Search Results for wrinkling

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 describes the various types of cushion systems used in forming presses and their effect on part quality. It begins with a review of the deep drawing process, explaining that wrinkling, tearing, and fracture are the result of excess or insufficient material flow, which can be prevented by maintaining the correct amount of holding force on the periphery of the blank. It then describes how blank holding force is generated in double-action presses and the extent to which displacement profiles can be adjusted on both the inner and outer slides. The discussion then turns to single-action presses that incorporate some type of cushion system. The chapters describes the many ways that cushion systems are implemented in forming presses and the force and displacement characteristics achievable with each method. It also explains how multipoint cushion systems are designed and how they facilitate uniform metal flow into the die cavity of large deep-drawn parts.

This chapter provides a detailed analysis of the deep drawing process. It begins by explaining that different areas of the workpiece are subjected to different types of forces and loads, equating to five deformation zones. After describing the various zones, it discusses the effect of key process parameters including the draw ratio, material properties, geometry, interface conditions, equipment operating speed, and tooling. It then walks through the steps involved in predicting stress, strain, and punch force using the slab method and finite element analysis and presents the results of simulations conducted to assess the influence of blank diameter, thickness, and holding force as well as strain-hardening and strength coefficients. It also discusses the cause of defects in deep drawn rectangular cups and presents the case study of a deep drawn rectangular cup made from an aluminum blank.

Tube hydroforming is a material-forming process that uses pressurized fluid to plastically deform tubular materials into desired shapes. It is widely used in the automotive industry for making exhaust manifolds, catalytic converters, shock absorber housings, and other parts. This chapter discusses the basic methods of tube hydroforming and the underlying process mechanics. It explains how to determine if a material is a viable candidate and whether it can withstand preforming or bending operations. It describes critical process parameters, such as interface pressure, surface expansion and contraction, and sliding velocity, and how they influence friction, lubrication, and wear. The chapter also provides information on forming presses and tooling, tube hydropiercing, and the use of finite elements to determine optimal processing conditions and loading paths.

The increased use of advanced high-strength steels to achieve weight reduction in automobiles has led to the development of innovative tool designs and manufacturing processes. Among these technologies and processes are: real-time process control, active drawbeads, active binders, flexible binders, and flexible rolling. This chapter presents the implementation, advantages, disadvantages, and applications of these processes and technologies.