Metalworking Fluids and Machining
6. May 2013
Establishing a more effective overall process reduce drilling time of a 0.31-inch-diameter, 7.8-inch-deep hole in tempered steel from 3 minutes to 10 seconds.
Blaser Swisslube uses its recently expanded 3,200 square-foot technology center in Switzerland to develop and test its metalworking fluids through challenging machining operations similar to those performed by its customers. The four-year-old technology center features a turn-mill, two five-axis machining centers and a five-axis tool-grinding machine. The company collaborates with customers, universities and trade associations on various machining projects to develop optimized processes through careful consideration of elements including machining parameters, tooling and fluid and fluid delivery.
A recent project conducted with the Technische Hochschule technical university in Aachen is a good example of the type of work that’s performed there. The goal was to reduce the machining time required to drill a deep hole in tempered steel with a diameter of 0.31 inch and depth of 7.8 inches. This operation had previously taken three minutes using conventional cutting oil.
The 42CrMo4 + QT steel (having a tensile strength of 1,000 MPa/145 psi) was machined on the company’s Mazak Variaxis 500. First, a Kennametal tool was used to drill pilot holes measuring 8-mm in diameter to a depth of 16 mm. This was followed by a 10-second non-pecking drilling operation using a Titex tool to the final depth of 7.8 inches. Cutting speed and feed for this operation were 394 feet per minute and 0.001 inch per revolution, respectively.
A water-miscible cutting and grinding fluid was pumped through the long drill at 870 psi for effective chip evacuation. It was important that the fluid was able to resist foaming at high pressure and prevent air bubbles from rising in the emulsion. This is because bubbles counteract the cooling action and reduce the flow rate, making it harder to effectively evacuate the chips. Ultimately, this more effective process reduced drilling time per hole from 3 minutes to 10 seconds. (Video of this operation can be found here.)
This is just one of many such projects performed at the company’s technology center. Company CEO Marc Blaser says tests like this demonstrate that productivity, economic efficiency and machining quality depend in large part on the quality of metalworking fluid as well as the expertise of machining specialists.