What level of detail can be expected from a consumer-grade SLS printer?

Question

I'd like to prefix this question with the fact that I know virtually nothing about 3D printers, aside from the general principles of how they work.

I've recently seen that SLS printers have become more affordable, to the point where in a few years they might be a compelling investment. I'm mainly interested in 3D printing miniatures for painting, and as such this one:

For scale, the miniature is about 150 mm long. I'm mainly worried about smaller details, such as the faces of the Gunner or Driver. Will a consumer-grade SLS printer be able to print to such level of detail?

Answer 1

Consumer Market?

While there are no "consumer level" SLS printers on the market currently, the question in itself is very interesting on a scientific level. The pricing edges for the consumer market for 3D printers can be somewhat estimated from the consumer electronics segment. This puts a maximum price tag of about 2000-2500 \$ onto it, comparable to a high-end PC.

Currently^{Feb. 2020}, most SLS machines come with 'inquire for price' or with prices of 5000 \$ or larger price tags, which indicates they are intended for professional or industrial use. Most SLS printers in consumer hands seem to be phased out older systems from second hand. So while there are for sure tries to get SLS more affordable, it is not there yet.

Resolution of SLS

SLS printers have resolutions based on two factors¹:

• grain size
• laser diameter

Generally speaking, the finer the grain and more focussed the laser, the better the resolution. Current industrial machines - even cheap ones - work with particle sizes between 20 and 80 µm, with the bulk being around 40 to 60 µm².

The laser focus point ranges generally in the "tens of µm"¹, and is listed with values between 50 and 300 µm for most ceramic powders in that paper.

Conclusion

As a rule of thumb, 50 µm seems to be the average nylon spot size, which is very much comparable with resin printers using SLA/mSLA/DLP technology. Details on miniatures are usually in the area of 100-200 µm, so are well achieveable with either.

Comparison SLS to SLA/mSLA/DLP

Resin technology has the benefit of being easier accessible with some entry level printes between 200 and 500 \$. Nylon SLS prints do demand a sealant but prints without any supports, Resin does at times need support.

Printing times for DLP/mSLA is not dependant on the ammount of space used, making packing the build surface with as many models as possible benefitial, while SLS, like FDM, works with a moving spot, so the ammount of models increases print time.

Both Technologies work with hazardous material - resin and very fine powders respecively - and demand proper PPE to handle them.

Answer 2

It's difficult to tell from your photo the level of detail required. A scale reference in the form of a metric ruler would be valuable. If, for example, the metallic eye on the gunner is 2 mm diameter, that would be 40 layers of 50 micron grains, allowing for substantial detail.

Consumer level SLS printers, such as the Sinterit Kit, use fifty micron nylon powder and is subject to some shrinking. This implies one can expect slightly smaller than fifty micron detail to appear.

One of our makerspace members purchased an SLS model from Shapeways. The surface is layer-free and one can see the individual granules under magnification. If you required a level of certainty of this detail, consider that you can create a model containing various levels of detail, then commission Shapeways to create it.

It's certain that they use a production level system, but one can inquire of Shapeways of the size of the powder that is used.