Polyjet is a technology that brings the accuracy of microscopic level and finishing to your 3D Printing. Learn about its components, technology involved, material used, benefits, limitations, and future scope,
Polyjet 3D printing is in some regards, the 3D version of inkjet printing, in which material is deposited, solidified and then the process continues from layer-to-layer, leading up to the final end-product.
But this form of printing is different from the standard fused deposition modeling, because here, we’re printing a microscopic layer in one go, through multiple jets (hence the name).
Why Polyjet 3D Printing?
Polyjet 3D printing allows us to build with multiple materials at the same time, without pausing the build in any capacity whatsoever.
This one reason alone gives polyjet printing an upper hand over other more traditional 3D printing methods because –
- We could have end products, with all the desired mechanical, thermal and visual properties, without post-processing.
- We could integrate graphics and text at build-time itself, which saves up on time and cost.
All this is not considering the fact that polyjet printing is highly precise, i.e., very small details are taken into consideration, this leading to a very smooth end-product, which requires little to no post processing (adding to the time and cost efficiency factor).
The reasons to adopt Polyjet 3D printing seem to be enticing, but how is it achieved in actuality?
What components do we need in order to do Polyjet 3D printing?
Well, we’ll first discover the components which are needed in Polyjet 3D printing, and how they exist in the Polyjet printer.
- Material container
- As the compounds, i.e. photopolymers, which are needed for Polyjet printing have to be sensitive to UV light, specialized containers need to be used so as to prevent premature solidification.
- Inkjet printhead and UV curing light
- The printhead and the UV curing light exist on the same bench, which has the freedom to move along the x and y axis.
- Build platform
- Better known as “bed” in the 3D printing community, this is the platform in which the final build happens.
- Support material
- As the material extruded during printing is liquid in nature, gel-like support materials are required to provide support to overhang areas of the design, as well as to the complicated parts of the design.
- As the bench housing the UV light is free to move along the x and y axis, use of an elevator is necessary in order to make the designs actually 3D. Thus this elevator is placed below the build platform in order to provide a level of depth in the final product.
Technology Behind It
The actual building process relies on the photo-chemical reaction between the photo-polymers and the UV light flashed during the printing process.
Each layer extruded in this way is hundredths of a millimeter thick, which means that the precision which can be achieved is not feasible, if not flat out impossible, by more conventional methods of 3D printing such as FDM or MJF.
This is the reason why the end-product from this type of printing is generally more smooth and refined.
How Does Printing Happen?
The final design (STL or OBJ or any other 3D object filetype) is loaded into the slicing software, where it is decided which part is to be printed with what mechanical, physical and optical properties.
Then the design is sliced into microscopic layers, which is then transferred to the Polyjet printer.
In the printer, the bed is prepared along with the support material, and then, the bench housing the UV curing light and the inkjet printhead moves in a to and fro motion, extruding trace amounts of build material, and solidifying it.
This process is repeated until a substantial enough layer, usually a few millimeters thick, is formed, at which point, the elevator lowers the build platform in order to continue with the printing process.
All these movements happen according to the final design as processed by the slicing software.
Due to the fact that the materials involved in the building process have to be sensitive to UV light, the choice of materials is not as broad as it is in other conventional printing methods such as Fused Deposition Modeling (FDM).
The material choice as of writing this article includes –
- Elastico (which goes on to have properties of rubber)
- Vero family material
- ABS+ (a mechanically strong plastic material, as well as resistance to high temperature)
- Dental material
- And many more …
Benefits of Polyjet 3D printing
- Easy and fast prototyping
- As polyjet printing allows build with multiple materials simultaneously, this naturally leads to faster build times than if you were to use other 3D printing methods.
- Smooth finishing with reliable accuracy
- Polyjet printing allows you to have accuracy up to thousandths of an inch, thus leading to smoother finishes and much more reliable products.
- Can handle complexity
- Support materials allow the printing of complex designs, and these support materials are easily removable after the print.
- More consumer ready products than using FDM whilst wasting less material
- The fact that polyjet printing works with liquid compounds and extrudes microscopic layers means that there’s less wastage, all while delivering on the accuracy and quality.
Limitations of Polyjet 3D printing
- Expensive technology as compared to FDM or MJF (multi-jet fusion)
- Use of support structures
- Use of support structures in itself is not a deal breaker, but the marks left during the removal process of the same leads to a much more dull product in the areas where it touched the final design.
- Limited materials to print
- As compared to FDM or MJF, the choice of materials is very limited, but research and development is going on to bring more materials on-board.
Future of Polyjet 3D printing
As printing technology continues to evolve by the hour, use of polyjet printing shall become more and more common, because the end product from this form of printing surpasses its FDM or MJF counterparts.
Also considering the fact that polyjet printing is much more quiet due to the fact that the motor only moves the bench in 2 axis of motion, as supposed to all 3 which happens in FDM might also be a factor for in-house producers.
This does not mean that Polyjet will completely replace FDM, for some materials like metal might never come to polyjet printing, but polyjet will surely give FDM a run for the title of most reliable 3D printing technology.