Spojení: +420 272 660 644
Registrace Přihlásit se

Zapomenuté heslo

Optimization of processing of powder injection molding feedstocks prone to phase separation

In the last decades Powder Injection Molding (PIM) became an effective technology for a mass production of precise and shape-complex metal and ceramic items. The main issue of PIM process is phase separation occurring during injection molding step. The phase separation causes defects which are detected mostly after final sintering, and thus leading to significant economic and ecological losses. The aim of the thesis is optimization of PIM process and detection of powder/binder separation during/after injection molding step, when the process is still reversible - materials can be regranulated and used again. Direct testing of molded samples, without any additional treatments or knowing an exact composition of used binders, is provided for a broad cast of PIM feedstocks including commercially available ones. The proposed testing method combines scanning electron microscopy with energy dispersive X-ray to detect changes in powder or binder concentrations due to a phase separation, which are then analyzed with a mathematical approach to provide the single variability parameter to quantify the tendency of the particular feedstocks towards phase separation. Further, rheological properties of PIM feedstocks were investigated with the special regard to wall slip effect, which serves as a parameter indicating phase separation during shear deformation. The results reveal the importance of the surface roughness and geometry of the processing tools for the wall slip development; therefore, these parameters should be considered for reliable testing to optimize the molding step of PIM. Finally, the influence of processing parameters such as injection molding temperature and debinding route on the sintered surface structure of PIM parts revealing signs of phase separation was investigated by contactless scanning. The obtained qualitative data were then treated with suitable statistical approaches to quantify the quality of the resulting PIM parts. This thesis provides the contribution to predict and reduce the phase separation of PIM feedstocks, thus positively influencing the effectivity of the PIM process.
Počet stran 52 stran
Datum vydání 13. 05. 2019
Pořadí vydání První
Jazyk anglický
Vazba e-kniha - pdf
Nakladatelství Univerzita Tomáše Bati ve Zlíně
Tématická skupina 5 - Technické vědy
Neprodejná publikace. Publikaci je možné poptávat zde: Neprodejné - volně dostupné na http://hdl.handle.net/10563/43791
Při poskytování služeb nám pomáhají cookies. Používáním webu s tím vyjadřujete souhlas. Další informace