Effect of Thermal Debinding Conditions on the Sintered Density of Low-Pressure Powder Injection Molded Iron Parts

Abstract

Low-pressure powder injection molding (LPIM) is a cost-effective technology for producing intricate small metal parts at high, medium, and low production volumes in applications which, to date, have involved ceramics or spherical metal powders. Since the use of irregular metal powders represents a promising way to reduce overall production costs, this study aims to investigate the potential of manufacturing powder injection molded parts from irregular commercial iron powders using the LPIM approach. To this end, a low viscosity feedstock was injected into a rectangular mold cavity, thermally wick-debound using three different pre-sintering temperatures, and finally sintered using an identical sintering cycle. During debinding, an increase in pre-sintering temperature from 600 to 850 °C decreased the number of fine particles. This decreased the sintered density from 6.2 to 5.1 g/cm3, increased the average pore size from 9 to 14 μm, and decreased pore circularity from 67 to 59%.

Polyvinyl pyrrolidone (PVP) as an efficient and biocompatible binder for metal alloy processing: A case study with Ti‐20Zr‐11Nb‐3Sn

“…From TGA, the effect of binder constituents and the debinding atmosphere on the thermal degradation of the binder can be understood. Whereas the melting behavior can be assessed by the DSC 65–68 . Figure 8 shows the TGA and DSC plots of the PVP (K 90), which implies that the PVP is degraded within the temperature of 500°C.…”

Structure and Properties of Co-Cr-Mo Alloy Manufactured by Powder Injection Molding Method

“…Additionally, the powder bed acts as a wicking medium to withdraw the molten binder out of the heated part. Therefore, this method of binder degradation can be called a thermal wick debinding process [21]. The results of thermogravimetric tests presented in the article [18] showed that the final debinding temperature of the pure EVA copolymer exceeds 500 • C regardless of whether it takes place in the air or the protective nitrogen atmosphere.…”

Optimization of metallic powder filaments for additive manufacturing extrusion (MEX)

“…Instead of using catalytic debinding, thermal debinding was selected, which shows no carbonaceous residues present during sintering, consistent with previous studies with lowpressure injection moulding [31], thus voiding the nitric acid used for catalytic debinding. The thermogravimetric analysis highlights that all of the organic constituents of the feedstock fully degrade, during the debinding stage (Fig.…”

“…The vol.% of each organic component in the feedstock was tailored to achieve the proper filament properties for MEX (rheology and flexibility/stiffness balance). The CPVC and [31]. For the CPVC evaluation, an increment of 1 vol.% powder content was made approximately every 10 min or after reaching a steady state.…”