Advanced FDM 3D-Printing Post-Processing Methods for Makers

2022-05-04 | By Maker.io Staff

A recent article investigated a few basic methods makers can use to rework 3D-printed components. That article introduced simple physical and chemical processes that can help improve a model’s dimensional accuracy and its appearance. This article investigates a few more advanced techniques for more experienced makers. While the basic approaches involve using simple woodworking tools, some more advanced methods require more specialized equipment or materials.

Creating 3D-Printed Components with Perfectly Smooth Surfaces

The last article introduced sanding and filling as two simple methods makers can employ to smooth the surface of simple 3D-printed components. However, both techniques only work on large, flat surfaces. You cannot easily rework the surface of parts with intricate details, such as small decorative figurines. Therefore, makers can employ one of the oldest techniques in 3D printing: acetone vapor smoothing.

The process works because acetone can melt certain 3D-printing materials, such as ABS. However, the process typically won’t work on other materials, for example, PETG or PLA. In its simplest form, you place the 3D-printed part in a sealable container, for example, an old glass jar. Then, you fill some acetone into the container. Make sure not to pour acetone directly on the component. The 3D-printed part should not come in direct contact with the liquid acetone. Next, place the lid on the jar. However, don’t seal the container to let the vapor escape. After a while, you’ll see how the acetone vapors start dissolving the outer layers of your 3D-printed component and smoothing the entire surface of the print.

Advanced FDM 3D-Printing Post-Processing Methods for Makers Several smoothing methods for 3D-printed components yield impressive results, and they can often completely erase the typical lines left behind by the FDM manufacturing process. Image source: Screenshot of Polymaker promo material. https://www.youtube.com/watch?v=_xn8aPIKtq8

Note that this method involves handling dangerous chemicals harmful to you and the environment. Make sure to use this method in a well-ventilated area. Keep the container away from open flames and electrical installations. Acetone vapors are highly flammable, and a single spark could cause an explosion or combustion. Always wear appropriate PPE when handling chemicals and dispose of the solution according to local regulations. Don't use the glass jar to store food or drinks afterward.

A More Convenient Method for Producing Smooth 3D-Prints

If the acetone method seems too involved, you can use a similar process that uses a different printing material and less dangerous chemicals. Polymaker PolySmooth is a 3D-printing material that lets you create 3D-printed parts with perfectly smooth surfaces. However, you have to use a dedicated machine, called the Polysher, for reworking the printed components.

Advanced FDM 3D-Printing Post-Processing Methods for Makers This image shows the Polymaker Polysher in action. You can see how the machine automatically creates and contains a very fine mist that creates a smooth finish on 3D-printed components. Image source: Screenshot of Polymaker promo material. https://www.youtube.com/watch?v=_xn8aPIKtq8

This machine offers makers a fully automatic way of polishing 3D-printed components by removing the visible lines that characterize FDM prints. The device contains a nebulizer that creates a fine mist of isopropyl alcohol (IPA). The chemical reacts with Polysmooth plastic and creates a perfectly smooth surface on 3D-printed parts.

In only a few minutes, the machine transforms rough-looking 3D-printed parts into components that look like they were produced using injection molding. The process is automatic, and you won’t have to calculate the right amount of alcohol to use.

Assembling Multi-Part Prints

I typically make sure that my multi-part designs only contain pieces that easily snap together. However, some situations force makers to create designs that can’t contain any snap-fit joints. In those cases, you can use two methods to combine multiple parts of a design into a single large piece.

The first method is straightforward, and it involves gluing two or more components using conventional super glue or any other adhesive that works for you. Here, you have to make sure that the two mating surfaces offer enough area for the glue to create a strong enough bond. Also, make sure to use glue that doesn’t contain solvents that might compromise the integrity of the plastic you use.

As mentioned above, acetone can melt certain plastics such as ABS. A more advanced alternative to using simple glue is to use acetone to weld two or more pieces of ABS. Welding creates a stronger bond than gluing, as it chemically melts and re-combines two plastic pieces into a single one. However, choosing the right amount of acetone is difficult. Too much could damage or warp the parts, and too little will not create a strong-enough bond. In addition, there are a few problems that go hand in hand with using acetone, as discussed above.

Summary

The more advanced methods discussed in this article mainly used chemicals that can dissolve plastic parts. By using just, the right amount of a chemical, you can dissolve the outer shell of a 3D-printed component to make the visible layer lines disappear. However, working with these chemicals can be dangerous when not done correctly. It’s advisable to work in a well-ventilated area and wear appropriate PPE. Also, make sure to keep acetone and IPA away from open flames and sparks, as they are highly flammable.

Besides creating a smooth surface, makers can employ acetone to weld two pieces of ABS together. The formed bond will be strong and rigid. However, using too much acetone might result in damaged or warped parts.