One advantage of hydraulics technology is its high power density. Hydraulic pumps are typically a small fraction the size of the electric motors that drive them, and the size and weight differential between pumps and gas or diesel engines is even more pronounced. An even bigger advantage is with actuators. Hydraulic cylinders only a few inches in diameter can generate forces to lift thousands of pounds, crush rock and concrete, or form high-strength steel into rugged components.
Of course, another advantage of hydraulics is its ability to control direction, speed, torque, and force using anything from simple manually operated valves to sophisticated electronic controls to command valves automatically. And even though electronic control of hydraulic valves continues to advance, processes improvements for manufacturing the valves themselves have not been as dramatic. But that has started to change.
Where We Are and May Be Going
Cartridge valve technology is widely used to integrate several control functions into a single manifold. Centrally locating multiple valves within a manifold can dramatically reduce space, weight, and cost compared to conventional circuits using line-mounted valves, hose, and connectors. But the space- and weight-conserving advantages of cartridge valves and manifolds (integrated hydraulic circuits) leave room for improvement. That’s because many of the passageways in manifolds must be located to prevent cross-drilled channels or provide enough material between channels for adequate strength.
Three dimensional printing overcomes these limitations by positioning flow channels precisely where they are needed and in a variety of shapes and sizes. This means flow channels can be spaced closer together than with conventional manifolds, which makes the finished product more compact and lighter. Furthermore, passageways connecting two or more internal channels don’t have to be machined from outside the manifold and subsequently plugged to prevent fluid from flowing out.
However, 3D printing isn’t limited to manifolds. Valve components themselves can also benefit from 3D printing. For example, valve spools usually contain circular flow paths, primarily because machine tools use rotating cutting tools. Instead, making flow paths with square cross-sectional areas instead of circular could increase flow capacity by 20%, because of the larger area of a square compared to a circle of the same width.
Additive Manufacturing
According to additivemanufacturing.com, 3D printing is a subset of additive manufacturing, which also encompasses, rapid prototyping, direct digital manufacturing, layered manufacturing, and additive fabrication. The website explains that additive manufacturing builds three-dimensional objects by adding layer-upon-layer of material, whether its material is plastic, metal, concrete, or some day, even human tissue. Once a CAD model is produced, the additive manufacturing equipment transfers data from the model and generates successive layers of powder, wire, sheet, or other material layer-by-layer to fabricate a 3D object.
