Microforming for the production of microscale components: A study on the effect of forming dies in microextrusion of metals

Micro products play a critical role in various fields, ranging from consumer electronics like watches and cell phones to advanced medical devices. These intricate parts cannot be manufactured using conventional methods, making microforming a viable solution for producing such components. The goal of the current study is to examine how various forming die conditions affect the production of microparts, namely through the metal microextrusion method. Three distinct die conditions were evaluated: dry die condition, lubricated die condition, and diamond-like carbon (DLC) coated die condition. To demonstrate the practical aspects of microforming, two different metals were employed in the study, with a micropin chosen as the representative micropart for investigation. During the microextrusion tests, various parameters were recorded, including force-displacement response, hardness, and surface roughness of the microextrudates. In comparison to uncoated and lubricated dies, the results show that using a DLC-coated die greatly decreased the extrusion force and enhanced the micropins’ surface polish. Additionally, the greatest pin length produced by the DLC-coated die was 7.9 and 12.7 mm for Cu and Al billets, while the uncoated die yielded a shorter pin length of 5.2 and 7.6 mm. However, the hardness of the microextrudates was found to be higher with the uncoated die, showing a trade-off between surface finish and material hardness.