Solidification of thermoviscoelastic melts. Part II: Effects of processing conditions on shrinkage and residual stresses

1995 ◽  
Vol 35 (4) ◽  
pp. 365-383 ◽  
Author(s):  
Wit C. Bushko ◽  
Vijay K. Stokes
Keyword(s):  
Residual Stresses ◽  
Processing Conditions

scholarly journals Fatigue Fracture Properties and Morphology of Polyoxymethylene (POM) Plates Produced under Moderate Processing Conditions

2018 ◽  
Vol 2018 ◽  
pp. 1-18 ◽  
Author(s):  
M. Berer ◽  
M. Halb ◽  
M. Feuchter ◽  
G. Pacher ◽  
G. Pinter
Keyword(s):  
Injection Molding ◽  
Residual Stresses ◽  
Fatigue Fracture ◽  
Hierarchical Structure ◽  
Strong Dependence ◽  
Combined Effect ◽  
The Other ◽  
Processing Conditions ◽  
Fracture Properties ◽  
Fracture Performance

The present study was inspired by different industry projects in which a strong dependence of the fatigue fracture performance of POM on the processing conditions was observed. To examine the relationships under more reproducible conditions, plates of two different POM homopolymer resins (one significantly nucleated) were produced by compression molding and by injection molding under moderate conditions. For the injection molding, three different mold temperatures were used. At specific locations, the plates were analyzed concerning their hierarchical structure on the micro- and nanolevel and concerning their fatigue fracture performance. For the fatigue fracture performance, the dependence on the processing conditions was rather small for the nucleated resin but much more significant for the other resins. This dependence could not be related to morphological effects only, and thus, a combined effect of morphology and residual stresses was assumed.

Processing Optimization of Optical Lens in the Injection Molding

2013 ◽  
Vol 813 ◽  
pp. 161-164 ◽  
Author(s):  
Chao Ming Lin ◽  
Chih Kun Wang
Keyword(s):  
Residual Stress ◽  
Refractive Index ◽  
Residual Stresses ◽  
Processing Parameters ◽  
Processing Conditions ◽  
Fringe Order ◽  
Optimal Method ◽  
Optical Lens ◽  
Injection Molded ◽  
Processing Optimization

The processing conditions during the manufacturing have critical effects on the optical performances of the molded lenses including the refractive index, isochromatic fringe order, and the fringed pattern. The objective of this work is to investigate numerically some effects of the molding conditions on the residual stresses of injection molded lenses, and then to optimal the processing parameters for reducing the residual stresses using the Taguchi method. The results show the optimal method is able to improve the residual stress and to produce a good fringed pattern.

Residual Stresses and Workpiece Deformation Due to Polishing and Plating of Computer Hard Disk Substrates

1999 ◽  
Vol 121 (1) ◽  
pp. 32-40 ◽  
Author(s):  
B. E. Klamecki
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Residual Stresses ◽  
Processing Conditions ◽  
Bending Moments ◽  
Stress Distributions ◽  
Material Deformation ◽  
Removal Processes ◽  
Insight Into ◽  
Shape Data

Residual stress distributions due to plating and polishing were determined for nickel-phosphorus plated aluminum alloy disks. Knowledge of these stresses provides insight into the material deformation and removal processes, information as to the effects of processing conditions on residual stress magnitude and can also serve as a basis for development of models of material deformation and removal in polishing. Measured disk shape data was fitted to an analytical solution for plate displacement due to bending moments, and residual stresses were calculated. Plating and polishing residual stresses were separated. Polishing residual stress is compressive indicating differential plastic deformation between the surface and interior regions of the workpiece. Residual stresses produced in polishing operations in which process motions were constrained so that polishing was unidirectional were measured. The results show large differences between amounts of deformation in the polishing direction and the direction perpendicular to it.

