For 3-D printing to become more competitive against traditional manufacturing, the technology has to vastly improve in terms of speed and smoothness. It can take anywhere from hours to days for a single object to be 3-D printed, putting it's at a serious disadvantage against a traditional manufacturing process like injection molding, which can easily produce thousands of parts in a day. Additionally, 3-D printing is an additive manufacturing process, meaning it produces objects in a layer by layer fashion, which can create a "stair casing" effect where you can see ridges in the finished object.

Compared to the smoothness that consumers have grown accustomed to with injection molded parts, 3-D printed parts often come off as cheap looking. In order to address the issue of smoothness, companies like Stratasys (NASDAQ:SSYS) offer high resolution printers that reduces the thickness of each layer. Stratasys' recently announced full-color multi-material Objet500 Connex3 can print in layers as thin as 16 microns.

Beyond Stratasys, Hewlett-Packard (NYSE:HPQ) has plans to enter the 3-D printing space with a printer that emphasizes speed and overall part smoothness. Earmarked for the professional service center, Hewlett-Packard hopes its competitively priced 3-D printer will attract some attention in the crowded market place.

In the following video, 3-D printing analyst Steve Heller gives investors an overview of where 3-D printing falls far behind traditional manufacturing.