Design examples – metal L-PBF

Design examples

What do successful metal Additive Manufacturing applications have in common?

Early movers of successful Additive Manufacturing applications have in common, that they originate from high end and high value component manufacturing. Typical examples are the medical, aviation, turbine, space as well as oil & gas industry. A little later, the machine industry became aware of the potential for metal Additive Manufacturing, too. Especially the tooling industry and special machinery in high-end segments are promoting the development of metal Additive Manufacturing applications.

Below we have summarized selected LPBF applications from different industries and in different materials

Hydraulic valve block for AIRBUS A380

Optimized AM design for a high-pressure hydraulic valve block

Source: EOS

User

Liebherr Aerospace / Airbus

Industry

Aerospace

Material

Stainless Steel

Classification

Qualified end part

Benefits of Additive Manufacturing

  • Weight reduction of 35% compared to conventional valve block
  • The new design integrated 10 functional elements into the new valve block, eliminating the complex piping system
  •  75% less production time: The new design eliminates several manufacturing steps and can be printed in 1 day. 
  • Identical performance figures to milled component from titanium forging

Gas burner for glass surface treatment

Optimized internal channels for improved gas flow and avoidance of support structures

User

Linde

Industry

Industrial

Material

Maraging Steel MS1

Classification

Qualified end part

Source: EOS

Benefits of Additive Manufacturing

  • Functional Integration: Integration of 15 individual components into 1, avoiding weld seams
  • Efficient: Homogenous flame front leads to good results during the surface glass treatment process
  • Short leadtime: 18 parts can be produced in one medium-sized printer, the printing time per part is 5 hours
  • Increased lifespan: Improved cooling channel design to reduce the thermal stress

911 GT2 RS Piston

Lightweight piston with integrated cooling duct

User

Dr. Ing. h.c.F. PORSCHE AG

Industry

Automotive

Material

Aluminium

Classification

Qualified end part

Benefits of Additive Manufacturing

  • Weight reduction of 10% compared to the forged series production pistons
  • Increased engine speed and up to 30 HP more power
  • Lower temperature load
  • Optimized combustion and improved efficiency

Catalytic reactors

Air purification component with optimized structure

Image source: AddCat

User

ADDCAT

Industry

Industrial

Material

Stainless Steel

Classification

End part

Benefits of Additive Manufacturing

  • Increased thermal conductivity thanks to design freedom
  • Energy efficient process by recovering the energy released from the reactor
  • Efficient conversion in a small reactor volume thanks to large surface area and low pressure drop

Stabilizer mount for a robot

Additive Manufacturing in Robotics Competition

User

South China University of Technology

Industry

Mechanical Engineering

Material

Aluminium

Classification

Functional Prototype

Benefits of Additive Manufacturing

  • Integration of 27 parts into 1 component
  • Weight reduction of 170 grams – a 42% weight reduction compared to the original CNC process
  • Production of 2 sets of stabilizers in 2 days

Anti-scatter grid

Thin wall structures to enhance image quality

Image source: Dunlee

User

DUNLEE

Industry

Medical

Material

Tungsten

Classification

Qualified end part

Benefits of Additive Manufacturing

  • Production of 100 micron thick walls at a positional accuracy of 25 microns
  • Energy efficient process by recovering the energy released from the reactor
  • Efficient conversion in a small reactor volume thanks to large surface area and low pressure drop

ARNO Cutting Tool

Patented coolant design for cutting tool

User

ROSSWAG

Industry

Tooling & Moulding

Material

Tool Steel

Classification

Tools and fixtures

Benefits of Additive Manufacturing

  • Patented coolant supply design
  • Coolant is directly delivered to the cutting zone for higher efficiency
  • Increased tool life and higher process security

Autoclave for High Pressure Applications

Autoclave at 225 bar operating pressure

Image courtesy: BASF

User

BASF

Industry

Mechanical Engineering

Material

Stainless Steel

Classification

Qualified end part

Benefits of Additive Manufacturing

  • Certified according to European Pressure Equipment Directive (2014/68/EU) Category III
  • Working at an operating pressure of 225 bar
  • The design features a more than two meter long interior channel for tempering fluid which winds around the container wall
  • The AM design enables faster temperature cycles, better regulation of an even temperature distribution as well as optimized tempering of the component

Combustion chamber

Patented coolant design for cutting tool

User

GF CASTING SOLUTIONS

Industry

Energy & Powerplant

Material

Nickel based alloy

Classification

Qualified end part

Benefits of Additive Manufacturing

  • Integrative housing design including static vanes
  • Significant cost and delivery time reduction due to functional integration

Optimized induction coils

Inductuon coils printed in copper

User

PROTIQ

Industry

Mechanical Engineering

Material

Copper

Classification

Non-qualified end part

Benefits of Additive Manufacturing

  • Freedom of design of the LPBF process offers new possibilities for coil design
  • The shape of the coil can be optimally adapted to the component to be heated.
  • AM production of an induction coil takes only a few days, conventional production takes up to several weeks.
  • The reproducibility of the coil is higher than manufactured conventially

Ion Engine Mount

AM optimized space components

User

THE BOEING CO.

Industry

Space

Material

Aluminium

Classification

Qualified end part

Benefits of Additive Manufacturing

  • The 702MP deployable ion engine mount includes three pieces that are 3D printed and work as an integrated assembly
  • The mission-critical part is standard on every 702MP derived spacecraft with xenon ion propulsion.
Sinter-based AM technologies and process chain

Sinter-based AM - a technology overview

Many different printing technologies - one sintering process

The sinter-based AM (SBAM) technologies have, as the name suggests, the sintering process in common. In this process, the printed green part is consolidated into a dense part and receives its final properties. The green part can be printed in advance using different technologies.They all have in common that metal powder is bound to the desired shape by a binder. The best-known printing technologies include Binder Jetting and Filament Material Extrusion.

