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.
| ISBN: | 978-80-7454-831-4 |
|---|
| EAN: | 9788074548314 |
|---|
| 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 |
|---|
Svaz českých knihkupců a nakladatelů