process ensures rapid production of pre-series technological prototypes and proof of concept at less production cost and time.

scholarly journals Dimensional Stability and Process Capability of an Industrial Component Injected with Recycled Polypropylene

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1063 ◽  
Author(s):  
José Eduardo Galve ◽  
Daniel Elduque ◽  
Carmelo Pina ◽  
Isabel Clavería ◽  
Raquel Acero ◽  
...  
Keyword(s):  
Environmental Impact ◽  
Dimensional Stability ◽  
Process Capability ◽  
Coordinate Measuring Machine ◽  
Storage Conditions ◽  
Dimensional Changes ◽  
Injection Process ◽  
Recycled Polypropylene ◽  
Measuring Machine ◽  
Recycled Material

The usage of recycled polymers for industrial purposes arises as one of the most promising methods of reducing environmental impact and costs associated with scrapping parts. This paper presents a systematic study of the dimensional stability of a raw and 100% recycled polypropylene subjected to realistic environmental conditions occurring along its working life. The component studied is an internal part of an induction hob assembly. Industrial samples manufactured with both materials, in the same mold, and in the same injection machine, are subjected to ejection conditions, storage conditions (50 °C), and extreme performance conditions (80 °C). Induced dimensional changes are registered and analyzed using a coordinate measuring machine, and a tactile sensing probe. To verify the process capability of the samples manufacturing, Cp and Cpk values are calculated to evaluate the suitability of the recycled material as an alternative. Results conclude that, although the use of recycled material implies slight differences in terms of dimensional stability due to the changes induced in the polymer structure, these differences are not significant enough to affect the injection process capability. Therefore, recycling arises as one effective method to reduce both overruns associated with the consumption of raw polypropylene material and its environmental impact.

Assessment of Free-Form Surfaces’ Reconstruction Accuracy

2017 ◽  
Vol 24 (2) ◽  
pp. 303-312 ◽  
Author(s):  
Artur Wójcik ◽  
Magdalena Niemczewska-Wójcik ◽  
Jerzy Sładek
Keyword(s):  
Accuracy Assessment ◽  
Coordinate Measuring Machine ◽  
System Structure ◽  
Free Form ◽  
Correction Algorithm ◽  
Reconstruction Accuracy ◽  
Machining Center ◽  
Cad Cam ◽  
Measuring Machine ◽  
Free Form Surfaces

AbstractThe paper presents the problem of assessing the accuracy of reconstructing free-form surfaces in the CMM/CAD/CAM/CNC systems. The system structure comprises a coordinate measuring machine (CMM) PMM 12106 equipped with a contact scanning probe, a 3-axis Arrow 500 Vertical Machining Center, QUINDOS software and Catia software. For the purpose of surface digitalization, a radius correction algorithm was developed. The surface reconstructing errors for the presented system were assessed and analysed with respect to offset points. The accuracy assessment exhibit error values in the reconstruction of a free-form surface in a range of ± 0.02 mm, which, as it is shown by the analysis, result from a systematic error.

scholarly journals Characterization of machining quality attributes based on spindle probe, coordinate measuring machine, and surface roughness data

2014 ◽  
Vol 1 (2) ◽  
pp. 128-139 ◽  
Author(s):  
Tzu-Liang Bill Tseng ◽  
Yongjin James Kwon
Keyword(s):  
Surface Roughness ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Quality Characteristics ◽  
Machining Parameters ◽  
Production Environment ◽  
Significant Interaction Effect ◽  
Machining Quality ◽  
Measuring Machine ◽  
Touch Probe

Abstract This study investigates the effects of machining parameters as they relate to the quality characteristics of machined features. Two most important quality characteristics are set as the dimensional accuracy and the surface roughness. Before any newly acquired machine tool is put to use for production, it is important to test the machine in a systematic way to find out how different parameter settings affect machining quality. The empirical verification was made by conducting a Design of Experiment (DOE) with 3 levels and 3 factors on a state-of-the-art Cincinnati Hawk Arrow 750 Vertical Machining Center (VMC). Data analysis revealed that the significant factor was the Hardness of the material and the significant interaction effect was the Hardness + Feed for dimensional accuracy, while the significant factor was Speed for surface roughness. Since the equally important thing is the capability of the instruments from which the quality characteristics are being measured, a comparison was made between the VMC touch probe readings and the measurements from a Mitutoyo coordinate measuring machine (CMM) on bore diameters. A machine mounted touch probe has gained a wide acceptance in recent years, as it is more suitable for the modern manufacturing environment. The data vindicated that the VMC touch probe has the capability that is suitable for the production environment. The test results can be incorporated in the process plan to help maintain the machining quality in the subsequent runs.

