Opening the technology hood
The 3DM Laser
The laser developed and patented by 3DM is designed to optimally match the energy absorption of thermoplastics. The idea came from the realization that the industry uses the wrong light source in SLS printing technology with plastic materials. To compensate, SLS solutions either change the materials by adding absorption improving additives or they use lasers with lower efficiency and adverse heating effects. These methods require extensive material development effort, which negatively affects material costs, creating a major obstacle for high-volume AM, and, in the end, yield a very limited range of materials supported by AM applications.
The 3DM laser is a semiconductor component with a very small footprint. It is a low-cost (around $10), high-power light source (up to 4W equivalent of a 20W CO2 laser). The laser can be designed to emit at any wavelength in the mid IR spectrum, thus optimally matching absorption properties of a large variety of material families.
Optimal material absorption offers an additional important advantage; Our ability to very accurately sinter the material in the Z axis and determine the melting and heating depth in the Z direction. This prevents printing distortions between printed layers and improves print quality compared to other commonly used SLS technologies.
The solution – Superior optical head
3DM's optical head design is based on an array of laser beams operating in parallel, where each beam is scanned independently to expose its own dedicated sub area of the print bed. The sub area size is pre-configured depending on the desired target speed of the printer. The printing table size can be designed to be in any rectangular shape needed. For example, a print bed size of 400x400mm with beam sub area of 100x100mm requires a configuration of 16 laser beams in the printer optical head.
The optical head includes a measurement subsystem dedicated to the alignment of the sub areas. Alignment is performed per layer in real-time based on measurements taken by the subsystem to fix X/Y scale changes, movement and rotation.
The design of the beam optical head maximizes the benefits of 3DM's internally developed QCL laser light source. The goal is to deliver superior laser beam performance with high power, high resolution, for an unprecedented range of materials, at significantly lower cost. The beam optical head may include from 1 to 6 QCL lasers depending on the required printer performance. Since lasers of the same wavelength are not easily combined, each pair of lasers are designed to transmit at a different wavelength that fits the energy absorption peak of a unique material family. Combining up to three pairs of QCL lasers can either triple the power for a single material family or expand the capability of the printer to support additional material families.
Advantages of the beam optical head:
High-power beam – Up to 24W capable of delivering very fast printing speed down to around 1 second for a sub area of 100X100 mm.
High resolution – Down to 10s of microns. 3DM prototype machines designed with 100 micron resolution (highest practical resolution considering the plastic particle size) demonstrate the fine detail printing capabilities and smooth surface finish that can be achieved with the 3DM laser.
Support for Virtually Any Material – Since 3DM designs the laser to support the material family's energy absorption peak, a new range of opportunities is now open for AM printers by supporting materials not seen in industrial AM.
No Material Alteration Required – No absorption additives are needed for already available materials. This minimizes the cost of materials, which is still a major factor in the cost of printed parts.
Polyamide material family
Most common material in 3D printing
printed sample pictures: PA12, PA11
Elastic material family
Used in elastic applications (i.e. sport goods)
printed sample pictures: Thermoplastic Polyurethane (TPU)