The achievement of high density at reasonable cost would be a definite advantage for the production of P/M components requiring high static and dynamic properties. The use of the electrostatic die wall lubrication technique appears as a very attractive route to promote densification. By reducing the level of friction at die walls, this technique should have the potential to also reduce density ...

A new approach in the method of depositing an external lubricant on the die walls of a powder metallurgy press has been developed which allows the compaction of parts from mixes with no or minimal lubricant content. By heating the die to moderate temperatures (70°C 100°C) and using new composite lubricants, optimum thickness lubricant layers can be deposited allowing the compaction-ejection of ...

We compared three different tracheal wall pressure measuring techniques in vitro. Using a high-volume, low-pressure, cuffed tracheal tube with an internal diameter of 7.5 mm and a model trachea, the pressure difference technique, the wall pressure membrane technique and the microchip sensor probe technique with and without lubrication were studied. Wall pressures were measured after sequential ...

The main objective of this work was to design a novel device for compaction of metal powders so that the green parts could be ejected with applying a negligible force and without the need for any lubricant in either an admixed form or applied to the die wall. For this purpose a 40 mm diameter one-piece die was envisaged which would elastically contracted 0.076 mm before compaction and after com...

I N T R 0 D U C T I 0 N In recent years, the application of double-flow rotary vane compressor in automotive air-conditioning systems has been increased because of its multiple cylinder characteristic. A certain problem is its high friction loss at higher speeds. The greatest amount of the friction is caused by the lubrication systems between the vane tip and the cylinder wall and between vane ...

the main objective of an extrusion die is flow balancing as an unbalanced flow causes a distorted product together with residual stress. in this paper a strategy is presented for flow balancing a u-shaped profile with different wall thicknesses. for this purpose, a choker bar is provided at thicker wall to locally restrict excessive flow passing through the thicker section. for optimal design s...

We present a collision model for particle-particle and particle-wall interactions in interface-resolved simulations of particle-laden flows. Three types of interparticle interactions are taken into account: (1) long- and (2) short-range hydrodynamic interactions, and (3) solid-solid contact. Long-range interactions are incorporated through an efficient and second-order-accurate immersed boundar...