Research of Favorable Conversion of Friction during Powder Compaction

Abstract

The warm powder compaction process is simulated by the finite element analysis software which is MSC/MARC. The thermal mechanically coupled analysis method is applied based on the updated Lagrangian Method to study the influence of different velocities ratio of die and punch υdie/υup-punch on the properties of green under different frictional condition. The results indicate that for cylindrical powder metallurgic products, different velocity ratios have great influence on the distribution of relative density and equivalent stress. The frictional force can be converted to the favorable force through adjusting the velocity ratio, and this method can obtain higher uniform distribution of relative density and stress of green.

An Investigation For Optimal Tool Kinematics In Powder Compaction Cycle To Minimize Density Gradient In Green Powder Compacts

“…Based on the overall observations the average relative density distribution over the final compact height is more uniform at the die-to-upper-punch velocity ratio, v die /v u-p , of 0.5, for all the cases of compact height-to-diameter ratio, h/d. Consequently, upon increase of v die /v u-p from 0 to 0.5, a decrease in density gradient is observed, identical to the trend recorded in experimental study conducted by Canta and Frunza [15], and simulation analyses conducted by Wang et al [115].…”

“…When v die /v u-p increases from 0 to 0.5, a decrease in density gradient is observed, identical to the trend recorded in experimental study conducted by Canta and Frunza [15], and simulation analyses conducted by Wang et al [115]. However, upon further increase of v die /v u-p from 0.5 to 1.0, a reverse trend is observed, with gradual increase in overall density gradient over the compact height; similar trend was also recorded by Wang et al [115]. The maximum density gradient is observed at v die /v u-p of 0 and 1.0, with an equivalent difference between the recorded maximum and minimum relative density values of 0.0273.…”

An Investigation For Optimal Tool Kinematics In Powder Compaction Cycle To Minimize Density Gradient In Green Powder Compacts

“…From Figure 57, representing density distribution over the point location of each mm of the compact height using constant friction coefficient, a symmetric trend in density distribution is observed over the compact height when the die to the upper-punch velocity ratio, v die /v u-p , is varied from 0 to 1.0. When v die /v u-p increases from 0 to 0.5, a decrease in density gradient is observed, identical to the trend recorded in experimental study conducted by Canta and Frunza [15], and simulation analyses conducted by Wang et al [115]. However, upon further increase of v die /v u-p from 0.5 to 1.0, a reverse trend is observed, with gradual increase in overall density gradient over the compact height; similar trend was also recorded by Wang et al [115].…”

“…Although, a modified version of the corresponding variable friction coefficient expression had to be employed, the ensuing simulation results compared more closely with the experimental results for the friction-assisted compaction of the cylindrical parts, presented by Canta and Frunza [15]. It is important to note that most of the simulation studies presented in the literature had employed a constant friction coefficient value [13,27,31,48,49,70,89,101,102,110,112,115,124,129]. However, as was shown earlier in this report, based on experimental studies, the fiction coefficient tends to vary and is a function of several parameters.…”

316L Metal Powder Compaction Simulation with Assisted Friction

“…This issue has been tackled by other authors [3,7,13] in the last 20 years, which shows an interest in optimizing the compaction process by converting friction forces at the contact the die/metal powder.…”