The use of polymeric materials and polymer -based composites as alternatives to
metals in conventional applications is a widely adopted strategy. These
materials provide advantages in terms of processability, cost-effectiveness,
and, most notably, weight reduction. This study aimed to develop and optimize
the injection molding process for producing PA9T (Polyphthalamide 9T) components
reinforced with varying amounts of glass fiber to achieve optimal mechanical and
physical properties. To enhance mechanical performance, different glass fiber
loadings were investigated. The study employed the Taguchi method with an L9
orthogonal array design. The selected variable parameters were material
composition (PA9T reinforced with 30, 35, and 50 wt% glass fiber), injection
pressure (1000, 1500, and 2000 bar), injection temperature (320, 330, and 340
°C), and injection speed (100, 125, and 150 mm/s). The Taguchi method was chosen
because it allows for the identification of optimal process parameters and the
evaluation of their influence on material properties while requiring
significantly fewer experimental runs compared to a full-factorial 34
design. The materials were evaluated based on mechanical properties through
tensile and flexural tests using a Universal Testing Machine. The density of the
injected specimens was measured using the Archimedes principle, while
fiber-matrix adhesion, porosity morphology, and fracture behavior were analyzed
via scanning electron microscopy (SEM). Results indicated that the glass fiber
content had the most significant influence on material strength, followed by
injection pressure, temperature, and speed, in that order. The study identified
1000 bar, 320 °C, and 100 mm/s and 50 wt% glass fiber as the optimal processing
parameters, ensuring that specimens produced under these conditions achieved
mechanical properties such as 230 MPa stress at break and elastic modulus of
19,3 GPa.