Influence of coolant conditions in ultrasonic assisted grinding of high performance ceramics

Abstract

Ultrasonic-assisted grinding finds its main application in the processing of hard, brittle materials. In particular through the superposition of the conventional feed rate and the high velocity with ultrasonic frequency, advantages in drilling processes can be reached. The application of ceramic and glass materials for high performance parts in the aerospace and aeronautical industries, in biomedical components and for parts exposed to wear in the automotive industry is steadily increasing due to their favorable properties. The drilling of these materials in their sintered state with high accuracy and reproducibility presents a significant challenge with respect to the choice of tool and the process parameters implemented. This paper focuses on the influence of the cooling lubricant in combination with different tool specifications on the grinding process. The grain size of the diamond grinding pins was varied in the range of 30 to 126 lm. As bond types, electroplated, sintered bronze and sintered Fe/Co bonds were investigated as well as the pressure of the cooling lubricant and the influence of these factors on the process behavior. In additional to the process behavior, the residual stress profiles of the workpieces were evaluated.

Ex Situ Residual Stress Analysis of Chemical Vapor Deposited Diamond Coated Cutting Tools by Synchrotron X‐Ray Diffraction in Transmission Geometry

“…Thus, critical failure of the cutting tool eventually results. [ 34,35 ] Taking into account the influence of the WC‐Co substrate material regarding the residual stress state, two effects are represented. First, a decrease in average residual stress is produced as the amount of phases within the substrate increases.…”

Ultrasonic-Assisted Milling of Hard-to-Cut Materials: Development and a Framework for Further Investigations

“…While dry machining avoids the problems related to cutting fluids, it potentially causes burning of machined surface, more friction/adhesion between tool and workpiece, and lower the tool life. Uhlmann et al [19] investigated the effect of the cooling lubricant when UAM of holes in Al 2 O 3 and their results showed that all grain sizes apart from 30 μm grain demonstrated relatively identical process behaviour with lower forces. The maximum reduction in forces was observed when using sintered bronze bonding type, while the lowest forces were observed with the galvanic bonded tools.…”

Abrasive machining of advanced aerospace alloys and composites

“…The development of ultrasonic assisted abrasive machining can be traced back to the mid-1950s, where reported advantages included reduced grinding temperatures and workpiece tensile residual stresses [42]. The majority of published work relating to ultrasonic assisted grinding (UAG) however has largely centred on hard/brittle materials such as ceramics and glass [179,221], with very limited literature available on UAG of nickel based superalloys or titanium alloys. Furthermore, much of the studies on UAG have involved surface grinding configurations with depth of cut typically limited to 0.3 mm [211], with relatively few papers addressing UAG under a creep feed arrangement (depths of cut !1 mm).…”