As is often the case with high-profile growth companies, the flashiest stocks are not necessarily the best investments. The more reliable companies, and the ones that subsequently carry less headline risk, are easy for investors to overlook because they operate out of the public's view.

In the 3D printing space, much of the media's attention is given to the companies that make the actual printing equipment, such as 3D Systems (DDD -0.84%) and Stratasys (SSYS -1.62%). However, one of the best-performing stocks in the industry has been Proto Labs (PRLB -0.91%), a producer of CNC-machined and injection-molded plastic parts.

Not a traditional 3D company
Proto Labs' main business is relatively straightforward: it provides customers with a fast and relatively less expensive way to obtain low volumes of any necessary prototype design models. The company takes the customer's 3D computer-aided design (CAD) model, analyzes the manufacturability data, and inputs it into a custom, automated injection mold tooling system to rapidly create the desired mold from a broad range of resins or metals. All of this is done in-house.

While there are other companies that offer similar services, Proto Labs claims to have the quickest turnaround in the business and can provide a substantial cost advantage depending on volume. 

Furthermore, since the company has been steadily expanding by purchasing new factories  and strengthening its mill capacity, Proto Labs has the ability to meet the stringent demands of its customers with regard to project size and completion time. This affords the company an advantage over smaller competitors that would likely struggle to deal with the exacting needs of Proto Labs' customers.

A more stable business
The main benefit of Proto Labs' business, which by nature focuses on individual customers and their specific design requirements, is that it is relatively predictable and stable.

In a recent conference call, management highlighted the fact that the company's existing customer base grew over 20% in the first half of 2013, meaning that repeat customers are coming back more often. It also means that management is successfully penetrating the company's customer base, which is extremely important as existing customers currently make up approximately 90% of Proto Labs' business.

However, management can only expand its existing customer base so much. There will come a time when the company has to consistently attract new customers, and it is at this time that management will really be put to the test. One thing is for certain, the dependable nature of Proto Labs' business means that management has some flexibility in its approach to win over new customers going forward.

Traditional 3D-type growth
While it very much a different business than well-known 3D companies like 3D Systems and Stratasys, the Proto Labs' model is still growing at a very aggressive rate. The growth rate are close to some of the more popular names in the 3D space. The following is a breakdown of Proto Labs' projected growth rate in 2014, compared to those of 3D Systems and Stratasys:


3D Systems

Proto Labs


Revenue Growth 2014




EPS Growth 2014




As the above data indicates, Proto Labs lags behind 3D Systems and Stratasys in terms of both revenue and EPS growth. The differences are not too drastic, though. Proto Labs is still expected to grow sales and earnings well above 20% in fiscal 2014, which is very impressive.

Final Foolish thoughts
The flashiest companies are not always the best investments, and they certainly are not the only ones an investor should consider. Proto Labs is a perfect example of this as it has consistently slipped under the radar despite providing impressive returns fueled by aggressive revenue and EPS growth.

The company's stock is up approximately 120% in 2013 alone. Few investors have noticed, though, probably because of the quiet nature of the company's customer-centric business. Although it is not a pure play on 3D printing, Proto Labs is certainly a pure play on aggressive small-cap growth.