Application of Carbon Dioxide Snow in Machining of CGI using an Additively Manufactured Turning Tool

Abstract

The application of conventional cooling lubricants for the tribological conditioning of machining processes involves high additional costs and health risks. The application of a cryogenic carbon dioxide (CO2) snow cooling strategy is an economical and environmentally sound alternative for oily cooling emulsions since it has a high cooling effect as well as a residue-free sublimation. This article introduces a laser additive manufactured tool holder with an integrated dual nozzle which enables CO2-snow jet application. Initially this work focuses on the characterization and the selection of a suitable nozzle geometry. The modular tool body features an adapted channel structure for process-reliable and targeted CO2-snow cooling for turning processes. This enables the simultaneous cooling of the rake and flank face with CO2-snow, as well as the application of cryogenic multi-component cooling of the rake face. In the context of this study, the focus lies on the technological evaluation of three different supply strategies during the continuous turning of compacted graphite iron CGI-450 at increased cutting speed. It was established that an efficient rake face cooling is indispensable to achieve a low thermal tool load, and thus lower crater wear behavior. Therefore, this study contributes to an improvement in cryogenic machining processes regarding the design of additively manufactured tool bodies for process-reliable CO2-snow cooling, as well as for the selection of supply strategies to minimize the thermomechanical tool load.

A novel indirect cryogenic cooling system for improving surface finish and reducing cutting forces when turning ASTM F-1537 cobalt-chromium alloys

“…Nevertheless, the feasibility of this cooling technique is still not fully understood, since as opposed to conventional cooling, cryogenic jet cooling is highly sensitive to the position of the nozzles in respect to the cutting tool and workpiece [23]- [25]. In some cases, the LN2 can overcool the workpiece or fail to impinge on the tool-chip interface correctly, bringing about adverse results in tool life and surface integrity [26], [27].…”

Characterization of Ceramics Coatings Processed by Sol-Gel for Cutting Tools

“…On the other hand, at moderate cutting speeds, there is the formation of built-up edge formation, abrasive and adhesive wear [24]. Recently, the CGI turning tests have been studied by many authors, as Tooptong et al [2]; Abdoos et al [24]; Yamamoto et al [25]; Heep et al [26]. Tooptong et al [2] investigated the flank wear when turning three cast irons (flake graphite iron (FGI), compacted graphite iron (CGI) and nodular graphite iron (NGI)) under dry conditions.…”

“…The application of the optimized coating resulted in a 40-60% improvement of the cutting tool life under the finishing turning of CGI. Heep et al [26] studied the CGI turning using carbon dioxide snow. The main results indicated that the efficient rake face cooling is essential for the reduction of thermal tool loads and has a significant effect on the crater wear behavior.…”