GB/T 39252-2020 English PDF (GB/T39252-2020)

GB/T 39252-2020: Additive manufacturing - Specification for powder bed fusion process of metal materials
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GB/T 39252-2020
GB
NATIONAL STANDARD OF THE
PEOPLE'S REPUBLIC OF CHINA
ICS 25.030
J 39
Additive manufacturing - Specification for powder bed
fusion process of metal materials
ISSUED ON: NOVEMBER 19, 2020
IMPLEMENTED ON: JUNE 1, 2021
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 5
4 General requirements ... 5
5 Process ... 8
6 Quality inspection ... 13
7 Technical data delivery ... 13
Appendix A (Informative) Record ... 14
Appendix B (Informative) Effect of process parameters on part forming quality ... 16
References ... 18
Additive manufacturing - Specification for powder bed
fusion process of metal materials
1 Scope
This standard specifies the general requirements, process, quality inspection, and
delivery of technical data for the powder bed fusion process of metal materials.
This standard applies to the powder bed fusion process of metal materials with lasers
and electron beams as energy sources.
2 Normative references
The following documents are essential for the application of this document. For the
dated referenced documents, only the versions with the indicated dates are applicable
to this document; for the undated referenced documents, only the latest version
(including all the amendments) is applicable to this document.
GB/T6003.1 Test sieves - Technical requirements and testing - Part 1: Test sieves
of metal wire cloth
GB 8702 Controlling limits for electromagnetic environment
GB/T 11651 Code of practice for selection of personal protective equipment
GB 15577 Safety regulations for dust explosion prevention and protection
GB/T 15605 Guide for pressure venting of dust explosions
GB 25493 Rapid prototyping machines by laser as processing energy - Technical
requirements for safeguarding
GB/T 35022 Additive manufacturing - Main characteristics and corresponding test
methods - Parts and powder materials
GB/T 35351 Additive manufacturing - Terminology
GB/T 37698 Additive manufacturing - Design - Requirements, guidelines and
recommendations
GB 50019 Design code for heating ventilation and air conditioning of industrial
buildings
accordance with the acceptance standards provided by the equipment manufacturer or
the relevant standards agreed upon between the supply and demand parties. The
equipment can only be used after passing the inspection.
4.2.3 Maintenance
4.2.3.1 The operator shall develop a maintenance plan according to the instruction
manual of the powder bed fusion equipment, and the maintenance content shall be
carried out in accordance with the instruction manual provided by the equipment
manufacturer or relevant standards.
4.2.3.2 Energy sources, scanning systems, etc. shall be calibrated regularly.
4.2.3.3 Maintenance or calibration results shall be recorded, and the record retention
time shall be in accordance with the instructions for use provided by the equipment
manufacturer.
4.3 Feedstock
4.3.1 Performance
The main performance indicators of metal powder include chemical composition,
particle size and particle size distribution, fluidity, oxygen content, sphericity rate, bulk
density, hollow powder rate, etc. The grade and chemical composition of metal powder
shall meet the requirements of relevant standards, or be determined by negotiation
between the supplier and the buyer before manufacturing. Metal powder inspection
indicators shall be determined according to process requirements, and other special
requirements need to be determined through negotiation between the supplier and the
buyer. Unless determined through negotiation between the supply and demand parties,
the inspection method shall be implemented in accordance with the requirements
specified in GB/T 35022.
4.3.2 Reuse
The used powder can be reused or mixed after being sieved and tested to meet the
requirements of 4.3.1, and the batch number shall be re-programmed, indicating the
number of reuses and mixing ratio. The screen shall comply with the provisions of GB/T
6003.1; if the used powder after screening does not meet the requirements of 4.3.1, the
supply and demand parties shall negotiate to determine its use or environmentally
friendly disposal.
4.3.3 Delivery and storage
4.3.3.1 The powder supplier shall provide the safety technical instructions and quality
certificate of the powder. The quality certificate shall include but not be limited to the
powder grade, batch number, physical and chemical properties, and other indicators.
