Today, Matrix will discuss with you the heat treatment of 3D-printed components.
Metal 3D printed parts usually need to undergo a heat treatment step after manufacturing. It reduces the internal stress formed during manufacturing and can change the part’s microstructure. This change in microstructure changes certain properties, such as toughness, hardness, etc. One way to thoroughly densify 3D-printed metal parts to reduce porosity is a hot isostatic pressing (HIP) treatment.
The HIP process involves placing the 3D finished product in a pressure vessel and then filling it with an inert gas (usually argon). The pressure is constantly increasing and can exceed the yield strength of the component while maintaining high temperatures. With rapid quenching, the more complex HIP process utilizes adjustable cooling and heating rates as well as pressure levels to accurately adjust the quality and tensile properties of the machined parts.
What effect does heat treatment have on polymer 3D-printed parts?
Through 3D printing technology, it is possible to accurately manufacture a variety of complex geometric shapes, however, it has a major disadvantage, which is, the need for thermal post-processing. These 3D-printed parts have poor mechanical properties compared to injection molding ones. Insufficient adhesion between the coated filaments and the stacked layers can result in poor mechanical properties of 3D-printed components.
The latest research, published in the journal Polymers, focuses on improving mechanical properties, particularly tensile and compressive strength. The researchers used PETG filaments with a diameter of 1.75 mm for the study. The results showed that the tensile strength of the polymer 3D-printed components increased significantly after heat treatment. The results showed that the heat-treated parts had excellent tensile strength, with the fully treated parts being 41.1% stronger horizontally than the untreated samples and 143.9% stronger vertically than the control group. The destructive compression test shows that the compressive strength value of the heat-treated sample is significantly increased, and the compressive stress is as high as 118 MPa. The study successfully revealed the positive effects of heat treatment after the manufacture of polymer materials.
Heat treatment of 3D-printed polypropylene parts for vacuum systems
A recent study in the Journal of Manufacturing and Materials Processing investigated the feasibility of applying a heat treatment process to encapsulate 3D-printed polypropylene under vacuum conditions. The study found that heat treatment is very effective for the packaging process.
The researchers performed 15 iterations on parts that were printed with 98% fill overlaps and sealed after heat treatment, with an average of 0.4 m Torr and a 95% confidence interval of 0.2 m Torr. The study found that the use of a heat gun at 400 degrees Celsius for 55 seconds to seal surfaces susceptible to vacuum was successful, which increased the minimum vacuum pressure achieved.
Does heat treatment affect the dimensional stability of 3D-printed components?
Researchers have published A study in Composites Part A that explores the effects of heat treatment on the stability and tensile properties of 3D-printed continuous carbon fiber (CCF) reinforced composites. The morphological changes and dispersion of the print layer are used to assess the dimensional stability of the sample. The 3D printing technology is based on the fuse manufacturing (FFF) method, called continuous filament manufacturing (CFF).
C-CCFRC and S-CCFRC are used to enhance samples with concentrated and separated CCF layers, respectively. After heat treatment at 100°C and 150°C, CCFRCs have excellent tensile properties, although dimensional stability is better at 100°C, especially S-CCFRC. Matrix crystallinity increased from 17.42% in untreated samples to 22.76% in 100 C heat-treated samples, an increase of 30.65%. It was also found that heat treatments at 100°C and 200°C reduced the permeability of the samples. The trend of lower permeability of the matrix after heat treatment is consistent with its dimensional shift. Therefore, heat treatment up to 100°C greatly improves the dimensional stability of the sample.
Effect of heat treatment on PLA parts?
Melt deposition molding (FDM) is a popular additive manufacturing technique, of which PLA is the most widely used material. In their latest study, published in Polymers, the researchers evaluated the performance of PLA components through 3-point bending tests after heat treatment and by varying the build direction, layer thickness, and speed.
The researchers used a PLA filament with a diameter of 1.75 mm. xz manufacturing configuration, 190°C nozzle temperature to prevent specimen breakage, and optimal printing parameters are 90 mm/s speed and 0.3 mm thickness. Samples manufactured using these Settings were thermally-posttreated at 75°C and the results showed an increase in bending stress. Finally, the results show that the elastic deformation and recovery during heat treatment do not significantly limit the maximum force. This research shows that orthoses can be 3D printed flat and then twisted to match the desired area of the human body.
