Application of Ultra-Small Micro Grinding and Micro Milling Tools: Possibilities and Limitations

Abstract

Current demands for flexible, individual microstructures in high quality result in high requirements for micro tools. As the tool size defines the minimum structure size, ultra-small tools are needed. To achieve tool diameters of 50 µm and lower, we investigate the complete manufacturing chain of micro machining. From the development of the machine tools and components needed to produce and apply the micro tools, the micro tools themselves, as well as the micro machining processes. Machine tools are developed with the possibility of producing the micro geometry (cutting edge design) of micro tools as well as plating processes to produce super abrasive micro grinding tools. Applying these setups, we are able to produce ultra-small micro grinding and micro milling tools with typical diameters of 50 µm and down to 4 µm. However, the application of such tools is very challenging. The article presents possibilities and limitations in manufacturing the micro tools themselves as well as microstructures made with these tools. A special emphasis will be on the influence of the tool substrate in micro milling and grain sizes in micro grinding.

Submerged micro grinding: a metalworking fluid application study

“…Relative to the tool substrate diameter, a grit size of 5-10 μm is a large grit size, beneficial in terms of tool life and easier to analyze post process. A previous study showed that it is the largest grit size to continually achieve a good grit density on the bottom surface of the tool when using electroless plating for the given tool substrate diameter [21].…”

“…This MWF was compared with dry machining and experiments with distilled water as a coolant. The experiments conducted with SDS were the only ones where the tool managed to machine the assigned cutting path of 0.5 mm [15]; however, the tools suffered from high amounts of adhesions and flattened abrasive grits, indicating high process temperatures [21]. In a follow-up study, an SDS solution, isopropanol, and the commercially available synthetic oil DiaMond 80 were used via MQL in a micro milling experiment.…”

Precision micro-milling process: state of the art

“…The continuing trend toward smaller feature sizes in micro-milling with higher precision and accuracy has led to demands for higher quality microtools, as the cutting tool edge radius defines the minimum UCT [ 139 ]. It was shown by Kirsch et al [ 140 ] that the material specifications of tool blanks highly influenced the quality and application of ultra-small microtools in the range of 4–50 µm. Generally, microtools are manufactured via grinding operations following the famous procedure by Aurich et al [ 141 ] for the design and machining of single-edge micro end mill tools with diameters between 10 µm and 50 µm and a variable helix angle.…”

Experimental Analysis for the Use of Sodium Dodecyl Sulfate as a Soluble Metal Cutting Fluid for Micromachining with Electroless-Plated Micropencil Grinding Tools

“…Table 1. Electroless-plating solution composition [20]. The abrasive grits are whirled up in the coating solution via a magnetic stirrer.…”