scholarly journals Development of cost reduced analog quartz watch with precisely worked engineering plastic parts.

1986 ◽  
Vol 52 (4) ◽  
pp. 635-638
Author(s):  
YUJI YAMAZAKI
2020 ◽  
pp. 116-122
Author(s):  
Emre Öztürk ◽  
Mehmet Aktaş ◽  
Tunç Şenyüz

The purpose of this research is to reach good correlation between sun load simulation and solar focusing test for exterior automotive lighting products. Light coming from sun is highly collimated (parallel rays) and focusable from lenses with concave structure. Focusing incidence leads to a hot spot on lens surrounding plastic parts which may cause melting failures at high temperature zones. Sun load simulation is performing to eliminate risk of discoloration, deformation, out gassing, coating failures and fire with prolonged exposure from field. Irradiance values in W/m2 defined in simulation as heat source depending of an angle of incidence of the sun radiation. At first step, simulation is performing with 5 degree intervals to define the critical zones then intervals decreased to 2 degree to detect the critical azimuth and inclination angles. Critical azimuth and inclination angles is checking with ray trace analysis to check the bouncing of sun rays and possible solution to eliminate focuses with design solutions. After numerical analysis to release and validate the automotive lighting products regarding the sun load test, measurement with first parts is necessary. Measurement is performing for all critical angles which have been detected at simulation with thermal camera under ultra high-collimation solar simulator. Measured temperatures are settled according to environment conditions and correlation is checking with simulations.


2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Tarun Bindal ◽  
Ravindra K. Saxena ◽  
Sunil Pandey

AbstractThe welding of thermoplastic pipes under a shear joint configuration using friction spin welding is investigated. The shear joint configuration consists of two cylindrical and concentric polypropylene plastic parts joined with each other at their interfacing cylindrical surfaces through frictional heat generation. The effects of welding pressure and rotational velocity on the joint overlap distance and joint strength between the parts of polypropylene plastic are evaluated. The study is of a specific application in making plastic pressure vessels and joining of pipes. The joint strength is tested by conducting the hydraulic pressure burst test. The burst test is conducted for welded specimens manufactured using different values of rotational velocity and welding pressure. It is observed that at the constant spin velocities, the welding pressure in the range 64.8 to 65.2 kPa produced better joint strength than the other values of welding pressure in the overall range 64–76 kPa. It is concluded that the suitable welding pressure range to manufacture polypropylene plastic pressure vessels in the shear joint configuration using friction spin welding is 64.5 to 65.2 kPa. Further, it is established that the user can control the joint overlap distance at 64.8 kPa welding pressure by selectively controlling the rotational velocity in the range of 700 to 2500 rpm.


Machines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 150
Author(s):  
Andrei Marius Mihalache ◽  
Gheorghe Nagîț ◽  
Laurențiu Slătineanu ◽  
Adelina Hrițuc ◽  
Angelos Markopoulos ◽  
...  

3D printing is a process that has become widely used in recent years, allowing the production of parts with relatively complicated shapes from metallic and non-metallic materials. In some cases, it is challenging to evaluate the ability of 3D printers to make fine details of parts. For such an assessment, the printing of samples showing intersections of surfaces with low angle values was considered. An experimental plan was designed and materialized to highlight the influence of different factors, such as the thickness of the deposited material layer, the printing speed, the cooling and filling conditions of the 3D-printed part, and the thickness of the sample. Samples using areas in the form of isosceles triangles with constant height or bases with the same length, respectively, were used. The mathematical processing of the experimental results allowed the determination of empirical mathematical models of the power-function type. It allowed the detection of both the direction of actions and the intensity of the influence exerted by the input factors. It is concluded that the strongest influence on the printer’s ability to produce fine detail, from the point of view addressed in the paper, is exerted by the vertex angle, whose reduction leads to a decrease in printing accuracy.


2006 ◽  
Vol 326-328 ◽  
pp. 187-190
Author(s):  
Jong Sun Kim ◽  
Chul Jin Hwang ◽  
Kyung Hwan Yoon

Recently, injection molded plastic optical products are widely used in many fields, because injection molding process has advantages of low cost and high productivity. However, there remains residual birefringence and residual stresses originated from flow history and differential cooling. The present study focused on developing a technique to measure the birefringence in transparent injection-molded optical plastic parts using two methods as follows: (i) the two colored laser method, (ii) the R-G-B separation method of white light. The main idea of both methods came from the fact that more information can be obtained from the distribution of retardation caused by different wavelengths. The comparison between two methods is demonstrated for the same sample of which retardation is up to 850 nm.


Author(s):  
Jiing-Yih Lai ◽  
Jia-Wei Wu ◽  
Pei-Pu Song ◽  
Tzu-Yao Chou ◽  
Yao-Chen Tsai ◽  
...  

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