Applications of Ultrasonic shot peening

Accelerated 3-D Shock and Vibration test with Ultrasonic shot peening

Small stainless steel balls in a specially designed ultrasonic chamber will be mechanically stimulated to impact parts placed in the chamber. The part is randomly and uniformly impacted in 3-spatial-dimensions by the steel balls with sufficient force to create a wide range of stresses.

Some applications include:

Ultrasonically accelerated mechanical and structural stability testing (of Watches, Micro-systems and Hi-Tech components).
Accelerated bolt unscrewing test (Watch industry, Micro-Systems).
For companies involved in the production of high tech micro-electronic and micro-mechanic components and systems it would be valuable to have a testing tool that can give rapid answers about mechanical reliability.
It is possible that such mechanical bombardment is able to simulate in just minutes of testing results equivalent to several weeks or months of testing using traditional testing methods.

This is particularly interesting in the R&D phase of new products when it is extremely profitable to have such accelerated testing possibilities. Immediate feedback about certain product resistance properties would significantly impact future exploitation and product reliability. Normally products are given to specialized testing laboratories, what usually takes weeks or months of different vibrations-testing, while the R&D team waits for positive or negative results. With accelerated testing important product and design improvements can be quickly analyzed and implemented to improve time-to-market and product reliability.

In one implementation the piece to be tested is hanging in the middle of ultrasonic chamber. Small metal balls (introduced in the same chamber) are randomly scattering and bouncing inside of the chamber, realizing uniform 3-D bombardment of the hanging solid piece (watch case, micro-mechanical system, high-tech component...). A few minutes of such treatment may correspond to more than a week of traditional 3-D vibration and shock testing.

Accelerated Surface Hardening and Stress Release without heating using Ultrasonic shot peening

The shot peening process is based on introducing compressive stresses into the surface of a metal part by controlled impact with spherical particles. By this the resistance against fatigue will be increased and therefore also the life of a component. In the space and aircraft-industries the advantages of the shot peening process are already known: increased fatigue-life of critical parts without any weight increase. We propose to use a specially designed ultrasonic chamber where the treated part is randomly and uniformly impacted in 3- dimensions.

Some applications include:

Watch-Industry parts, Various Micromechanics, Military Parts, Aerospace
Parts, Medical Parts, Surgical Components and Implants

Some of the known beneficial effects that can result due to high power peening treatment are:

Formation of a white layer up to 10 microns in depth with exceptional corrosion resistance, abrasion resistance, and lubricity.
Plastic deformation of the surface.
Elimination of tensile stress and the introduction of favorable compression stress up to 12 millimeters in depth.
Altering the surface finish resulting in a smoother surface and eliminating defects.
Improvement in endurance and corrosion resistance. Up to 250% and 400% respectively.

Shot peening is also used in applications where the effects of fatigue were caused by grinding, electrical discharge- and electrochemical-machining (EDM and ECM), electroplating, anodizing, thermal spraying and welding. It also can help increase resistance to fretting, galling, cavitation erosion, stress-corrosion cracking, intergranular corrosion and hydrogen-embrittlement.

Examples of Shot Peenning in Action