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Riemer O.,LFM Laboratory for Precision Machining | Bohmermann F.,LFM Laboratory for Precision Machining
Annual Technical Conference - ANTEC, Conference Proceedings | Year: 2013

High volume production of micro parts from metals or plastics requires appropriate replication processes like micro metal forming or micro injection molding. Regardless which replication process is applied micro molds and their manufacture - very often made from hardened tool steels - Are crucial for an economic success. Here precision milling has shown its great potential and examples for the mold making as well as replication are given. Nevertheless, the decisive measure for parts' quality are often their mechanical properties and testing of micro parts shows specific challenges.

Brinksmeier E.,LFM Laboratory for Precision Machining | Glabe R.,LFM Laboratory for Precision Machining | Schonemann L.,LFM Laboratory for Precision Machining
Precision Engineering | Year: 2012

Triple mirror retroreflectors are essential components for safety applications, communications and measurement equipment. While downscaling of characteristic dimension is possible for triangular retroreflectors, this is a challenging task for full-cube retroreflectors, due to the absence of continuous tool paths. Thus, the Diamond Micro Chiseling (DMC) process has been developed which allows the machining of full-cube retroreflectors by overlapping a series of sharp-edged pyramidal microcavities. In the past, this has been successfully demonstrated on a small-scale up to 3 mm × 3 mm with a structure size of 150 μm. Industrial applications, however, require the structuring of areas which are significantly larger than 10 mm × 10 mm. This paper will introduce the technology for machining such pattern with the help of the DMC process. Particular attention will be given to the measurement procedures and required tolerances for performing an in situ tool change as well as the optimization strategies for reducing the required process time. © 2012 Elsevier Inc. All rights reserved.

Brinksmeier E.,LFM Laboratory for Precision Machining | Riemer O.,LFM Laboratory for Precision Machining | Robert C.,LFM Laboratory for Precision Machining | Twardy S.,LFM Laboratory for Precision Machining
Key Engineering Materials | Year: 2012

This paper presents two alternative approaches in mold making for micro forming processes. The quality of formed micro parts is mainly dominated by the process parameters and the surface characteristics of the applied forming tools. Forming dies with advanced micro structures can improve the result of forming processes compared to tools with smooth surfaces. Here an approach of micro ball end milling is described to generate the macro geometry as well as an engineered surface texture on micro forming tools in one machining step. In addition to the surface topography, the die material has a decisive influence on the forming result and durability of the forming tool. Therefore single crystalline diamond represents an promissing material for forming tools, because of its unique material characteristics. On the other hand single crystalline diamond requires unreasonable high efforts for its geometrical shaping. Therefore, this paper will introduce a new approach to machine single crystalline diamond by thermo-chemical material removal. © (2012) Trans Tech Publications, Switzerland.

Brinksmeier E.,LFM Laboratory for Precision Machining | Glabe R.,LFM Laboratory for Precision Machining | Schonemann L.,LFM Laboratory for Precision Machining
CIRP Journal of Manufacturing Science and Technology | Year: 2012

In this paper, technologies used for the generation of functional surface structures for optical applications will be reviewed and two novel processes introduced. In many cases, these structures are generated by diamond machining processes into mold inserts for replication purposes or for direct application as metal optics. However, the spectrum of machinable structures is limited by the applied kinematics and tool shapes. For example, the generation of pyramidal prismatic structures with sharp edges is not possible. In order to extend the spectrum of machinable geometries, novel processes like Diamond Micro Chiseling (DMC) or nano Fast Tool Servo (nFTS) assisted turning, have been developed. © 2011 CIRP.

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