Ultrasonic Machining (USM)

                       Ultrasonic machining

Ultrasonic machining, also known as ultrasonic impact grinding, is a machining operation in which a vibrating tool oscillating at ultrasonic frequencies is used to remove material from the workpiece, aided by an abrasive slurry that flows freely between the workpiece and the tool. It differs from most other machining operations because very little heat is produced. The tool never contacts the workpiece and as a result the grinding pressure is rarely more than 2 pounds, which makes this operation perfect for machining extremely hard and brittle materials, such as glass, sapphire, ruby, diamond, and ceramics.

 

Surface finish

The surface finish of ultrasonic machining depends upon the hardness of the workpiece/tool and the average diameter of the abrasive grain used. Up close, this process simply utilizes the plastic deformation of metal for the tool and the brittleness of the workpiece. As the tool vibrates, it pushes down on the abrasive slurry (containing many grains) until the grains impact the brittle workpiece. The workpiece is broken down while the tool bends very slightly. Commonly used tool material consist of nickel and soft steels. advantage 1-any material can be machined regardless of their electrical conductivity 2-good surface finish obtained and higher structure integrity

Ultrasonic machining is suitable for machining of hard, brittle materials including:

• Glass
• Sapphire
• Alumina
• Ferrite
• PCD
• Piezoceramics
• Quartz
• CVD Silicon Carbide
• Technical Ceramics 

 

Applications for ultrasonic machining include:

• Tight-tolerance round thru-holes for semiconductor processing equipment components
• Micromachined and micro-structured glass wafers for microelectromechanical systems (MEMS) applications
• High-aspect ratio thru-vias; 25-to-1 aspect ratios are possible in glass and advanced material

                                  

Advantages of ultrasonic machining include:

• The process is non-thermal, non-chemical, and non-electrical, leaving the chemical and physical properties of the workpiece unchanged. This low-stress process translates into high reliability for your critical applications.
• Multiple features can be machined at the wafer or substrate level simultaneously, and the process is scalable. Our process is often the highest quality and lowest cost solution.
• Ultrasonic machined features have vertical side walls, enabling you to preserve valuable space for your designs that translate into higher productivity.
• The process integrates well with semiconductor and MEMS processes. Machined features can be aligned to previously patterned, machined, or etched substrates.