Comparison of microstructure and mechanical properties of plastic mould steel for physical application

In this paper, plastic mold steel S136 and S136 SUP were studied for microstructural observation and mechanical properties through metallographic, SEM, EDS, XRD, hardness test and impact test. The results showed that after the same heat treatment, the martensite structure of S136 SUP was denser, the carbides were more uniform and finer, and the hardness was slightly lower but the toughness was greatly increased compared with that of S136. the residual austenite content of S136 and S136 SUP were 2.46% and 10%, respectively, and the heat treatment hardness was 50.1 HRC and 49.1 HRC, respectively. The impact toughness was 90.6 J and 299.1 J.

Simple method for constructing and repairing tissue microarrays using simple equipment

Objective Many methods for tissue microarray (TMA) construction were described in previous reports. Because TMA-based methods are expensive and complicated, their widespread application may be restricted. This study aimed to develop a simple method for TMA construction. Methods High-density TMAs were constructed using simple equipment, and hematoxylin and eosin and immunohistochemical staining were performed to analyze the effect on the TMA block. Results A recipient block with 162 holes of 0.9 mm in diameter was prepared using a mini-drill and plastic mold. Tissue cores of 1.0 mm in diameter were obtained from multiple donor blocks with stainless-steel capillary tubes driven by the mini-drill. Under the fixation and guidance of the plastic mold, tissue cores could be easily injected into the holes in the recipient block by inserting a stainless-steel wire into the stainless-steel tube with the tissue core and then pressing using the stainless-steel wire. Conclusion A high-density TMA block with 162 1.0-mm cores was created. This new modified technique could be a good alternative in many laboratories.

The Mechanical Properties of Granular Soils Injected by Silica Fume-Lime Mixtures

Soil In this study, granular soil material was stabilized by using injection method under laboratory conditions. As additive, the mixtures of silica fume and lime were used for this experimental study. The mixtures that are turned into slurries by adding water were injected to the granular soil media prepared in the cylindrical plastic mold. Then these samples were cured for 1, 7 and 28 days. The end of curing time, all samples were tested in accordance with unconfined compressive tests and obtained unconfined compressive strength values of injected granular soil samples were compared with that of the natural granular soil samples. As a result, it is concluded that the he mixtures of silica fume and lime can be successfully used for the improve of granular soils in the geotechnical applications.

Investigation Of Corrosion Behavior On Plastic Mold Steel

Günümüzde, endüstride kullanılan plastik kalıp çeliklerinde yaşanan en büyük problemlerden biri korozyon sorunudur. Bu çalışmada dört farklı plastik kalıp çeliği numunesine (A1, A2, A3, A4) sertlik ve korozyon testleri uygulanmıştır. Sertlik testleri, sertlik-işlenebilirlik ve sertlik-korozyon direnci olarak incelenmiş olup, dört farklı numune arasından en iyi özelliklere sahip takım çeliği önerilmiştir. Sertlik-işlenebilirlik özelliklerine göre en iyi numune 31 HRC değeri ile A2 numunesidir. Korozyon deneyleri %3.5 NaCl çözeltileri içinde gerçekleştirilmiştir. Her numunenin korozyon oranı, Tafel Ekstrapolasyon yöntemi ile hesaplanmıştır. Sertlik-korozyon direnci değerleri karşılaştırıldığında, 0.237 µm değeri ile A2 numunesi diğer numuneler arasında en yüksek korozyon direnci değerine sahiptir. Bu deneyler sonucunda, A2 numunesinin dört farklı plastik kalıp çeliği numune arasından bu özelliklere göre seçilmesi en uygun numune olduğu belirlenmiştir.

Experimental Study on Mold-Lay Filament instead of Wax in Investment Casting Process

Metal casting with investment casting method is metal casting which has the ability to produce accurate parts and has a controlled fineness. Current technological developments are very influential in the development of investment casting. One of them has been found mold-lay filament as a substitute for wax, which is now wax is one of the main components in investment casting process. Mold-lay filament is printed using a 3D Printer machine. In this study, the wax in the investment casting process was replaced by a mold-lay filament with the specifications 0.75kg / 0.55 lb of 1.75mm MOLDLAY filament, prints at temperatures of 170-180 ° C. The result show that mold-lay flutes are also able to come out well from slurry molds, but require more time than wax, this is because one of the plastic mold-lay compositions, which takes a long time for the moldlay fillment to come out of the mold. Further research suggestions are needed further testing in terms of roughness of the product with moldlay filament and compared with wax. This will also see if there are any remaining moldlay filaments from the mold.

Surface hardening characteristics of press die cast iron and plastic mold steel according to laser heat input

In this study, the surface heat treatment of mold materials was performed using a high-power laser heat source and surface hardening characteristics were investigated. Laser surface heat treatment is a hardening method in which a surface is heated using high-density energy and self-quenched through rapid cooling. Hence, the heat input during laser heat treatment is important. The heat input for the surface hardening of each material was compared, and it was found that the heat input for each mold material was different. Additionally, die cast iron has higher thermal conductivity compared to mold steel, resulting in a larger heat input during heat treatment.

Fabrication of Optimally Micro-Textured Copper Substrates by Plasma Printing for Plastic Mold Packaging

Micro-embossing using plasma printed micro-punch was proposed to form micro-groove textures into the copper substrate for plastic packaging of hollowed GaN HEMT-chips. In particular, the micro-groove network on the copper substrate was optimized to attain uniform stress distribution with maximum stress level being as low as possible. Three-dimensional finite element analysis was employed to investigate the optimum micro-grooving texture-topology and to attain the uniform stress distribution on the joined interface between the plastic mold and the textured copper substrate. Thereafter, plasma printing was utilized to fabricate the micro-punch for micro-embossing of the micro-grooving network into the copper substrate as a designed optimum micro-texture. This plasma printing mainly consisted of three steps. Two-dimensional micro-pattern was screen-printed onto the AISI316 die surface as a negative pattern of the optimum CAD data. The screen-printed die was plasma nitrided at 673 K for 14.4 ks at 70 Pa under the hydrogen-nitrogen mixture for selective nitrogen supersaturation onto the unprinted die surfaces. A micro-punch was developed by mechanically removing the printed parts of die material. Then, fine computer numerical control (CNC) stamping was used to yield the micro-embossed copper substrate specimens. Twelve micro-textured substrates were molded into packaged specimens by plastic molding. Finally, gross leak testing was employed to evaluate the integrity of the joined interface. The takt time required to yield the micro-grooved copper substrate by the present method was compared to the picosecond laser micro-grooving; the former showed high productivity based on this parameter.