New Cutting Fluids Improve Part Finishes, Surface Speeds And More

Choosing the proper cutting fluid for its metalworking equipment has always been a primary focus at ATK-CCI Speer (Lewiston, Idaho), a division of Alliant Technical Systems, which manufactures ammunition and related products. Issues such as cutting fluid life and its effects on the shop's part finishes are primary concerns.

In May 2003, the company began using a new cutting fluid, Rustlick Ultracut 270R by ITW Rocol North America (Glenview, Illinois). Since then, this bio-stable, semi-synthetic cutting fluid has been used for various applications. Because the company machines all types of metals (ferrous and nonferrous), it was critical that the cutting fluid be versatile. High lubricity and rust protection were other qualities Speer was looking for when choosing a cutting fluid.

According to company employees, this fluid has lived up to these expectations and more. For example, the machinist running Speer's Hardinge CNC lathe and GN-600 Super Slant CNC lathe explains that before discovering Rustlick Ultracut, the cutting fluid in the sump would sour within 30 to 60 days (especially in the summer heat), and tramp oil skimmers did not help the problem. According to the company, the tank had to be cleaned and the cutting fluid had to be replaced every 4 to 6 weeks.

Once the company began using Rustlick Ultracut, however, this problem was remedied quickly. Speer once went through 30 gallons of cutting fluid in 6 months, changing it every 30 to 60 days. Now, 6 gallons of coolant are replaced every 6 months.
Better part finishing is another benefit. The company no longer needs to use an additive or spray cutting fluid to achieve its required finish. This gives machinists more control over the cutting fluid, according to Vaughn Robertson from Melbran Distributing, Inc., the company's supplier.

Finish speed has also improved substantially with the use of cutting fluid. "Our machines are older models, and our parts are mostly small," says one machinist. "This complicates producing good finishes, especially on tool steel. The new cutting fluid allowed us to increase the feed and decrease the spindle-to-floor time by 50 to 60 percent."

The coolant dilution ratio has also improved. The previous coolant ratio was 10:1 or heavier. With Rustlick Ultracut, the ratio has been 20:1, with a ratio of 40:1 used for adding because of evaporation. These ratios have allowed ample rust protection and minimal cleanup on the parts prior to the next process.

For more efficient coolant management, Speer uses Rustlick wheel skimmers to control tramp oils, which are set on timers for easier maintenance. This process, coupled with the use of this cutting fluid, ensures the elimination of bactericide and fungicide in the coolant tanks and machine cavities.

In the near future, the company hopes to switch all 15 of its machines' cutting fluids to Rustlick Ultracut 370R.