Friday, August 17, 2012

Three's a Charm in Fluid End Machining

By Scott Turner, Drilling Manager

Fracking, a method of releasing oil or gas from underground formations, seems to be growing in popularity throughout the United States, most notably in Pennsylvania, West Virginia, New York and Texas. After all, today’s advancements in fracking technology are making it possible to economically recover huge reserves of natural gas that would otherwise be too difficult to mine.

A fluid end is an important component of high-pressure hydraulic fracking operations, primarily for natural gas, where solution is pumped into the ground. And because fracking is such a taxing operation, fluid ends require regular replacement, typically lasting between two and seven days. 

Fluid end production involves several machining operations, from cutting and cubing to roughing and finishing. In fact, manufacturers invest a lot of time and materials in the development of fluid ends, making it critical to keep scrap at minimum. 

While Seco has all of the necessary milling, threading and drilling tools for complete, cost effective fluid end production, highly notable is its custom SD609, a special modular drilling head with a three-points-of-contact design that stabilizes deep-hole drilling, especially at the breakthrough point. During the rough machining phase of fluid end production, the SD609 can accurately drill through-holes that are more than 5 inches in diameter, and 57 inches deep, going in from each side of the part. Seco is also in the process of developing an extension for the SD609 that will enable it to drill even deeper holes.     

Prior to the development of the SD609, fluid end manufacturers were losing machining balance and finding it difficult to achieve 100 percent even cutting forces when breaking through the solid 4340 and P20 steel billets from which these fracking components are machined. The SD609 solves these issues by featuring an adjustable center drill, indexable inserts and multiple carbide guide pads shimmed close to the cutting diameter. The shimmed guiding pads and periphery insert make up the unique three-points-of-contact design that supports the drill head when breaking through the hole.

In most large, deep-hole applications, when the drilling head breaks through the bottom of the hole, there is a loss of stability and a risk of the drill head becoming damaged and interfering with the integrity of the component. There are two major advantages to Seco’s three-points-of-contact design. First of all, the center drill and pads make it possible to keep the drill straight so that it does not drill off center. This also provides stability when the drill begins breaking through the bottom of the hole. Effective chip removal is the second advantage in that the SD609 allows the chips to move past the drill head and flow out of the hole. Keep in mind, however, proper coolant flow for effective chip removal must be maintained. Seco recommends at least 1,000 psi of coolant pressure and 12 gallons per minute for coolant flow when using the SD609.    

Seco also developed a special fluted, long-reach holder that complements the SD609 and increases its capabilities. This holder helps maintain stability throughout the drilling process because its diameter is closer to the actual finished hole size. The holder, made of high tensile tool steel with chrome plating, provides the mechanical means to effectively remove chips, resulting in faster machining and lower production costs.

Overall, the SD609 brings flexibility, stability and performance to large, deep-hole drilling applications. While its primary use right now is in the machining of fluid ends, other manufacturers who require big diameter holes can benefit from this customized solution. Because Seco realizes every application is different, the company is always ready to work with its customers on developing the best possible solution for addressing a unique challenge—in fact that’s how the SD609 came about in the first place.    

About the Author  
Scott is the drilling manager for Seco, responsible for the product development, applications support and marketing of advanced hole-making solutions. In his spare time, he enjoys participating in outdoor activities such as jet skiing, snow skiing and golfing. Contact Scott at

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