The infrared camera application for calculating the impact of the feed screw thermal expansion on machining accuracy

2017 ◽  
Author(s):  
A. Matras
Keyword(s):  
Thermal Expansion ◽  
Infrared Camera ◽  
Machining Accuracy ◽  
Feed Screw ◽  
The Impact

scholarly journals Unravelling thermal stress due to thermal expansion mismatch in metal–organic frameworks for methane storage

2021 ◽  
Author(s):  
Jelle Wieme ◽  
Veronique Van Speybroeck
Keyword(s):  
Thermal Expansion ◽  
Thermal Stress ◽  
Pressure Coefficient ◽  
Metal Organic Frameworks ◽  
Methane Storage ◽  
Thermal Expansion Mismatch ◽  
Thermal Pressure ◽  
Temperature Changes ◽  
Metal Organic ◽  
The Impact

Thermal stress is present in metal–organic frameworks undergoing temperature changes during adsorption and desorption. We computed the thermal pressure coefficient as a proxy for this phenomenon and discuss the impact of thermal expansion mismatch.

The Study of Underfill Epoxy Hardness in Reducing Curing Process Time for Flip Chip Packaging

2011 ◽  
Vol 462-463 ◽  
pp. 1194-1199
Author(s):  
Zainudin Kornain ◽  
Azman Jalar ◽  
Rozaidi Rashid ◽  
Shahrum Abdullah
Keyword(s):  
Thermal Expansion ◽  
Flip Chip ◽  
Ball Grid Array ◽  
Process Time ◽  
Curing Process ◽  
Curing Time ◽  
Hold Temperature ◽  
Flip Chip Packaging ◽  
Time Cycle ◽  
The Impact

Underfilling is the vital process to reduce the impact of the thermal stress that results from the mismatch in the co-efficient of thermal expansion (CTE) between the silicon chip and the substrate in Flip Chip Packaging. This paper reported the pattern of underfill’s hardness during curing process for large die Ceramic Flip Chip Ball Grid Array (FC-CBGA). A commercial amine based underfill epoxy was dispensed into HiCTE FC-CBGA and cured in curing oven under a new method of two-step curing profile. Nano-identation test was employed to investigate the hardness of underfill epoxy during curing steps. The result has shown the almost similar hardness of fillet area and centre of the package after cured which presented uniformity of curing states. The total curing time/cycle in production was potentially reduced due to no significant different of hardness after 60 min and 120 min during the period of second hold temperature.

scholarly journals Climate Change Implications Found in Winter Extreme Sea Level Height Records around Korea

2021 ◽  
Vol 9 (4) ◽  
pp. 377
Author(s):  
Dong Eun Lee ◽  
Jaehee Kim ◽  
Yujin Heo ◽  
Hyunjin Kang ◽  
Eun Young Lee
Keyword(s):  
Climate Change ◽  
Thermal Expansion ◽  
Sea Level ◽  
El Niño ◽  
El Nino ◽  
Winter Season ◽  
Storm Tracks ◽  
Daily Maximum ◽  
The Impact ◽  
Level Height

The impact of climatic variability in atmospheric conditions on coastal environments accompanies adjustments in both the frequency and intensity of coastal storm surge events. The top winter season daily maximum sea level height events at 20 tidal stations around South Korea were examined to assess such impact of winter extratropical cyclone variability. As the investigation focusses on the most extreme sea level events, the impact of climate change is found to be invisible. It is revealed that the measures of extreme sea level events—frequency and intensity—do not correlate with the local sea surface temperature anomalies. Meanwhile, the frequency of winter extreme events exhibits a clear association with the concurrent climatic indices. It was determined that the annual frequency of the all-time top 5% winter daily maximum sea level events significantly and positively correlates with the NINO3.4 and Pacific Decadal Oscillation (PDO) indices at the majority of the 20 tidal stations. Hence, this indicates an increase in extreme event frequency and intensity, despite localized temperature cooling. This contradicts the expectation of increases in local extreme sea level events due to thermal expansion and global climate change. During El Nino, it is suggested that northward shifts of winter storm tracks associated with El Nino occur, disturbing the sea level around Korea more often. The current dominance of interannual storm track shifts, due to climate variability, over the impact of slow rise on the winter extreme sea level events, implies that coastal extreme sea level events will change through changes in the mechanical drivers rather than thermal expansion. The major storm tracks are predicted to continue shifting northward. The winter extreme sea level events in the midlatitude coastal region might not go through a monotonic change. They are expected to occur more often and more intensively in the near future, but might not continue doing so when northward shifting storm tracks move away from the marginal seas around Korea, as is predicted by the end of the century.

