3D Printing 100 Times Faster With Light
3D Printing 100 Times Faster With Light: What Are The Implications?
A new 3D-printing technique could render a three-dimensional object in minutes instead of hours—at up to 100 times current speeds.
The experimental approach uses a vat of resin and some clever tricks with UV and blue LED lights (no lasers needed) to accelerate the printing process.
The technique looks almost like a time-reverse film loop of an object dissolving in a reservoir of acid. But instead of acid, this reservoir contains a specially-designed resin that hardens when exposed to a particular shade of blue light. Crucially, that hardening (the technical term is polymerization) does not take place in the presence of a certain wavelength of UV light.
The resin is also particularly absorbent at the wavelengths of both the blue and UV light. So the intensity of UV or blue light going in translates directly to the depth to which light will penetrate into the resin bath.
The brighter the light beam, the further it penetrates and the further its effects (whether inhibiting polymerization in the case of UV light, or causing it in the case of blue light) will be felt in the bath along that particular light path.
Light is an universal and omnipresent phenomena, yet its use in 3D printing remains limited to post-processing of printed objects. This changes with the recent findings in the research of light as a new additive manufacturing medium.
In this article, we explore the emerging role of light for 3D printing, how it can accelerate the process, what are the challenges and implication for designers and manufacturers. Readers familiar with additive manufacturing will be aware that most efforts so far have focused on using UV or other light sources as a post-processing step after 3D printing objects.
The reasons for this are manifold: UV curing is cheap and widely available; it doesn’t require any additional software or hardware support; and it works fast on even simple home printers.
Can light-based additive manufacturing be democratised?
Light-based additive manufacturing has been around for a couple of decades, with a few industrial systems commercially available. Yet, it hasn’t gained as much attention as UV-based systems, as it is more complicated and less accessible.
The availability of cheap and easy to use UV-based 3D printers has created a new market for digital manufacturing, and democratised it to the point that even high schools are teaching kids how to use these machines. However, UV-based printers still require a dedicated room, and special operations in clean rooms.
If a system doesn’t have a dedicated room, the risk of exposure to harmful UV rays is significant. With light-based systems, no such concerns exist. The machines can be placed next to the operator, and don’t pose any health risk.
The Benefits of Light-Based 3D Printing
- Speed: One of the main advantages of light-based additive manufacturing is speed. While UV systems still add the parts in a relatively fast manner, light-based systems can increase the speed of parts production 100 times.
- No Environment Limitations: A UV-based system operates within a controlled environment: Users must work in a lab with a controlled temperature and humidity. A light-based system, on the other hand, doesn’t need any specific environment: It can be used in a warehouse, a factory, or a home workshop.
- No UV Restrictions: UV systems are strictly regulated because of the risk of skin damage, and the risk of damage to the surrounding environment. Light-based systems don’t pose any health risk, or environmental damage.
UV Light Acceleration
Not all light-based systems are created equal. Some use UV light as an additive material, while others use blue light. UV light-based additive manufacturing has been around for decades. The technology is simple, and its use has been democratised with the introduction of low-cost 3D printers.
It is widely used in the aerospace sector, and in other industries, such as architecture and construction. With UV light, the polymerization of photo-initiators is accelerated by the UV light. This light is in the UV spectrum, and is harmful to the human eye. Moreover, UV light is harmful to many other materials, such as the printing materials and the machine components. This is why UV light-based 3D printers are usually located in a separate room.
UV light is absorbed by materials, including the printed parts. In fact, the printed parts are generally more sensitive to UV light than the photo-initiator. This is why UV light-based additive manufacturing can only be carried out in a controlled environment.
Limitations of the Technology and The Road Ahead
- UV Light: One of the main limitations of the UV light-based additive manufacturing system is that it is restricted to the UV spectrum. This is great for polymerizing the photo-initiator, but useless for adding a new material.
- No Line Speed: UV light-based additive manufacturing is a batch process. This means that one batch can be produced at a time, and the process must be stopped between batches. The speed of a UV light-based process can be increased by increasing the power of the UV lamps, but this comes at the cost of damaging the printed parts.
- No New Materials: While UV light can be used to polymerize new materials, this is only possible if the materials already have a photo-initiator attached to them. UV light-based additive manufacturing is unable to polymerize materials without a photo-initiator attached.
This is why UV light-based additive manufacturing can only be used to print with pre-existing materials.
Other potential benefits of Light Based 3D printing
- Environment: Although UV systems can be placed in a separate room, the risk of exposure to harmful UV rays remains. UV light is absorbed by materials, and the risk of damage to materials is thus significant. Blue light, on the other hand, is only absorbed by certain materials, and poses less risk of damaging surrounding materials.
- Materials: UV light can be used to polymerize a limited number of materials. Blue light, on the other hand, can be used to polymerize virtually any material. This means that blue light-based additive manufacturing can be used to print with materials that UV light cannot be used with.
- Materials Transparency: UV light-based additive manufacturing systems can only be used to print opaque materials. Blue light-based systems, on the other hand, can be used to print semi-transparent materials.
This is an important advantage for designers, and opens up new design possibilities.
Conclusion
The road to democratisation of blue light-based additive manufacturing remains long. The technology is more complicated than UV systems, and will require more investment.
The cost of producing a blue light-based system is also higher, with larger system components. The increased cost and complexity are compensated for with the increased range of materials, and the lower risk of damaging surrounding materials.
This means that blue light-based additive manufacturing has the potential to be a game-changer for digital manufacturing.
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