Tool wear and tool life are intricately tied together, and can have a big impact on your bottom line. Besides the cost of replacement parts, there are costs from downtime, reduced reliability, need for additional NDE, and lost capacity that can add up to be substantial. The factors that lead to tool wear are mechanical, thermal, chemical, and abrasive. During chip formation a significant amount of heat is generated, particularly on the flank of the tool. Due to the cyclical nature of the cutting operation these thermal loads pulsate leading to thermal fatigue of the tool material.
Types of Tool Wear:
As a result of load factors exerted on the cutting tool edge, a few basic mechanisms dominate metal cutting. These mechanisms are:
- Diffusion wear – affected by chemical loading on the tool and is controlled by the metallurgical composition of the tool and coating material;
- Abrasive wear – affected by the hardness of the tool material and is controlled by the carbide content of the cutting tool material;
- Oxidation wear – causes gaps to occur in coated films and results in a loss of the coating at elevated temperatures;
- Fatigue wear (static or dynamic) – this is a thermomechanical effect and leads to the breakdown of the edges of the cutting tool;
- Adhesion wear – occurs at low machining temperatures on the chip face of the tool and leads to the formation of a built-up-edge, and the continual breakdown of the built-up edge and the tool edge itself.
Machining and Abrasive Tool Selection:
Machining is a widely used process for producing intricate shapes on components and artifacts and for providing precise tolerances that are required especially for the manufacture of parts at various scales. Modern machining requires the use of minimum quantities of lubricants, dry machining capability, high cutting speeds, and long tool lives. However, existing tool materials have proven to be sub-standard compared to newly developed nanostructured thin film coatings. There is also a growing need for specially developed cutting tools for machining nanocrystalline metals and alloys. G2MT has expertise in selecting the best tool inserts and mill bits for the metal/metal alloy being machined, analysis of the tool wear, and failure mechanisms from the machining process.