<p>420 stainless steel is a material that offers the advantages of higher hardness and corrosion resistance. It is often used in parts requiring wear, corrosion, and high-strength resistance. Additionally, the manufacturing process improves the processing technology of complex shapes that cannot be achieved by traditional subtractive processing, and also shortens the product development schedule. However, the grains of additively manufactured materials are smaller and more directional than those of conventionally rolled steel, resulting in more complex parts with lower ductility. High-temperature melting and laser scanning speed affect the performance of additively manufactured parts in terms of porosity and surface roughness. A rough surface can influence the parts’ corrosion resistance, friction, and aesthetics. Therefore, this study employed different parameters in metal additive manufacturing (MAM) processing and grinding to improve the performance of 420 additively manufactured stainless steel. The experimental results show that variations in laser power and laser scanning speeds affect the density and tensile strength of the parts. The grinding process using a diamond wheel with a CFRP hub also improves the surface roughness of 420 additively manufactured stainless steel.</p>