Three-dimensional printing is a non-conventional additive manufacturing process. It is different from the conventional subtractive manufacturing process. It offers exceptional rapid prototyping capabilities and results that conventional subtractive manufacturing methods cannot attain, especially in applications involving curved or intricately shaped components. Despite its advantages, metal 3D printing will face porosity, warpage, and surface roughness issues. These issues will affect the future practical application of the parts indirectly, for example, by affecting the structural strength and the parts’ assembly capability. Therefore, this study compares the qualities of the warpage, weight, and surface roughness after milling and grinding processes for the same material (316L stainless steel) between rolled steel and 3D-printed steel. The experimental results show that 3D-printed parts are approximately 13% to 14% lighter than rolled steel. The surface roughness performance of 3D-printed steel is better than that of rolled steel for the same material after milling or grinding processing. The hardness of the 3D-printed steel is better than that of the rolled steel. This research verifies that 3D additive manufacturing can use surface processing to optimize surface performance and achieve the functions of lightness and hardness.

The injection molding process is one of the most widely used methods for polymer processing in mass production. Three critical factors in this process include the type of polymer, injection molding machines, and processing molds. Polypropylene (PP) is a widely used semi-crystalline polymer due to its favorable flow characteristics, including a high melt flow index and the absence of a need for a mold temperature controller. Additionally, PP exhibits good elongation and toughness, making it suitable for applications such as box hinges. However, its tensile strength is a limitation; thus, glass fiber is added to enhance this property. It is important to note that the incorporation of glass fiber increases the viscosity of PP. Multi-cavity molds are commonly employed to achieve cost-effective and efficient mass production. The filling challenges associated with geometrically balanced layouts are well documented in the literature. These issues arise due to the varying shear rates of the melt in the runner. High shear rate melts lead to high melt temperatures, which decrease melt viscosity and facilitate easier flow. Consequently, this results in an imbalanced filling phenomenon. This study examines the impact of runner size, gate size, polymer viscosity, and molding process on the filling imbalanced problem in multi-cavity injection molds. Tensile bar injection molding was performed using conventional injection molding (CIM) and microcellular injection molding (MIM) techniques. The tensile properties of the imbalanced multi-cavity molds were analyzed. Flow length within the cavity served as an indicator of the filling imbalance. Additionally, computer simulations were conducted to assess the shear rate’s effect on the runner’s melt temperature. The results indicated that small runner and gate sizes exacerbate the filling imbalance. Conversely, glass fiber-filled polymer composites also contribute to increased filling imbalance. However, foamed polymers can mitigate the filling imbalance phenomenon.

Biochips play an important role in both medical and food industry safety testing. Moreover, magnetic activated cell sorting is a well-established technology for biochip development. However, biochips need to be manufactured by precision instruments, resulting in the high cost of biochips. Therefore, this study used magnetic-activation and mechanics theories to create a novel disc that could manipulate the microfluidic flow, mixing, reaction, and separation on the runner of the disc. The goal of the research was to apply in the field of biomedical detection systems to reduce the cost of biochips and simplify the operation process. The simulation and experimental investigation showed that the pattern of the reaction chamber was stomach-shaped and the reservoir chamber was rectangular-shaped on the disc. The microfluid could be controlled to flow to the reaction chamber from the buffer and sample chamber when the disc spun at 175~200 rpm within three minutes. This was defined as the first setting mode. The microfluid could then be controlled to flow to the reservoir chamber from the reaction chamber when the disc spun at 225 rpm within five to ten minutes. This was defined as the second setting mode. This verified that the pattern design of the disc was optimized for control of the microfluid flow, mixing, reaction, and separation in the runner of the disc by different setting modes.

Using microfluidic flow for biological detection is a non-invasive method that can replace traditional invasive testing methods to achieve fast and accurate results. The design of the detection device and lab-on-a-disk (LoaD) can impact performance in accurately identifying biological features. Therefore, we created a novel device to extract cancer cells from a heterogeneous cell population by centrifugal-force-driven microfluidic flow and magnetic labeling. Two-stage centrifugal force and a specially designed LoaD were used to drive microfluidic flow and control its movement to designated areas. The purpose was to allow the CD44 antibody–magnetic bead complex (CD44 beads), which specifically binds to the abundantly present CD44 receptors on identifiable cancer cells, to flow into the reservoir well, while the biological mixture containing the cancer cells is retained in the capture well. Fluorescence imaging as well as flow cytometric analysis revealed the successful retention of the microbead-bound cancer cells in the magnetic area, while the remaining biological mixture was retained in the reservoir area. The entire separation process took less than 2 h.

3D printing is a non-traditional additive manufacturing process. It is different from the traditional subtractive manufacturing process. It offers exceptional rapid prototyping capabilities and results that traditional subtractive manufacturing methods cannot attain, especially in applications involving curved or intricately shaped components. Despite its advantages, metal 3D printing will face porosity, warpage, and surface roughness issues. These issues will affect the future practical application of the parts indirectly, for example, the structural strength and the parts assembly ca-pability. Therefore, this study compares the qualities of the warpage, weight, and surface rough-ness after milling and grinding processes under the same materials (316L stainless steel) between general rolled steel and 3D additive steel. Experimental results show that 3D printing parts are approximately 13% to 14% lighter than the general rolled steel. The surface roughness performance of 3D printing steel is better than general rolled steel under the same material after milling or grinding processing. The hardness of the 3D printing steel is better than that of the gen-eral rolled steel. The research verifies that 3D additive manufacturing can use surface processing to optimize surface performance and achieve the functions of lightness and hardness.

Tungsten carbide (WC) has been widely utilized in recent years in the hardware, mechanical, and chemical industries and in national defense because of its high hardness, anti-wear, low temperature, and anti-corrosion properties. However, using it for grinding is also challenging because the WC material has high hardness and brittle characteristics. The typical hub of a diamond wheel is made of steel. In high-speed grinding, the steel hub of the diamond wheel is subjected to gravity and centrifugal forces, which cause grinding wheel vibration, poor workpiece processing quality, and a short machine life. Therefore, this study used a carbon-fiber-reinforced thermoplastic (CFRP) hub to replace the steel hub when grinding the WC workpiece. It aimed to investigate methods to reduce oscillation, improve chip efficiency, and increase accuracy in the WC workpiece. The research results demonstrated that using a CFRP hub in the grinding wheel can reduce the oscillation when the peripheral speed of the grinding wheel is at 20–100 m/s. Additionally, the surface roughness average (Ra) of the workpiece can be reduced to 3.2–25.4% and the ten-point height of irregularities (Rz) can be reduced to 18.9–44% compared to using a steel hub in the grinding wheel.