prEN ISO/ASTM 52957

SLOVENSKI STANDARD
01-maj-2025
Dodajalna izdelava keramičnih izdelkov - Konstruiranje - Smernice za
konstruiranje (ISO/ASTM DIS 52957:2025)
Additive manufacturing of ceramics - Design - Design guidelines (ISO/ASTM DIS
52957:2025)
Additive Fertigung von Keramiken - Konstruktion - Konstruktionsleitlinien (ISO/ASTM DIS
52957:2025)
Fabrication additive de céramiques - Conception - Lignes directrices relatives à la
conception (ISO/ASTM DIS 52957:2025)
Ta slovenski standard je istoveten z: prEN ISO 52957
ICS:
25.030 3D-tiskanje Additive manufacturing
81.060.99 Drugi standardi v zvezi s Other standards related to
keramiko ceramics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/ASTM DIS
ISO/TC 261
Additive manufacturing of
Secretariat: DIN
ceramics — Design — Design
Voting begins on:
guidelines
2025-03-10
ICS: 25.030
Voting terminates on:
2025-06-02
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Reference number
© ISO/ASTM International 2025
ISO/ASTM DIS 52957:2025(en)
DRAFT
ISO/ASTM DIS 52957:2025(en)
International
Standard
ISO/ASTM DIS 52957
ISO/TC 261
Additive manufacturing of
Secretariat: DIN
ceramics — Design — Design
Voting begins on:
guidelines
ICS: 25.030
Voting terminates on:
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
© ISO/ASTM International 2025
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
USER PURPOSES, DRAFT INTERNATIONAL
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ISO/CEN PARALLEL PROCESSING
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Published in Switzerland Reference number
© ISO/ASTM International 2025
ISO/ASTM DIS 52957:2025(en)
© ISO/ASTM International 2025 – All rights reserved
ii
ISO/ASTM DIS 52957:2025(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Manufacture and properties of ceramic parts . 4
4.1 General .4
4.2 Properties and applications .4
4.3 Process .9
4.4 General design recommendations for ceramic parts .11
5 Design freedom and limitations of additive manufacturing .11
5.1 General .11
5.2 Functional orientation . 12
5.3 Integration of functions . . 12
5.4 Freedom to use undercuts . 12
5.5 Topology optimization and lightweight design . 12
5.6 Part orientation and anisotropy . 12
5.7 Support structures . 13
5.7.1 General . 13
5.7.2 Support material equal to build material . 13
5.7.3 Support material not equal to build material . 13
5.8 Surface finish . 13
5.8.1 General . 13
5.8.2 Stair-step effect .14
5.9 Porosity .14
5.10 Build Platform Interface .14
6 Additive manufacturing processes suitable for ceramics .15
6.1 General . 15
6.2 Material extrusion (MEX) — Cold plastics and thermoplastics .16
6.2.1 General .16
6.2.2 Process description .16
6.2.3 Process-related special features for the design .17
6.3 Binder jetting (BJT) .17
6.3.1 General .17
6.3.2 Process description – Starting material powder .18
6.3.3 Process description – Starting material suspension .18
6.3.4 Process-related special features for the design .19
6.4 Vat photopolymerization (VPP) .19
6.4.1 General .19
6.4.2 Process description . 20
6.4.3 Process-related special features for the design .21
6.5 Material jetting (MJT) .21
6.5.1 General .21
6.5.2 Process description . 22
6.5.3 Process-related special features for the design . 22
7 Specific strengths and application fields .23
7.1 General . 23
7.2 Material extrusion . 23
7.3 Binder jetting . 23
7.4 Vat photopolymerization . 23
7.5 Material jetting . . 23
Bibliography .24

© ISO/ASTM International 2025 – All rights reserved
iii
ISO/ASTM DIS 52957:2025(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent
rights identified during the development of the document will be in the Introduction and/or on the ISO list of
patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
The committee responsible for this document is ISO/TC 261, Additive manufacturing, in cooperation with
ASTM Committee F42, Additive Manufacturing Technologies, on the basis of a partnership agreement between
ISO and ASTM International with the aim to create a common set of ISO/ASTM standards on Additive
Manufacturing.
