Application Note | 3D Printing Tribology
Comparison of Ridge Spacing and Wear Rate on 3D Printed Materials
How Print Ridge Spacing Changes the Wear Rate of Additively Manufactured Parts
Research & Experimental Testing
Frank Liu
Visual Design & Editorial
Andrew Shore
Introduction
3D printed material is gaining rise due to its ability to create a large variety of shapes and features without the use of time consuming input. 3D printing does have its limitations, however, such as in the lack of materials that can be used and strength of products. To understand how the quality of 3D printed materials can be improved, the NANOVEA Tribometer can be used to conduct wear testing.
Importance of Wear Testing on 3D Printed Parts
To test the quality of the 3D printed material, wear testing can be used to estimate their lifetime and wear resistance. Creation of different surface features may be able to withstand external wear better. For this reason, 3D printed samples with different ridge spacing were used to give insight. The use of NANOVEA’s Tribometer is ideal for this type of testing since it is able to conduct linear reciprocating tests across the ridges. Being able to conduct anisotropic wear tests removes directionality as a variable.
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Measurement Objective
In this study, the NANOVEA tribometer is used to wear into three 3D printed samples. Each sample is made of the same type of material, but varies in the spacing of its ridges. The samples are labeled from A to C with respect to the ridge spacing. Sample A has the largest spacing between ridges, while C has the smallest.
NANOVEA T2000 High Load
Pneumatic Tribometer
Test Procedure
| Test parameter | Value |
|---|---|
| Normal force | 10 N |
| Rotational speed | 200 rpm |
| Duration of test | 10 min |
| Distance traveled | 20.0 m |
| Atmosphere | Air |
| Temperature | 24 °C (room) |
| Wear track amplitude | 5 mm |
| Ball material | SS440C |
| Ball diameter | 6 mm |
Table 1: Test parameters for the wear test on 3D printed materials.
Results and Discussion
| Sample | Surface (mm²) | Volume (µm³) | Max. depth (µm) | Mean depth (µm) |
|---|---|---|---|---|
| A | 6.441 | 181333156 | 137.8 | 28.15 |
| B | 4.311 | 91048478 | 95.32 | 21.12 |
| C | 3.999 | 87872402 | 97.55 | 21.98 |
Table 2: Volume-of-a-hole results of the wear tracks (from Fig. 2).
| Sample | Wear rate x 10⁻⁷ (mm³/Nm) |
|---|---|
| A (largest spacing) | 9085.589 |
| B | 4552.424 |
| C (smallest spacing) | 4393.620 |
Table 3: Wear rate for all samples.
From the testing conducted, the wear rate appears to decrease as ridge spacing decreases. One reason this may be is due to more consistent contact area between the surface and the ball as ridge spacing decreases. The wear rate observed from the tests shows a large difference between Sample A and B but not between B and C. This leads to assume that there may be a point where minimizing ridge spacing will no longer influence wear rate and the surface will act as a smooth surface.
Conclusion
The effects between wear rate and ridge spacing were investigated with the NANOVEA Tribometer. By using the instrument’s ability to reliably apply the same test parameters on three 3D printed samples, the wear rate can be compared. The volume of a hole was obtained using our 3D Non-Contact Profilometer. The 3D printed samples with smaller ridge spacing have shown to display a lower wear rate than the ones with a larger ridge spacing.
The NANOVEA Tribometer offers precise and repeatable wear and friction testing using ISO and ASTM compliant rotative and linear modes, with optional high temperature wear, lubrication and tribo-corrosion modules available in one pre-integrated system. An optional 3D non-contact profiler is available for simple in-situ depth measurements or high resolution 3D imaging of wear tracks in addition to other surface measurements such as roughness.
Frequently Asked Questions About Wear Testing 3D Printed Parts
Why wear-test 3D printed parts?
Wear testing estimates the lifetime and wear resistance of 3D printed material, which has limitations in available materials and product strength, and shows how surface features from the print can help it withstand external wear.
How was the effect of ridge spacing tested?
Three samples of the same material, differing only in ridge spacing (A largest, C smallest), were worn in linear reciprocating tests across the ridges under identical conditions: 10 N, 200 rpm, 5 mm amplitude, 20 m, with an SS440C ball.
Does ridge spacing change the wear rate?
Yes. The wear rate decreased as ridge spacing decreased: 9085.589 x 10⁻⁷ mm³/Nm for A, 4552.424 for B and 4393.620 for C, possibly because the contact area between the surface and the ball becomes more consistent.
Is there a limit to the benefit?
The large difference between A and B but not between B and C suggests a point where reducing ridge spacing no longer influences the wear rate and the surface acts as a smooth surface.
How was the wear volume measured?
With a 3D non-contact profilometer: a volume-of-a-hole analysis of each wear track gave the lost volume, from which the wear rate is calculated.
Which instrument was used?
The NANOVEA Tribometer in linear reciprocating mode, with a NANOVEA 3D non-contact profilometer for the wear track volumes.
