Novel Electrical Joints Using Deformation Machining Technology—Part II: Experimental Verification
This is the second part of the paper related to the exploration of deformation machining technology (DMT), originally developed at Bauman Moscow State Technical University, as it may apply to making electrical joints and comparing their performance to bolted and welded electrical joints. The DMT process is used to generate tooth-like profiles on two opposing surfaces that make the electrical joints which are later joined by applying a mechanical load. Part I contained a more detailed explanation of the DMT process and the description of the results of computer modeling of DMT joints in copper and aluminum. This paper provides the experimental results of the mechanical and electrical performance of copper and aluminum DMT joints which were compared to bolted and welded electrical joints of identical geometries. Measurements of tensile strength and electrical resistance, after thermal cycling and short-circuit testing, show equivalent or better performance of copper DMT joints compared with copper bolted and welded joints. In addition, it is observed that copper DMT joints have superior performance when compared with aluminum DMT joints, this was attributed to lesser gap filling and the springback effect that occurs after the mechanical load for making the joint is removed. The computer modeling results reported in Part I of this paper support these observations.
MDT: Micro Deformation Technology
Micro-Deformation Technology (MDT) is a proprietary material deformation process that was originally developed for the production of engineered heat transfer tubing. The patented process employs a fixed tool, which mechanically and plastically deforms the work piece to form finite and repeatable channels. These channels are developed in one continuous pass or multiple passes of the tool and the geometric shape and angle of the tool define the final channeled form. The MDT process can achieve a variety of channles form. The MDT process can achieve a variety of channel depths, channel widths, fin shapes and angularity. It can be applied to rounds, sheet and contoured work pieces. MDT is readily adaptable to conventional machining and milling equipment. The MDT process can be performed on nearly any ductile material. Materials ranging from titanium, stainless steel, silver, aluminum, copper, to the non-metallic materials like Teflon, polyethylene, rubber and PVC have been successfully processed. Most materials can be channeled in excess of 250 channels/inch. The process generates no material fines and lubrication is not required for most applications. MDT is therefore ideal for precious metal conversion and secondary cleaning steps are generally not required. Channeling sheet from opposite sides, MDT is capable of producing fine meshes via the intersection of the angled channel depths. The repeatable and uniform channels produce an extremely uniform pore distribution from a solid body. The unique attributes of MDT make it an enabling technology. By itself or in combination with current processes, it opens capability that previously did not exist. Potential applications include: filters and screens; catalyst substrates; heat transfer; material flow and separation; heat pipes; surface cladding and adhesion; capillary structures; surface preparation; and solid surface lubrication, to name only a few.Copyright © 2003 by ASME
A New Vacuum Pressure Infiltration CFRP Method and Preparation Experimental Study of Composite
In order to prepare a carbon-fiber-reinforced polymer composite (CFRP) with ideal microstructure and properties, a new vacuum pressure infiltration CFRP method is proposed based on an analysis of existing CFRP preparation process methods. Research on composite material preparation systems was carried out by using this new method principle. The system mainly includes a fiber pre-forming module, a vacuum heating infiltration module, a hot-press curing molding module, and a data acquisition control module. Under the conditions of natural curing at 0 MPa + 6 h + 25 °C, vacuum heating curing at –0.05 MPa + 30 min + 80 °C, and hot-press curing at 0.7 MPa + 5 min + 50 °C, a two-dimensional (2D) CFRP with excellent microstructure and properties was successfully prepared. Observing the microstructure of the prepared composite material, it can be found that the inside of the composite material was sufficiently and uniformly infiltrated, and common preparation defects such as holes and delamination were effectively controlled. Through the performance test, the bending strength of the material reached 790 MPa.