PA 12 (SLS)

Hollowing

If possible, try to hollow out your part. This avoids deformation and discoloration during the printing process. You can either hollow out your part without a surface hole, which means that unsintered powder will remain trapped inside, or you can design a strategically placed hole (two would be even better) so that the unsintered powder can be easily removed after printing. If the part needs to be reclosed, design a lid with a diameter allowing for 0.5 mm play between the part and the lid.

If your part has walls thicker than 9 mm, our production team may hollow out the part to prevent deformation and discoloration. For parts with wall thickness higher than 20 mm wall thickness, this is done by default. In that case, the powder will stay trapped inside.

Warpage and deformities

We strongly recommend that you do not design large, flat plains in dimensions like an A4 page. In most cases, your model will deform. This process is called “warping”. Creating support ribs under your plane does not solve the problem, but rather increases the chance of deformation even more. The key here is to avoid large flat planes.

Interlocking or moving parts

It is possible to print interlocking and moving parts or single-build assemblies in PA 12 (SLS). Parts that are printed together should have a minimum clearance of 0.5 – 0.6 mm. If you want to print a chain, spacing between your surfaces is crucial. The more space you can afford the better. The more complex your part is, the more difficult it becomes for us to evacuate unsintered powder from the interior when the part is taken out of the 3D printer. Please get in touch with our team before ordering parts of this kind to ensure printability and avoid disappointments.

Assembly

When designing parts that need to be assembled, it’s important to maintain enough distance between the parts. A perfect fit in your CAD software does not necessarily ensure a perfect fit after printing because your software ignores the friction present in the real world. Therefore, always leave at least 0.6 mm between the different parts. For parts with large surfaces and wall thicknesses, you will need to maintain even more distance between the parts. In cases like these, please get in touch with our team to check printability.

In order to help us print your parts with the best possible dimensions for assembly, please design your files with an orientation equal to the relative orientation of your parts in the final assembly.

Embossed and engraved details

For engraved text or surface details, we recommend letters with a minimum line thickness of 1 mm, a depth of 1.5 mm, and an overall height of at least 4.5 mm. Embossed text or surface details should be thick enough that they will not break during production or transport. We recommend letters that have a line thickness of at least 0.8 mm, an overall height of at least 3 mm, and a depth of at least 0.8 mm.

Interior polishing

The small size of the polishing stones means that they can easily get stuck inside small holes. Therefore, we recommend that any openings which need polishing should be larger than 6.5 mm in diameter. This helps prevent stones from getting stuck inside your model. 

Also, note that the inside of your model will always be less polished than the outside. In fact, your part will not be polished at all on the inside if the holes are smaller than 6.5 mm because the stones will not be able to enter.

Rounded edges

If your part contains sharp edges, these will be rounded off. Rounded corners and smooth transitions between surfaces will have a higher degree of polishing than sharp edges.

Watertightness

Please be aware that the sealing agent improves how watertight your design is but does not guarantee a fully watertight product as this depends on several factors, including the complexity of your design, the temperature of your surroundings, the pressure used, the liquid used etc. We recommend this finish for decorative use and advise testing your application first before fully using it.