As it goes mainstream, additive manufacturing opens new opportunities for the composites industry.
In one sense, there’s nothing new about additive manufacturing of composites, since hand lay-up and automated lay-down are both additive processes. But the type of additive manufacturing that’s grabbing industry headlines today – often referred to as 3-D printing – is very different from conventional manufacturing methods.
Using a design stored in a CAD file, additive manufacturing equipment adds successive layers of a material (liquid, powder, sheet materials) to fabricate a 3-D object. There are many different ways to do this, from selective laser sintering (powder bed fusion) to sheet lamination (laminated object manufacturing) to material extrusion (fused deposition modeling) and binder jetting (the original 3-D printing). Today, the term 3-D printing has become almost interchangeable with additive manufacturing and encompasses all of these methods and more.
While additive manufacturing has been around for more than 30 years, it’s only recently that the industry has taken a closer look at composite materials.
“There’s lots of excitement about composites today,” says Lawrence Gasman, founder and president of SmarTech Markets Publishing, which follows the industry. “The dynamic within the industry is to move to ever more complex materials as a way for the materials companies – and through them the equipment companies – to get a competitive advantage.” Two years ago, the hot topic at additive manufacturing conferences was metals; this year it’s composites.
Gasman says one reason for the increased interest is that major industrial labs capable of working with composite materials are beginning to do more work with additive manufacturing. In addition, while companies currently use the technology primarily for prototyping, the focus is shifting to small volume production of complex parts. Composites are a good fit for such applications.
“When you bring 3-D printing and composites together, you get something more than the sum of the parts,” says Gasman. “Potentially you could make grids within grids; you can make structurally-sound structures that you can’t make any other way.”
Manufacturers utilize composites because of the great mechanical performance they get in strength-to-weight ratios, stiffness-to-weight ratios, etc. Combine that with additive manufacturing, and they can eliminate some of the problems inherent in today’s manufacturing methods, says Timothy Schniepp, business development director for composite tooling at Stratasys.
“Most conventional methods to produce composites are extremely labor intensive; not only does it take significant amounts of time and money to produce such structures, there’s also variability any time there’s direct touch labor involved in building high performance parts,” says Schniepp. When a composite structure is built for an aircraft, for example, a good percentage of its costs involves inspections and quality tests. “As we move towards additive manufacturing, not only do we get rid of all that touch labor and time involved, but we should, in theory, cut out a lot of that variability.”