What is PolyJet 3D Printing? How it works?
PolyJet is a 3D printing technology that allows us to produce smooth and detailed objects with high accuracy. It is also called Material Jetting and was developed back in 1998 by Israeli 3D printer manufacturer Objet Geometries. PolyJet is considered to be one of the most accurate 3D printing technology with accuracy of up to 0.016 mm which allows it to create highly detailed as well as complex geometrical objects with accuracy and also provide smooth finishes.
PolyJet can print multi-coloured 3D parts along with using different materials in different areas of the object, thanks to how PolyJet printing works. It is also compatible with Pantone colour ranges which makes enables it to print almost infinite range of colours. Along with being one of the most accurate printing technologies, PolyJet is also one of the fastest printing technologies out there as it can print multiple objects at once in a line.
PolyJet works similar to the commonly used 2D Inkjet printers. Just as drops of ink are jetted on paper in Inkjet printing, PolyJet uses tiny nozzles to deposit liquid photopolymers onto a tray. In PolyJet, these layers are continuously printed on top of each other to create a solid 3D object of desired shape. PolyJet prints in a line which makes it capable of printing multiple objects at once.
Simultaneously, the material is also being cured by UV light. The polymers are heated to 30-60 degrees C. This process requires support to protect the parts from warping or losing their shape, which are concurrently printed with the part. Supports can be made from different materials which can dissolve in water without leaving any significant trace.
Supports are printed in PolyJet to prevent the parts for distortion and maintain accuracy. However, the support removal process is fairly simple as the materials used for support are easily soluble and leave little to no trace once removed.
As we already know, the polymers in PolyJet don’t require very high temperatures to cure which prevents it from warping and causing distortions and lead to excellent reproduction. This contributes to the high accuracy and smooth surface finishing of PolyJet. However, as the size of the parts get larger, they tend to start losing their structural accuracy and the resins start to shrink, which results in one of the major limitations of the PolyJet technique.
When compared to Stereolithography (SLA), PolyJet shares some similarities with SLA as they both use photopolymers. However, since SLA uses vat polymerization which requires more heat than PolyJet, which requires 30-60-degree C.
When compared to Fused Deposition Modelling (FDM), PolyJet is expensive and more focused on industrial use. One of the key differences between these two technologies is that PolyJet printed parts are relatively weaker than parts printed using FDM 3D printer.
PolyJet also has multiple print heads which means multiple materials can be used to print simultaneously. This has proven to be highly useful and its success in full colour printing have influence the development of Multi Jet Fusion 3D printing.
As mentioned above, PolyJet is also one of the fastest 3D printing technology currently available which makes it a much better choice as compared to other 3D printing technologies such as Selective Laser Sintering, which uses a fixed-point printing method. Although, if printing of larger part is required, PolyJet starts to show its weakness and other printing methods such as Binder Jetting can be used.
Along with being one of the most accurate and fastest printing technology, PolyJet also allows large variety of materials to be used. These materials can range in colour, chemical properties, strength etc. which makes it a very versatile technology with respect to the materials that can be used. To be considered an option for PolyJet printing, the materials are required to have low viscosity and be able to be jetted in droplet form. However, these materials don’t come cheap and can cost anywhere in between $300 and $1000 per kg.
We have gone through different aspects of PolyJet printing technology and can summarize its advantages and disadvantages.