For decades, as the type of valves being manufactured changed, so did the needs of manufacturers. Makers that once produced high volumes of simple valves, today focus predominantly on low-to-medium volumes of complex, high-precision products made from exotic materials to serve applications from oil and gas to nuclear power.

Inflexible, single-process equipment has been replaced by advanced machine tools with multi-tasking, 5-axis, and done-in-one part processing capabilities. These agile, automated machines quickly changeover from one part family to the next, while their strength, repeatability, and precision meets current machining requirements. Most important, the advanced machine tools produce high quality valves quickly.

The most popular advanced machine tools in small-to-medium-sized valve manufacturing include multi-tasking machines configured with twin turning spindles and twin tool turrets (plus Y-axis capabilities) or with a turning spindle and a B-axis milling spindle. For larger valve processing, shops prefer multi-tasking machines that can cut big parts requiring both ID and OD work and do so in single workpiece clampings.

Twin-spindle/twin-turret

Twin turning spindle/twin tool turret multi-tasking machines work well with medium-to-large-sized valve workpieces that require 5-axis machining. Equipped with bar feeders, these machines offer the same performance as high-volume machines can accommodate a wider range of part sizes.

These machines allow shops to change over jobs in a matter of minutes instead of days. Additionally, they provide the processing flexibility to quickly adjust for varying part volumes, switch from one job to the next, and squeeze in those frequently occurring hot emergency jobs.

However, some twin-spindle/twin-turret machines go beyond the capabilities of other comparable multi-tasking machines by performing both chuck and bar work simultaneously to further increase production flexibility. For example, the Mazak Hyper Quadrex 200 MSY multi-tasking machine gives shops the ability to take on jobs that involve chucked workpiece sizes up to 13.5" in diameter and bar-fed parts from 0.25" to 2.5" in diameter, processing both cylindrical-shaped components as well as prismatic parts. And with Y-axis capabilities, the machine performs off-centerline machining and completes valve parts in single setups through multi-tasking operations – milling, turning, drilling, boring, and tapping.

Unlike similar machines, both turning spindles on the Hyper Quadrex offer equal power and speed at 5,000rpm and 30hp, as well as full C-axis CNC control for part positioning and contouring at a resolution of 0.0001°. The spindles can operate together or separately, allowing a single valve part to be machined on all surfaces through a coordinated hand-off between the two spindles, or two different valve parts can be machined simultaneously on one machine.

Additionally, the upper and lower 12-station, 24-position tool turrets accommodate fixed and rotating tools. Both turrets mill with 7.5hp rotary tool capability. These turrets can operate independently or together on the same part, creating opportunities for the machining of two features simultaneously or balanced machining strategies.

In balanced cutting operations on the Hyper Quadrex 200 MSY for example, upper and lower turret X-axes arranged in line work together on the same valve part feature as rough and finish turning, rough and finish milling, or opposed feature drilling, tapping, or boring. In cases where the part configuration permits, balanced machining significantly increases metal removal to shorten cycle times.

For valve manufacturing company Richards Industries in Cincinnati the versatility of multi-tasking machines such as the Hyper Quadrex allows the shop to quickly changeover from one part family to the next. The machine’s larger tool magazine capacities, compared with single-spindle/single-turret equipment, allow for redundant tooling that significantly reduces machine changeover times. The machine’s single-setup part-processing capability makes it possible for Richards to hold very tight tolerances and provide the highest quality parts in short turnaround times.

Turning spindle/B-axis milling

Conval Inc., a valve manufacturing company in Somers, Conn., uses a twin turning spindle/B-axis milling spindle multi-tasking machine from Mazak because it can process various part types and materials.

With the Integrex i-100S, components are not pigeonholed to one particular machine or manufacturing cell because the multi-tasking machine can, if needed, process any of the shop’s components. Changeovers on Conval’s Integrex can take less than 20 minutes – beneficial because the shop goes from one job to the next anywhere from five and eight times per day with job lot sizes varying from one to 10 pieces.

The Integrex i-100S combines the capabilities of a high-powered turning center with those of a full-function machining center. It has a second turning spindle and a lower tool turret, eliminating multiple setups, fixtures, handling, and non-cut time. As a result, job changeovers drop and part accuracy improves because workpieces do not have to travel from one machine to the next.