scholarly journals An assessment of the impact of improvised versus conventional laboratory equipment on students’ performance in thermal expansion

2019 ◽  
Vol 15 (1) ◽  
pp. 135-140
Author(s):  
Kizito Ndihokubwayo ◽  
Jean Uwamahoro ◽  
Irénée Ndayambaje
Keyword(s):  
Thermal Expansion ◽  
Secondary School ◽  
Secondary School Students ◽  
Statistical Significance ◽  
Test Design ◽  
Lower Secondary School ◽  
School Students ◽  
Laboratory Equipment ◽  
Post Test ◽  
The Impact

Science education in Rwandan schools still faces a number of challenges including the lack or shortage of equipment available for science experiments. This paper describes research conducted to assess the impact of using improvised versus conventional laboratory equipment in experiments. Eighty-five lower secondary school students were assessed using a semi-experimental post-test design on thermal expansion of bodies. Data analysis using a t-test produced a t-Stat of 2.74 over a t-Critical of 1.98 indicating a statistical significance between the two experimental groups in favour of the group using improvised equipment. As a result, it is recommended that improvised equipment be used in those instances in which there is a lack or shortage of conventional equipment since students’ achievement was similar regardless of the type of equipment used.

Effect of layer thickness on irreversible thermal expansion and interlayer strength in fused deposition modeling

2017 ◽  
Vol 23 (5) ◽  
pp. 943-953 ◽  
Author(s):  
Anthony A. D’Amico ◽  
Analise Debaie ◽  
Amy M. Peterson
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Flexural Strength ◽  
Layer Thickness ◽  
Fused Deposition Modeling ◽  
Thermal Strain ◽  
Content Type ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
The Impact

Purpose The aim of this paper is to examine the impact of layer thickness on irreversible thermal expansion, residual stress and mechanical properties of additively manufactured parts. Design/methodology/approach Samples were printed at several layer thicknesses, and their irreversible thermal expansion, tensile strength and flexural strength were determined. Findings Irreversible thermal strain increases with decreasing layer thickness, up to 22 per cent strain. Tensile and flexural strengths exhibited a peak at a layer thickness of 200 μm although the maximum was not statistically significant at a 95 per cent confidence interval. Tensile strength was 54 to 97 per cent of reported values for injection molded acrylonitrile butadiene styrene (ABS) and 29 to 73 per cent of those reported for bulk ABS. Flexural strength was 18 to 41 per cent of reported flexural strength for bulk ABS. Practical implications The large irreversible thermal strain exhibited that corresponding residual stresses could lead to failure of additively manufactured parts over time. Additionally, the observed irreversible thermal strains could enable thermally responsive shape in additively manufactured parts. Variation in mechanical properties with layer thickness will also affect manufactured parts. Originality/value Tailorable irreversible thermal strain of this magnitude has not been previously reported for additively manufactured parts. This strain occurs in parts made with both high-end and consumer grade fused deposition modeling machines. Additionally, the impact of layer thickness on tensile and flexural properties of additively manufactured parts has received limited attention in the literature.

Analysis of the Effects of Multi-Clamps Fixture on Workpiece Location Errors

2008 ◽  
Vol 375-376 ◽  
pp. 619-625 ◽  
Author(s):  
Guo Hua Qin ◽  
Shi Ping Sun ◽  
Zhi Xiong Chen ◽  
Tie Jun Wu ◽  
Zhi Qiang Ao
Keyword(s):  
Contact Forces ◽  
Machining Accuracy ◽  
Location Error ◽  
Location Errors ◽  
Numerical Tests ◽  
Proposed Model ◽  
One Step ◽  
Fixture System ◽  
The Impact ◽  
Novel Design

Multiple clamps are frequently used to serve the purpose of workholding in a fixture. So multiple clamping forces including their magnitudes, placements and application sequences, greatly influence contact forces and workpiece machining accuracy. In this paper, the impact of multiple clamping forces on workpiece location error is formulated analytically for a workpiece-fixture system. The proposed model takes into account the varying contact forces and friction force during entire clamping operation. It reveals that the historical accumulation of clamping steps influences heavily the final distribution of contact forces in the workpiece-fixture system. In addition, based on effect of contact forces from one step to another on workpiece location, a novel design model is presented to optimize the multiple clamping forces in order to minimize the workpiece location errors. Some numerical tests are finally demonstrated to validate the proposed model and approach.

