Search Results for tool wear

In contrast to most plastic deformation processes, the shape of a machined component is not uniquely defined by the tooling. Instead, it is affected by complex interactions between tool geometry, material properties, and frictional stresses and is further complicated by tool wear. This chapter covers the mechanics and tribology of metal cutting processes. It discusses the factors that influence chip formation, including tool and process geometry, cutting forces and speeds, temperature, and stress distribution. It reviews the causes and effects of tool wear and explains how to predict and extend the life of cutting tools based on the material of construction, the use of cutting fluids, and the means of lubrication. It presents various methods for evaluating workpiece materials, chip formation, wear, and surface finish in cutting processes such as turning, milling, and drilling. It also discusses the mechanics and tribology of surface grinding and other forms of abrasive machining.

This chapter covers the practical aspects of machining, particularly for turning, milling, drilling, and grinding operations. It begins with a discussion on machinability and its impact on quality and cost. It then describes the dimensional and surface finish tolerances that can be achieved through conventional machining methods, the mechanics of chip formation, the factors that affect tool wear, the selection and use of cutting fluids, and the determination of machining parameters based on force and power requirements. It also includes information on nontraditional machining processes such as electrical discharge, abrasive jet, and hydrodynamic machining, laser and electron beam machining, ultrasonic impact grinding, and electrical discharge wire cutting.

This chapter discusses the types of failures that can occur in sheet metal forming tools and explains how to mitigate their effects. It describes the factors that influence galling and wear and the benefits of special treatments and coatings. It provides information on through hardening, case (surface) hardening, and nitriding as well as hard chrome plating, vapor deposition, and thermal diffusion coating. It explains how to measure wear resistance using various tests and provides guidelines for selecting tool materials, treatments, and coatings.

This chapter discusses the types of sensors used in sheet forming operations and the information they provide. It explains how force sensors protect equipment from overloads due to tool wear, friction, and misfeeds, how displacement and proximity sensors help to prevent die crashes, how acoustic emission, ultrasonic, and eddy current sensors detect tool breakage and part defects such as cracks, and how roller ball and optical sensors measure material flow. It also discusses the role of draw-in, wrinkle, oil-monitoring, and vision sensors and explains how material properties can be derived in real time from various sensor outputs.

This chapter provides an overview of the blanking process and the forces and stresses involved. It discusses the factors that affect part quality and tool life, including punch and die geometry, stagger, clearance, and wear as well as punch velocities, misalignment, and snap-thru forces. It also discusses ultra-high-speed blanking, fine blanking, and shearing, and the use finite-element simulations to predict part edge quality.

This chapter focuses on the metallurgical factors governing the machinability of stainless steels. It begins by describing the chemistry, cleanliness, structure, processing history, and the cross-section size of the stock of the different grades of stainless steel. This is followed by a general description of the machining behavior of the stainless steel families, namely ferritic, martensitic, austenitic, precipitation hardening, duplex, and super stainless steels. The beneficial effect of controlled inclusions is then discussed. The chapter ends with a section providing information on high-speed tool steel and carbide tooling, along with tool coatings and coolants applicable to stainless steel.