Design Guide

graphic - Support for overhang

Support for overhangs

In the case of DLP Bottom-Up 3D printing, care must be taken in layer-by-layer printing to ensure that the following layer is ≤ to the 3D layer printed. This is not the case for edge areas in steep overhangs. The following rule applies:

A support structure is recommended for overhangs > 45°.
For overhangs > 60°, support is absolutely required.

graphic: avoid support

Avoid support

Support structures leave slight imprints after removal. This is why it is advantageous to dispense with supports through smart design.

Graphic: Avoid sudden cross-cuts

Avoid abrupt cross-section variation

Abrupt cross-sectional jumps have the consequence that the shrinkage significantly increases the likelihood of crack formation during subsequent thermal treatments. This problem can easily be circumvented by radiusing.

Bild_Maximale_Abmessungen_GB_Neu

Maximum Dimensions / Bounding Box

The available effective bounding box is: 81.9 x 51.4 x 156.8 mm for alumina and 75.3 x 47.2 x 146.5 mm for zirconium oxide. These values apply less the shrinkage during sintering.

Graphic: Precision

Precision

The precision of the process is mainly determined by the shrinkage in the sintering process. The shrinkage processes are controlled by us during production. The following tolerances apply: ± 1% of the length but a maximum of ± 0.1 mm. Higher levels of precision can be achieved by iterative approximation.

graphic: minimum clearance

Minimum clearance

If the distance of contours of a component is too small, there is a likelihood that this distance will be less than in the CAD model, or the gap may even be entirely filled by the material with the contours undesirably merging into one. The technical cause for this phenomenon is the overpolymerisation of the starting material.

Recommendation: keep a clearance of 0.5 mm

Graphic: Delay during sintering

Delay during sintering

Large, thin surfaces tend to warp due to lack of rigidity during sintering. For this reason the use of stiffening ribs is recommended in the construction of such thin surfaces.

Graphic: Free standig wall

Free standing wall

Thin, vertically freestanding walls are particularly risk-sensitive in additive manufacturing. The lack of rigidity during sintering as well as 3D printing play a role here. The influencing factors for rigidity are the height of the wall and the wall thickness. The following conditions are recommended for the design:
1. y = 3 mm, x restricted only by the installation space
2. y = 1 mm, x < 5 mm
3. y = 0.15 mm, x < 2 mm
4. y = 0.15 mm for mutually supporting walls
          (e.g. cross profile), x restricted only by the installation space

Bild_Maximale_Wandstaerke_Neu

Maximum wall thickness

Due to the necessary debinding during which a thermal decomposition and degassing of the polymer occurs, the wall thickness must be < X* mm - depending on the material. Stronger wall thicknesses significantly increase the cracking probability of thermal treatment. Wall thickness can also be achieved through design adjustments (intrusions, penetrations, depressions).

*FormAlox 999 = 4 mm, FormAlox 998 = 5 mm, FormAcon 3Y = 3 mm

Graphic: Free overhangs

Free overhangs

For overhangs of 60° - 90° part of the currently created layer will not be supported. The process is designed that a length of < 1 mm can be tolerated. Free overhangs > 1 mm could be produced, but would lead to deformation.

Graphic: Penetrations

Penetrations

It is recommended that penetrations are > 0.4 mm. Smaller penetrations can be produced, but there is a likelihood that material residues will adhere to the inner surfaces during the cleaning process.

Consequence: The penetration is undesirably smaller than required.

Bild_Kanaele_Neu

Channels

As for penetrations the cleaning process after 3D printing is the limiting factor for penetrations as for channels.

Conclusion: The channels should be > 1 mm.

Graphic: Hollow component

Hollow component

No enclosed cavities are allowed in the component. An opening is necessary so that the superfluous material can be removed during cleaning.

Graphic: Included parts

Included parts

In principle included parts are 3D printable, but should be avoided if possible. During thermal treatment, the parts undergo a phase in which the polymer parts have already been removed but the sintering has not yet begun. Here, the components must not be exposed to any mechanical stress, which can hardly be guaranteed with included parts.

Graphic: Threads

Threads

Metric threads ≥ M2 are not a problem for additive manufacturing, even if both parts - screw and nut - are made of ceramic.

Graphic: Geometrical texture

Geometrical texture

A flat output surface is required for adhesion to the construction platform. If this is not the case, a support structure is required.

Graphic: Pixel resolution

Pixel resolution

The effective pixel resolution, taking shrinkage into account, is 32 micrometers.

Download

 

Steinbach AG – your professional partner for technical ceramics in 3D-printing

With us you have a professional contact partner serving you from the consulting up to the delivery of your 3D-ceramic components. Call us, we are looking forward to the new technical challenge.

Any queries regarding this product? Then contact us using this form or call:

+49 5231 9607-73

We will be happy to advise.

Contactform