Optimization of thermal distribution in ceramics and LTCC structures applied to sensor elements

1998 ◽  
Vol 15 (2) ◽  
pp. 34-38 ◽  
Author(s):  
Reinhard Bauer ◽  
Leszek J. Golonka ◽  
Torsten Kirchner ◽  
Karol Nitsch ◽  
Heiko Thust
Keyword(s):  
Thermal Properties ◽  
Thick Film ◽  
Laser Cutting ◽  
Simple Structure ◽  
Infrared Camera ◽  
Heat Distribution ◽  
Thermal Distribution ◽  
Package Density ◽  
High Package Density

Thermal properties of Pt or RuO2 thick‐film heaters made on alumina, aluminum nitride or low temperature co‐fired ceramics (LTCC) were compared in the first step of our work. Special holes to improve the heat distribution were included. Several heater layouts were analysed. The heat distribution was measured by an infrared camera, at different heating power. Second, the optimization of LTCC constructions was carried out. The simple structure of LTCC permitted the achievement of a high package density. It was possible to integrate a heating element made from special thick‐film ink as a buried film, inside a substrate. An important step in our technology was the making of the holes. A pattern of holes (achieved by punching or laser cutting) around the heating area permitted a changeable heat gradient. The quality of lamination and the structure of the buried elements were investigated with an ultrasonic microscope.

Scanning Electron Microscopy in Hybrid Microelectronics

1976 ◽  
Vol 34 ◽  
pp. 456-457
Author(s):  
S. Khadpe ◽  
R. Faryniak
Keyword(s):  
Integrated Circuits ◽  
Thick Film ◽  
Integrated Circuit ◽  
Failure Modes ◽  
Three Dimensional ◽  
Circuit Components ◽  
Hybrid Microcircuit ◽  
Electrical Connections ◽  
Scanning Electron

The Scanning Electron Microscope (SEM) is an important tool in Thick Film Hybrid Microcircuits Manufacturing because of its large depth of focus and three dimensional capability. This paper discusses some of the important areas in which the SEM is used to monitor process control and component failure modes during the various stages of manufacture of a typical hybrid microcircuit.Figure 1 shows a thick film hybrid microcircuit used in a Motorola Paging Receiver. The circuit consists of thick film resistors and conductors screened and fired on a ceramic (aluminum oxide) substrate. Two integrated circuit dice are bonded to the conductors by means of conductive epoxy and electrical connections from each integrated circuit to the substrate are made by ultrasonically bonding 1 mil aluminum wires from the die pads to appropriate conductor pads on the substrate. In addition to the integrated circuits and the resistors, the circuit includes seven chip capacitors soldered onto the substrate. Some of the important considerations involved in the selection and reliability aspects of the hybrid circuit components are: (a) the quality of the substrate; (b) the surface structure of the thick film conductors; (c) the metallization characteristics of the integrated circuit; and (d) the quality of the wire bond interconnections.

scholarly journals Investigation of Cutting Quality of Remote DOE Laser Cutting in 0.5 mm Stainless Steel

2017 ◽  
Vol 89 ◽  
pp. 164-171
Author(s):  
Sigurd Lazic Villumsen ◽  
Morten Kristiansen
Keyword(s):  
Stainless Steel ◽  
Laser Cutting

Optimization of the quality of laser cutting and power consumption

2007 ◽  
Author(s):  
Ch. Sipavichius ◽  
A. Amulevichius ◽  
K. Mazheika
Keyword(s):  
Power Consumption ◽  
Laser Cutting

scholarly journals APPLICATION OF EARTH AND STRAW MIXTURES IN MODERN BUILDING

2016 ◽  
Vol 1 (15) ◽  
Author(s):  
Ivan Hegediš ◽  
Neđo Đurić ◽  
Arpad Čeh ◽  
Golub Karaman ◽  
Danilo Vunjak ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Energy Consumption ◽  
Architectural Design ◽  
Mechanical And Thermal Properties ◽  
Structural Elements ◽  
Wooden Frame ◽  
Energy Consumption Reduction ◽  
Consumption Reduction ◽  
Modern Building

Building with earth is widespread and still mostly based on traditional experiences. Increasing demandsin energy consumption reduction during the construction and exploitation of buildings put more andmore in the focus the good features of houses built with earth.Testing of earth mixtures with othernatural materials showed that it can get even a quality of bricks, which indicates the lack of appropriatestandards for this type of construction.Testing are performed with mixes of earth and straw intended forrammed earth and adobe construction.This method of preparation and construction applies in alternate construction with straw bales and it isalso used in the construction of prefabricated panels with wooden frame filled with a mixture earth andstraw where it is possible to build prefabricated structures or as a filling of wall screens in skeletalstructural system of larger dimensions and number of floors.Laboratory tests have shown that the mechanical and thermal properties of this material fulfilled thehigh demands for the construction of modern buildings. Based on the presented results it can proceedthe development and testing of structural elements for that kind of building.Also, based on results, in the article the authors presented possibilities of architectural design ofvarious building possibilities of objects, as practical examples of prefabrication applied in somecountries.

