scholarly journals Research on the machining process modeling of a rotational mold using CAM applications

2021 ◽  
Vol 343 ◽  
pp. 04006
Author(s):  
Aurel Mihail Ţîţu ◽  
Alina Bianca Pop

Rotational molding is a unique process, with a high growth rate, which allows the use of geometries and materials adapted to particular needs. It is superior to other manufacturing methods in terms of low cost, break-even point and size of parts that can be manufactured. Rotational molding products are often a substitute, with a lower mass, for traditionally used materials. In this scientific paper it is analyzed the recent literature related to the field of rotational molding processes. It also addresses the issue of processing a rotational mold, with the main purpose of optimizing the cutting regime. In this context, it is highlighted the way of processing the surface of the outer mold based on deductions of direct observation criteria. The factors considered in this regard are the route, the type and diameter of the tool, the speed and depth of cutting - given that the goal is to achieve a minimum quality of the required surface obtained by technology and a minimum base time. At the end of the paper, the contribution of this research is highlighted along with the arguments presented in support of the statement that this rotational molding process is of particular interest because it has a great potential to meet many surface quality requirements, while reducing cycle times.

1997 ◽  
Vol 471 ◽  
Author(s):  
D. Endisch ◽  
K. Barth ◽  
J. Lau ◽  
G. Peterson ◽  
A. E. Kaloyeros ◽  
...  

ABSTRACTSrS:Ce is an important material for full color electroluminescent (EL) flat panel displays. Using a combination of SrS:Ce/ZnS:Mn and appropriate color filters high quality full color displays have been demonstrated [1]. Major issues for commercially viable process integration of SrS:Ce are the combination of high luminance, high growth rate, and process temperatures below 600°C for compatibility with low cost glass substrates. This work describes the process development and optimization of metal-organic chemical vapor deposition (MOCVD) of SrS:Ce. MOCVD is a promising candidate for deposition of SrS:Ce because it can provide the required growth rates and allows control of crystal structure and stoichiometry. Growth of SrS:Ce was performed in the temperature range from 400°C to 530°C using Sr(tmhd)2, Ce(tmhd)4, and H2S as precursors. The structure of the SrS:Ce was found to be strongly dependent on the H2S flow. A brightness of 15 fL and an efficiency of 0.22 lm/W has been achieved (40 V above threshold voltage, 60 Hz AC). Film analysis included Rutherford backscattering (RBS), X-ray diffraction (XRD), atomic force microscopy (AFM), and EL measurements. Results on the correlation between process parameters, film structure, grain size and EL performance will be presented.


2012 ◽  
Vol 717-720 ◽  
pp. 193-196 ◽  
Author(s):  
Valdas Jokubavicius ◽  
Björn Lundqvist ◽  
Philip Hens ◽  
Rickard Liljedahl ◽  
Rositza Yakimova ◽  
...  

Heteroepitaxial growth of 3C-SiC on 0.8 and 1.2 degree off-oriented 6H-SiC substrates was studied using a sublimation growth process. The 3C-SiC layers were grown at high growth rates with layer thickness up to 300 µm. The formation and the quality of 3C-SiC are influenced by the off-orientation of the substrate, the growth temperature (studied temperature range from 1750 °C to 1850°C), and the growth ambient (vacuum at 5*10-5mbar and nitrogen at 5*10-1mbar). The largest domains of 3C-SiC and the lowest number of double positioning boundaries were grown using nitrogen ambient and the highest growth temperature. The combined use of low off-axis substrate and high growth rate is a potential method to obtain material with bulk properties.


2015 ◽  
Vol 821-823 ◽  
pp. 133-136 ◽  
Author(s):  
Takanori Tanaka ◽  
Naoyuki Kawabata ◽  
Yoichiro Mitani ◽  
Masashi Sakai ◽  
Nobuyuki Tomita ◽  
...  

The reduction of the growth pressure was demonstrated to have the same effect as the addition of chloride-containing gas on preventing the Si nucleation and the epitaxy with high growth rate (>50 μm/h) was achieved by using the decreasing pressure condition in a horizontal CVD reactor without chloride-containing gas. The quality of a 30-μm-thick epilayer grown with 40 μm/h was also investigated. Downfall and triangle defect density in the layer was as low as 0.16 /cm2, indicating that a high quality epitaxial wafer can be easily obtained under the condition with high throughput in the sinple CVD system.


