1. The Heart of the Valve: Body, Block and Internal Passages

Every high-performance hydraulic valve relies on an intricate masterpiece of precision engineering; the valve body and block. A valve body and block is much more than a simple metal enclosure. These components develop and maintain an intricate network of pathways that direct and shape fluid power. The performance metrics of each valve including; leakage rate, pressure drop, time response, and life expectancy are dependent on the quality of the network of structures inside the valves:

These key components are responsible for the capability of the entire assembly and are predicated on precision and surface integrity. The surface finish of the internal bores and flow passages obviously affect the dynamic flow of the fluid and the risk of leakage past seals and spools. The geometric precision and concentricity of these flow channels are critical to ensuring that the spool and poppet components will freely move within their limits both at normal and the maximum compression rates of pressure and temperature. Any deviation no matter how trivial has the potential to result in some level of performance inconsistency. Therefore, the largest variable for a manufacturer is the vendor selected. For a hydraulic valve manufacturer to efficiently manage these variables to achieve a consistent level of quality and repetition, is the foundation for developing reliability and high-performance. It demands careful inspection and consideration of every detail from raw material to final inspection.

2. The Challenge of Manufacturing: Common Problems Associated with Hydraulic Components

The core role of producing these critical pieces is a substantial set of manufacturing issues, which may be beyond the capabilities of the average machine shop.

Dimensional stability: The wall thickness on complex hydraulic valve body parts is typically emphasized with a high relative density of interconnected ports. The machining process are all producing stresses that could influence either the “flatness” of sealing surfaces, or the “alignment” of the critical bore holes or ports.

Deep hole drilling: Even the most skilled technician will have a hard time producing deep, small diameter holes that are straight and possess the same finishes consistently. Any variation in diameter will affect the spool path or create turbulence in the fluid path.

Deburring the internal cross holes: When drilled passage intersect, burrs are created and quite often burrs are sharp and can be very difficult to remove in spaces that are not accessible. Burrs that are not completely removed will break loose through an operations cycle creating destructive contaminants that further shred or damage critical seals and precision surfaces in the hydraulic system.

Holding tight tolerances: The functional integrity of the hydraulic block is a complete measure of holding incredibly tight tolerances throughout a complete production run of similar valves. This means absolutely zero tolerance; if just one component is out-of-specification, it could shut the valve off and fail.

These challenges separate conventional machining from true precision manufacturing. Addressing these issues takes not only skill, but in many cases specialized technology and most importantly a quality-focused process.

3. The Solution – Swiss-Type CNC Machining is the Answer

This is where advanced manufacturing technology specifically Swiss-type CNC machining, can really help with the production of critical hydraulic components. Originally developed for the watch making industry, the Swiss lathe allows us to overcome the hurdles previously described.

The hinge pin on this superior technology is in the design. The guide bushing provides unique support for the bar stock very close to the cutting tools and effectively minimizes deflection from tool pressure that is always a consideration on a conventional lathe, and especially when machining thin complex parts. Today’s CNC Swiss machines are multi-functional machining centres that offer turning, milling, drilling, and tapping capabilities all in one set up.

This “done-in-one” feature is incredibly important. Because all machining is done with the part on the same means of support, it never needs to be moved, and re-clamped onto a different means of support. This is how cumulative errors are avoided along with ensuring great concentricity and positional accuracy between features – precisely what is important for a complex hydraulic valve body – and the increased stability and rigidity allows more aggressive machining of difficult materials, i.e. stainless steels – which leads to superior surface finishes important for dynamic sealing.

This advantage in technology is why, increasingly, leading engineers and OEMs are sourcing specialists in high-volume precision swiss machining products. Companies like swiss machine products inc can now apply this technology and process products made for swiss screw machine products and cnc swiss machining products, with a level of complexity, accuracy, and repeatability, which cannot be realized with older equipment. For hydraulic applications it means dependable and leak-free performance, and much longer service life with the final valve product.

4. Material and Finishing: The Last Steps Towards Optimal Performance

While precision machining is the main part of a reliable valve, putting the right material to work and applying finishing processes are what can take a component from good to great; final steps that ensure the valve can withstand the remove conditions of a hydraulic system.

The material choice does have an impact to strength, corrosion resistance, and compatibility with various hydraulic fluids. Some common choices include:

#Stainless Steel (303, 304, 316): Stainless steel has high corrosion resistance, is easy to machine, and yields high strength and tough designs; it is suitable for all sorts of demanding applications in solution of chemical, marine, and food.

#Carbon Steel: Maybe the weakest of the options on the list, but high strength and high wear resistance allow for heavy duty hydro applications with the appropriate coatings or plating (to resist rust as they most likely will not have corrosion resistance)

#Brass: very good when machined, and corroded pretty well naturally. Used lower pressure systems (greater than 40 barg) like machine components and certain seal housings etc.. Also used for manifolds or connectors

Once critical components have been machined, they typically have finishing processes selected. Both hydraulic valve body parts sometimes they spend time honing or polishing to get the ultra smooth surface finish of bore holes which we all know is especially important regarding seal life and the amount of internal leakage. For hydraulic valve blocks, most do go through some electroplating, passivation (stainless steel), or electroless nickel plating (non-peg)* treatments on critical surfaces for improved surface hardness and corrosion protection* which preserves the integrity of the assembly over time.

5. Conclusion: The Choice of Manufacturing Partner is Key

The progress from block of metal to hydraulic valve component achieves one of precision, able, and supported by a technology base. As demonstrated, the performance, reliability, and service life of a hydraulic valve is no more and no less than the result of exceptional manufacturing practice. The potential challenges created by the requirements of the standard hydraulic valve body and block complexity = a manufacturing choice that provides well beyond competitive tolerances (= extreme stability), precision, and speed = the solution Swiss type CNC machining.

In today’s market, the selection of a manufacturing partner may be one of the most important decisions an engineer, or OEM can make = a partnership beyond buying parts. Selecting a vendor who has the right technology & quality control systems, and has a depth of experience to qualify materials, is an investment in your product, and respresentative to your brand and reputation.

Whether you are designing the next iteration of hydraulic systems, or improving a product you are getting, the first part is understanding how advanced machining and finishing processes make such a difference. The next part is finding a supplier or partner who can provide you with high-precision cnc swiss machining products from your understanding of them.

This article is sponsored by the technical team at Falcon CNC Swiss, one of the first and leading precision CNC Swiss machining services and providers of quality components in the hydraulic, aerospace, and medical markets. We specialize in complex parts made to exact specifications and tolerances. See what we can do for you at www.falconcncswiss.com.