Conventional Hot Extrusion
12
Citation
12
Reference
10
Related Paper
Citation Trend
Abstract:
Abstract Hot extrusion is a process in which wrought parts are formed by forcing a heated billet through a shaped die opening. This article discusses nonlubricated and lubricated hot extrusion. The two nonlubricated hot extrusion methods are forward or direct extrusion and backward or indirect extrusion. The article illustrates the significance of extrusion speeds and temperatures in hot extrusion. It describes the basic types of presses used in the hot extrusion of metals. The article provides information on the characterization of extruded shapes and explains the operating parameters, including extrusion velocity, amount of pressure required, and type of lubricant, for successful and efficient hot extrusion. The article concludes with a discussion on applications and design methodology that provides insight into CAD/CAM of extrusion dies.The present research concerns study of the effects of micro-pits arrays formed on the taper die by experimental verification using. A series of taper die with micro-pits with different location at existence of die were design. A taper without micro-pits was used as a reference. The lubricant is additive free paraffinic mineral oil. P2 is a low viscosity lubricant while P3 is a high viscosity lubricant. The experimental results are focusing on the extrusion load, billet surface roughness, and grid pattern observation. From the result, the micro-pits array affected on surface roughness if the lubricant viscosity is higher but the extrusion load also become higher.
Cite
Citations (0)
Recently, there is greater concern for industries to maintain lubricant flow along the extrusion process, which is important to obtain the best quality of the final products. One of the most cost-effective methods is surface texturing. In this research, surface texturing was embedded on a tapered die sliding contact surface to explore its effectiveness on a finished product from a cold extrusion process. Palm oil–based lubricant was tested for cold extrusion processes and mineral oil was used for comparison purposes. It was found that a textured tapered die (TA) performed a diminished extrusion load compared to an untextured tapered die (NA) and improved the performance of other test parameters. As an alternative lubricant, refined, bleached, and deodorized (RBD) palm kernel oil presents results similar to those of commercial extrusion oil in terms of extrusion load and product quality. Based on the results, it is proven that surface texturing and palm oil–based lubricant can be considered as an alternative approach for implementation in industry.
Dry lubricant
Cite
Citations (5)
Hydrostatic equilibrium
Friction loss
Friction Factor
Hydrostatic pressure
Cite
Citations (5)
In this study, specially designed slit inserts were fabricated and used in extrusion for the extraction of remnant polymer blocks stuck in the slit capillary after experiments. The polymer blocks were characterized using X-ray photoelectron spectroscopy(XPS), secondary ion mass spectrometry(SIMS) and scanning electron microscopy(SEM) for the presence and structure of the inferred lubricant layer which is formed during the extrusion of HDPE/Dynamar(a fluoroelastomer processsing aid) blends. The layer was found to be present with an approximate thickness of 5 - 15 μm, depending on the extrusion conditions. Moreover, adhesive failure at the polymer melt/lubricant layer interface was found to be the failure mode associated with the lubrication. Furthermore, the relation between the lubricat...[ Read more ]
Die swell
High-density polyethylene
Polycarbonate
Cite
Citations (0)
Through analysis of cold extrusion process of the stationary bowl,the cold extrusion process of the stationary bowl and the selection of its equipment are presented.And the polymer lubricant and the bonderizing and saponifying process are analysed.The lubricating process to use the polymer lubricant for the billets is put forward.The means of the upsetting and the structure of the extrusion die are discussed.And the parts are extruded successfully.
Cite
Citations (0)
Abstract Backward extrusion processes are widespread when producing various axisymmetric hollow products. This process is characterized by high values of specific pressures. The meaningful task to be achieved is to reduce loads during this process implementation. The use of active friction forces to reduce loads seems to be promising. The use of a floating die with a protrusion on a cylindrical surface, which will facilitate the billet material pushing, is proposed. For theoretical justification of the process, the provision is made to use the finite-element method. The procedure was simulated for different geometric relationships of the tool, the floating extrusion die path velocities and the billet position relative to the extrusion die. The provision is made to analyze the influence of deformation parameters and velocity parameters on the change in force of the studied procedure. Based on the research findings, the conclusions on the expediency of the studied method use for its practical implementation have been made.
Bar (unit)
Position (finance)
Cite
Citations (4)
Abstract Numerical solutions for an isothermal case are presented for the direct extrusion process of a cylindrical body with viscous plastohydrodynamic lubrication at high operating temperature and pressure. The extrusion pressure at die predicted by the present theory, and measured correspondingly by experiment are seen to agree well. As such, this agreement supports the validity of the assumptions in the present theory. For this typical experimental case, the additional data, which are not measured by experiment, are calculated by the present theory. Furthermore, a more fundamental understanding is provided for design data with regard to the interaction of the physical parameters such as extrusion ram speed, percent reduction in area, half of the included die angle, preheat billet temperature, exit pressure of lubricant film, lubricant properties, and extruded materials. These design data are offered in a form whereby they may be applied broadly to a variety of practical direct extrusion processes.
Isothermal process
Cite
Citations (1)
The paper presents recent studies in simulation of thin profile extrusion technology with the emphasis on interaction between the material flow and the state of the tooling set. To take into consideration die deflection and gradient of the temperature across the die and mandrel during the entire process cycle a transient coupled thermo-mechanical model has been built on the basis of QForm-Extrusion program. The paper explains the background for this model and some tests to verify its accuracy. Practical implementation of this model at several die making and extrusion companies has shown it to be of higher accuracy compared to the results of rigid die simulation.
Mandrel
Material Flow
Transient (computer programming)
Cite
Citations (10)
Brass
Copper alloy
Cite
Citations (0)
The warm extrusion technology of air cylinder bolt-protected screws used for the national locomotive was studied.The warm extrusion technology parameters,such as bullets,die temperature,the cooling and lubrication of die were determined,the structure of punch and die was designed,and the extrusion process was analyzed by LS-DYA software.The results show that the warm extrusion die structure of the air cylinder bolt-protected screw is reasonable,and can provide theoretic basis for the production of similar products.
Extrusion moulding
Cite
Citations (0)