How to Buy a 3D Printer

There has never been a time where there are more choices available in the 3D printer or rapid prototyping market.  Promises abound for fantastic performance at ridiculously low prices.  While there is no doubt that lower prices are of great benefit to the end user, one must still be wary of less than adequate performance in a system that is offered at a too-good-to-be-true price point.

So, how does one go about choosing the correct system?  First, it’s important to outline the criteria for the system that you plan to purchase.

Most important is the quality of the parts that the machine produces:  accuracy, detail, surface finish, strength etc.

Secondly, one needs to examine the machine performance:  build speed, ease of use, software interface, ease of maintenance.

Finally, examine the post process.  This is an issue that most vendors try to avoid.  When the machine is done printing the part, what else needs to happen before it is useable?  Does it need to dry?  Does it need a post curing operation? Are there supports to remove?  Does it need to be sanded, or infused with some other chemical?

Once you’ve established all of your criteria, compile them into a “decision matrix”.  This is where you rate the performance of each machine in each of the categories, and rate how important each category is to your final decision.  By compiling a decision matrix, you’ll avoid being manipulated by an aggressive sales person into making an emotional decision about part color or ABS plastic when those particular machine characteristics may not be the most critical to your application.

Here is an example:

Criteria Importance Rating Weighted Rating
Accuracy 10 9 90
Detail 10 9 90
Resolution 10 9 90
Build Speed 7 8 56
Material Strength 7 7 49
Color 1 5 5
Material Cost 5 7 35
Post Processing 9 10 90
Software interface 9 10 90
    Total Score 595


One can clearly see in this example that weighting the importance of certain characteristics of the system can greatly impact the over-all score.  For example, a more accurate system with a poor color rating will have a higher overall score than a less accurate system with better color importance.

When evaluating 3D printers, most buyers will request a test or benchmark part to be printed.  This is a great way to evaluate the types of parts that a certain machine can produce.  Be sure to select a CAD file that represents the types of parts that you plan to print.  Stay away from the “I want to test the limits of this machine” parts, with paper thin features and microscopic holes.  These types of parts are great for an academic analysis, but don’t really gage how well a system will operate in the real world.

The best way to evaluate a system is to see that system in person.  Though most 3D printers are not portable, most vendors will allow you to visit their showroom for demonstration.  It is very important to see the entire process, from importing the STL into the control software, to post processing the final part.  Some vendors may not want you to witness the entire process.  A machine that boasts a very fast build time may have an excruciatingly long and tedious post process.  It’s important to understand these details before you buy.

If you plan to do a lot of 3D printing or prototyping, owning your own system will ultimately be more cost effective than using a service bureau.  Develop your matrix and complete it for each model that you are considering.   The machine with the highest composite score will be the bset choice.  You’ll be able to produce more parts, more quickly and more securely, helping you to bring  your new products to market faster.

NeoMetrix Technologies, Inc. (  is a leading provider of solutions for rapid product development throughout the southeastern United States, focusing on 3D laser scanning, reverse engineering and rapid prototyping.  NeoMetrix is also a top reseller for Konica-Minolta Sensing America, Objet Geometries and Rapidform Software.