Italian hydraulics manufacturer Aidro has introduced metal additive manufacturing to create a new generation of hydraulic solutions and to overcome the limits of traditional manufactured components. This new technology allows the company to achieve fast lead time and better performances thanks to the optimization of the internal channels.
Using a new engineering approach, Aidro can design and print customization solutions with complex geometries. The lightweight and compact hydraulic products can integrate multiple parts into one. AM has proven to be ideal for small numbers of parts for specific applications.
On the basis of its 35+ years of experience in hydraulics, Aidro considers additive manufacturing to be ideal good for future developments. In order to take advantage of benefits of AM the company is developing metal 3D printed valves and blocks, producing prototypes in a matter of a few hours.
The image above shows a 3D hydraulic valve block printed in stainless steel for controlling a single-acting cylinder. This is an example of how to re-design a traditional hydraulic block with a different and innovative design approach. By placing the valves where necessary they can connect as desired. The internal channels of the valve block are optimized for a better flow and space savings. The potential for leakage is removed because auxiliary drilling is no longer necessary.
First of all, in order to establish the benefits of AM on hydraulics, the company analyzed the main manufacturing methods. On one hand is traditional manufacturing: starting with a larger piece of material, layers are removed, or subtracted, to leave the desired shape with CNC Machining. The starting workpiece is derived from a metal casting mold or from a metal bar.
On the other hand additive manufacturing: we consider only metal 3D printing because generally, metal parts are used in most hydraulic systems due to their high-pressure ratings. Plastics 3D printing is most popular and plastic have naturally higher resistance to corrosion than metals but have lower strength and durability, making them less suitable for hydraulic systems.
3D printing proves more economical for small volumes of complex hydraulic components. For prototyping it enables printing different models of the same prototype at the same time. Furthermore, subtractive processes can take up to 30-60 days in case of CNC machining from a metal bar or take a few months (from 6 to 12 months) in case of casting. For 3D printing, the hydraulic components can be printed on demand in a matter of days. If the printed parts require tooling, the lead time may increase up to 1 or 2 weeks.
Oil hydraulic products’ materials must have adequate strength and corrosion resistance to safely handle the high pressures characteristic of hydraulic systems. The most common materials used in traditional Hydraulics are carbon steel, stainless steel and aluminum. 3D printing can offer a higher materials selection with the same manufacturing process. Thus the choice is between stainless steel (AISI316L, 17-4PH), aluminum, titanium (Ti6Al4V), Inconel (625 or 718), or Maraging steel.
In another specific test case, a stackable valve body was redesigned for 3D printing in order to have a lightweight hydraulic valve. Additive manufacturing enabled a strong reduction of the material used for production, and the final weight of valve was reduced by 60%. With the addition of the pressure-reduction cartridge, we have created a direct operated pressure reducing valve in stainless steel. While, normally, the standard pressure reducing valves are made in steel zinc plated. Moreover, during the pressure tests, the 3D printed valve has demonstrated the same results as the traditionally manufactured valves.
To test the materials variety offered by additive manufacturing, the hydraulic valve was 3D printed in stainless steel, aluminum and in Maraging steel. The first material offers an high corrosion resistance, and it is widely used for special applications, such as oil&gas, yacht and naval. Aluminum is lightweight and Maraging steel is known for possessing superior strength and toughness without losing malleability.