The machine’s milling spindle with Y-axis travel and B-axis rotation delivers full 5-axis machining capability, so shops can process round parts with secondary operations, fully prismatic parts from solid slugs or from castings (chucked or bar fed work), and highly contoured sculptured parts. At the same time, the machine’s standard 36-tool (72-tool optional) capacity contributes to shorter job changeovers.



Trending toward barstock

As multi-tasking machines become more prevalent, valve makers have paired the machine with bar feeders to create standalone, self-contained automated systems that enhance output and machine utilization. Producing as many parts as possible from bar stock also helps reduce material costs – less material is machined away – especially important for valve shops working with expensive materials such as 316 stainless, F22 carbon steel, Inconel, Nitronic 50. Plus, time and manpower needed to cut and deburr blanks for each job are eliminated.

Many valve manufacturers machine all their bonnets, bushings, and specialty internal components out of bar stock. With multi-tasking machines that handle larger diameter bar stock, valve shops can produce even more of their components that way. The Integrex i-100 BARTAC-S multi-tasking solution, for instance, employs a large 4.4" spindle bore to bring high levels of productivity to the machining of bar material up to 4" in diameter.

The machine also features two turning spindles and a milling spindle that allow for full 5-axis machining and done-in-one operations to reduce lead times and improve workpiece accuracy by eliminating multiple setups.

Mazak’s Intelligent Bar Loader System automatically feeds out material the required distance from the chuck and minimizes the bar remnant. Also, an optional chuck pressure management system automatically changes according to part programs to accommodate a wide variety of workpieces. The system maintains not only the set chuck pressure per workpiece, but also the same pressure when changing material.



Large valve components

Besides dealing with tough part materials, stringent testing requirements and extremely high quality standards, valve manufacturers such as Emerson Process Management, in Marshalltown, Iowa, face the added challenge of large size valve components. For instance, valve body sizes of 40" and bigger with extremely complex features and produced in low or one-off lot sizes are common for such shops.

As with shops that produce small-to-medium-sized valves, large-valve makers look for speed, versatility, and flexibility in their machine tools to go from one type of valve to another as quickly as possible. But, these shops tend to place more emphasis on the capability to clamp/move a part once and machine it complete – as is the case with machine tool technology like that of Mazak’s Orbitec 20 machining center and its Integrex e-1550V II multi-tasking machine.

The ideal way to generate turned features on very big cumbersome valve parts is to do so while they remain clamped and stationary and let the cutting tool move around them.

The Orbitec 20 is a standalone valve body production center that completes most valve and other large part machining operations in one clamping, while also maintaining tight tolerances. In addition, the machine can be integrated with Mazak’s horizontal machining centers and the company’s Palletech solution to form a fully automated system that provides 100% complete done-in-one valve manufacturing.

For valve bodies and other large workpieces requiring turned features, the Orbitec 20 efficiently generates phonographic finishes on flange surfaces, machines tapered bores, and performs feed-out grooving operations. It also does trepanning, internal grooving, and concave machining.

The machine’s facing head configuration is basically a circle within a circle for linearly interpolated X-axis tool movement, as opposed to a linear slide. This provides internally counterbalanced machining and less part interference – nothing is protruding beyond the rotating head – when working on larger diameters.

For large valve processing, today’s advanced multi-tasking machine technology basically fuses together the capabilities of a horizontal machining center with those of a vertical turning center. The result is a machine that performs turning and milling for done-in-one processing of big, heavy, difficult-to-handle valve components – in this case, those measuring up to 78.74" in diameter and 56.69" tall.

Available C-axis rotary machine tables make workpiece positioning and turning operations possible, while powerful and rigid milling spindles with B-axis tilt from -30° to 120° accommodate both rotating (milling) tools and static ones (inserts) for turning. An ample tool capacity of 40 tools standard (up to 348 optional with Mazak’s Tool Hive) and two-pallet changer further enhance part-processing versatility.

Meeting valve consumer demands can be tough for manufacturers such as Richards Industries, Conval, and Emerson. But with the help of advanced machine tools, many manufacturers can meet high expectations.