Rasmus Solmer Eriksen

Tool Design and Manufacturing for Bulk Forming of Micro Components

The central part of the metal forming processes are the forming tools. In the macroscale, these tools are manufactured by means of machining‐ and drilling operations and subsequently hardened. Due to the required precision, this approach is not possible in the microscale. An investigation of alternative tool manufacturing techniques has been carried out, including μ‐EDM, electroforming and machining operations. A series of universal forming tools for simple microcompoents has been manufactured using different techniques, allowing side‐by‐side comparison. A series of ejectors and punches have also been manufactured using a combination of grinding and μ‐EDM processing. Critical tooling parameters including geometry, yield strength, surface roughness and production time has been recorded. A silicon replica method has been utilized to measure the internal geometry of the microforming tools.

Micro-bulk Forming

This chapter firstly introduces the background of micro-bulk forming, backed by the description of conventional cold forming processes based on which fundamental issues concerning micro-bulk forming such as size-effects, work materials, and tool materials are discussed. These considerations are considered in a press and tool system design which is described in detail in this chapter, especially on machine precision, tool-guide, and handling system design. Finally, micro-tribology and process analysis of micro-bulk forming are described.

Chapter 7 – Micro-Bulk-Forming

Publisher Summary Bulk forming is used extensively in a wide range of industrial applications. Within the production of transmission elements for the automotive industry, the bulk forming process is the standard. A typical forming process requires multiple forming steps and comes in a wide range of variants. The industrial popularity of the bulk forming process still relies on the underlying theory of material flow and behavior, something that has not changed since the early days of forging. Micro-bulk forming is the utilization of the bulk forming process to form micro-components. Material knowledge is central for the bulk forming process, which fundamentally relies on differences in flow stress between two materials. These two materials are often termed “workpiece material” and “tooling material,” relating to their respective functional purpose in the bulk forming process. In micro-bulk forming the geometrical tolerances of the tool are very narrow and deflections of the tool during heat treatment often exceed the total allowable tolerance deviation of the tool.