Improving Plastic Thermoform Quality with Uniform Heating Technology

2010 ◽  
Vol 97-101 ◽  
pp. 204-208
Author(s):  
Zhi Guo Zhang ◽  
Chen Lin ◽  
Da Kui Feng ◽  
Ray Still

The experimental studies were conducted to study the plastic thermoforming heating process. The heaters performance has been evaluated from two different ways: heating water calorimeter for heating efficiency and heating plastics for thermoform processes. The studies of the heaters include gas-fired heater and electric heater. Transient heating processes of plastics were also studied to investigate the heater’s performance on plastics. The surface temperature of plastic at the end of heating process was measured by IR camera. The heating cycle time, surface temperature uniformity of plastic and energy consumed for the heating cycle by different heaters were discussed. The pros and cons of different heaters for plastic heating process were also discussed in this paper.

2018 ◽  
Vol 245 ◽  
pp. 04002
Author(s):  
Iurii Murashov ◽  
Vyacheslav Shestakov ◽  
Vladimir Skornyakov ◽  
Irina Savelieva

The article is dedicated to nonstationary simulation of induction heating technology for the production of seamless large diameter tees. A mathematical model of induction heating process representing a multi-physical (heat transfer and electromagnetism) task for technology of tees production is developed. Numerical simulation was carried out for a flat spiral inductor. The developed model was verified according to the results of experimental studies. The hydrodynamic 3D mathematical model is developed for the design of the inductor cooling system. Optimal operating modes are determined by simulation results and confirmed by experimental data. The calculation results are presented for pipes with wall thicknesses: 15 mm, 40 mm, 60 mm, 70 mm.


2013 ◽  
Vol 58 (3) ◽  
pp. 919-922 ◽  
Author(s):  
K. Granat ◽  
B. Opyd ◽  
D. Nowak ◽  
M. Stachowicz ◽  
G. Jaworski

Abstract The paper describes preliminary examinations on establishing usefulness criteria of foundry tooling materials in the microwave heating technology. Presented are measurement results of permittivity and loss tangent that determine behaviour of the materials in electromagnetic field. The measurements were carried-out in a waveguide resonant cavity that permits precise determination the above-mentioned parameters by perturbation technique. Examined were five different materials designed for use in foundry tooling. Determined was the loss factor that permits evaluating usefulness of materials in microwave heating technology. It was demonstrated that the selected plastics meet the basic criterion that is transparency for electromagnetic radiation.


Author(s):  
Anna Lubkowska ◽  
Monika Chudecka

Thermography is widely used in the medical field, including in the detection of breast disorders. The aim of the research was to characterize the range of breast surface temperature values, taking into account the entire area of the mammary gland and, independently, the nipple, in healthy women. An additional aim was to assess the symmetry of the breast temperature distribution (using an IR camera) and the correlation of temperatures with the content of adipose tissue. Thermograms were made for the right and left breasts, each time delineating the area of the entire breast and a separate area of the nipple, chest, and abdomen. Analyzing the intergroup differences in temperature of selected body areas (Tmean), it was shown that, in all cases, they were significantly higher in younger women. Statistical analysis showed no significant differences between breast and nipple temperatures in relation to the body sides. The highest temperatures within the mammary gland were recorded for the nipple area. The use of the high-resolution digital infrared thermal imaging method in early and screening preventive diagnoses of changes in the mammary gland requires individual interpretation of the results, taking into account the assessment of the physiological pattern of temperature distribution in both breasts.


Author(s):  
Kennethrex O. Ndukaife ◽  
George Agbai Nnanna

An Infrared thermography (IRT) technique for characterization of fouling on membrane surface has been developed. The emitted spectral power from the fouled membrane is a function of emissivity and surface morphology. In this work, a FLIR A320 IR camera was used to measure surface temperature and emissivity. The surface temperature and the corresponding emissivity value of various areas on the fouled membrane surface is measured by the infrared camera and recorded alongside its thermogram. Different fouling experiments were performed using different concentrations of aluminum oxide nanoparticle mixed with deionized water as feed solution (333 ppm, 1833 ppm and 3333 ppm) so as to investigate the effect of feed concentration on the degree of fouling and thus its effect on the emissivity values measured on the membrane surfaces. Surface plots in 3D and Line plots are obtained for the measured emissivity values and thickness of the fouling deposit on the membrane surface respectively. The results indicate that the IRT technique is sensitive to changes that occur on the membrane surface due to deposition of contaminants on the membrane surface and that emissivity is a function of temperature, surface roughness and thickness of the specimen under investigation.


