Testing the Strength of Hollow, 3D-Printed PLA Spheres

Share this Article

Researchers from Romania have studied the mechanical properties of parts fabricated from polylactic acid, releasing the details of their recent study in ‘Mechanical Behavior of 3D Printed PLA Hollow Spherical Parts Under Axial Compression.’

Often used in the construction of bearings and spherical joints, spherical parts usually assist as intermediates in the movement of other components; for example, they may allow rotation to occur or for one part to slide smoothly toward another. Filled spheres tend to be more rigid, while cave spheres are elastic.

Users may employ both metallic and non-metallic materials, and the authors note that ‘plastics present a particular interest.’ In this study, the researchers focused on cave spheres produced from plastic while under compression.

Expected elastic behavior of a spherical hollow part under the action of an axial compression force

While there are numerous methods for fabrication of parts, additive manufacturing is of interest to the authors in this study—especially in terms of the following results:

  • Surface roughness
  • Surface layer properties
  • Material homogeneity

“In the case of the technological process of manufacturing the spherical parts, some process input factors can influence the surface roughness of the final product,” explain the researchers. “If 3D printing is taken into consideration as a manufacturing solution, then the process seems to be simple enough and of good quality from the surface aspect.

“In practice, there is some important kind of stresses which are convenient for the technical uses of the parts. For example, the compression stress reveals how resistant is a spherical part under a certain force until the part is deformed and loses the properties of being used.”

A hollow sample part was 3D-printed to understand more about typical mechanical properties, along with compression-resistance, and elastic behavior.

“Sometimes there are situations when the elastic behavior under compression axial forces is of technical and functional interest,” said the authors.

The sample was composed in an L9 Taguchi orthogonal design, featuring four different variables for three experimental levels. Nine combinations are considered total with that particular design, revealing the effects of axial compression tests. A simulation was prepared, using the finite element method, offering insight into material behavior before beginning formal research—along with assisting in projections for crack generation.

Simulation using the finite element method of the new shape of the plastic spherical hollow part under the action of the axial compression force (wall thickness h= 2 mm, axial force max. Fa=7.189,97 daN)

Test pieces obtained by 3D printing before applying the axial compression tests

The test sample was printed with silver metallic PLA on an Ultimaker 2+, with no finishing permitted after fabrication—lest new elements introduced into the part could affect compression testing.

Experimental conditions and results

“One could remark the similarities between the plastic spherical hollow parts behaviors simulated employing the finite element method and the real behavior proved by the experimental testing; this means that the considerations formulated when theoretically analyzing the deformation conditions of the spherical parts were correct,” concluded the authors.

“The analysis of the model showed that the maximum influence on the elasticity of the parts was exerted by the printing plate temperature. As expected, the increase of the part wall thickness determines an increase of the plastic spherical part elasticity. In the future, extended experiments could be developed, to evaluate the effect exerted also by other manufacturing process input factors on the behavior of the parts under axial compression efforts.”

Researchers continue to find better ways to predict and improve mechanical properties, studying other influences like color, porosity, and more. What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: ‘Mechanical Behavior of 3D Printed PLA Hollow Spherical Parts Under Axial Compression’]

 

Share this Article


Recent News

MULTI-FUN Consortium Aims to Improve Metal 3D Printing

JCRMRG’s 3D Health Hackathon Aims for Sustainable 3D Printed PPE



Categories

3D Design

3D Printed Art

3D printed automobiles

3D Printed Food


You May Also Like

3D Printing Webinar and Virtual Event Roundup, July 7, 2020

We’ve got plenty of 3D printing webinars and virtual events to tell you about for this coming week, starting with nScrypt’s webinar today. 3Ding and Formlabs will each hold a...

Featured

Interview: Redefine Meat CEO’s Insight into New Alternative Meat & 3D-Printed Food

Amid lifestyle changes toward wellness and health, as well as an inclination of industries to adopt disruptive technologies, the 3D printed plant-based meat industry could go from niche to mainstream...

NIST Grants $1.4 Million to America Makes for 3D Printed PPE

As the COVID-19 pandemic has swept the world and changed life as we know it in many ways—along with opening up many questions for the future—makers, researchers, and medical inventors...

Featured

French Army Deploys Massive Military Print Farm for Spare Parts

The French Army has recently partnered with HAVA3D, a prominent distributor and integrator of additive manufacturing solutions based out of Le Mans, France, to deploy one of the largest 3D...


Shop

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