Study on the Fatigue Strength of Welding Line in Injection Molding Products under Different Tensile Conditions

Abstract

The fatigue performance of polypropylene (PP) at various amplitudes and frequencies on fatigue cycles under tensile test conditions is investigated in this study. The results show that increasing the frequency leads to a decrease in fatigue cycles due to increased cycle time. The decline rate can be divided into two stages, between 1 and 5 Hz. The first stage rapidly decreases fatigue performance as the frequency increases from 1 Hz to 2 Hz or 3 Hz. The second stage has a lower reduction rate, which occurs between 2 Hz or 3 Hz and 5 Hz due to the strengthening effect of increasing frequency. Furthermore, increasing the amplitude from 0.1 mm to 0.4 mm reduces the fatigue cycle due to the higher deformation rate. In summary, expanding both amplitude and frequency reduces the fatigue performance of the PP material. Moreover, according to the scanning electron microscope microstructure, increasing the frequency results in more microcracks in the polymer matrix.

Influences of Material Selection, Infill Ratio, and Layer Height in the 3D Printing Cavity Process on the Surface Roughness of Printed Patterns and Casted Products in Investment Casting

“…During printing, the layer height was set at 0.2 mm, and the infill was varied from 0 to 100%. The variations of the infill density selected in this study were based on recent research [ 27 , 28 ]. With an increase in the infill ratio from 0 to 100%, the printing time and weight of the printed specimen gradually increased ( Table S1 and Figure S4 ).…”

Research Progress on Low-Pressure Powder Injection Molding

“…Mold filling is one of the most crucial processes in the PIM process that must be controlled to produce a complete mold filling and to avoid defects like voids, welding lines [163], jetting, warpage [164], fractures, and sinks [165].…”

High strength injection molding welding and interface crystal phase changes in polyamide 6

“…Thermoplastic resins may be effectively melted and joined together, and the thermoplastic engineering materials well behave under impact loads 2 . Extensive research studies have been conducted by researchers on the injection molding process of resin materials, focusing on the formation of weld lines during the molding process, 3 strength of the molded parts, and their service life 4 . However, a single molding process is insufficient owing to as the inevitable need to connect different components arises.…”