2020 ◽  
Vol 39 (1) ◽  
pp. 54-62
Author(s):  
Hua Chen ◽  
Junjiang Chen ◽  
Weijun Wang ◽  
Huan Lin

AbstractThe multimode resonant cavity is the most common cavity. The material often shows on selective heating performance during the heating process due to the effect of microwave heating having a closely relationship with the electromagnetism parameters. This paper is based on finite difference time domain method (FDTD) to establish the electromagnetic-thermal model. The electromagnetic sensitivity property parameters of sodium chloride including relative dielectric constant, loss angle tangent and water content of sodium chloride is studied during the heating and drying process. The heating rate and the electric field distribution of sodium chloride, at the different water content, were simulated with the electromagnetic characteristic parameters changing. The results show that with the electromagnetic sensitivity property parameters varying, the electric field strength, heating rate and steady-state temperature of the heating material will all have a variety in the cavity. Some measures are proposed to improve the heating efficiency and ensure the stability of the microwave heating system in the industrial application.


2021 ◽  
Vol 2129 (1) ◽  
pp. 012096
Author(s):  
Md Ashequl Islam ◽  
Nur Saifullah Kamarrudin ◽  
Ruslizam Daud ◽  
Ishak Ibrahim ◽  
Anas Rahman ◽  
...  

Abstract Predicting thermal response in orthopedic surgery or dental implantation remains a significant challenge. This study aims to find an effective approach for measuring temperature elevation during a bone drilling experiment by analyzing the existing methods. Traditionally thermocouple has frequently been used to predict the bone temperature in the drilling process. However, several experimental studies demonstrate that the invasive method using thermocouple is impractical in medical conditions and preferred the thermal infrared (IR) camera as a non-invasive method. This work proposes a simplified experimental model that uses the thermocouple to determine temperature rise coupled with the thermal image source approach. Furthermore, our new method provides a significant opportunity to calibrate the thermal IR camera by finding out the undetected heat elevation in a workpiece depth.


2018 ◽  
Vol 12 (3) ◽  
pp. 221-226 ◽  
Author(s):  
Andrzej Borawski

Abstract Among the many elements of a modern vehicle, the braking system is definitely among the most important ones. Health, and, frequently, life, may rest upon the design and reliability of brakes. The most common friction pair used in passenger cars today is a disc which rotates with the road wheel and a cooperating pair of brake pads. The composite material of the pad results in changing tribological properties as the pad wears, which was demonstrated in experimental studies. The change is also facilitated by the harsh operating conditions of brakes (high and rapid temperature changes, water, etc.). This paper looks into how changing tribology reflects on the heating process of disc and pads during braking. And so a simulation study was conducted, as this method makes it possible to measure temperature in any given point and at any time, which is either impossible or extremely difficult in real life conditions. Finite element method analyses were performed for emergency braking events at various initial speeds of the vehicle reflecting the current road speed limits.


2018 ◽  
Vol 138 ◽  
pp. 217-234 ◽  
Author(s):  
Rene Prieler ◽  
Markus Mayrhofer ◽  
Christian Gaber ◽  
Hannes Gerhardter ◽  
Christoph Schluckner ◽  
...  

2021 ◽  
Vol 63 (5) ◽  
pp. 273-279
Author(s):  
Xiao Zhao ◽  
Qi Zhang ◽  
Xiang Xu ◽  
Zhibin Shen ◽  
Bo Zhang

Uneven surface emissivity will cause illusory temperature variation in infrared surface temperature mapping. For this reason, most of the detailed reviews on the use of infrared thermography (IRT) for leakage detection have mainly focused on surfaces with homogeneous emissivity or the recognition of negative temperature gradients, while reports on sensing hot fluid leakage for uneven surface emissivity are very rare. In this study, a hypothesis is put forward and a new leakage detection method is proposed that uses a transient heating-cooling-heating process in association with a subtraction method of infrared images to eliminate the disturbance of inhomogeneous valve surface emissivities. A theoretical analysis is established that is experimentally tested as a case study. The results shows that the hypothesis is clear and the effect of the uneven emissivity is suppressed for the recognition of positive temperature gradients (hot fluid leakage) on a metal valve sample. The current work provides new insights on the modification of the surface emissivity under certain conditions, which has been a major limitation of passive IRT in the past.


2012 ◽  
Vol 225 ◽  
pp. 49-54 ◽  
Author(s):  
Kamil Abdullah ◽  
Ken Ichi Funazaki

This paper presents the investigation on the effects of the blowing ratio of multiple shallow angle film cooling holes. Multiple film cooling holes having a shallow hole angle (θ = 20°), arranged to perform in-line hole configuration has been considered in the present study. The investigation focuses on the effects of high blowing ratio of the film cooling effectiveness which have been carried out at ReD= 3100 and BR = 2.0, 3.0 and 4.0. The experiments make use of the IR camera in capturing the surface temperature to determine the film cooling effectiveness. The contours of the film cooling effectiveness distribution together with plots on laterally average film cooling effectiveness along the x/D are presented. The discussions have been made with a support of the temperature field captured at x/D = 3, 13, 23, and 33. The results clearly show the benefit of the employment of shallow hole angle (θ = 20°) at high blowing ratio which is much more superior in comparison to the common hole configuration (θ = 35°).


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