A growing area of interest for mold manufacturers is the production of molds for nano size components or for parts which have nano size features. That is to say, features which are less than 500 microns in size, or components less than 1mm in size. The applications include medical devices, such as bioresorbale components which can be permanently implanted in a patient, and electromechanical parts such as extremely small hinges.

The production of molds for these applications presents some very special problems as factors such as heat distortion and the accuracy of the CNC code and the machine itself can make the difference between success and failure.

Japanese company, Shinkoh Mold solved some of the practical problems associated with the technology.  According to Shinkoh, “We run the spindle for 30 minutes before we start cutting to ensure an even temperature and to avoid problems with heat induced expansion. We also use spindle speeds of 13,000 rpm to keep the temperature constant, and we reduce approach angles to 1 degree to minimize cutter loading.” The company has also developed some standard CAM strategies based on a combination of WorkNCs re-machining and finishing toolpaths to go with its distortion avoidance methods.

Fine tuning of this technology has enabled the Shinkoh Mold to successfully machine with 0.2mm diameter tools 10.5 mm long, which is a length to diameter ratio of 26 and a remarkable achievement. If you have some experience of micro machining we’d like to hear it…..