4.3.3.2 Powder should be stored in closed, anti-static, flame-retardant containers in a
dry, cool, non-corrosive environment. Powder storage shall be carried out in accordance
with the environmental conditions provided by the powder supplier.
4.3.3.3 Necessary measures shall be taken to prevent powder from being contaminated
during use, storage, transportation, screening, cleaning, etc.
4.4 Environment
4.4.1 Working environment
The recommended working environment for powder bed fusion equipment and
powders is as follows:
a) Ambient temperature: 5 ℃~35 ℃;
b) Relative humidity: ≤75%.
4.4.2 Site requirements
The site where the equipment is installed shall have good ventilation and lighting
conditions and shall be implemented in accordance with the regulations of GB 50019.
The ground-bearing capacity shall comply with the equipment manufacturer's
requirements.
4.4.3 Magnetic field
Magnetic field requirements mainly apply to powder bed melting equipment using
electron beams as energy sources. The magnetic field strength of the environment in
which they are located shall not affect the electron beam focusing and scanning
deflection control.
4.5 Security
4.5.1 The safety protection of powder bed fusion equipment using laser as an energy
source shall comply with the regulations of GB 25493.
4.5.2 The explosion-proof pressure relief device of the build chamber of the powder
bed fusion equipment using laser as the energy source shall comply with the regulations
of GB/T 15605.
4.5.3 The electromagnetic radiation surrounding the powder bed fusion equipment
using electron beams as the energy source shall comply with the regulations of GB 8702.
4.5.4 Powder bed fusion equipment shall be well grounded.
4.5.5 The explosion-proof safety of powder operations during use, storage, cleaning,
5.2 Model design
5.2.1 Designers can obtain part models through three-dimensional software modeling
or scanning entities.
5.2.2 The model design of parts shall comply with the relevant provisions of GB/T
37698.
5.3 Data processing and process parameter setting
5.3.1 Data processing shall include but not be limited to file editing, format conversion,
support design, slicing, scan path planning, etc.
5.3.2 The format of the data file shall comply with the equipment requirements, and the
model file shall be in a format that can be recognized by the powder bed fusion
equipment software, such as STL, AMF, 3MF, and OBJ. When performing data
processing (such as format conversion and slicing), the operator shall ensure that the
data is not lost and traceable and the relevant content is fully recorded. For the recorded
content, see Appendix A.
5.3.3 The building orientation and placement shall be determined based on factors such
as the part's structure, performance requirements, forming time, support removal, and
ease of powder cleaning. At the same time, the gaps between the parts shall be checked
to ensure that the parts do not interfere with each other.
5.3.4 For parts that require the addition of support structures, factors such as the type,
quantity, and removal of supports shall be considered.
5.3.5 The specimen can be taken directly from the part, or the sample along with parts
can be built separately.
5.3.6 The number, building orientation, and placement of the sample along with parts
shall be determined.
5.3.7 The orientation and position description of parts and test specimens shall comply
with the regulations in ISO/ASTM 52921.
5.3.8 To set the corresponding parameters according to the material type and part
performance, please refer to the process parameter package provided by the powder bed
fusion equipment manufacturer.
5.4 Forming preparation
5.4.1 Feedstock
Feedstocks used for forming manufacturing shall comply with the requirements of 4.3.
5.4.2 Protective gas
Whether protective gas (such as nitrogen, argon, and helium) is needed is determined
based on process requirements. When a protective gas is used, its purity shall be no less
than 99.9%.
5.4.3 Equipment
5.4.3.1 Powder bed fusion equipment shall be in good condition.
5.4.3.2 The material of the build platform shall have good metallurgical compatibility
with the feedstocks, and the thickness, flatness, and roughness shall meet the process
requirements. Impurities and oil stains on the surface shall be removed before use. After
the build platform is installed and fixed as required, the parallelism and distance
between the build platform and the powder spreader shall comply with the regulations
of the powder bed fusion equipment manufacturer.
