Feedstock preparation, as well as its characterization, is crucial in the production of highly sintered parts with minimal defect. The hard metal powder - particularly, cemented carbide (wc-co) used in this study was investigated both physically and thermally to determine its properties before the mixing and injection molding stage. Several analyses were conducted, such as scanning electron microscopy, energy dispersive X-ray diffraction, pycnometer density, critical powder volume percentage (cPvP), as well as thermal tests, such as thermogravimetric analysis and differential scanning calorimetry. On the basis of the CPVP value, the feedstock, consisting of wc-co powder, was mixed with 60% palm stearin and 40% polyethylene at an optimal powder loading, within 2 to 5% lower than the CPVP value. The CPVP spotted value was 65%. The feedstock optimal value at 61% showed good rheological properties (pseudoplastic behavior) with an n value lower than 1, considerably low activation energy and high moldability index. These preliminary properties of the feedstock serve as a benchmark in designing the schedule for the next whole steps (i.e. injection, debinding and sintering processes).
Proses penyahikatan pelarut telah diterima dengan meluas dalam proses pengacuanan suntikan logam (MIM) berdasarkan kemampuannya meningkatkan proses penyahikatan. Bahan pengikat boleh larut yang dikeluarkan dari jasad anum akan menghasilkan liang-liang yang akan membantu meningkatkan kadar penyahikatan terma. Kertas ini membentangkan pengoptimuman proses penyahikatan pelarut dengan menggunakan kaedah Taguchi. Pengaruh pembolehubah penyahikatan pelarut seperti suhu pelarut, taburan saiz partikel, beban serbuk dan tekanan penyuntikan juga dibincangkan. Dua jenis serbuk SS316L digunakan dalam kajian ini iaitu serbuk pengatoman gas dan pengatoman air. Kajian ini mendapati bahawa suhu pelarut memainkan peranan yang sangat penting dalam proses penyahikatan
pelarut dan menyumbang sebanyak 91.602% (bagi serbuk pengatoman gas) dan 84.978% (bagi serbuk pengatoman air) terhadap kadar pengeluaran bahan pengikat. Bagaimanapun, taburan saiz partikel serbuk hanya menyumbangkan sebanyak 6.638% dan 12.228% bagi serbuk pengatoman gas dan pengatoman air masing-masing terhadap kadar pengeluaran bahan pengikat. Suhu pelarut menunjukkan tahap signifikan yang sangat tinggi iaitu α = 0.005 bagi kedua-dua jenis serbuk tersebut. Walau bagaimanapun, taburan saiz partikel serbuk SS316L menunjukkan tahap signifikan yang sederhana iaitu α = 0.025 dan α = 0.01 bagi kedua-dua padatan serbuk tersebut.