Stratasys, 3D Printing

3D Printing Sacrificial Cores for Carbon Fiber Composite Layups

By Juan Carlos Gandiaga on September 25, 2018

 Sacrificial CoresWe want to tell you about a great application for our Stratasys FDM printers: 3D printing sacrificial cores. This is perfect for creating composite parts (such as hollow carbon fiber auto parts) with higher precision than traditional methods. Perhaps the best part is that it doesn’t require much complexity or expense on the 3D printing side, and the results are arguably better than you get with traditional methods. You’re getting the end-use part, in the real composite material, but with more design flexibility and smooth surfaces inside and out.

Here’s a quick explanation of how 3D printing sacrificial cores works. It all starts with the end-use part, say a carbon-fiber turbo inlet tube for a car, being designed in 3D CAD. The hollow part is then filled in the CAD system to make a solid core model. It’s this core as a mold—not the end-use tube—that we will 3D print.

 Sacrificial Cores

Our core CAD model is now 3D printed in a soluble material. If you’re familiar with FDM printing, you’ve probably already guessed that we can simply use the “support” material for the model itself. Typically, support material is used during printing to support overhangs, but then gets dissolved away after the part is removed. Here, we actually keep the support material, because it’s our mold for wrapping in carbon fiber. It’s as easy as clicking an option in the FDM printer software! You can choose a solid mold fill, or sparse for faster printing and quicker removal.

So our 3D printed soluble core part is now printed and ready for composite layup and curing. What’s great about the 3D printed core is it can have complex geometry that would be difficult or impossible to create using traditional core methods. After the carbon fiber (with the 3D printed core inside) is cured, the soluble core is dissolved away.

The result? An end-use part carbon fiber tube that looks smooth on the outside and inside—all thanks to 3D printing. From large-scale parts to small scale soluble cores (such as 1mm diameter) can be achieved. Here’s a bit more detail on why this technique is actually better than the traditional method.

Why 3D Printed Sacrificial Cores Are Better (Big Benefits)

Typically, sacrificial cores are made from eutectic salt, ceramic or urethane. These options present several challenges:

  • Can limit part geometry
  • Requires machined tooling to make
  • Uses harsh removal procedures

The impact of 3D printing soluble cores on manufacturing and time will be noticeable at any scale:

Average lead time savings: 50% – 85% from design to final part

Average cost savings: 75% – 95% from design to final part

 Sacrificial Cores

Reduced labor:
  • Less tooling and setup
  • No bonding of composite sections
  • Hands-free core manufacturing

Improved composite parts:

  • Single-piece construction
  • More features, including integrated hardware
  • Control over surface finish and accuracy
  • Core only: part’s internal surfaces
  • Core and mold: part’s internal and external surfaces

Lower risk:

  • Minimal investment
  • Easier to modify
  • Greater 
  • ST-130  Sacrificial Tooling - Step1 Step3 2durability
  • Improved consistency
  • Higher part yield

Ready to learn more? Contact us to discuss how you can create more robust, complex cores that result in composite parts with improved performance and functionality!