Experimental Investigations for Statistically Controlled Rapid Moulding Solution of Plastics Using Polyjet Printing

2010 ◽  
Author(s):  
Rupinder Singh ◽  
Varinderjit Singh ◽  
Manohar Singh Saini
Keyword(s):  
Plastic Material ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Point Of View ◽  
Experimental Investigations ◽  
Economic Point ◽  
The Past ◽  
Measuring Machine ◽  
Plastic Components ◽  
Polyjet Printing

Rapid prototyping (RP) has been in evidence for the past twenty years and is being widely used in diverse areas, from the building of aesthetic and functional prototypes to the production of tools and moulds for technological prototypes. The purpose of the present study is to experimentally investigate statistically controlled rapid moulding (RM) solutions for plastic components using polyjet printing (PP). Starting from the identification of component/benchmark, prototypes with three different type of plastic material were prepared, at different orientations. Measurements on the coordinate measuring machine helped in calculating the dimensional tolerances of the components prepared. Some important mechanical properties were also compared to verify the suitability of the components. The study highlighted the best orientation, support material quantity and type of plastic material for the selected component from dimensional accuracy and economic point of view as RM solution for plastic components. Final components prepared are acceptable as per ISO standard UNI EN 20286-I (1995). This process ensures rapid production of statistically controlled pre-series technological prototypes and proof of concept at less production cost and time.

Dimensional Tolerance of Casting in the Bridgman Furnace Based on 3D Printing Techniques

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 299
Author(s):  
Xintao Zhu ◽  
Fu Wang ◽  
Dexin Ma ◽  
Andreas Bührig-Polaczek
Keyword(s):  
3D Printing ◽  
Investment Casting ◽  
Systematic Approach ◽  
Low Cost ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Metal Casting ◽  
Measuring Machine ◽  
Printing Techniques ◽  
Short Times

In this article, the feasibility and the dimensional accuracy based on the 3D printing technology during investment casting of non-vacuum and Bridgman furnace are investigated based on the coordinate measuring machine to calculate the dimensional tolerances through a systematic approach. The research proved that both the investigated RC solutions are effective at obtaining cast technological prototypes in short times and at low cost, with dimensional tolerances that are completely consistent with metal casting processes.

Evaluation of Different Internal Structure and Build Orientation for Multijet Modeling Process

2013 ◽  
Vol 315 ◽  
pp. 587-591 ◽  
Author(s):  
M.N. Hafsa ◽  
M. Ibrahim ◽  
S. Sharif ◽  
M.F.M. Omar ◽  
M.A. Zainol
Keyword(s):  
Surface Roughness ◽  
Internal Structure ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Part Quality ◽  
Modeling Process ◽  
Measuring Machine ◽  
Complex Parts ◽  
Processing Steps ◽  
Better Than

Rapid Prototyping (RP) technology has proven its capability to produce complex parts with shorter lead time. This advantage could benefit tremendously in application such as the Investment Casting (IC) process. The focus of the study is the production of sacrificial IC patterns produced using Multijet Modeling (MJM) RP technology. It includes the evaluation of dimensional accuracy and the surface roughness of part with a hollow and quasi hollow inner support patterns. Different internal structure's pattern were developed using CAD software, and the part were fabricated using MJM technique in two different build orientations. Analyses were done using Coordinate Measuring Machine (CMM) and the surface roughness tester. Results show that part built with 90º orientation is better than part built with 0º orientation both in terms of accuracies and roughness. Different internal structure similarly affects the final part quality, though the post processing steps also have their influence, thus making it no clear different among the parts. However, it demonstrated parts with square structure produced the best dimensional accuracy and the part with hatch structure produced the best surface roughness.

Computer-Aided Coordinate Metrology

1993 ◽  
Author(s):  
Hong-Tzong Yau ◽  
Chia-Hsiang Menq
Keyword(s):  
Three Dimensional ◽  
Coordinate Measuring Machine ◽  
Computer Integrated Manufacturing ◽  
Integrated Manufacturing ◽  
Coordinate Metrology ◽  
Cad Cam ◽  
Measuring Machine ◽  
Three Dimensional Coordinate ◽  
Inspection Machine ◽  
Accuracy And Repeatability

Abstract Three-dimensional coordinate metrology has gained much attention in recent years. On one hand, the accuracy and repeatability of a coordinate measuring machine (CMM) are approaching the sub-micron level. On the other hand, there is hardly any part that exists of which the dimensions cannot be measured with a CMM. This paper presents the recent development and applications in three-dimensional coordinate metrology. The emphasis has been placed in the utilization of computers and integration with CAD/CAM systems. Three important technologies, namely, CAD-directed inspection, three-dimensional optimal match, and reverse engineering are presented and discussed. With computers and CAD/CAM support, three-dimensional coordinate metrology has become an active part of the computer-integrated manufacturing (CIM). Its versatility and high degree of automation have made the CMM a universal inspection machine for quality control of manufactured parts in computer integrated manufacturing.

Sign in / Sign up

Export Citation Format

Share Document