© ISO/ASTM International 2025 – All rights reserved
iv
DRAFT International Standard ISO/ASTM DIS 52957:2025(en)
Additive manufacturing of ceramics — Design — Design
guidelines
1 Scope
This document specifies ceramic part properties, design freedom, strengths and applications of additively
manufactured parts made of ceramic materials. It aims at product planners and designers and provides the
necessary basic knowledge about ceramic parts and the possibilities specific to additively manufactured
ceramics, including strengths and limitations of the most commonly utilized ceramic additive manufacturing
methods. In-depth previous knowledge in these areas is not assumed.
2 Normative references
The following document is referred to in the text in such a way that some or all their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO/ASTM 52900, Additive manufacturing — General principles — Fundamentals and vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/ASTM 52900 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
binder system
mixture of different organic/inorganic materials that can be dissolved in suitable solvents and agglutinate
the raw material in the green body after shaping
3.2
green body
composite material made from organic matrix and embedded (ceramic) particles after shaping by means of
additive manufacturing
Note 1 to entry: The green body is produced from the starting material.
Note 2 to entry: The properties of the green body are essentially defined by the organic components.
3.3
downskin angle
δ
angle between the build platform plane and a downskin area D whose value lies between 0° (parallel to the
build platform) and 90° (perpendicular to the build platform)
[SOURCE: VDI 3405 Part 3]
© ISO/ASTM International 2025 – All rights reserved
ISO/ASTM DIS 52957:2025(en)
Key
D downskin area
U upskin area

normal vector
n
Figure 1 — Upskin angle (υ) and downskin angle (δ) according to VDI 3405 Blatt 3
3.4
debinding
process for removing all organic components from the green body
3.5
pellets
at room temperature solid starting material in the form of bulk material without defined geometry
Note 1 to entry: pellets can, for example, be transferred into defined shapes via injection moulding or extrusion
processes and solidified by removing components of the binder system or cooling the mixture previously heated for
liquefaction.
3.6
shaping
conversion of the starting material into a green body with defined geometry
3.7
sintered part
part after sintering with the final (ceramic) properties
3.8
granulate
solid, flowable starting material for powder bed-based additive manufacturing processes (AM processes)
Note 1 to entry: Granulate is a specially produced compound of many individual powder particles that has significantly
improved flow properties compared to a powder spill.
3.9
green processing
mostly machining of the green body to realise the desired geometry or surface quality
Note 1 to entry: The subsequent shrinkage during sintering should be taken into account and compensated for by an
appropriate oversize.
Note 2 to entry: Green processing can include the removal of support structures and the integration of special
geometric features.
© ISO/ASTM International 2025 – All rights reserved
ISO/ASTM DIS 52957:2025(en)
3.10
brown body
green body that has undergone pyrolysis/debinding
Note 1 to entry: The brown body has very low mechanical strength, as the individual particles adhere to each other
solely due to surface forces as well as frictional and positive locking.
3.11
hard machining
mostly machining of the sintered part to achieve the desired geometry or surface quality to the final
dimension
Note 1 to entry: Due to the high hardness of the sintered part, hard machining is very time-consuming and places very
high demands on the machining processes and tools.
3.12
cleaning
removal of adhering excess starting material from the green body
3.13
raw material
basic starting materials that are converted into the final, dense ceramic materials during the sintering process
Note 1 to entry: Usually the raw material is not mouldable (e.g. powder).
Note 2 to entry: Some raw materials (e.g. clay) can be used directly as a starting material without a binder.
3.14
shrinkage
volume reduction of a part during a process step
Note 1 to entry: Volume reduction due to (machining) material removal is not referred to as shrinkage.
3.15
sintering
thermal process for compacting and bonding the (ceramic) particles, taking place at temperatures below the
melting temperature
Note 1 to entry: Generally, sintering is accompanied by shrinkage.
Note 2 to entry: The temperature during sintering is above the debinding temperature but below the melting
temperature of the composite.
3.16
suspension
liquid starting material
EXAMPLE slip, ink, paste
Note 1 to entry: The suspension can be solidified by removing components of the binder system or initiating cross-
linking reactions.
3.17
upskin angle
υ
angle between the build platform plane and an upskin area U whose value lies between 0° (parallel to the
build platform) and 90° (perpendicular to the build platform)
[SOURCE: VDI 3405 Part 3]
Note 1 to entry: see Figure 1
© ISO/ASTM International 2025 – All rights reserved
ISO/ASTM DIS 52957:2025(en)
3.18
white machining
mostly machining of the white body to realise the desired geometry or surface quality
Note 1 to entry: The subsequent shrinkage during sintering should be considered and compensated for by an
appropriate oversize.
