MIM TECHNOLOGY AS A METHOD OF MANUFACTURING PRECISION PARTS FROM METAL-POWDER COMPOSITIONS, INCLUDING TITANIUM ALLOYS (review)

The overview of MIM technology application (injection molding technologies for parts based on metal-powder compositions) as a method of manufacturing precision parts from metal-powder compositions is represented in this article. The features of the manufacturing of parts by additive technologies are also considered. The main stages of the technological process are given. Applied industries and using material statistic data are reflected. The focus was made on analyze of opportunity of application MIM technology in the manufacturing parts from titanium alloys.

Developments and Recent Progresses in Microwave Impedance Microscope

Microwave impedance microscope (MIM) is a near-field microwave technology which has low emission energy and can detect samples without any damages. It has numerous advantages, which can appreciably suppress the common-mode signal as the sensing probe separates from the excitation electrode, and it is an effective device to represent electrical properties with high spatial resolution. This article reviews the major theories of MIM in detail which involve basic principles and instrument configuration. Besides, this paper summarizes the improvement of MIM properties, and its cutting-edge applications in quantitative measurements of nanoscale permittivity and conductivity, capacitance variation, and electronic inhomogeneity. The relevant implementations in recent literature and prospects of MIM based on the current requirements are discussed. Limitations and advantages of MIM are also highlighted and surveyed to raise awareness for more research into the existing near-field microwave microscopy. This review on the ongoing progress and future perspectives of MIM technology aims to provide a reference for the electronic and microwave measurement community.

Comparative Study of Adhesion of Brackets with Metal Injection Molding (MIM) Technology and Welded bases: In vitro Study

Introduction: Brackets bonded to enamel surface depend on the adhesion material and the quality of the bracket base. Objective: The aim of this study was to compare the shear bond strength of metallic brackets with Metal Injection Molding (MIM) technology base or welded base. Materials and Methods: Forty mandibular extracted premolars mounted in acrylic resin blocks were divided randomly into two groups, both bonded with Transbond XT. In Group 1, brackets with MIM technology bases (Masel) were used, and in group 2, brackets with a welded base (Morelli) were used. After 24 hours, all brackets were tested for shear bond strength in a universal testing machine. Intergroup comparison was performed with an independent t test. Results: MIM base brackets showed a mean maximum load registered of 107.55 N, a mean shear bond strength of 9.58 MPa with a standard deviation of 5.80 MPa and the welded base brackets showed a mean maximum load of 167.37 N, a mean shear bond strength of 13.28 MPa with a standard deviation of 2.58 MPa. The difference between the two groups was statistically significant, indicating a higher shear bond strength of the welded base brackets. Conclusion: It was concluded that the brackets with welded bases presented a significantly higher shear bond strength than the brackets with MIM bases.

Development of Ultra-Fluid Compositions of Feedstock for Metal Injection Molding

In this paper, to reduce the cost of production of parts by injection molding technology of metal powder mixtures (MIM technology), it is proposed to use metal powder mixtures (feedstock) with high fluidity for the manufacture of green parts. High fluidity is achieved by increasing the proportion of paraffin wax in the binder. This can significantly reduce the pressing pressure when pressing the feedstock into the mold cavity to values less than 1 bar, and eliminate the use of expensive injection molding machines with high compression pressure. High fluidity also allows the use of powders with large particle sizes, which significantly reduces the cost of feedstock. The absence of high pressure on the mold walls during the pressing of the feedstock allows the use of molds made of cheaper materials such as silicone, plastic, gypsum and others.

Comparison of Shear Bond Strength of MIM Technology Brackets with Conventional and Rail-Shaped Mesh Bases: An In Vitro Study

Objective: The objective of this study was to evaluate in vitro the shear bond strength of two types of MIM (Metal Injection Molding) technology brackets, one with conventional mesh base and the other with rail-shaped mesh base. Materials and Methods: Forty human premolars received the bonding of 2 types of brackets: Group 1- 20 Synergy metal brackets (Rocky Mountain) with conventional mesh base and Group 2-20 H4 brackets (OrthoClassic) with rail-shaped mesh base. Both brackets were bonded with Resilience photopolymerizable resin (OrthoTechnology). The specimens were coupled to a Tinius Olsen universal test machine where the shear test was performed using a chisel. In addition, the amount of remaining resin in tooth crown with the ImageJ program was evaluated and the Adhesive Remnant Index (ARI). Intergroup comparison was performed by the independent t test and Chi-square test. Results: There was no statistically significant difference between the groups for any of the measures evaluated indicating that the mesh type of the brackets’ base with MIM technology did not influence the shear bond strength of the brackets (shear bond strength, p=0.191; maximum load registered, p=0.244). There was also no difference between the percentage (p=0.602) and area of remaining resin in the teeth (p=0.805) and IRA (p=0.625) between the Synergy and H4 groups. Conclusion: Shear bond strength was similar in the two types of brackets with MIM technology evaluated. In addition, the remaining resin in the dental enamel of two types of brackets were also similar.

The Development of New Materials and Modes of Casting Metal Powder Mixtures (MIM Technology)

In the present work, to reduce the cost of production of the parts with MIM technology, proposed to use a new metal powder mixture (feedstock are presented) with the increased size of the powder to 50 microns. New feedstock are presented recommended for use in the manufacture of parts with a wall thickness of 5 mm. Shows the main physical and technological properties of new metal powder mix (feedstock) 40ХМА of steel intended for the manufacture of parts via MIM technology. Given the results of determination of granulometric composition and particle shape. The obtained values of tensile strength, hardness and roughness. The results of determining the dependence of viscosity on shear rate. For simulation of rheological properties of selected elastic-visco-plastic model of Bingham type with nonlinear dependence of viscosity on shear rate and temperature. The example of the calculation of feedstock fill the cavity of the mold. The analysis of defects in green part, associated with an irregular velocity field in the flow channels feedstock form.