2014 ◽  
Vol 778-780 ◽  
pp. 75-78 ◽  
Author(s):  
Takayuki Shirai ◽  
Katsunori Danno ◽  
Akinori Seki ◽  
Hidemitsu Sakamoto ◽  
Takeshi Bessho

P-type 4H-SiC bulk crystals have been grown at a high growth rate of 1.0 mm/h by solution growth using Si-Cr-Al based melt. The crystals grown from solution with an Al content of 10at% show low resistivity of 35 mcm, which is two orders of magnitude lower than commercialwafers (Resistivity: 2500 mcm). The low-resistivity crystals have flat surface and few solvent inclusions. These results indicate that solution growth is a suitable method for fabricating low-resistivity p-type substrates with low cost.


2018 ◽  
Vol 28 (3) ◽  
pp. 129 ◽  
Author(s):  
Hasil Tamsil

Muscovy duck is a type of waterfowl that has a relatively better growth and percentage compared to ducks. Duck meat has high-quality because of its low fat and savory flavor. Muscovy duck is relatively resistant to the disease and is able to use low-quality feed, but has the disadvantage of low egg production. The development of Muscovy duck as a producer of meat can be done through two approaches, namely the long-term and short-term. The long-term approach is carried out by selecting Muscovy duck which has high growth rate and high meet quality. The selection can be done in two ways, namely directly on the nature of growth and the quality of meat, and indirectly by choosing a marker of growth (morphology, biochemistry or diversity of DNA/ RNA). Short-term selection can be done by bringing in superior Muscovy duck from the outside to be developed by farmers and crossing male Muscovy duck with the layer Indian Runner ducks to produce Serati ducks.


2021 ◽  
Author(s):  
José Alfonso Abecia ◽  
Silvia Luis ◽  
Francisco Canto

Abstract Background: Recent studies have shown that melatonin implants administered during pregnancy reduced neonatal lamb mortality and produced high survival rates at weaning. This study was designed to quantify the effects of melatonin implantation of ewes and lambs immediately after lambing on the growth of lambs and the quality of milk throughout lactation.Results: In experiment 1, treatment with melatonin the lambs did not have a significant effect on liveweight (LW) (±S.E.M.) at weaning or average daily gain (ADG) until weaning. These results were similar in experiment 2, although lambs reared by melatonin-implanted ewes presented significantly (P<0.05) higher LW at weaning and ADG than did lambs from control ewes. The effect of melatonin implantation of the mothers was particularly evident in male lambs, so that male lambs reared by treated ewes presented significantly higher LW at week 2, 3, and 4 than did male lambs reared by control ewes. The fat content of milk was significantly (P<0.05) higher in implanted ewes than it was in control ewes at day 45 of lactation. Protein and lactose content of milk did not differ significantly between groups. In experiment 3, using artificially-reared lambs, melatonin treatment of the lambs at birth did not have a significant effect on LW at weaning, or ADG. Conclusions: Melatonin treatment of ewes at lambing induced a high growth rate of their lambs and increased the fat content of the milk; however, the direct treatment with melatonin of the lambs at birth did not have an effect in their growth rate.


Author(s):  
L. M. Fijalovych ◽  
Ya.I. Kyryliv ◽  
G. А. Paskevych

The article deals with the possibility of using feed additives in the feeding of broiler chickens and the peculiarities of their effect on the poultry organism. Contemporary data on the biological role of nutrients and energy in the feeding of broiler chickens are presented. The characteristics of the main feeds for poultry and the ways of reducing their prime cost in the conditions of broiler farms are given. The basic principles of effective feeding of poultry with forages of different content of metabolic energy and crude protein are considered, taking into account their assimilation in the body. Provided compound feed recipes and practical tips. It is established that high growth rate of broiler chickens in the start and groove periods (5–39 days) is provided by high-protein compound feeds – 23% (1–2 weeks), 21% (3–5 weeks) and exchange energy of 298 kcal and 305 kcal, respectively. With further cultivation in the finish forage the protein content in the forage decreases and the level of metabolic energy increases (up to 309 kcal). However, for each cross applies its own technology of cultivation and different rates of nutrients in raw materials. It is clear that effective breeding of broiler chickens is not possible without the proper rationing and use of protein and feed energy. Of course, provided that the supply of biologically active substances also corresponds to the normalized amount. Thus, the quality of poultry products is directly dependent on the quality of feed and the efficiency of transformation of feed energy into products.


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