4 Vital things on Post-Processing 3D Printed Parts
Author: Aaron Chen Date Posted:10 January 2019
There can be some circumstances when a 3D part can be used directly after it is being printed. On the other hand, there are also some instances where support material is needed. This is used to handle overhangs in the design.
After 3D printing, these support structures must be carefully removed. Apart from that, the finish of the 3D part should also be considered. With this, post-processing 3d printed part is usually required.
The post-processing steps that to be used for the 3d printing project may depend on the material and the 3D printing technology being used. Furthermore, post-processing can be time-consuming comparing with the actual printing process.
In order to have a better understanding on this process, here is a guide to post-processing 3D printed parts. Read more below.
What is post-processing?
Post-processing stage starts after a 3D part is removed from the 3d printer. After this phase, the 3D part is processed so that it will look even better. It also aims to add some finishing touches on the 3D part.
Post-processing includes some steps that are important to make it suitable for use. These steps may vary from one technology to another.
It will generally include basic forms like support structure removal and cleaning. This will be the primary phase of post-processing.
For the second stage, it will include steps such as sanding, filling, painting, etc. to improve the aesthetics of a 3D part.
Post-processing options for different 3D printing technologies
Below are the common post-processing options for three common 3D printing technologies.
- Basic support removal
In this process, the support structure is either cut or broken off and leaves the model with a rough surface. As a result, the overall geometry of the object is not altered. It also gives customer full control over its finish. However, for accurate results, high level of skill is required.
- Wet sanded
Wet sanding is ideal for 3D parts with complex geometries. In this process, high-grade sandpaper is used to get a smooth surface finish.
- Mineral oil finish
This has a similar finish comparing to wet sanded. The only difference is the mineral oil layer that is added after the sanding process. This finish is appropriate for mechanical parts. However, paint will not adhere well to its surface.
For FDM, below are some of the common post-processing options.
- Support removal
Support removal is a basic post-processing stage for any 3D printing technologies. It is separated into 2 categories; standard and dissolvable.
For this method, you only have to remove the support from the print with little effort. Moreover, support removal will not alter the entire geometry of the 3D part.
Sanding is done after supports are removed or dissolved. Basically, a 3D part is smoothened using sandpaper with different grits to remove any obvious imperfections.
Sanding requires minimal equipment unlike any other methods. Likewise, costs are reduced since you only need sandpaper.
Nevertheless, this method will require a lot of time and effort especially for 3D parts with tiny details. Since it is a manual process, surface may be uneven which affects its dimensional accuracy.
- Gap filling
After the sanding process, there may be some gaps that are visible on the print. These gaps were formed from incompletely printed layers due to toolpath constraints. With this, gap filling process is used.
This technique can be done by filling the gaps and voids with epoxy. For larger gaps, an autobody filler is used which will require additional sanding.
Since SLS printing uses powder based fusion process, its parts often have a powdery and grainy finish. Hence, post-processing is needed. Here are some of the post-processing options used for SLS 3d printing.
- Standard finish
This option is often used for its good accuracy since the overall geometry of the 3D part is not altered. After the object is removed from the built chamber, all unsintered powder must be removed from the 3D part via plastic bead blasting. As a result, you will get a matte and grainy finish.
Dyeing is known to be a cost-effective method to add colour to SLS prints. With this technique, a 3D part is submerged in a hot colour bath. In this way, all the internal and external surfaces of the model are fully covered with colour.
- Metal coating
For metal coating, materials such as copper, stainless steel, nickel, gold, etc. are deposited onto the 3D parts. This is done in order to increase its electrical conductivity and strength.
Issues regarding post-processing
There are some issues that may arise when it comes to post-processing. Here are some of them.
- Increase labour cost
Post-processing can be completed by manual work. Thus, more labours are needed. Although need machines or equipment are needed, they may still require a skilled and experienced staff to operate it well.
- Can be time-consuming
The main advantage of 3D printing is its speed to produces parts. However, post-processing can be time-consuming. This is because the 3D part may undergo different stages to complete the post-processing process.
- There can be inconsistency
The quality and final print can be inconsistency for 3D parts that undergo post-processing. The fact that post-processing is a manual job, discrepancy between design and outcome can happen if the worker handling post-processing is not skilled enough.
Tips on Post processing 3D parts
- Removing your 3D print from the build plate
Once the printing is finished, it is important to remove the 3D part from the build plate with care. One uncareful move can distort or destroy the printed part. For PLA printers, using a spatula to remove 3D parts can help.
- Cleaning off supports
It is recommended to remove all supports from the 3D part before it is cured. Removing supports after the curing process may shatter the 3D part and leave some small divots or holes on the object.
- Cleaning the 3D part
When printing, there may be some excess resin left on the 3D printed part. If you let it harden, it will alter the real shape of the model.
In some cases, some resin may also drip off your work surface. It will become sticky for a long time which allows it to attract dust and small debris.
To prevent this, you can cover the work surface with plastic sheets or paper towels which collects any drips or spills. Then fill paper towel halfway with isopropyl alcohol.
Post-processing is an vital stage in 3D printing. It is not just about making your 3D parts look better and aesthetic but also to make it durable and smooth as well as increase mechanical properties etc. It may cost you a little extra time, money and effort, but it will be worthwhile overall.