Related Glossary Terms
Condition of vibration involving the machine, workpiece and cutting tool. Once this condition arises, it is often self-sustaining until the problem is corrected. Chatter can be identified when lines or grooves appear at regular intervals in the workpiece. These lines or grooves are caused by the teeth of the cutter as they vibrate in and out of the workpiece and their spacing depends on the frequency of vibration.
The relative ease of machining metals and alloys.
Drilling deep holes that are too large to be drilled by high-pressure coolant drills or gundrills. Trepanning generates a solid core and normally requires a big, powerful machine. Shallow trepanning operations can be performed on modified engine or turret lathes or on boring machines. See boring; drilling; spade drilling.
Sandvik Materials Technology offers Sanmac, a stainless steel material that can significantly increase machining rates. Year on year Sandvik Research & Development has applied and tested process improvements upgrading the melt of Sanmac material. The result is the introduction of new generation Sanmac, a dedicated stainless steel material available in a range of grades that not only offer machinability at similar rates to carbon steel, but also exhibit excellent chip breaks and have consistent machinability from heat to heat and lot to lot, according to the company. Thus greatly reducing operator setup times.
“In the past, when machine shops change from machining carbon steel to stainless they had to slow down the machining speeds and change settings due to frequent vibration, chatter, gumming of tools and poor chip breaks,” explains Sandvik global product manager Viktor Stefansson. “Now, with new generation Sanmac, machining speeds of up to 240 m/min are achievable as a result of the material’s consistency. And you can actually hear the difference! Couple this with the use of Sanmac hollow bar and machine shop productivity gains of up to 20 percent are achievable.”
The company offers a variety of Sanmac hollow bar material grades, including duplex Sanmac 2205. The material is particularly appropriate for the manufacture of mechanical seals, valve bodies, flow meters, pumps, and associated components for the oil and gas sector.
“Replacing solid bar with hollow bar eliminates the need for trepanning, when producing components with a central bore, which causes material to work harden and is detrimental to subsequent machining operations,” explained Sandvik product manager Dave Shollock. “Using near-net-shape hollow bar available off-the-shelf from our Houston distribution center, customers gain an immediate productivity advantage removing a complete operation along with all the associated costs.
“In one customer case, selecting Sanmac hollow bar meant they were able to triple production machining three components in the time it normally took to produce one from solid bar.”
The company works in close collaboration with sister company Sandvik Coromant, developing stainless bar and hollow bar materials concentrating on enhanced machining capabilities, such as increased speeds, improved component finishes and consistently longer tool life.