Layer height is an important factor in 3D printing that plays a significant role in determining the resolution and quality of the final print. How do you determine the best 3D printing layer height? We’ll explore how layer height works in different 3D printing technologies, including Fused Deposition Modeling (FDM), Programmable PhotoPolymerization (P3), and Stereolithography (SLA).
We will also discuss the various factors that can affect the properties and performance of 3D printed parts, such as the type of material used, and the specific printing process and settings employed. By understanding the relationship between layer height and these other factors, engineers and other professionals can optimize their 3D printing processes to achieve the desired results for their specific applications.
FDM 3D Printing Layer Height
In Fused Deposition Modeling (FDM) 3D printing, the layer height is determined by the nozzle size and the extrusion width. Stratasys FDM printers offer four layer heights: 0.005″, 0.007″, 0.010″, and 0.013″. The default extrusion width is twice the layer height for Stratasys printers. If your intended part is for display purposes, then a smaller layer height in combination with an aesthetic material like ASA or Diran would produce an appearance quality print. If your part is supposed to be strong and durable, then a larger layer height with a material like Nylon-CF10 would produce a durable design. It’s worth noting that not all FDM materials can be printed at the listed layer heights, as some materials may have a lower melting point or may be prone to warping.
One of the key features of Stratasys FDM printers is the ability to customize the printing process through the use of the GrabCAD Print software. The Insight program, built into GrabCAD Print, allows users to customize the toolpath, extrusion size, support structures, and more features for select Stratasys printers. This allows users to fine-tune the printing process to achieve the best possible results, whether they are looking for high resolution or strong and durable parts.
P3 3D Printing Layer Layer Height
In Programmable PhotoPolymerization (P3) 3D printing, the layer height is determined by the distance the build plate is from the Teflon sheet in the tray. The Stratasys Origin One machine primarily offers two layer heights: 50 microns and 100 microns. A smaller layer height will result in a higher resolution print, but it will also double the printing time. P3 prints have a higher resolution than FDM prints due to the smaller pixel size and on the projector screen and fine motor control of the vertical axis.
Depending on the material used, some of the UV light used to cure each resin layer may actually penetrate through the resin and cure previous layers more than when they were initially formed. This could factor into allowable overhangs, support-free angles, and bond strength to the build plate. The best 3D printing layer height will depend on the part geometry.
With the Open Material License (OML), Origin One users can customize various settings to control how the layers are cured during printing. Exposure duration, separation distance, build tray lowering/raising speed, cure depth coefficient, and more are all settings that can be changed to affect how layers cure and bond to previous layers, or bond to the build tray. Users can also see what settings are preprogrammed into the machine for the Validated materials then work backwards from there to change one or two settings for a specific print.
SLA 3D Printing Layer Height
In Stereolithography (SLA), the layer height is determined by the laser spot size, laser power, and the distance the build platform is lowered after each layer is cured. The Neo machine primarily offers two layer heights: 0.002″ and 0.004″. Neo prints generally have the highest resolution of the mentioned 3D printing technologies due to the variable beam spot size feature and the high-power laser.
In the Stratasys Neo machines, the laser will intentionally infiltrate deeper than the intended layer height of the part and cure resin several layers down. This refines the laser into a point as the outside edges of the laser are less intense than the center, refining the resolution. The higher power laser also decreases build time significantly, especially for darker materials like Somos WaterShed Black.
The best layer height for your part is entirely dependent on which material properties you desire the most. In FDM printing, smaller layer heights mean prettier parts with a smoother surface finish, but also weaker and longer to build. Larger layer heights mean stronger parts, but noticeable stair stepping. In P3, 50-micron layers mean higher resolution prints, but double the printing time, and 100-micron layers mean faster prints but slightly more green parts.
For SL on the Neo, factors such as the density, viscosity, photosensitivity, and color of your resin, and other variables affect the ‘needle tip’ of your laser when penetrating the resin to produce your part. The best 3D printing layer height for SL parts that are usually designed for accuracy will benefit from the Neo’s HD mode and lower layer heights, whilst production and service shops may consider SD mode and larger layer heights to be optimal for productivity.