Aerospace Composites: A look at how they relate

How do you see the role of composites changing in the Aerospace industry?
Composites are dramatically changing the aerospace industry, especially since the introduction of new models such as the A350XWB (coming soon) and the B787. They are utilizing a high content of composites due to such benefits as weight reduction effecting carrying load and reduced emissions.

However, this is also challenging the production methods, especially in automation. As volumes increase and the materials – especially when composites (CFRP) are stacked with titanium – and machining becomes tough, machine utilization needs to be high in order to keep costs down.

How do you determine what cutting tool should be used for machining composites?
We see a clear mix of high quality carbide tools with more advanced coatings to ensure higher quality holes and predictable tool life as well as PCD (diamond) tools, which improve predictable and stable production methods and quality. Titanium stacked materials with composites raise the bar even higher and here, PCD is a key ingredient; it is demanding to use and application know how is required. Vein (sintered) PCD technology drills are a clear benefit here, where the drill point can be optimized to reduce drill thrust and cutting forces, another benefit within the aerospace segment.

What is being done to improve the efficiency of machining composites?
The usage of PCD or high-tech carbide products are a clear benefit, but hole quality and dimensional CPK values are linked to reducing production costs due to the elimination of secondary operations. This is an important combination of application know how and products, and this is where Sandvik Coromant comes in, offering a package of products and process knowledge.
 

As composites change, so must the cutting tools. Where do you see cutting tools headed from where they are today?
New geometries, grades, and coatings in development, and we see a stronger development in the years to come. However, it is also linked to knowing how to apply them in the best way in order to benefit the features of the product. As production volumes increase, the priority is to keep production costs down in demanding applications.


What difficulties do you see in the future of machining composites?
As applications increase into new areas within the aerospace segment, the need of the automated process increases. This will include holemaking in demanding materials (such as stacked materials, composites, and titanium). Automation of demanding materials is difficult with carbon fiber dust, metallic chips, hole tolerance, and hole quality are difficult to manage, especially without some kind of manual control.

What are some of the advantages and disadvantages of machining composites, and the difference in the quality of machining composites versus other material?
The abrasive nature of the material wears out the cutting tools, drills, and milling cutters fast. The combination of metallic stacks dramatically increases this, especially titanium. High demand is put on certain features, which are very different from the standard metal materials:

• Hole entry and exit quality: No delamination, splintering, and fraying of the carbon fibers;
• Surface finish: Smooth surface through holes going over the layers of fibers and resin; and
• Tough hole tolerance: As composites are fairly heat resistant, which results in abrasive tool wear, the holes are tricky to manage when demands on dimensions increase. The heat generated at the cutting edge can affect the hole quality, but with application knowledge and the correct geometry and grade of tool, this can be minimized.

Do you see other industries following aerospace and moving toward composites?
Composites are increasing in other areas, such as in the energy sector, including wind turbine blades and housing. Here, the material is key to build larger structures while reducing weight at the same time. Carbon fiber is stronger than, for example, fiberglass, which is currently used, and its strength results in thinner and longer structures reducing weight and efficiency.

Another area is automotive, where the needs to minimize the carbon footprint and reduce running costs are driving the need for weight reduction. Today, automotive is mostly focused on super-sports cars, but, within a number of years, we will see carbon fiber composites enter the automotive car sector in a larger scale and volumes will increase. Well-known automotive brands have already signed agreements with material manufacturers of carbon fiber to ensure this development.

Sandvik Coromant
Fair Lawn, NJ
coromant.sandvik.com/us