Contributing Author: Johanna Brito, Marketing Communications Manager
Advances in digital technology have enabled additive manufacturing to revolutionize industrial production by incorporating fast, precise methods to create fully unique three-dimensional objects. Also known as 3D printing, additive manufacturing is the process of joining materials to make objects from a 3D model by adding layer by layer from the bottom up. Laser Additive Manufacturing (LAM) enables new approaches in product design because it uses laser beam technology to melt and solidify material in a powder bed, allowing new freedom in design. Let’s explore how this technology is revolutionizing industrial production.
There are three types of laser additive manufacturing processes. Stereolithography (SLA), Selective Laser Sintering (SLS) and Selective Laser Melting (SLM). SLA uses UV laser sources to solidify photo-reactive resins layer by layer with fine details. SLS uses CO2 lasers to sinter polymers such as polyamides that are in the form of powder. In the case of SLM, layers of fine metal powder are melted together to form the final structure by fiber lasers. In all three LAM processes, the laser beam is steered by a laser beam scanner at high speed to the target locations on the build plane defined by the 3D model. The scan controller and software convert the 3D model job into a series of motion and laser control commands to synchronize laser beam scanner motion and laser firing.
Reducing the cost of part built and improving the part quality have been two key challenges for expanding LAM applications, particularly for SLM. Laser beam steering is critical, and scanner and controller selection impacts those system-level performances directly. For example, how accurately the scanner steers the laser beam to the target location of the build plane determines the part geometric precision. A high-quality part also requires that the uniform laser density is delivered at the materials to ensure homogenous material properties. This requires precise coordination of the laser firing/modulation and scanner motion. The scanning speed when the laser is on and jumping speed while the laser is off also determines the overall process throughput, thus the cost per part built.
Industries and Markets
Stereolithography has been used to produce medical models for implants and prototyping parts since the 1990s. The medical models have been used to aid the manufacture of personalized implants. With the capability to build larger 3D parts and quick turnaround, prototyping parts made by SLS process are increasingly used in the design cycle for automotive, aerospace, military and electronics hardware. Those polymer-based 3D parts are sometime also used as final products. In recent years, Selective Laser Melting has shown the most rapid growth as it builds functional parts that go into implants, dental, automobile and aerospace. SLM technology has demonstrated the capabilities to build complex geometries and light-weight structures that are difficult to achieve with conventional subtractive manufacturing methods. It is also flexible and cost-effective when building custom parts such as individual dental parts.
There are many galvanometer-based laser beam scanner products on the market today. Each configuration has benefits and limitations depending on the LAM system level requirements and the priority of those requirements. The typical factors under considerations when choosing a scanner include:
- Laser wavelength and optical power
- Feature size or beam size
- Build rate or scanning speed
- Position accuracy
- Build size or envelop
- Ease of integration
SLA, SLS and SLM use different types of laser and laser power and require different beam size on the build plane. The scanning mirrors and coatings need to be tailored to accommodate the difference. And the physical size of the finished part, build rate and minimal feature size often dictates the complexity of the laser scanning system and its integration.
Cambridge Technology’s Solutions for LAM
Cambridge Technology offers a wide range of scanning products that system integrators can choose from based on the trade-offs of various requirements. For example, a desktop system may be best served by an 83xxK series XY galvo set mounted on a small block and driven by a low-noise analog server for a very compact scanning footprint. Also available is an easy-to-use DC series digital server. Conversely, a machine producing large, high-quality metal parts may require multiple 3-axis full-digital scan heads for high accuracy and stability. In addition to the various options of XY scanning sets and scan heads, adding intelligent scanning control offered by our ScanMaster Controller (SMC) orchestrates laser lasing with scanning motion, further improving accuracy, processing flexibility, and throughput.
There are many reasons LAM is revolutionizing industrial production to those adopting this new technology, and many are seeing its benefit in every day production. LAM enables new industrial design not possible through conventional methods, making it easier to create and replace a system. And lastly, the laser beam scanning technology play a fundamental role in the success of production of functional parts by laser additive manufacturing. To learn more about our LAM solutions, click here.