Key Engineering Materials Vol. 861

Abstract: Welding electrode arc welding, upside welding, single side welding, double side forming welding operation technology is the most difficult welding process in manual arc welding operation. It is an operation technology that senior welding operators must master, and it reflects the technical level of the welding welder. . In this paper, the welding operation essentials and operation skills of backing welding, filling welding and cover welding are studied for the welding operation of the back welding test board, which creates a theoretical basis for the improvement of the welding operator's operation skills.

Abstract: This work is done to determine the effects of the input factors of powder mixed electrical discharge machining (PMEDM) process on the material removal rate (MRR). In the study, the workpiece is cylindrical parts made from 90CrSi alloy steel. Also, five factors containing the pulse on time T_on, the powder concentration C_p, the pulse off time T_off, the pulse current IP, and the server voltage SV were discovered to find their impact on MRR. In addition, the Taguchi method and ANOVA analysis were used to design experiment and analyze the results. In addition, an optimal model of the MRR was introduced. Also, the model has been well verified by comparison with testing, and so it can be used for further studies in the PMEDM process.

Abstract: This paper deals with the effect of input parameters of Powder Mixed Electric Discharge Machining (PMEDM) process on the surface roughness when processing cylindrical shaped parts. In this work, the workpiece material is 90CrSi alloy tool steel and the nanopowder is silicon carbide. Also, five input parameters including the pulse on time, the pulse off time, the powder concentration, the current and the server voltage were selected to investigate their influence on the surface roughness. Taguchi method and ANOVA analysis were used and the effect of input parameters on the surface roughness was presented. Moreover, optimum input parameters for minimum surface roughness was suggested.

Abstract: In this paper, the influence of paraffinic oil on the physical mechanical, thermal and adhesion properties of three blends of EPDM Buna EP T.6465, Keltan 5260Q and Keltan 6160 D and CIIR have been investigated. The results showed that the tensile strength values and elongation at break of keltan 5260Q/CIIR and keltan 6160 D/CIIR with 10 wt.% paraffinic oil represent the improvement of 57.8%, 57.6% and 71% to 81% respectively, compared with one without oil. The mean peel force of EPDM keltan 6260D with 10% oil loaded is about 36% and 32.5% higher than that of EPDM keltan 5260Q and EP.T 6465 blends respectively. With suitable oil content, in this case is 10% wt., the thermal resistance of keltan 5260 Q and 6160D seems to be higher than that of without processing oil and suitable for thermal resistance rubber application.

Abstract: This study has developed an alternative compounding formulation and process for natural rubber latex (NRL) foams for hand exercising application. Deprotenized natural rubber latex was used as raw material and a combination of DIXP and TBzTD, which were fugitive and high molecular weight accelerators, respectively, was used to lower allergenic potential and harmful nitrosamines. The NRL foams were prepared to various densities, characterized by Scanning Electron Microscopy (SEM) and tested for hardness index, accelerated ageing and compression set in comparison to the foams with conventional compounding formulation. With the same processes, the foams with these two different formulations were found to have similar densities and hardness indices. However, the foams using DIXP and TBzTD accelerators performed better in compression set and accelerated ageing tests.

Abstract: Micro-structured optical film is one of the micro-optical elements and has a great market demand. This article studies the microstructured optical film formed by UV imprinting: The influence of embossing pressure on microstructure replication accuracy was explored. The larger the pressure, the better the material filling. When the pressure is 5N, the microstructure replication is complete; The relationship between the radiation intensity and warpage deformation was explored, and the decrease in the intensity of the UV light source can effectively reduce the warpage deformation; The influence of the material formula on the optical properties of the product was explored. When the oligomer content was 55%, the film had a high light transmittance. At the same time, the prepared film was subjected to an apparent inspection with good microstructure replication accuracy.Microstructured optical elements are widely used in optical fields such as semiconductors, lasers, beam shaping ^[1-2] and solar energy ^[3-5] due to their unique advantages such as small size and high performance. As a key component in many industries, it has a high market demand rate. However, the microstructure forming process is complicated, the manufacturing cost is high, and the accuracy is difficult to guarantee, which has restricted its development. With the advancement of science and technology and the increase in market demand, more and more researchers and enterprises have put their eyes on the research of preparing micro-structured optical elements.At present, the commonly used microstructures are mainly icrolens array ^[6-8], and the processing methods include micro-imprinting ^[9-10], etching ^[11], electron beam direct writing, and micro-injection ^[12], etc. This article studies the UV-curing embossing process in micro-embossing. This processing method has the advantages of fast molding, high efficiency, and environmental protection. And this process is conducive to mass production and has a broad market application prospect.In this paper, the forming process and material formulation of microstructured optical film prepared by light-cured micro-imprinting were investigated, and the microstructure morphology of the preparation was analyzed apparently.

