Getting a Better Grip on Toolholding Systems

Like many shops, Applied Engineering, Inc. (Yankton, SD), spends quite a bit of money on tools each year. So the shop was pleasantly surprised when a new toolholding system began doubling tool life and cutting overall costs. “We’re always looking at ways we can improve our processes,” said Greg Husman, the company’s optimization manager. “What we’ve found is that balancing and heat shrinking our toolholders gives us repeatable and predictive results.”

Based in Yankton, the company is a 165-employee shop that specializes in short- and long-run aluminum components for several industries, mainly aerospace and aircraft. Many of those components are used in navigation and weather radar systems for commercial aircraft. The company also launched its own line of compound bows, making itself more diversified and competitive in a different market.

With dozens of horizontal machining centers that rotate up to 20,000 rpm, Applied Engineering knows that proper toolholding is critical to extending its tool life and investment. It’s also a key factor in machining accuracy and repeatability. But until recently, proper toolholding came at a high cost.

PRESSURE IS ON
Applied Engineering had been spending $40,000 per year on parts for its existing toolholding system, which required specially designed collets to be pressed into toolholders. Though the system achieved decent runout, the costs were difficult to justify. A few years ago, the shop began searching for a comparable system that was less expensive. It found one a few years ago while visiting the booth of Haimer USA, LLC (Villa Park, IL) at the IMTS 2012 show.

Considered by many to be the industry standard for heat shrink toolholder systems and toolholders, the Haimer shrink fit system claims to have higher gripping torque, accuracy, and balance repeatability than do other systems. A key difference is that it uses heat rather than collets or hydraulics to grip a part. With the push of a button, the toolholder is heated up and the cutting tool is inserted. Then the holder is cooled down in 30 seconds. As a result, the toolholder and cutting tool become virtually one piece.

Applied Engineering decided to give the system a try and the results were eye-opening. They reflected a dramatic improvement in runout, gripping force, and balance, the three main variables in toolholding. Tool life increased from 80 parts to more than 600 parts on a consistent basis. “This system paid for itself in less than a year,” noted Husman. “Not only have we increased tool life on many of our tools, but the quality of our parts is increasing just from the repeatability of tooling. We’ve also noticed an improvement in surface finishes and cycle times. Though we still use both systems in order to remain diversified, the Haimer system is a better fit and much more economical.”

Another key benefit was balance repeatability and balance options. Because there are no moving parts with the shrink fit system, additional fine tuning is not often necessary. However, the company decided to purchase Haimer’s modular balancing system to improve tool life for its other toolholding system. “The balancer alone has helped us beat tool life expectations by at least 20 percent,” explained Husman. “When combined with the shrink fit system, which helped us improve runout from .0007 in to .0002 in, we can achieve near perfect conditions. This balancer can be used for any of our toolholdling systems; the heat shrinking just takes it one step further.”

Because of the high gripping torque of this shrink fit system, the shop also noticed a reduction in scrap. In fact, the company was able to cut its scrap in half last year, thanks in part to the new system. Now the company is spending less money on tools and toolholding, but achieving many more benefits, including higher quality parts. Ultimately, this system is a good fit (pun intended). “We’ve been very pleased with their products and the service they offered,” added Husman. “They provided training on the shrink fit system and balancer soon after delivery and have been quick to answer additional questions. They’ve been very good to work with.”

The shop also discovered other benefits of using this type of shrink-fit system, including:

• Unsurpassed accuracy
  A properly produced shrink fit chuck can guarantee 0.00012 in (3 microns) maximum run-out at three times the cutting tool diameter. This accuracy is very repeatable from operator to operator and is guaranteed for life.
• Availability of slim profiles
  Shrink fit chucks are available with three-degree draft angles and very slim profiles.  They also can be modified to be straight walled if needed, in order to prevent toolholder collision with the workpiece.
• Gripping torque
  A shrink fit chuck grips the cutting tool 360 deg around the shank. This leads to a very high gripping torque that prevents the cutting tool from moving during roughing or finishing operations. This greatly aids in the reduction of scrapped parts.
• Extended reach options
  Shrink fit chucks can utilize shrink fit extensions that provide the user with many options with standard products. When machining deep cavities, one can place shrink fit extensions into standard shrink fit chucks, getting unsurpassed toolholder lengths with very little run-out.
• Balance repeatability and options
  Shrink fit chucks offer the best balance repeatability of any toolholding system on the market since there are no moving parts. In many cases, there is no need for additional balancing.
• Reduction of tool changing time/less toolholder accessory inventory
  Nothing beats the tool change time of shrink fit chucks if the process is joined with a capable inductive shrink fit machine. Tool changes can be done in 5 seconds to 10 seconds, and most importantly, consistently. This allows the toolholder assembly more time in the machine making chips, than out of the machine waiting to be changed. Also, a shop needs very little additional toolholder accessory inventory (i.e., collets, nuts, seal disks, etc.). This simplifies the process.
• Setup cleanliness and consistency
  A shrink fit chuck typically is a sealed system by design. Therefore, the introduction of contaminates in the bore are minimized. In addition, these shrink fit holders provide a consistent accuracy from one tool change to the next, allowing for production reliability. This is especially beneficial for those shops running lights out. There are no variables — such as over-tightening or under-tightening a collet nut or not cleaning out a chuck sufficiently. Everyone in the shop sets the tools the same.
• Coolant options
  Shrink fit chucks allow for easy delivery of coolant or air/oil mist down to the cutting edge of the cutting tool. This helps with the proper removal of chips and can also aid in providing better finishes.
• Availability of shrink chucks
  Most of the major toolholder builders in the world now offer shrink fit chucks as a standard. Therefore, shops are not roped into proprietary high precision collets or press fit systems that are only available from one manufacturer.
• Lifetime guarantee/no maintenance
  When a shop integrates a full shrink fit system, it has the assurance that the toolholder will last the life of the machine tool without any required maintenance.

The Haimer parent company is a medium-sized family business located in Igenhausen, Germany. Founded as a one-man operation in 1977, it grew into a 300-person company that has become a market leader in the field of ultra-precision toolholders and special machines designed for specific applications, with a product line that includes toolholders, balancing machines, 3D sensors, inductive shrink fit machines and solid carbide endmills.

Investing heavily in education and continuous improvement, Haimer educates its staff in- house through its three-year apprenticeship program and invests 8 percent to 10 percent of profits in research and development for its product development team.

Applied Engineering, Inc., 2008 East Highway 50, Yankton, SD 57078, 605-665-4425, Fax: 605-665-1479, www.appliedeng.com.

Haimer USA, LLC, 134 E. Hill Street, Villa Park, IL 60181, 630-833-1500, Fax: 630-833-1507, sales@haimer-usa.com, www.haimer-usa.com.