Quality Control Options for Polymer Additive Manufacturing

Additive manufacturing offers limitless possibilities, as it can create highly complex geometries that aren’t possible with other technologies. What’s not to love? While using additive manufacturing for polymer parts is streamlined compared to traditional manufacturing methods, successfully building parts is a multi-step process. Each step, from the initial design to the post processing, is critical to guarantee that the part is exactly as you need it to be.

That’s why choosing between a comprehensive set of dimensional, surface, and material property-related inspection reports is helpful. Different options provide varying levels of insight that can be invaluable to understanding your part. This guide will explain each choice and when they’re best suited for your part.

These quality control and testing options are available on the MakerVerse platform for parts created with Selective Laser Sintering (SLS), Fused Deposition Modeling (FDM), and Multi Jet Fusion (MJF). Depending on the part type, complexity, and intended final use, you might want to consider one of these options. By choosing the right test, you could save a lot of time or money by getting the in-depth insights needed to know that your part is up to your standards.

Quality Inspection

This is a standard option included in every order on the MakerVerse platform. Every part is inspected in person by additive manufacturing application engineers. In addition to the visual inspection, the team takes basic dimensional measurements. These experts can determine if there are any immediate issues with the final print – and then work with the suppliers to fix these problems.

When to use this: Always, as it’s included with every order.

Optical Dimensional Measurement

With this option, you can compare the dimensional properties of the printed part to the original design.

First, moving fringe patterns are projected onto the part’s surface with a high-power blue light source. High-quality stereo cameras capable of high resolutions capture the reflections from the projection. Ambient non-blue light is filtered out to measure the dimensions of the printed part. When choosing an optical dimensional measurement, you’ll receive an inspection report providing false-color pictures from three different angles.

When to Use This: When free-form structures or contours need to be quickly measured for accuracy

Want to up your additive manufacturing design game? Check out this design guide for Fused Deposition Modeling.

Tactile CMM Scan

A coordinate measuring machine (CMM) provides exact dimensional measurements of your printed part. With this test, you can see how the printed part compares to your original design with a precision of up to 3 μm. Costs and lead times are higher than an optical dimensional measurement, but the scan is more accurate.

In this scan, a highly sensitive tactile sensor touches the part’s surface. The sensor measures coordinate data points, sends the data to a computer, and then compares the findings to the original design file. The CMM can determine the slightest deviations between the actual part and the drawing specifications. You’ll receive a report of five physically measured points that can be compared to the original file.

When to use this: When you need the highest levels of accuracy to measure the geometry of your part

Tensile Test

Choosing a tensile test provides important data on the mechanical properties of the printed part, such as maximum stress, strain, elongation, and other properties.

In a tensile test, tensile bars are printed with your order. These bars are then placed in a universal testing machine and pulled until failure. This test is conducted according to ISO 527, the standard for determining the tensile properties of polymers. You’ll receive an inspection report with the results from the tensile test with the delivery of your parts.

When to use this: When mechanical properties of your part are critical to its end use. Or you want to evaluate the quality of a process or machine involved in creating the part.

Density Test

Testing for density is a quality control measure to ensure the consistency of your part that isn’t possible with a surface-level examination.

For this test, density cubes are printed with your order. These cubes are then measured through cross-section to determine the exact density. Once measured, you can see how the density compares to the properties of the material you chose to print in. An inspection report with the results from the density test will be submitted with the delivery of the parts.

When to use this: When mechanical properties of your part are critical to its end use. Or, you need to evaluate a process or machine involved in creating the part

Surface Roughness Measurement

A part’s surface roughness can affect its durability, friction, and other factors, so getting the roughness within an acceptable range is essential for industrial use.

A sensitive stylus is dragged along the surface up to 50mm distance, measuring the heights and valleys with a precision better than .03μm. The measurements are extrapolated to the entire surface, computing roughness metrics. This process is all performed to the DIN ISO 4287 standard. You will receive a report with your part, including the heights and valleys from the up to 50mm path and the computed Rz and Ra values.

When to use this: When the surface roughness is critical to the function of the part

Quality Control Cheat Sheet

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