Study Looks at Effects of Surface Slope and Build Orientation in Material Jetting 3D Printing

Share this Article

Several studies have analyzed the surface finish of 3D printed objects, but very few have looked at the surface finish and dimensional accuracy of those 3D printed through material jetting. Material Jetting is a 3D printing process where a material is jetted from a nozzle usually an inkjet head or similar. This material is then cured by an external light source such as a laser or UV lamp. Objet Polyjet, a Stratasys technology is the major commercialized material jetting technology. Stratasys’ Objet systems produce smooth parts using photopolymers jetted by inkjet print heads and then cured by UV. These parts can even be made into gradient materials with different softness or hardness at different locations. Visually arresting Polyjet parts do have their limitations. Traditionally parts have been brittle and have low heat deflection. Due to this very few studies have been done with the performance of Objet Polyjet parts. Many considered these kinds of parts fine for prototypes but did not see real world end-use part applications. Over the past years, Material Jetting materials have been improved however and the performance of these parts has increased significantly. A new study, “Effect of surface slope and build orientation on surface finish and dimensional accuracy in material jetting processes,” is therefore very timely. In the study, the researchers used a material jetting process to 3D print specimens with a flat area and four feature designs, such as spherical and prismatic holes and protrusions. They were printed in two orientations and scanned with a white-light profilometer to quantify the surface texture, areal, and material ratio parameters for dimensional accuracy and areal fidelity.

“The results indicate that surface slope and build orientation appear to have a greater influence on the recessed features compared to the protruded ones,” the researchers state. “The height and volumetric functional surface parameters are significant and show better surface finish for the 0º surface slope compared to 45º. Also, prismatic and recessed features might benefit from printing on a 45º sloped surface while the design fidelity of cross-sections in holes and protrusions greatly vary depending on the specimen slope. The contributions of this work include illustrating the potential for increased production, resolution and fidelity capabilities if 3D printing equipment could incorporate tilting print trays, adaptable print orientation, and local angles, among others.”

The researchers found that orientation was a statistically significant factor, and that to achieve the minimum self-supporting angle, critical angled faces should be oriented in the YX direction on the build tray.

“Stair-stepping is one of the major artifacts on the printed surfaces due to sloping part features,” the researchers add. “The stairstepping effect happens when a surface orientation is not orthogonal to the axis of the source of energy. This study aims at uncovering the effects of stair-stepping on surface parameters.”

The four features – spherical and prismatic protrusions and holes, as well as a flat area, were fabricated with an Objet30 3D printer, and factorial analyses were performed to observe the effects of the surface slope and build orientation on each of the surface parameters. Broadly, the researchers explain, the height, functional material ratio, and functional volume groups stood out with the most statistically significant parameters.

Several conclusions were drawn from the study as a whole:

  • The introduction of a surface slope creates stair-stepping which affects different aspects of surface characteristics
  • The height and volumetric functional parameters are significant and show better surface finish for the 0° surface slope compared to the 45°
  • Build orientation affects the shape and direction of stair-steps
  • The orientation that is across the printing head direction (YX) has faster decay (sharper), and the surface is dominated by high spatial frequency components of a texture pattern
  • The build tray can be tilted to variable degrees to increase the dimensional accuracy and creates sharper edges for some designs such as  polygons and features with recess designs

“If manufacturers were to provide more advanced machines with tiltable print trays and the printing parameters such as localized build orientation, surface slope, and selective support structures, it would be possible to achieve higher levels of dimensional accuracy, design fidelity, and surface finish,” the researchers state. “Immediate future work includes developing design guidelines for material jetting technology.”

Discuss this and other 3D printing topics at 3DPrintBoard.com or share your thoughts below.

 

Facebook Comments

Share this Article


Related Articles

Effect of Build Orientation on the Microstructure and Mechanical Properties of SLM 3D Printed Titanium

Researchers Look at Fatigue Response of DMLS 3D Printed Maraging Steel



Categories

3D Design

3D Printed Art

3D Printed Food

3D Printed Guns


You May Also Like

The R&D Tax Aspects of 3D Printing Anatomical Models

Hospitals are beginning to integrate 3D printing technologies into their operations to better prepare surgeons for high-risk procedures. Practice makes perfect, but when it comes to healthcare, no two surgeries...

Disney Research Uses 3D Printing to Bring Animated Characters to Life

As one would expect, the team at Disney Research is very familiar with 3D printing, and has of course used the technology for countless innovations. They have been behind the...

It’s No Fairytale: Todd Grimm Shares His Treasure Trove of 3D Printing News at RAPID

This year’s RAPID + TCT was jam packed with new 3D printing technology and was by far the largest 3D printing expo that I’ve personally seen. There was an awful lot...

Wacker Debuts Silicone 3D Printing Technology to North American Market at IDTechEx

As the entire industry looks to push the capabilities of 3D printing technology to the next level, the demand for advanced materials has never been greater. For about 70 years...


Training


Shop

View our broad assortment of in house and third party products.


Print Services

Subscribe To Our Newsletter

Subscribe To Our Newsletter

Join our mailing list to receive the latest news and updates from our 3DPrint.com.

You have Successfully Subscribed!