INVESTIGATION OF MICRO-PITS FORMATION ON BILLET SURFACES IN PLANE STRAIN EXTRUSION

Extrusion is a process of pushing a material through a die to yield a desired cross-section product. The application of surface texture has become well known for enhancing tribological performance. In this research, the effect of micro-pits embedded on a work piece lubricated with vegetable oil using plain strain extrusion were studied and compared with those seen with mineral-based oil lubricant. The experiments were conducted at room temperature (around 27℃). A taper die with a 60 die half-angle, with micro-pits array, was prepared. Test lubricants used were paraffinic mineral oil (PMO) VG460 and VG95 and refined, bleached and deodorized (RBD) palm stearin. The results were analysed to determine the extrusion load and the billet’s surface roughness and plastic deformation. RBD palm stearin was recorded as having the highest extrusion load (83.15 kN).

THE EFFECTS OF THE DIE HALF ANGLE OF TAPER DIE ON PLANE STRAIN EXTRUSION

In this research, a study of the effect of a die half angle on the extrusion process has been performed. The experiments were conducted at room temperature around 27 °C. Two types of taper die with different die half angles (45° and 60°) were prepared. The test lubricants used were paraffinic mineral oil VG460 and Refined, Bleached and Deodorized (RBD) Palm stearin. The material of the workpiece (billet) was annealed with A1100 aluminium. The experimental results were focused on the extrusion load, tool and workpiece surface roughness and plastic deformation of the workpiece. The resultant relative velocity was calculated using a visioplasticity method. The results shows that a taper angle of 60° recorded higher resultant relative velocity with a lower extrusion load and surface roughness compare to the taper angle of 45°. The comparison study between Paraffinic Mineral Oil and RBD Palm Stearin shows no significant effect in both taper angles tested.

Alternative Lubricants: Study on Plant-Based Lubricants in Metal Forming Process

In this paper, the effect of metal-to-metal contact from the application of plant-based lubricants, RBD palm olein and jatropa were investigated by cold work forward plane strain extrusion experiments. A pair of taper die and a symmetrical workpiece (billet) was placed inside extrusion rig which acted as main experimental apparatus. The billet material was annealed pure aluminum A1100 with radius 5 mm in deformation area. The experimental result shows that the lower viscosity index, will lead to lower friction effect to the deformed area, as well as product area.

DETERMINING ALTERNATIVES FOR METAL FORMING LUBRICANTS: A STUDY USING PLANE STRAIN COLD EXTRUSION PROCESS OF JIS-A1100 PURE ALUMINUM BILLET

Lubrication is very important in metal forming processes to control wear and friction at the interface between interacting surfaces. Non-renewable resources, such as plain mineral oils are widely used due to its ability to act as a supplier to wearing contacts; it may function as a film material or even sustain chemical transformations to become a film material. Since non-renewable resources can only last for more than a decade, renewable resources have been studied in order to find alternative lubricants that can present similar results in terms of extrusion load and product quality. Two renewable lubricants were analyzed (RBD palm olein and jatropha) together with an additive free paraffinic mineral oil, VG32, which acted as a reference lubricant. The experiment used a cold work plane strain extrusion apparatus that consists of a pair of taper die and a symmetrical work piece (billet). The billet material was made of annealed pure aluminum JIS-A1100 with radius of 5 mm in the deformation area. It was found that higher viscosity lubricants produced low extrusion load and friction during metal forming process with no major severe wear on product quality. Based on the results, it was proven that renewable resource based lubricants can be considered as a substitute for common lubricants used in the industry, since they present similar results with those currently applied in the industry.

Study of Alternative Lubricants for Cold Extrusion Process of A1100 Pure Aluminum

Lubrication in metal forming process is very important to control wear and friction at the interface between interacting surfaces. Non-renewable resources, such as mineral oil are widely used since a beginning due to its ability to act as a supplier to the wearing contact which functions as a film material or sustains chemical transformation to become a film material. Since it is will not last for a few more decades, renewable resources had been studied in order to find an alternative lubricant with presents similar results in terms of extrusion load and product quality. Two renewable lubricants were analyzed (Palm Kernel and Palm Stearin) together with additive free paraffinic mineral oil VG460 will act as a comparison lubricant. The experiment used a cold work plane strain extrusion apparatus consisting of a pair of taper die and a symmetrical work piece (billet). The billet material was annealed pure aluminum A1100 with radius of 5mm at the deformation area. It was found that palm Palm Kernel and Palm Stearin performed slightly high extrusion load, however they show no severe wear on product surface. Based on the results, it is proven that renewable based lubricants can be considered as a substitute to common mineral based lubricants used in the industry.

Evaluation of Paraffinic Mineral Oil as Lubricant in Cold Work Extrusion Process

In this paper, the effect of frictional constraint from the application of three different viscosity of additive free paraffinic mineral oil as lubricant were investigated by cold work forward plane strain extrusion experiments. The experiment used a cold work plane strain extrusion apparatus consist of a pair of taper die and a symmetrical workpiece (billet). The billet material was annealed pure aluminum A1100 with radius 5 mm in deformation area. The experimental result shows that the higher viscosity, will lead to lower friction effect to the deformed area, as well as product area.

Effect of Surface Roughness of Pure Aluminium A1100 on the Cold Work Extrusion by Using Different Angles of Taper Die

The study presented in this paper is focused on the effect of surfaces roughness of pure aluminium A1100 on the cold work extrusion process by three different angles of taper die. Different angles of taper die will affect the surface roughness of the workpiece. To protect the surface and to reduce friction, lubricants are often used in extrusion process [1]. Different lubricants may have different optimum taper die angle that are suitable to be applied. Two types of materials used in this experiment are steel SKD 11 for taper die and aluminium A1100 for workpiece and different angles applied are 30o, 45o, and 60o. Moreover, with respect to each angle, three different types of lubricants were used which are Daphne Draw S Series, Palm Olein, and EFB bio oil. The Universal Testing Machine and Surface Roughness Tester were used in this experiment. The result obtained from the experiment shows that at 30o of taper die angle were producing the smooth product surfaces for each lubricant and Daphne Draw S Series could reduce the surface roughness compared to other lubricant test.

The Influence of Lubricant Viscosoty in Cold Work Forward Extrusion Using Micro–Pits Tool

The present research concerns on the study of the effects of micro–pits arrays formed on taper die using cold forward plane strain extrusion experiments. Each pit was of reverse pyramids configuration having 330 microns diagonal length. The pits were 860 microns apart each others. Two additive free paraffinic mineral oils with low viscosity (P2) and high viscosity (P3) were used in this experimental work. The experimental results were compared with the results obtained from the plane strain extrusion experimental works with taper die without micro–pits (NA). The experimental results focused on the extrusion load, billet surface roughness and billet grid pattern on inclination slope. From the results, the existence of the micro–pits array on the taper die surface affected the extrusion load. At the same time, the micro–pits array affected the extruded billet surface roughness after the experiments. From this experiment, we could conclude that the micro–pits formed on the taper die (PA) would control the frictional constraint on the taper die compared to those without the micro–pits (NA). However, high viscosity lubricant (P3) was found to cause more effects compared to low viscosity lubricant (P2).