Abstract: 3D printed carbon fiber reinforced composites (CFRP) have shown great potential in lightweight application. Here, we report a prepreg carbon fiber reinforced polyamide composite by fused filament fabrication 3D printing process. The influence of layer thickness and carbon fiber layers on mechanical properties of 3D printed parts was well studied. With the incorporation of prepreg carbon fibers, the value of tension and flexural strengths of 3D printed CFRP parts could achieve 2.7 and 13.6 times compared to neat polyamide, respectively. Result illustrates that with the prepreg process the carbon fiber have good interface bonding strength with neat polyimide. This work could also be used for more 3D printing composite systems.

Abstract: This study investigated the effect of polylactic acid (PLA) on the mechanical properties and biodegradability of a ternary blend comprising of thermoplastic starch (TPS), Polybutylene adipate terephthalate (PBAT) and PLA. The binary blend (TPS/PBAT) and ternary blend (TPS/PBAT/PLA) with various contents of PLA were prepared through a twin-screw compounding using an intensive mixing screw design. In order to observe the microstructure in blends, the SEM observation revealed the two types of morphology in the blends including (1) some TPS domain that still remained immiscible in all blends and (2) the partially compatible of binary and ternary blends. For the mechanical properties of the blends, the addition of the PLA component led to an improvement of the tensile strength and modulus. For the simple soil burial test, it found that binary film was fully disintegrated within one month, whereas the ternary blend films were also broken down but still remained in small pieces of fragile films. Finally, it can be suggested that the presence of TPS brought to the biodegradation of blends in soil burial test, while incorporating with PLA led to retardation in degradation rate.

Abstract: In this research, the biodegradable film of poly (butylene adipate-co-terephthalate) (PBAT) would be used as the polymer matrix. The influence of zeolite (as the filler) type and content were investigated on the mechanical and barrier properties of film packaging. Zeolite was treated with (3-aminopropyl) trimethoxy silane. Films were produced by cast film extruder. Effects of different types of zeolite (5A and 13X) as well as zeolite loading (1-5 wt%) on mechanical properties and permeability of gases (oxygen, carbon dioxide and water vapor) of PBAT composites films have been extensively studied. Tensile properties of PBAT incorporated with zelolite 5A are higher than the one with zeolite 13X. In addition, increasing zeolite content into PBAT film is likely to improve Young’s modulus with the sacrifices of both tensile strength and percentage of elongation at break of PBAT film. For barrier properties, PBAT/zeolite 5A possessed lower permeation both of oxygen and carbon dioxide gases than PBAT/zeolite 13X. The effect of zeolite content plays a major role on oxygen and carbon dioxide permeability of composite films. PBAT/zeolite composite film could certainly extend the ripening period of Homthong bananas for approximately longer than one week.

Abstract: Additive manufacturing (3D printing) is a hopeful technique that is used to produce complex geometry parts in a layer-by-layer method. Fused deposition modeling (FDM) is a popular 3D printing technology for producing components of thermoplastic polymers. In FDM process, the part quality is influenced strongly by the printing parameters. Until now, these parameters stil need to be investigated. Therefore, in this study, the influence of FDM 3D printing parameters on the tensile strength of product will be investigated. By experiment, three parameters, that is, layer height, solid layer top, and first-layer height, were studied. The investigation shows that the layer height is the only parameter impacted the tensile strength of the product.