Additive Manufacturing

When design and manufacturing professionals glance at a high-resolution additively manufactured part and assess it as "high accuracy" they make a big mistake. High resolution can make a pretty part, but this high resolution itself does not mean the part is accurate. In other words, that perfect-looking part with smooth surface, sharp edges, and fine detail might not hold a tight tolerance. And even if an additive machine can make an accurate part, this accuracy might not be repeatable.

An upcoming Stratasys webinar and subsequent white paper, entitled "The Accuracy Myth: Don't Make the Mistake of Confusing Resolution with Accuracy" explains how accuracy, repeatability and resolution apply to additive manufacturing. Learn more and register for the webinar.

Below is the first of four excerpts from the white paper, which will be available after the webinar, November 16.

"Over the years, some engineers have slid into using resolution attributes such as layer thickness or dots per inch as a careless shorthand term for accuracy."

"Resolution does not, in fact, translate directly to a system's overall accuracy. One simple way to visualize the real-world distinction between these two concepts is to imagine that two measuring sticks of differing length are both marked as 12 inches long, yet the second stick is actually 1 inch shorter. The first stick is divided into 1/16-inch increments, and its true length is verified at precisely 12 inches. Even though the shorter stick reads "12 inches," it is verified to be only 11 inches long. But this shorter measuring stick is divided into 1/32-inch increments, which is twice the resolution of the 12-inch measuring stick."

"The 12-inch ruler with 1/16 inch increments exhibits lower resolution but high ultimate accuracy. The 11-inch ruler with the finer increments does the opposite: It exhibits high resolution but low absolute accuracy. The same goes for additive manufacturing systems. Some make parts like the first ruler with finely resolved features but lower overall dimensional accuracy. Others turn out parts with lower, but acceptable, resolution and excellent accuracy."