Interface Cracking of Plastic Electronic Package under Temperature and Humidity Environment

2007 ◽  
Vol 353-358 ◽  
pp. 2940-2943
Author(s):  
Xu Chen ◽  
Shu Feng Zhao ◽  
Linda Zhai
Keyword(s):  
Thermal Expansion ◽  
Vapor Pressure ◽  
Crack Propagation ◽  
Crack Length ◽  
Structural Model ◽  
Electronic Package ◽  
Temperature And Humidity ◽  
Interface Cracking ◽  
The Impact ◽  
Humidity Environment

Structural model of plastic electronic package under temperature and humidity is constructed, and the coupling of the thermal and moisture impact on structure field is implemented. The impact of thermal expansion, hygro-swelling and vapor pressure increases with increasing initial defect, especially the impact of vapor pressure. At certain crack length, KI and KII induced by thermal expansion is proportional to temperature difference, and KI and KII induced by vapor is proportional to vapor pressure. The impacts of thermal expansion and hygro-swelling on ERR decrease during crack propagation, but the impact of vapor pressure increases significantly.

A Finite Element Analysis of the Normal Combination Round and Spline Broach Based on ANSYS

2011 ◽  
Vol 383-390 ◽  
pp. 1831-1836
Author(s):  
Guang Guo Zhang ◽  
Jing Sheng ◽  
Feng Wang
Keyword(s):  
3D Model ◽  
Machining Accuracy ◽  
Element Analysis ◽  
Partial Fracture ◽  
Whole Process ◽  
Traditional Design ◽  
Design Cycle ◽  
3D Solid ◽  
The Impact ◽  
3D Solid Modeling

In the traditional design of round broach ,the impact tools of broach maybe unable to achieve the requirements for the processing precision, or even occur the situation of partial fracture due to a exaggerated partial deformation. In this article, by using Pro/E we complete the 3D solid modeling and the dimensional parameterization of the impact tools for combination round and spline broach, then import the 3D model into ANSYS, to analyze and solve the whole process of load and deformation at work. It can effectively improve the machining accuracy and the reliability of round broach, shorten the design cycle and reduce cost.

scholarly journals Properties of core-half wrapped shell structure wood-polymer composites containing glass fiber-reinforced shells

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 9088-9102
Author(s):  
Runzhou Huang ◽  
Xian Zhang ◽  
Zhuangzhuang Teng ◽  
Fei Yao
Keyword(s):  
Thermal Expansion ◽  
Glass Fiber ◽  
Polymer Composites ◽  
Mechanical Performance ◽  
Impact Resistance ◽  
Shell Layer ◽  
Flame Resistance ◽  
Wood Polymer ◽  
Wood Polymer Composites ◽  
The Impact

Glass fiber (GF) is commonly applied as a filler in the preparation of polymer composites. Due to the presence of GF, composite mechanical performance, flame resistance, and thermal performance could be greatly improved. The influence of a GF-filled polymer shell layer was investigated relative to the morphology, mechanical, thermal, and fire flammability performance of the core-half wrapped shell structured wood high-density polyethylene (HDPE) composites prepared via co-extrusion. The use of the relatively less-stiff pure HDPE with high linear coefficients of thermal expansion (LCTEs) lowered the general thermal stability and modulus of the wood polymer composites (WPCs). Flexural and thermal expansion properties were improved for the GF-filled HDPE shells in comparison to the unmodified material, enabling a well-balanced performance of this novel core–shell material. Implementation of GF-modified HDPE or unmodified HDPE layers as a shell for WPC core remarkably improved the impact resistance of the co-extruded WPCs. In comparison with composites possessing unmodified HDPE shell, the flame resistance performance of the shell layer was slightly improved in case that the GF content was below 25 wt%. A slight decrease in composite general heat release and rate was discovered in case that the GF content was greater than 25 wt%.

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