H13 is a widely used versatile tool steel, and is well known for its excellent combination of high resistance to compression, thermal shock and abrasion. H13 is heavily used for more hot work tooling applications than other grades of tool steel as well as a variety of cold work conditions because of its high toughness and good stability in heat treatment. H13 covers a wide range of application from die casting, extrusion dies and high toughness and polished (up to A1 grade) injection mold components.
H13’s high carbon content, makes it extremely difficult to weld or process with standard Metal Laser Sintering parameters. The carbon content is easily vaporized and can contaminates the powder surface during the welding process, which may lead to issues such as internal flaws, porosity and thermal cracks, especially in the area of stress concentration.
In order to find the solution to the challenge, Farsoon’s application team joined hands with U.S. industrial partner Next Chapter Manufacturing in an ongoing program to develop advanced process parameters to produce robust H13 tooling using Laser Sintering process.
Figure 1: Lifter design featured with conformal cooling circuit. Image courtesy: Next Chapter Manufacturing
One example from this collaboration is a lifter used for cooling and separating the plastic parts from the core in injection mold production, which is employed in the internal undercut area with snaps and an enclosed shape. By adding an 1/16-inch NPT conformal water circuit design to the geometry of the lifter (Figure 1) and additively produced on a Farsoon FS271M system, Next Chapter Manufacturing was able to deliver 4 lifters in only 8 days. The lifters can be directly installed in the factory system, the new conformal design helps accelerates the cooling process and eliminate the warpage in the finished part. The optimized lifters improved production volume with the original factory settings, reducing the cycle time from 48 seconds to only 30 seconds, and achieving an annual savings of $100,000.
“We decided to partner with Farsoon Technologies because its system is open, which means we can develop specific processes that enable us to print H13 and other tool steels efficiently.” Says Jason Murphy, president of Next Chapter Manufacturing, “This open parameter system also enables us to do test builds and refine our process to improve robustness and speed further. The technology of the Farsoon machine gives designers a significant amount of additional freedom to provide the most efficient designs for additive manufacturing, which other machines do not offer.“
Figure 2. (Left) Metal Laser Sintering process on Farsoon FS271M system. (Right) Metallographic image of as – built H13 part. Image courtesy: Farsoon Technologies
At present, Farsoon’s application team has conducted a large number of tests to develop processing parameters including the laser power, scanning strategies, internal – stress releasing as well as heat treatment for parts using H13. The optimized parameter set helps eliminate the thermal cracks (figure 2) when welding and delivering a high relative density of over 99.0%. The additively produced H13 parts also showed excellent mechanical properties that are fully comparable to wrought H13 material, achieving as -built hardness of approximate 50 HRC (chart 1). The outstanding as – sintered H13 part performance, as well as Farsoon’s open parameter strategy offers user the freedom for further developing the process that is best tailored to their tooling applications.
Chart 1: Mechanical properties comparison of H13 part by forging process and Farsoon metal laser sintering process (in development). By Farsoon Technologies.
With the company philosophy “Open for Industry”, Farsoon is committed to providing customers with comprehensive additive manufacturing solutions, especially suited for new material development. Up to now, Farsoon has successfully launched 16 process parameters for metal powder sintering, and intensively developing specialized material such as tungsten, tantalum, pure copper, maraging steel 18Ni300, and nickel-based alloys, providing multiple lightweight, functional and customized metal 3D printing material solutions for aerospace, automotive, molding, medical, dental and other industries.
