The post-processing treatment of isostatic compression with different temperatures is improved with the interlayer bonding of the polylactic acid (PLA) parts. This bonding enhanced the tensile strength, percentage of strain, and elastic modulus of post-processed PLA samples through the tensile test. Here, the tensile strength is improved by about 127 % compared to untreated PLA due to interlayer bonding and the compressive force with 140 °C. Compression and flexural tests are utilized to examine the post-processed parts’ compression and flexural strength. It significantly improves the compressive and flexural strength of the post-processed parts, increasing to about 55 % and 64.5 % compared with the untreated PLA parts. Additive manufacturing of PLA parts is significantly progressed in the 3D printing of biodegradable and eco-friendly components through a layer-by-layer deposition.