Surface Quality of Pulsed Laser Cutting of Difficult to Machine Steel

2011 ◽  
Vol 299-300 ◽  
pp. 1016-1019
Author(s):  
Tie Jun Li ◽  
Jing Tang ◽  
Li Jun Yan ◽  
Yang Wang
Keyword(s):  
Surface Quality ◽  
Laser Cutting ◽  
Pulsed Laser ◽  
Cutting Parameters ◽  
Quality Factors ◽  
Good Separation ◽  
Machine Steel ◽  
Optimum Cutting ◽  
Super Alloy

This paper presented the experiments of Nd:YAG pulsed laser cutting of titanium alloy, super-alloy and stainless steel sheet, and investigated the influences of different laser cutting parameters on the surface quality factors focusing surface morphology. In comparison with air-, argon- and nitrogen-assisted laser cutting, argon-assisted laser cutting comes with unaffected surface quality and is suitable for laser cutting with subsequent welding requirement. With analyzing the interaction between pulses overlapping rate and energy, the results show that medium pulse overlapping rate and lower pulse rate helps to improve the surface roughness with pulsed laser cutting. And the results would be beneficial to find optimum cutting parameters for good separation surface.

HIGH TEMPERATURE PROPERTIES OF MINIATURIZED THICK-FILM COMPONENTS

2012 ◽  
Vol 2012 (CICMT) ◽  
pp. 000400-000405
Author(s):  
Damian Nowak ◽  
Andrzej Dziedzic ◽  
Tomasz Piasecki ◽  
Tomasz Baraniecki ◽  
Jacek Reiner
Keyword(s):  
High Temperature ◽  
Laser Beam ◽  
Thick Film ◽  
Nd:Yag Laser ◽  
Laser Cutting ◽  
Laser System ◽  
Frequency Range ◽  
High Temperature Properties ◽  
Conductive Path ◽  
Conductive Films

This paper presents systematic studies of thick-film or LTCC microcomponents (capacitors, inductors) made with the aid of laser-shaping and operating at temperature up to 450 °C. The minimum dimensions i.e. conductive path width and spacings were about 30 μm. Such small patterns have been created by laser cutting of fired Au- or Ag-based conductive films. Laser system equipped with Nd:YAG-laser (beam wavelength of 1064 nm) was applied. The inductance, capacitance, as well as parasitic impedances were measured in the frequency range from 10 kHz to 110 MHz and temperature between 25 °C and 450 °C.

Analysis of the Influence of Transient State of the Overhead Pipeline Placed in an Open-Air Space on the Accuracy of its Insulation Assessment Based on the Results of Outer Shell Thermovision Diagnostics

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Tadeusz Kruczek
Keyword(s):  
Thermal Insulation ◽  
Thermal Protection ◽  
Thermal State ◽  
Infrared Camera ◽  
Transient State ◽  
Weather Conditions ◽  
Heat Losses ◽  
Energy Accumulation ◽  
Measurement Results

Abstract The proper thermal diagnostics of pipeline insulation is an important problem. The heat losses from the pipelines depend distinctly on the quality of this insulation. Changes in weather conditions cause transient accumulation of energy in the pipeline insulation and may cause difficulties during evaluation of the quality of the pipeline thermal insulation. Generally, the goal of this investigation was to identify the scale of energy accumulation inside thermal insulation. This is important because during the calculation of heat losses from thermal pipelines on the basis of infrared camera temperature measurement results usually a steady thermal state inside the insulation is assumed. In order to determine the distributions of the temperature inside the insulation, the calculations of the temperature changes inside the pipeline insulation for real changeable meteorological conditions with the use of software ansys-fluent and others have been carried out. Both the heat transfer between the inner pipeline tube and outer pipeline shell and energy accumulation inside the pipeline elements were considered. For the pipeline insulation evaluation purpose, different coefficients for the analysis of energy accumulation scale were defined and used. The measurement results of the temperature of inner pipeline tube and outer pipeline shell gathered during the operation of the special experimental rig were used as input data for the aforementioned numerical simulations. In these calculations, they constituted the first (Dirichlet's) boundary condition. The conclusions resulting from this work are useful for specialists involved in the technical evaluation of the thermal protection features of pipelines.

scholarly journals Selected Properties of the Surface Layer of C45 Steel Parts Subjected to Laser Cutting and Ball Burnishing

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3429 ◽  
Author(s):  
Agnieszka Skoczylas ◽  
Kazimierz Zaleski
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Laser Cutting ◽  
Experimental Studies ◽  
Hardened Layer ◽  
Ball Burnishing ◽  
Absolute Value ◽  
The Impact ◽  
Compressive Residual Stresses

In this article, we report the results of experimental studies on the impact of ball burnishing parameters on the roughness, microstructure and microhardness of the surface layer of laser-cut C45 steel parts. We also analysed the distribution of residual stresses generated in the surface layer of these parts. Laser-cut parts often require finishing to improve the quality of their surface. The tests performed in this study were aimed at assessing whether ball burnishing could be used as a finishing operation for parts of this type. Ball burnishing tests were performed on an FV-580a vertical machining centre using a mechanically controlled burnishing tool. The following parameters were varied during the ball burnishing tests: burnishing force Fn, path interval fw and the diameter of the burnishing ball dn. Ball burnishing of laser-cut C45 steel parts reduced the surface roughness parameters Sa and Sz by up to 60% in relation to the values obtained after laser cutting. Finish machining also led to the reorganization of the geometric structure of the surface, resulting in an increase in the absolute value of skewness Ssk. This was accompanied by an increment in microhardness (maximum microhardness increment was ΔHV = 95 HV0.05, and the thickness of the hardened layer was gh = 40 µm) and formation of compressive residual stresses in the surface layer.

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