Note 2 to entry: White machining processing can include the removal of support structures and the integration of
special geometric features.
3.19
white body
green body or brown body in which initial sintering of the particles, including the formation of sinter necks,
has been initiated by thermal treatment
Note 1 to entry: The mechanical strength of the white body is significantly higher than that of the brown body, but still
significantly lower than that of the sintered part.
4 Manufacture and properties of ceramic parts
4.1 General
In this clause, the properties and applications are first presented (4.2). Then the ceramic manufacturing
process is explained (4.3), from which general design recommendations are then derived (4.4).
4.2 Properties and applications
The specific properties of ceramic materials, which in various relationships typically cannot be matched by
other materials, offer versatile applications.
Compared to metals, ceramic materials can offer higher hardness, thermal resistance, corrosion resistance
and wear resistance, as well as lower density and thermal expansion. An essential difference of ceramic
materials compared to metals is that ceramics do not show plastic deformation but fail after elastic
deformation when the load limit is exceeded.
An initial overview of the properties of ceramic materials is given in Table 1. The last column lists properties
of structural steel for comparison. The properties listed in Table 1 can vary depending on the processing
and raw materials utilized.
© ISO/ASTM International 2025 – All rights reserved
ISO/ASTM DIS 52957:2025(en)
Table 1 — Overview of typical properties of ceramic parts in comparison with structural steel
[1,2]
according to
Material
Porcelain Aluminium Zirconium Silicon ni- Silicon carbide Structural
Material property
c
oxide oxide tride steel
(SSiC)
a b
(> 99 %) (3Y-TZP) (SSN) St 37
Density
2,2 3,9 5…6 3,2…3,3 3,08…3,15 7,8
in g/cm
Flexural strength
50 300…450 500…1 000 700…1 000 260…500 340…470
in MPa
Young’s modulus
60 300 200…210 290…330 350…450 200…210
in GPa
Fracture toughness
– 4…5,5 5,8…10,5 5…8,5 3,0…4,8 200
1/2
in MPa m
Thermal expansion
4…7 7…8 10…12,5 2,5…3,5 4,0…4,8 10…12
–6 –1
in 10 K
a
3Y-TZP – tetragonally stabilised zirconium oxide with 3 % molar content of yttrium oxide
b
SSN – low pressure sintered silicon nitride
c
SSiC – sintered silicon carbide
Figure 2 to Figure 5 illustrate the relationship between different properties for selected ceramics compared
to metals. In this way, characteristics of ceramic materials can be both quickly compared among each other
[2]
as well as to metals .
The literature values given were determined with standardized test specimens from conventional
manufacturing processes. In additive manufacturing, there are different manufacturing methods and
material formulations, which means that the property values can vary greatly. Porosity is particularly
affected by this. For example, density and flexural strength decrease as porosity increases.

© ISO/ASTM International 2025 – All rights reserved
ISO/ASTM DIS 52957:2025(en)
Key
X density, in g/cm
Y flexural strength, in MPa
1 silicon nitride
2 silicate ceramics
3 silicon carbide
4 aluminium oxide
5 zirconium oxide
6 metals
Figure 2 — Relationship between density and flexural strength for selected ceramics compared
to metals
© ISO/ASTM International 2025 – All rights reserved
ISO/ASTM DIS 52957:2025(en)
Key
X young’s modulus, in GPa
Y hardness, in GPa
1 silicon nitride
2 silicate ceramics
3 silicon carbide
4 aluminium oxide
5 zirconium oxide
6 metals
Figure 3 — Relationship between Young’s modulus and hardness for selected ceramics compared
to metal
© ISO/ASTM International 2025 – All rights reserved
ISO/ASTM DIS 52957:2025(en)
Key
‒1 ‒1
X thermal conductivity, in Wm K
Y flexural strength, in MPa
1 silicon nitride
2 silicate ceramics
3 silicon carbide
4 aluminium oxide
5 zirconium oxide
6 metals
Figure 4 — Relationship between thermal conductivity and flexural strength for selected ceramics
compared to metals
© ISO/ASTM International 2025 – All rights reserved
ISO/ASTM DIS 52957:2025(en)
Key
‒1 ‒6
X coefficient of expansion, in 10 K
Y flexural strength, in MPa
1 silicon nitride
2 silicate ceramics
3 silicon carbide
4 aluminium oxide
5 zirconium oxide
6 metals
Figure 5 — Relationship between coefficient of expansion and flexural strength for selected
ceramics compared to metals
4.3 Process
The same basic process principle applies to all ceramic materials for conventional and additive manufacturing
(Figure 6). From the mostly powdery raw materials, a starting material is first prepared from which a green
body is created during the subsequent shaping process. The green body corresponds to a composite material
consisting of an organic matrix and ceramic particles embedded in it. Only the shaping of the green body is
usually carried out using AM, if ceramic parts are manufactured. In conventional manufacturing, a tool (i.e.,
a mould) should be created for shaping, whereas in AM the green body is built up layer-by-layer based on a
CAD model.
