Address: 35264 Topps Industrial Pkwy., Willoughby, OH 44094, USA | Tel: (440) 946-1040 | Fax: (440) 946-0725 | E-mail: sales@ohiobroach.com

RIDGID DEMANDS!

The RIDGID® Original Heavy-Duty Pipe wrench is the largest selling professional tool of its type in the world; it's a genuine American Classic.

Basically unchanged in design since its introduction in 1923, one of the wrench's most attractive features is a replaceable heel jaw. This is the sharply serrated lower jaw of the wrench and is critical to the tool's ability to grip pipes tightly.

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Since its origination, these jaws have been cold rolled on pieces of equipment almost as old as the tool itself. "The problem was the machines were worn out," says Gary Fildes, project engineer, Ridge Tool company. "We couldn't get new parts and maintenance costs were high."

He adds, however, that production backlogs, because of machinery downtime or out-of-spec parts, caused real problems.

For smaller RIDGID pipe wrenches, those with handle lengths from 6" to 10", Ridge Tool had purchased a single broaching machine in 1990 from The Ohio Broach and Machine Company, Willoughby, Ohio.

Because of the success with the smaller machine, Fildes recommended broaching to replace the older machinery. "From our experience with the earlier broach, we believe we could achieve quality consistently and avoid production bottlenecks."

Examining options other than broaching to form the part, Fildes admits that milling was the only other real option, but not attractive. "Milling would involve too many handling steps. I wanted to reduce the number of operations we had been performing to drop the cost per part," adds Fildes.

Traditional manufacturing of the jaw required nine operations. Lengths of steel stock were sawn to length then deburred. The parts were then cold rolled to form clamping radii. This rolling created end burrs which were removed with end grinding. Sized and ground parts were then gash milled to form a tongue angle and deburred, again. A machining cell then milled the jaw's serrated teeth and drilled the roll-pin hole. Rough grinding then eliminated two clamping radii on each part. These parts were then heat treated, finish ground for cosmetics and moved to the finished parts area.

"That's a lot of physical handling," observes Fildes. It also took a lot of time.

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With the new dual ram broaching machine, Ridge now produces the same part in seven seconds and involves only five manufacturing steps once steel stock is cut to size.

With the broaching machine's automated feed system and sophisticated controls, Fildes admits this is a production broaching system. The system starts with the elimination of the cold rolling operation. The broaching technique also eliminates the need for the clamping radii required for traditional milling operations.

The same steel stock is cut to length and fed into an automatic parts feeder for the broaching machine. The machine broaches the part complete, including tongue angle, teeth and external dimensions. Broached parts are drilled for the roll-pin, heat treated, finish ground and sent to finished parts.

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The broaching system has delivered both reduced manufacturing costs and maintained part quality. "We've significantly reduced costs with a process that is a lot less labor intensive and realized huge savings in perishable and non-perishable tooling," states Fildes.

With the significant reduction in general part handling and specific reductions in time required for milling and grinding set-ups, labor costs are reduced. Labor costs required to maintain older production equipment and non-perishable tooling costs are also eliminated.

With the elimination of the milling steps, Ridge has also realized sizable savings in perishable tooling, such as end mills.

With broaching, Ridge has four sets of broaches (two for each ram) of the new machine. these 60" broaches are maintained and sharpened by Ohio Broach.

"We used to sharpen broaches in-house," says the project engineer. But, to maintain the shear angles, progression and tooth form, he admits a CNC dresser is required. With Ohio Broach using a CNC dresser on its design, Ridge is realizing 15,000 to 20,000 broaching cuts before the tools need resharpening. "And, we're taking a lot of metal off these parts," he notes, explaining that approximately 25% of the original stock weight is removed during the broaching process.

"We have also achieved consistent part quality with broaching," says Fildes. He notes that, following broaching, there is no additional deburring or dimensional grinding required.

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To achieve the production rates and cost reductions Ridge sought, The Ohio Broach and Machine Company designed the entire broaching system, from auto-feeding through programmable controls and chip conveying system.

"The automation was the most complicated part," concedes Fildes. Using dual Allen-Bradley 550 controllers, Ohio Broach used remote I/O for sensors. According to Fildes, the system uses approximately 50 sensors. Using remote I/O significantly reduced the wiring between the controls and the machine. "And, the controllers are cheaper than push-buttons," says Fildes.

The dual broaching machine sits in a 6' pit to accommodate the unit's foundation, coolant system, chip conveyor and hydraulic reservoir.

A key to the productivity of the entire system is an automated parts feeder for the first ram. This feeder accepts the cut-to-length stock, orients the pieces and stacks them for loading into the broach.

With the first broaching ram, the parts are essentially sized and dimensioned, including cutting the tongue angle and flats. Removed from the first broach, the part is automatically transferred and mounted on the second broach by an Ohio Broach custom-designed transfer system. The second broach cuts the teeth into the jaw.

To determine the position of each broach position during a cycle, which is critical for automated part transfer, Ohio Broach designed in magnetic rod sensors. In a very tough manufacturing environment, Fildes describes these sensors as "bullet-proof."

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Because of Ridge Tool's earlier experience with a smaller broaching machine, the selection of broaching as the best technique for the task was fairly simple.

"From that decision point," explains Fildes, "it took eight months to engineer and build the machine, one month of production run-off with the machine at Ohio Broach and one month to install. Then we were making parts."