There are some differences between printing a part with MJF technology in Fast or Top Mechanical mode: you can choose between optimising costs or improving the technical performance, tolerances and definition of your print. 



PA12 Fast or PA12 Top Mechanical? Which is better for your 3D printing?


What is Nylon PA12?

Before we get into this, let's take a step back and understand what Nylon PA12, also known as Polyamide, is. Nylon is one of the most widely used plastics in Additive Manufacturing, thanks to its durability and high strength-to-weight ratio.  It originated in the early 1940s and its main use has been in the textile industry, especially for the production of women's stockings. Thanks to its excellent resistance to wear, it has entered various production sectors, becoming one of the most widely used plastics in industry. 

Nylon, especially PA12, printed with MJF technology, makes an object with isotropic mechanical properties in all 3 axes: x, y and z.



The term ISOTROPE refers to a body which, when stressed by a certain physical phenomenon, such as traction, presents the same characteristics in all directions. For example:

  • If I take a 3D printed part with MJF technology, its mechanical resistance to traction will be identical on all 3 axes. If I pull the part in all directions, nothing will change;
  • if I print a part with FDM technology, the mechanical resistance on the z-axis will definitely be lower.


This is the fastest and most economical. In this mode, the printer tries to minimise all downtime and creates layers of material that are thicker than normal, for example 0.11 mm. compared to the normal 0.08 mm. generating a considerable reduction in costs and time.  However, the surface mechanical properties, such as the degree of finish, are different from the standard.

  • This is the preferred method for parts that do not require aesthetic finishes or considerable mechanical loads (static parts).


This is the best print quality that can be achieved with MJF technology. The parts produced have

  • dimensional tolerances of 0.3 mm, thanks to the thickness of the various layers of 80 microns and a higher quality of details on the x and y axis;
  • higher performance in terms of mechanical resistance.


Which do you need? Fast or Top Mechanical printing? Whatever it is, you can choose your mode in the Quote.

Happy 3D Printing with PolyD!