Endmilling is a mainstay of micromachining. And while micro and macro milling operations share certain similarities, there are several key differences—and surprises.
One eye opener when shopping for micro-endmills is their cost—as the size goes down, the price goes up. Sometimes way up. Where a commodity 1/8” endmill might cost $6, a micro version 1/10th that size can cost five times as much or more. Adding insult to injury, you’ll likely go through a lot of them compared to their larger cousins. These things are fragile. Why the price difference?
There are several challenges to making micro-endmills, starting with the grinder. “It sounds obvious, but the machine must be designed to grind small tools,” said Mike Wochna, president of Cleveland-based Melin Tool Co. “There are a number of things required for this, including thermal stability, vibration control and extreme accuracy.”
As the tool diameter decreases and its features shrink, the grit size of the grinding wheel must be reduced as well, according to Wochna. And as grit size goes down, complications increase. With tools smaller than 1mm in diameter, it becomes increasingly difficult to accurately see and measure features, so you’ll need special inspection equipment and trained personnel to operate the equipment.
Read the rest: http://www.micromanufacturing.com/content/not-same-old-grind