Bone tissue engineering requires biomimetic materials; however, pure polylactic acid (PLA) exhibits limited osteoinductivity and produces acidic byproducts upon degradation. To address these limitations, this study fabricated PLA scaffolds using fused-deposition modeling (FDM) with four distinct lattice structures (rectangular, triangular, gyroid, and 3D honeycomb) and incorporated hydroxyapatite (HA) at 0, 10, 20, and 30 wt% via injection molding. Mechanical properties were evaluated via compression, three-point bending, and tensile testing. The results revealed that increasing HA content significantly reduced structural strength and increased brittleness across all test modes. Specifically, specimens with 30 wt% HA exhibited a 70.8% reduction in bending strength relative to pure PLA (from 58.60 MPa to 17.07 MPa), while tensile strength decreased by 46.1% at just 10 wt% HA (from 37.54 MPa to 20.23 MPa). Although the triangular lattice achieved the highest absolute compressive load, the rectangular lattice provided a superior load-to-weight ratio and greater plastic deformation capacity before fracture. Consequently, these findings indicate that the rectangular pattern at 70% infill density combined with HA addition limited to ≤10 wt% represents the most mechanically balanced design for bone defect repair applications. Based on the mechanical characterization performed in this study, and drawing on published evidence regarding the biological properties of PLA/HA composites, these scaffolds represent a mechanically promising candidate for further evaluation in bone tissue regeneration. Biological validation through in vitro and in vivo studies is required before clinical relevance can be established.

Bone tissue engineering requires biomimetic materials, but pure polylactic acid (PLA) lacks osteoinductivity and produces acidic byproducts during degradation. To address these limitations, this study fabricated PLA scaffolds using fused-deposition modeling with four distinct lattice structures (rectangular, triangular, gyroid, and honeycomb) and incorporated hydroxyapatite (HA) at ratios of 0%, 10%, 20%, and 30% via injection molding. Mechanical properties were evaluated through compression, bending, and tensile testing. The results revealed that increasing HA content significantly reduced structural strength and increased brittleness. Specifically, specimens with 30% HA showed a 50% reduction in bending strength, while tensile strength dropped by approximately 46% at just 10% HA. Although the triangular lattice maximized absolute load capacity, the rectangular lattice provided a superior load-to-weight ratio and greater plastic deformation before fracture. Consequently, these findings suggest that the rectangular pattern with 70% infill density demonstrates the most suitable mechanical properties combined with limited HA addition (< 10%) to balance necessary mechanical integrity with the enhanced bioactivity required for repairing large bone defects. These PLA/HA composite scaffolds offer a promising approach for advanced bone tissue regeneration.

Verification activity in a streamline manufacturing system is one of the most important activity to make sure that the design requirements and the actual product specifications are met. It helps designer or manufacturing engineer as a feedback by detecting issue at early stage. However, we have to select the most effective verification method that will lead to low cost and relatively fast production. Many industries make machined components that are mounted to welded frame, the locations of the components may float with a larger tolerance to the welded frame than the feature to feature tolerance needed for mounting hole pattern. The composite tolerance is needed for this particular case. The most suitable method for gathering measurement data for small batch production is either automatically using CMM or manually using pin gages and size measurement devices. While, the data processing step can be done by graphic analysis or paper gage method for inspecting composite positional tolerance. The innovation of this journal is changing the way of data processing method by reducing the papers (coordinate grid and polar overlay) required for graphic analysis and converting them into mathematical model that can be processed by computer. Hence, we call this virtual graphic analysis. The benefits of using virtual graphic analysis are reducing cost and time of overall inspection process.

Polylactic acid (PLA) reinforced with hydroxyapatite (HA) has attracted significant attention as a candidate biomaterial composite due to its biodegradability, bioactivity, and tunable mechanical properties. However, the strain-rate-dependent mechanical response of Stereolithography (SLA) 3D printed PLA+HA composites and its constitutive representation remain insufficiently explored, limiting predictive modeling for load-bearing applications. A simplified Zhu–Wang–Tang framework was employed to construct a constitutive model. This study presents an integrated experimental and constitutive modeling approach that combines quasistatic strain-rate characterization, simplified ZWT constitutive modeling, and complementary surface and microstructural characterization. PLA + HA composites containing 1, 5, 10, and 15 wt.% HA were fabricated by SLA and tested under compressive loading at strain rates of 10-4 s-1 and 10-3 s-1. The experimental true stress–true strain data were used to identify the nonlinear elastic and Maxwell I parameters using a sequential fitting procedure. The simplified ZWT model successfully reproduced the strain-rate-dependent mechanical response of the investigated composites with a high agreement with the experimental results. Surface wettability measurements demonstrated improved hydrophilic behavior with increasing HA content, while scanning electron microscopy (SEM) revealed progressively increased particle clustering and localized micro-void formation at higher HA contents, providing direct microstructural evidence supporting the observed mechanical behavior. This study establishes a constitutive basis linking HA content, strain-rate-dependent mechanical response, and microstructural characteristics of SLA-printed PLA+HA composites, providing a foundation for future numerical simulations of polymer-based biomedical components.