October 2008 Edition

DRILLING

Adding Savings by Subtracting Chips

Using friction drilling cut out chips and saved a shop time, money, and effort as well as improved safety

Companies frequently re-examine their business methods in order to look for cost-cutting opportunities. At the same time, they seek out best practices for increasing employee safety on the production floor. Unfortunately, those two objectives are often in conflict because employee safety measures, such as safer machinery and additional training, increase expenses.

Tubular Products Co., Birmingham, AL, was able to meet both objectives with a single process: a chipless drill application from Flowdrill, Inc., St. Louis. The system not only reduced the number of operations needed to complete a job, it also eliminated equipment and decreased the number of accidents had by the company.

The company, a division of Samuel Manu-Tech Inc., specializes in the design, fabrication, and assembly of tubular steel products, including those used in vehicles. It employs 160 people at its 150,000 ft² facility.

After Tubular Products manufactured a frame for a golf cart/utility vehicle for several years, the customer was interested in redesigning it.

"The redesign included threaded inserts," Craig Armstrong, engineering manager at Tubular Products, said. "The cost of the threaded insert was pretty substantial along with the costs associated with drilling the insert hole and installing that insert into the tube."

To reduce cost, the company investigated using thermal drilling, where friction is used to drill holes into the metal, eliminating the use of welded nuts or inserts. Armstrong contacted Flowdrill to produce a lower-cost solution.

Chipless Drilling

The Flowdrill system is a method for the extrusion of holes using a four-lobed tungsten-carbide friction drill. When rotated at a high speed and pressed with high axial force into sheet metal or thin walled tube, generated heat softens the metal and lets the drill feed forward, produce a hole, and form a bushing from the displaced material. It’s a clean process requiring fewer operations for completion.

The system uses the parent material without removing any material away from the customer’s piece being drilled. Riveted and weld nuts require drilling in multiple stages, which produces chips and debris.

Flowdrill’s process is less polluting and safer since it doesn’t create material chips. This process eliminates the need for purchased fasteners by creating a parent metal extrusion that is typically three times the original wall thickness.

The extrusion can be threaded using a specially-designed tap system that cold-forms the threads, keeping the process clean. The process is completed in two steps, so multiple production operations often can be removed from the production line.

"We worked with our customer throughout the design process and incorporated this system into it from the beginning," Armstrong said. "It was with the customer’s blessing that we went forward with working with the new process," Armstrong said.

Automated tables were constructed to let a fabricated part be placed on the table to drill both the standard and Flowdrill holes. This allowed for a one-piece flow; previously this took multiple operations with different machines.

"We built the tables and integrated the system to use the bit. Flowdrill completed it to our satisfaction," Armstrong said.

Savings on Many Levels

The reduced number of operations resulted in savings for the company. Quality control costs were reduced by consolidation into one operation instead of multiple operations, since each time a part is touched there’s the opportunity for something to go wrong.

"The cost of quality was substantial in the previous design, which was a major reason for the change," Armstrong said.

The company is able to train one operator to perform the task, instead of training several, decreasing the training costs, too. The time needed to produce the part was reduced by 80 percent.

Employee safety improved with the system. Since the number of operations was reduced, employees moved parts less frequently, resulting in reduced exposure to rotating drill heads. This process cut time lost to accidents by 50 percent.

To create the frame to customer specs, the company invested about $375,000. Armstrong estimated that the return the first year was $500,000.

"We thought that the product worked well. An additional benefit was its repeatability. We’ve never had any issues where we needed something from the supplier that they didn’t immediately provide."

Tubular Products uses the chipless Flowdrill process for other applications, too, and has examined using these automated tables with other customers.

"Our use of these bits has doubled in the past two years, so we’ve had opportunities to share the savings, efficiency, and productivity improvements with other customers," Armstrong said.

By eliminating chips, the number of operations, and equipment, the company’s costs per hole was reduced. Passing the savings onto customers, Tubular Products lets it compete in a shrinking economic market. Flowdrill, Inc.

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What do you think?
Will the information in this article increase efficiency or save time, money, or effort? Let us know by e-mail from our website at www.ModernApplicationsNews.com or e-mail the editor at pnofel@nelsonpub.com.