Stainless Steel 3D printing design rules
This documents describes the applicable design rules for the Stainless Steel 3D printing process on Shapeways.
- About the production process
- Maximum object size
- Minimum wall thickness
- Make large and irregular shapes hollow
- No moving parts
- Models must be self-supporting
- Watch out with very thin connections
- A combined example: bird in a cage
About the production process
Stainless Steel powder is deposited layer by layer. A printing head also deposits a binding material. This binder solidifies what will become your product. After your product has been built up it is gently lifted out and put into an oven. At this stage your product is still very delicate brittle and porous. The product is then infused with bronze. The bronze permeates your entire product and solidifies it. Next, your product is 'fired' in an oven. At very high temperatures, the metal particles fuse together into a solid object.
After firing, the object is cured. Later the outside of the product is sanded and polished mechanically by tumbling. We have a movie showing you the entire production process here
Maximum object size
The Stainless Steel has the largest build volume of any 3D printing process we offer. The maximum build volume is 100cm by 45cm by 25cm.
For the 2 Gold Plated Stainless Steel finishes, the maximum build volume is 31cm x 26cm x 20cm.
For the 2 Antique Bronze finishes, the maximum build volume is the same as for Stainless Steel.
Minimum wall thickness
The minimum wall thickness for Stainless Steel is 3mm.
Avoid abrupt changes in thickness
Like above, an abrupt change in thickness will cause quite a bit of stress and distortion during firing and cooling of your object. In the example below, the transition occurs where the 'flame' connects to the body.
If an area has a transition from thick to thin it would have to have a large radius to prevent cracking.
” by Lsutehall
No moving parts
In metal, loose parts are a problem. Objects such as chains, or a ball within a ball is problematic:
“A 3D mesh & 2D chain
”, by saint
If you do want to do any kind of moving or loose part a 10mm gap between both loose parts is necessary. Any loose part can not be longer than 80mm. Even keeping this into account the loose parts might fail.
Models must be self-supporting
This technique cannot print 'floating' object parts. For example, the following material would not work:
“Escheresque Face peeling
”, by BAROBA
Think of your product as being made of clay. It will need to self support itself throughout the production process. Initially the product is very fragile. If you picture a wine glass: if the stem is too thin it will collapse, if the bowl of the glass is too large or heavy, it will collapse. You will have to pay close attention to see if the product is self-supporting and if any cross section is not too thin.
Watch out with very thin connections
The droplet below necks down to a very thin cross-section. The droplet on the end is large then goes to a small cross-section. This might collapse. This product can be printed with sucess in Stainless Steel but it is close to the limit of what is possible.
“Water Crown Chopsticks stand
”, by wuct88
A combined example: bird in a cage
As an illustration, here's a product and the requirements that it needs to satisfy:
- The bird inside the cage cannot be loose and should be attached to the cage. (No moving parts requirement).
- The bird would have to be hollow. (Preventing distortion and cracking of irregular and large bodies).
- Also the wire cage cross-section needs to be 3mm.
“Happy bird micro
” by Michiel Cornelissen
Different sizes can lead to different results
small parts up to 50 by 50mm
95% of these parts print successfully. They can have very thin walls of below 1mm. But, the most important reason for failing is that the parts are not strong enough or do not self-support
Medium to large parts less than 200 by 200 by 100mm
These parts need wall thicknesses of 3mm. Why? The part is larger so the internal structures supporting the part need to be stronger.