© ISO/ASTM International 2025 – All rights reserved
ISO/ASTM DIS 52957:2025(en)
Figure 6 — Schematic representation of the production process for technical ceramics
Subsequently, debinding and sintering of the parts are necessary to realize the ceramic properties in the
part. For AM parts, these two processes correspond to those conventionally manufactured, whereby the
process control should be adapted to the respective decomposition properties of the binder systems used as
well as to the realized volume fraction of ceramic material in the starting material.
During debinding, all organic components should be removed from the green body to allow complete
compaction of the material during final sintering. Shrinkage usually occurs during the process of sintering
and can also occur during debinding. Shrinkage can be compensated for by scaling up the green body
dimensions, as this is reproducible with a homogeneous distribution of particles in the green body, but
not necessarily the same in all spatial axes. While debinding is carried out purely thermally (usually in
a temperature range between 100 °C and 500 °C) or by means of a combination of solvent extraction or
catalytic decomposition of the organic components followed by thermal decomposition, sintering requires
significantly higher temperatures (usually > 1 000 °C).

© ISO/ASTM International 2025 – All rights reserved
ISO/ASTM DIS 52957:2025(en)
Machining is possible on the green body, the sintered white body, or on the sintered part, whereby the
demands on the machining process and tools increase from the green to the sintered body, but no further
shrinkage occurs on the sintered body. When machining the green or white body, the subsequent shrinkage
should be considered and compensated for accordingly.
Sintering leads to compaction and solidification of the moulded body through the formation of material
bridges between the powder particles. Shrinkage occurs when internal porosity is filled and the volume
of the body decreases. Typical values for shrinkage in one spatial direction (linear shrinkage) are between
10 % and 20 %. Shrinkage depends on the characteristics of the raw materials and process control variables.
For volume shrinkage, this results in shrinkage of approximately 35 % to 65 %. The shrinkage should be
considered in the design of the green body by means of volume scaling.
4.4 General design recommendations for ceramic parts
Ductile materials compensate for local overloads with elastic strain according to Hook’s Law and with the
plastic deformation reserve. This does not apply to hard and brittle materials, they are not fault tolerant.
This means that there are significant differences in the load capacity of parts made of ductile (metallic) and
brittle (ceramic) materials. This requires different design guidelines.
Ceramic materials generally exhibit high compressive strength but low tensile strength. This behaviour is in
contrast to the load-bearing capacity of metals and should be taken into account as a fundamental distinction
when designing parts. The second important aspect is the sintering process and the associated shrinkage.
Due to the complete lack of a ceramic’s ability to plasticly deform, ceramics fail spontaneously after elastic
deformation and when local material strength is reached. High stresses occur especially in small radii, sharp
edges, steps, shoulders, bores. This is further dramatized when sharp points or linear forces are applied.
Therefore, when designing a ceramic part, it is advisable to avoid geometric shapes that act as notches (stress
concentrations) or at least to use them only in a weakened form. A particular strength of ceramic materials
is their high compressive strength. A primary goal of a design suitable for ceramics should therefore be to
make optimum use of this property and to keep the number of areas in which the part is subjected to tensile
and/or bending stress as few as possible. Stress concentrations in tensile-stressed areas should be avoided.
These principles are often not given sufficient attention. There is often a desire to have a part that was
originally designed to be fabricated with m
...