Despite the massive sell-offs that 3D Systems (DDD 5.03%) and Stratasys (SSYS 3.81%) have experienced in 2014, the biggest names in 3-D printing are still very expensive on paper. For investors with a small appetite for buying expensive stocks, buying 3D Systems or Stratasys and participating in the long-term growth potential that 3-D printing offers may not be an option. Investors finding themselves in this predicament should look behind 3D Systems and Stratasys and focus on companies that stand to benefit from implementing 3-D printing technology into their operations.

Companies like General Electric (GE -1.80%) or Boeing (BA -0.87%) have massive manufacturing presences, and over the long term, could benefit greatly from adopting 3-D printing more into their operations. Both General Electric and Boeing already use 3-D printing because it allows for products to be developed faster and more efficiently. General Electric currently has plans to 3-D print 45,000 jet engine fuel nozzles a year for its upcoming leap engine, and the nozzles are expected to take to the skies in the coming years. Boeing already uses 3-D printing for non critical airplane components such as heating vents in commercial planes flying today.

As 3-D printing technology continues to advance, Boeing and General Electric will be able to make better use of it in its operations. Interestingly, General Electric already has a plan for 50% of the products its manufactures to "touch" 3-D printing in the next 20 years. Clearly, there are attractive efficiencies built into how 3-D printed objects are made.

In the following video, 3-D printing specialist Steve Heller and industrials bureau chief Blake Bos look beyond 3D Systems and Stratasys to find alternative ways for investors to get some exposure to 3-D printing. Of course, investors thinking about investing in General Electric or Boeing for the potential that 3-D printing may improve long-term profitability should understand that buying such large companies is likely going to result in more subdued returns than buying 3-D printing stocks outright.