Carbides

Carburizing ◽  
1999 ◽  
pp. 51-75
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Residual Stresses ◽  
Alloying Elements ◽  
Processing Conditions ◽  
Carbide Phases ◽  
Composition And Structure ◽  
Fracture Behaviors ◽  
Fatigue And Fracture ◽  
Carburizing Process

Abstract This chapter discusses the formation of free carbides and their effect on case-carburized components. It explains how alloying elements influence the composition and structure of carbide phases produced at cooling rates typical of carburizing process. It describes the morphology and distribution of the various types of carbides formed and explains how they affect mechanical properties such as hardness, residual stresses, fatigue and fracture behaviors, and wear resistance. It also provides guidance for determining what processing conditions to avoid and when and why parts should be rejected.

Mechanical Characterization of Photoresist Polymer Coatings as a Function of Processing History

1991 ◽  
Vol 226 ◽  
Author(s):  
Kun Tong ◽  
Jeffery F. Taylor ◽  
Richard J. Farris
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Practical Importance ◽  
Uv Curing ◽  
Polymer Coatings ◽  
Curing Temperature ◽  
Processing Conditions ◽  
Stress Development ◽  
History Of ◽  
Different Origins

AbstractPhotoresist polymer coatings in the film-substratum systems usually generate selfinduced residual stress during processing. It is believed that the residual stress is the driving force for buckling, cracking and delamination of the polymer coatings. Analysis of the residual stress development during processing is of great interest and practical importance.Holographic interferometry technique has been developed for the direct measurements of general 2-dimensional stresses in thin films.[l] It turns out that it is a powerful technique to analyze residual stress development in polymer coatings during processing. By directly measuring the residual stress for each processing stage, the history of residual stress evolution can be closely followed and the residual stresses generated from different origins can be separated. By varying UV curing dosage, thermal curing temperature and the sequence of thermal and UV curing procedures, different residual stresses from various processing conditions can be comprehensively analyzed. Combining these data with mechanical properties of the coating offers valuable information for better understanding of the processing mechanism and enables one to optimize processing conditions for the best product capability.

Formation of defects in implanted hipox-structures

1992 ◽  
Vol 50 (2) ◽  
pp. 1406-1407
Author(s):  
Peter Pegler ◽  
N. David Theodore ◽  
Ming Pan
Keyword(s):  
High Pressure ◽  
Cross Section ◽  
Semiconductor Devices ◽  
Silicon Substrates ◽  
Processing Conditions ◽  
Pressure Oxidation ◽  
Deep Trench ◽  
Local Oxidation ◽  
Trench Isolation ◽  
And Behavior

High-pressure oxidation of silicon (HIPOX) is one of various techniques used for electrical-isolation of semiconductor-devices on silicon substrates. Other techniques have included local-oxidation of silicon (LOCOS), poly-buffered LOCOS, deep-trench isolation and separation of silicon by implanted oxygen (SIMOX). Reliable use of HIPOX for device-isolation requires an understanding of the behavior of the materials and structures being used and their interactions under different processing conditions. The effect of HIPOX-related stresses in the structures is of interest because structuraldefects, if formed, could electrically degrade devices.This investigation was performed to study the origin and behavior of defects in recessed HIPOX (RHIPOX) structures. The structures were exposed to a boron implant. Samples consisted of (i) RHlPOX'ed strip exposed to a boron implant, (ii) recessed strip prior to HIPOX, but exposed to a boron implant, (iii) test-pad prior to HIPOX, (iv) HIPOX'ed region away from R-HIPOX edge. Cross-section TEM specimens were prepared in the <110> substrate-geometry.

Method to evaluate residual stresses in the laser cutting process

2002 ◽  
Vol 12 (1) ◽  
pp. 27-41 ◽  
Author(s):  
Y. Zamachtchikov ◽  
F. Breaban ◽  
P. Vantomme ◽  
A. Deffontaine
Keyword(s):  
Residual Stresses ◽  
Laser Cutting ◽  
Cutting Process
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