By Mark Christopher, Bosch Rexroth Corp., Pneumatics, Lexington, Ky.

Maintaining high production levels and efficiency is crucial in the lumber processing industry. To do this, one major timber processor recently shrank its pneumatic valve replacement inventory from the size of a 20 ft2 room to the size of a filing cabinet drawer, which in turn increased productivity uptime.

The drastic reduction in inventory — along with many other benefits — came from Bosch Rexroth, who had proposed and developed unified standards for pneumatic valve interfaces based on ISO/EN and CNOMO standards.

The new standards allow easy troubleshooting and parts replacement required to meet the timber producer’s aggressive production goals (one million board feet per day). Better yet, the standardized valve component approach opens up a better world of flexibility and time-efficiency for new and established timber processing plants.

In the beginning
The idea for a new set of valve component standards for the timber industry can be traced back to Bosch Rexroth’s involvement in providing ISO/VDMA (ISO 15552) cushioning of cylinders on processing lines. The cylinders were combined with standard valves and controllers provided by several suppliers. The good news for timber producers: production quickly increased, from about 120 to more than 200 boards per minute. The bad news: maintaining this production level soon led to a confusing jumble and high inventory of replacement pneumatic parts, with inter- and even intra-manufacturer incompatibilities. For example, if a valve coil burned out, the hunt was on for a new valve that would meet a particular manufacturer’s specification. If a manifold or individual sub-base from Supplier X would only interface with a Supplier X directional control valve, an urgent call might be needed for a replacement unless spares were kept in inventory.

This was inefficient enough during regular business hours, but could become a larger problem during late night or weekend shifts. As a result, timber producers often build up a huge inventory of non-interchangeable and proprietary valve, operator, controller, manifold, and sub-base components — increasing costs and operator training time.

Bosch Rexroth developed an imaginative but simple solution: Establish overall standards for valve components based on existing ISO, EN, and CNOMO specifications. Few standards for valve components existed, and these focused on small valves (less than 26-mm width) not used in the timber industry. To provide components that would interface with each other regardless of manufacturer, standards would have to be combined specifically for timber industry applications.

A common mechanical interface standard means any EN 175301-803 solenoid connector can be used on all valves regardless of size or function.

ISO 5599-1 pattern on manifold or individual sub-base allows versatility like mixing valves such as Bosch Rexroth’s CERAM and Series 581 valves, shown here.

Engineering groups from Bosch Rexroth began by reviewing standards and trends emerging within the pneumatic valve industry and used “bigpicture” thinking to ensure the most appropriate resolution. For example, an integrated electromechanical solution with a cleaner machine appearance is possible by using an integrated electrical connection in conjunction with an ISO 5599-2 mechanical valveto- sub-base interface. But in the harsh and abusive timber industry environment, wiring encased in a manifold can make fault tracing difficult and add to maintenance costs. If an integrated solution is not used, it means involving additional CNOMO and EN standards.

Initial results
When all factors were taken into consideration, Bosch Rexroth developed the following valve component standards:

• ISO 5599-1 — Mechanical interface between valves and sub-bases (no integrated electrical connections). This allows any ISO valve to be fit to the base with socket head screws and without need to alter the plumbing.
• CNOMO E06.05.80 with EN 175301- 803 — Mechanical interface between the valve and its corresponding operattor. This allows for a common operator to any pilot-operated valve regardless of the size of the valve.
• EN 175301-803 (formerly DIN 43650) — Mechanical interface between solenoid operator and solenoid connector. Bosch Rexroth also specified the optimum spacing of the spades on the solenoid to add even more commonality.

This may seem like a great many standards and numbers. But because they are common to all pneumatic valve manufacturers, the standardization initiative has proven to be a complete success. By stocking one common form of valve connector, users can obtain parts from any manufacturer to interface with any valve regardless of size or function. And this simple concept has opened up a whole new world of productivity, cost-effectiveness, and convenience, including:

• On-the-fly troubleshooting and replacement of parts to reduce downtime and maintain high productivity
• Dramatically reduce the size, complexity, and expense of inventory
• Operator training requirements can be reduced from a full day to 30 min, and
• Replacement parts can be ordered from virtually any manufacturer (including Bosch Rexroth competitors) meeting the new standards.

These successes, seen in a single new sawmill, have sparked interest by at least three other timber industry firms. Bosch Rexroth is prepared to extend the same concept to other pneumatics elements, including cylinders. For the timber industry, the pneumatic parts standardization concept may well become as important to future solutions as any of the parts themselves.

For more information, visit www.boschrexroth-us.com/BRP, or email info@boschrexroth-us.com.