Micromachining Tidbits

Improvement in micro-tool geometries and finishes have been key to enabling Challenge Machine to get the most out of its high-speed equipment. The shop uses tools as small as 0.001 inch in diameter.

Micromachining is becoming a bigger part of Challenge Machine’s business. In fact, I profile their efforts in this article.

During my visit to the Blaine, Minnesota, shop, I picked up on a few tricks it uses to be more effective at machining micro features. Here are a few I cite in the article above:

• The shop sometimes starts the creation of square-edge micro-slots by first using a ball end mill to essentially rough out the slot before coming back with a standard end mill to create the sharp corners. This minimizes the load on the standard end mill.
• Pecking cycles are used for some micro-drilling operations, and the pecking feed distance depends on the material and hole size. However, Challenge Machine has found that some applications lend themselves to drilling without pecking. This is often the case for polyetheretherketone (PEEK), requiring an adjustment of speeds and feeds to generate the proper chip size per tooth so chips can be evacuated out of the hole.
• The shop tries to integrate deburring operations during the machining cycle as much as possible to minimize manual deburring work. If face milling is required after holes are drilled, the shop might slowly run a drill backward down each hole to remove any burrs that milling created.
• Challenge Machine also commonly provides micromachining lessons to its customers. For nearly every prototype project, the shop works closely with the customer to offer design-for-manufacturability (DFM) suggestions. For example, a part with a callout for a 0.001-inch tip radius would require the shop to use a 0.002-inch-diameter tool. If the designer can accept a 0.0015-inch tip radius, then the shop can use a cutter with a 0.003-inch diameter to speed the machining process.