Additive manufacturing & 3D printing has almost no limitation in realizing any geometry due to its layer-by-layer manufacturing manner, while producing small-sized, interconnected pores is one of its major challenges. In this study, we report that, by creatively combining additive manufacturing with foaming agent, interconnected pores (~ 26 vol.% porosity) with pore size of 2–30 μm have been successfully achieved. One of the most important applications of such unique structure is for developing the so-called breathable mould steel. Breathability is rather demanding for the mould industry, since it is capable to eliminate the trapped, detrimental gas during injection moulding and therefore much improve the quality of as-injected parts. It will be revealed by the study that, due to a good selection of the foaming agent (ie CrNx), the as-printed breathable steel has a great combination of compressive strength (~ 1.3 GPa), strain (~ 26%), microhardness (~ 360 HV) and corrosion res istance, along with sufficient breathability. These mechanical properties are even superior to the commercial PM-35 breathable steel. Based on detailed microstructural characterization, the affecting factors to the pore forming are studied, and the importance of the novel approach developed by the current study has been addressed.
Breathable steel is a kind of fine-grained spheroidal powder stainless steel sintered at high temperature. It is evenly covered with tiny exhaust holes in all directions. It is also called porous material or porous metal.
Metallographic breathable steel
In the metallographic structure (ESEM) of the porous die steel, a large number of three-dimensional spatially interconnected holes are randomly distributed.
Material: EM191 (S136 / 1.2083 / 420)
Breathable steel aperture:
0.03-0.05mm (normal delivery period)
0.01-0.03mm (the delivery time is slightly longer)
Irregular honeycomb
Advantages of breathable steel
Good air permeability, the surface contour of the casting is clear
Filling resistance is reduced, filling power can also be reduced
The clamping force of the mold can be reduced
Reduced mold weight, only 2/3 of the original, saving material
To sum up: it can simplify the design of the mold structure and the variety of choices for the injection molding machine and die casting machine models. The development and application of 3D printed breathable steel is more energy-efficient and resource-saving.
Custom made of breathable steel
ESU Laser is in the product service of mold breathable steel: it can be customized according to customer needs.
Customized breathable steel:
According to the shape of the part, leave 0.8mm margin on one side for breathable steel
According to the trapped area of the part, do area ventilation steel printing and solid steel printing.