5.4.3.3 The build chamber shall be cleaned before powders of different grades or
batches are added to avoid cross-contamination.
5.4.3.4 The protective gas type, oxygen content, vacuum degree (electron beam), gas
pressure and build platform preheating temperature of the build chamber shall be
ensured to meet the forming process conditions.
5.5 Forming process
5.5.1 The forming process is completed with computer assistance.
5.5.2 The main process parameters shall be recorded, and the specific process parameter
monitoring and recording shall be determined through negotiation between the supply
and demand parties.
5.5.3 If an interruption occurs during the forming process, the interruption status shall
be recorded, evaluated, and dealt with based on the evaluation results.
5.5.4 Please refer to Appendix B for the impact of process parameters on the forming
quality of parts.
5.6 Powder cleaning
5.6.1 After the forming is completed, the parts should be cooled to ambient temperature
or a specific temperature in a protective atmosphere or vacuum environment before
powder cleaning.
5.6.2 Anti-static brushes, explosion-proof vacuum cleaners, high-pressure air, etc. can
be used for powder cleaning. Parts shall not be damaged during powder cleaning.
6 Quality inspection
6.1 Requirements
6.1.1 Necessary quality inspection shall be carried out before parts are delivered. The
supply and demand parties shall negotiate to determine the random inspection method,
test items, and technical indicators as delivery and acceptance conditions.
6.1.2 The main characteristics and test methods of parts shall meet but not be limited to
the provisions of GB/T 35022.
6.1.3 The mechanical performance evaluation of parts shall comply with the provisions
of GB/T 39254.
6.2 Re-inspection
The purchaser can conduct re-inspection according to the requirements of 6.1 according
to the agreement between the two parties. If the re-inspection result is unqualified, it
will be resolved by negotiation between the supply and demand parties.
7 Technical data delivery
Delivered parts shall contain, but are not limited to, the following information:
a) Supplier information (name, address, and contact information);
b) Parts' name, material grade or composition;
c) Parts' certificate of conformity;
d) Product standard number;
e) Number of parts;
f) Date of production;
g) Post-treatment records;
h) Product packaging, transportation, storage, and other requirements.
Appendix A
(Informative)
Record
A.1 Software information
Record the name, version, and other information of the software involved in the forming
process, such as design software, pre-processing software (such as slicing software and
support software), control software, and operating system.
A.2 Data information
Record part-forming data, mainly including part model data and data processing
information.
A.3 Forming process records
Forming process records include but are not limited to the following information:
a) Feedstock's manufacturer, grade, performance, and batch number;
b) Powder reuse status, including screening, number of reuses, number of
batching, batching ratio, etc.;
c) Build platform material and thickness;
d) Type, purity, and flow rate of protective gas;
e) Forming process parameters when laser is used as an energy source, including
oxygen content in the build chamber, preheating temperature of the build
platform, powder layer thickness, laser power, scanning speed, scanning
strategy, spot size, etc.;
f) Forming process parameters when the electron beam is used as an energy
source, including electron beam size, scanning speed, scanning strategy, build
chamber vacuum degree, powder layer thickness, build platform preheating
temperature, etc.;
g) Build chamber temperature after electron beam forming is completed;
h) Post treatment, including all mechanical processing, chemical treatment, heat
treatment, etc.;
GB/T 39252-2020
GB
NATIONAL STANDARD OF THE
PEOPLE'S REPUBLIC OF CHINA
ICS 25.030
J 39
Additive manufacturing - Specification for powder bed
fusion process of metal materials
ISSUED ON: NOVEMBER 19, 2020
IMPLEMENTED ON: JUNE 1, 2021
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 5
4 General requirements ... 5
5 Process ... 8
6 Quality inspection ... 13
7 Technical data delivery ... 13
Appendix A (Informative) Record ... 14
Appendix B (Informative) Effect of process parameters on part forming quality ... 16
References ... 18
Additive manufacturing - Specifi...