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Reduce Distortion in Additive Manufacturing with AniForm-AM

During Additive Manufacturing materials contract as they cool from processing temperatures. This creates residual stresses that cause the part to distort and deviate from the intended geometry, which can make it difficult to meet dimensional tolerance requirements. AniForm-AM simulates the process to predict the distortion and then compensates the geometry such that the part distorts into the desired shape. Click the animation below to see how a compensated geometry results in a final part that is within the tolerance requirements.

Compensated geometry printed Nominal geometry printed Part within tolerance Part out of tolerance

Benefits:

  • Achieve tighter tolerances – Produce accurate, high-quality parts for demanding applications with tight tolerance requirements.
  • Reduce development lead times and costs – Produce quality parts with fewer design and manufacture iterations.
  • Avoid post-processing – Stop relying on post-post processing to achieve dimensionally accurate parts.
  • Reduce material waste and energy consumption – Stop manufacturing parts destined for the scrap bin.

Why AniForm-AM?

  • Simple workflow – Expertise in Finite Element Analysis (FEA) is not required to use AniForm-AM. A simple user-interface and an automated meshing algorithm allows simulations to be set-up in minutes.
  • Robust Finite Element Solver – AniForm-AM uses AniForm Core, an implicit FE solver that has a track record of reliably running simulations for major companies in the Aerospace and Automotive industries.
  • Excellent visualisation – The part distortion, temperature, stresses and strains are all predicted at every simulation iteration, allowing the process to be visualised and inspected in great detail.

Case Study

To demonstrate how AniForm-AM works let’s take this simple bracket as an example. The bracket is to be manufactured with Poly-Ether-Ether-Ketone (PEEK) due to it’s excellent mechanical properties and high operating temperatures. However, distortion is a known problem with this material.

As the drawing below shows, the bracket has multiple critical tolerance requirements that must be met in order to pass quality inspection checks. For this demonstration let’s focus on the perpendicularity requirement on the rear face shown on the side-view to the the right. This specifies that the entire rear face must remain within a 0.2mm-wide tolerance zone perpendicular with Datum Face A. This will ensure that the bracket can sit flush with the two perpendicular surfaces that it joining.

Nominal Simulation Results

An initial simulation of the nominal geometry is shown in this video. It is subtle, but you can see the slight distortion of the part whilst the part is being printed and when it cools.

If we compare the predicted geometry to the nominal geometry with a surface deviation plot, we can see a significant disparity between the two. The part has shrunk during the process, and this is causing there to be around a 0.8mm deviation around the edge of the part.

Uniform Scaling Compensation

A common approach to reducing distortion is uniform scaling, where the the part is uniformly expanded to counteract shrinkage. In this case, applying a 1% scaling in Z and a 2% scaling in X and Y effectively compensates for this global distortion when we rerun the simulation and removes the large deviation previously seen on the part edge. However, the top of the part still deviates by 0.4mm from the intended surface due to non-uniform shrinkage, which exceeds the 0.2mm tolerance requirement. A tolerance plot confirms that only part of the surface meets the specified tolerance zone, meaning the bracket would fail to meet design requirements.

AniForm-AM Compensation

AniForm-AM can automatically generate the compensated geometry from the results of the initial simulation. If we run the simulation of this compensated geometry and again compare the nominal geometry, we can now see that the part closely conforms to the nominal geometry after distortion has occurred successfully meeting the 0.2mm perpendicularity tolerance. It should be noted that it is only the simulation result that is perfectly compensated. The part may distort slightly differently in reality, but the difference between final part geometry and the nominal geometry will be significantly reduced.

Once the ideal compensated geometry has been found, we can apply this compensation to our original .stl file in AniForm and then export it for use in a slicing software.

📩 Ready to Simulate Your AM Process?

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