In this section, you learn everything about the sinter-based AM  process chain and get an overview of the different printing technologies.

Goal and structure of this course

This course is aimed at engineers, designers and other professionals that are working closely with sinter-based AM technologies. The goal is to cover the most important aspects that will enable engineers and designers to fully grasp the capabilities and technical limitations of the printing technologies and the sintering process to succeed in technology selection and part design. Besides going through the course from the beginning until the end, this course can also act as a constant source of knowledge while working on AM projects. 

The course is structured into the following sections.

This section will start with an overview of the sinter-based AM process chain and its printing technologies, followed by a technology deep dive into the most important aspects of the BJT technology, followed by a closer look at the debinding and sintering step also including sintering simulation .

The second section will provide an overview of the different materials that are available as well as part characteristics that can be achieved with the BJT process and typical methods for quality assurance. Finally, several common defects in the BJT process are presented. 

The last section will act as a guideline for designers. Besides generally describing the process when designing for Additive Manufacturing, actionable restrictions and guidelines for the BJT process are provided. The final section will present several design examples from different industries. 

What you will find in this section

Sinter-based AM process chain

From digital model to finished part

Data preparation

Simulation to compensate the deformation during the sintering step, nesting of parts and definition of printing parameters

Printing

Through various printing processes, different feedstocks such as metal powders, filaments, pellets or dispersions are processed into green parts

Unpacking

Unpacking of fragile green parts needs to be done carefully and is typically a manual process.

Debinding

Debinding describes the process of removing the binder which results in a brown part

Sintering

To reach the structural integrity of a metal part, a sinter process is required. The powder particles fuse together to a coherent, solid structure via a mass transport that occurs at the atomic scale driven via diffusional forces.

The brown part shrinks ~13-21 % in each direction.

The process chain of sinter-based technologies differs from other AM Technologies. Especially the post-printing processes (debinding and sintering) are crucial to achieve the intended mechanical properties.

Technology principle

How does Binder Jetting work?

Binder Jetting is a powder based Additive Manufacturing technology in which a liquid polymer binder is selectively deposited onto the powder bed binding the metal particles and forming a green body.

The metal powder is applied to a build platform in a typical layer thickness of 40 µm to 100 µm. Subsequently a modified 2D print head apply a binder selectively onto the powder bed. Depending on machine technology a hardening or curing process of the binder is performed in parallel for each layer and/or at the end of the whole build. During the in-situ curing process a heat source is used to solidify the binder and form a solid polymer – metal powder composite.

Working Principle of Binder Jetting

Afterwards the build platform moves downward by the amount of one layer thickness and a new layer of powder is applied. Again, the liquid binder is deposited and hardened in the required regions of the next layer to form the green body. This process is repeated until the complete part is printed. After the complete printing process is finished the parts have to be removed from the “powder cake” meaning the surrounding loose but densified powder. To improve the removal of the excess powder from the green body often brushes or a blasting gun with air pressure are used.

To create a dense metal part the 3D printed green body has to be post-processed in a debinding and sintering process. Similar to the metal injection molding process BJT parts are placed in a high temperature furnace, where the binder is burnt out and the remaining metal particles are sintered together. The sintering results in densification of the 3D printed green body to a metal part with high densities of 97 % to 99,5%, dependent of the material.

Printing Technologies

Metal Binder Jetting

Binder Jetting is a powder based Additive Manufacturing technology in which a liquid polymer binder is selectively deposited onto the powder bed binding the metal particles and forming a green body.

The metal powder is applied to a build platform in a typical layer thickness of 40 µm to 100 µm. Subsequently a modified 2D print head apply a binder selectively onto the powder bed. Depending on machine technology a hardening or curing process of the binder is performed in parallel for each layer and/or at the end of the whole build. During the in-situ curing process a heat source is used to solidify the binder and form a solid polymer – metal powder composite.

Working Principle of Binder Jetting

Material Extrusion

Binder Jetting is a powder based Additive Manufacturing technology in which a liquid polymer binder is selectively deposited onto the powder bed binding the metal particles and forming a green body.

The metal powder is applied to a build platform in a typical layer thickness of 40 µm to 100 µm. Subsequently a modified 2D print head apply a binder selectively onto the powder bed. Depending on machine technology a hardening or curing process of the binder is performed in parallel for each layer and/or at the end of the whole build. During the in-situ curing process a heat source is used to solidify the binder and form a solid polymer – metal powder composite.

Working Principle of Binder Jetting

Mold Slurry Deposition

Binder Jetting is a powder based Additive Manufacturing technology in which a liquid polymer binder is selectively deposited onto the powder bed binding the metal particles and forming a green body.

The metal powder is applied to a build platform in a typical layer thickness of 40 µm to 100 µm. Subsequently a modified 2D print head apply a binder selectively onto the powder bed. Depending on machine technology a hardening or curing process of the binder is performed in parallel for each layer and/or at the end of the whole build. During the in-situ curing process a heat source is used to solidify the binder and form a solid polymer – metal powder composite.

Working Principle of Binder Jetting

Metal Selective Laser Sintering

Binder Jetting is a powder based Additive Manufacturing technology in which a liquid polymer binder is selectively deposited onto the powder bed binding the metal particles and forming a green body.

The metal powder is applied to a build platform in a typical layer thickness of 40 µm to 100 µm. Subsequently a modified 2D print head apply a binder selectively onto the powder bed. Depending on machine technology a hardening or curing process of the binder is performed in parallel for each layer and/or at the end of the whole build. During the in-situ curing process a heat source is used to solidify the binder and form a solid polymer – metal powder composite.

Working Principle of Binder Jetting