The hydraulic valve block is an important part of the hydraulic system, usually in a compact square design with multiple internal passages that allow it to control the oil pressure distribution of large machines or systems in automotive or industrial environments. Heavy-duty agricultural or construction vehicles, such as excavators or lifts, also require hydraulic blocks as control units.
The interior of the hydraulic valve block is very complicated. Generally, a relatively simple valve block has about 40-60 holes, and a complicated one has hundreds of holes. These holes constitute a criss-cross internal network, but for convenience. On CNC machine tools, these holes are generally straight holes, but sometimes they are set to be inclined holes.
So why does 3D printing (additive manufacturing) have advantages in the processing of hydraulic valve blocks? Primarily because additive manufacturing allows for a higher level of design freedom to reduce weight and improve the shape of the internal passages to achieve the desired flow.
Traditionally made hydraulic block
Traditional hydraulic block production leads to very high processing costs: everything starts with a large cast (or forged) metal block that is machined through a milling and drilling process to form an internal oil passage.
Therefore, first drill a hole from above and then drill a hole from below. Finally, the two holes are joined horizontally. Then to prevent oil from escaping from the side, the thread must be cut and a thread with a grub screw is required to close the horizontal connection.
These limitations due to the processing technology make the oil circuit very complicated and cause a key problem in the traditional hydraulic block: the oil flow is very inefficient.
Let’s take a closer look at the shortcomings of traditionally manufactured hydraulic blocks. Unfortunately, there are many factors that can cause an adapter failure:
1. Sharpened edges of the channel connection area
The edges of these connected areas create burrs that cannot be removed. These burrs are usually not loose, so they cannot be removed by turbulence or other means.
2. Loss of efficiency
The channel pressure of the oil flow can easily be higher than 300 ba, and when the oil flow hits the connection area between the channels, the turbulent flow will cause a large amount of pressure loss and low efficiency.
3. Contamination causes failure
The grub screw only reaches a certain point, and in the area where there is no oil flow, a dirt reservoir is formed, which eventually leads to damage or malfunction of the valve in the entire system.
4. Leakage from adjacent channels
The longer the borehole, the harder it is to drill straight. The long drill begins to “chatter” at some point. If the hydraulic block is compact and the wall thickness is small, leakage may occur in adjacent channels. Especially in the case of high pressure of the oil flow, it is easy to cause wear and leakage.
5. Equipment downtime risk
If the hydraulic block fails, a new hydraulic block must be ordered. Waiting time causes the machine to stop.
DfAM redesigned hydraulic block to increase flow efficiency
The additive manufacturing process allows for a completely free geometric design without the risk of hole overlap. And the hydraulic block produced by additive manufacturing is quite light, which not only reduces material waste but also can be made smaller.
1. Reduce weight by up to 80%, reducing material costs
The redesigned hydraulic valve block reduces weight from 30 kg to 5.5 kg, and the lightweight hydraulic block improves operator operability.
2. No dead zone where dirt is collected
The design of the oil passage does not include any dead ends or sharp corners. Therefore, there is also no area for collecting dirt, which avoids the risk of dirt damaging the servo valve.
3. Improve flow efficiency
Horizontal holes are no longer needed and the oil can now flow around the corners without being disturbed by corners and edges.
4. Design features to improve energy efficiency and reliability
For more complex hydraulic blocks, the oil passage length can be adjusted to each other. In general, the longer the oil passage, the more friction and loss of the wall. The shorter the channel, the smaller the friction and the lower the risk of leakage. Shorter channels and sharp corners without turbulence mean higher energy efficiency. In addition, a thin-walled structure can be realized by metal 3D printing, and the wall thickness can be adjusted as needed.
5. Rapid design iteration without mold cost
Additive manufacturing gives users more time to make final design decisions and has the flexibility to respond to everything. With 3D printing, you can adjust your design at any time. For traditional manufacturing processes, such as investment casting, if the drilling location is to be changed to optimize oil flow, a new casting mold must be produced.
Post time: Oct-09-2018