Introduction to Additive Manufacturing: Part One

Extracto:

Additive manufacturing is a relatively recent manufacturing method which has become a key area of interest in multiple industrial sectors.
Deriving from CAD models the process can be used to create solid yet highly complex parts and pushes towards a tool-less manufacturing environment meaning improved quality and better efficiency in many cases.

Additive manufacturing (AM) is the process of joining materials to make objects from Computer Aided Design (CAD) model data, usually layer upon layer, as opposed to subtractive manufacturing methods. Additive manufacturing is also called 3D printing, additive fabrication, or freeform fabrication.

Additive manufacturing is a novel method of manufacturing parts directly from digital model by using layer by layer material build-up approach. This tool-less manufacturing method can produce fully dense metallic parts in short time, with high precision. Features of additive manufacturing like freedom of part design, part complexity, light weighting, part consolidation and design for function are garnering particular interests in metal additive manufacturing for aerospace, oil & gas, marine and automobile applications.

A computer-aided design (CAD) is created and exported to stereolithography (STL) file format that is read by the AM equipment. There are many techniques available, which can be categorized according to their raw material. They are: (1) powder-based, (2) liquid-based, and (3) solid based. Some examples of powder-based techniques include selective laser melting (SLM), selective laser sintering (SLS), and electron beam melting (EBM). Liquid-based techniques include stereolithography apparatus (SLA) and polyjet while solid-based techniques include laminated object manufacturing (LOM) and fused deposition modeling (FDM). The strengths of AM compared to conventional manufacturing methods are listed further.

Basically, any material can be produced by one or another AM technique today. These materials can be divided into four main categories: plastics, metals, ceramics, and composites.

Today, a variety of plastics with vastly different mechanical, chemical and environmental properties can be additively manufactured, except for imidized materials. Polyimides are a group of polymers with exceptionally high heat and chemical resistance that are yet to be used in AM. These materials vary in transparencies, thermal or mechanical properties. Polyamides are the most popular thermoplastics used in plastic laser sintering due to their widespread use in injection molding. However, the specific grades of polyamides used in AM have different physical properties and wider processing windows as compared to their injection molding counterparts even though they are chemically identical.

The range of polymers used in AM encompasses thermoplastics, thermosets, elastomers, hydrogels, functional polymers, polymer blends, composites, and biological systems.

The most commonly used metals in AM are steel and its alloys due to their availability, reasonable cost, and biocompatibility as bone and dental implants. Titanium and its alloys are less commonly used followed by nickel, aluminum, copper, magnesium, cobalt-chrome, and tungsten. Precious metals such as gold are also used as summarized in Tables 1-4. Ceramics are widely used in AM as shown in Table 5. Also, crack-free metal matrix composites (MMC) of 99.9% density can be coupled with tungsten carbide-cobalt (WC-Co), ceramic or nonferrous reinforcements to enhance the mechanical properties. Such 3D printed composites are usually used in extreme environmental conditions, which include the oil and gas, mining, automotive, or power industry due to its high hardness and wear resistance. The uniform fine microstructure contributes to the increased hardness, eliminating any need for further improvements in mechanical properties through costly post-processing or heat treatment procedures.

In Tables 1-5 are summarized the materials used in Additive Manufacturing.



Table 1:Types of metal alloys used in AM



Table 2:Titanium alloys used in AM



Table 3:Nickel alloys used in AM



Table 4:Non-ferrous alloys used in AM



Table 5:Types of ceramics used in AM


References

1. Additive Manufacturing Technology Assessment, QTR Chapter 8, Accessed Feb 2018;

2. V. Bhavar, P. Kattire, V. Patil, S. Khot, K. Gujar, R. Singh: A Review on Powder Bed Fusion Technology of Metal Additive Manufacturing, 4th International Conference and Exhibition on Additive Manufacturing Technologies-AM-2014 September 1-2, Bangalore, India;

3. C. K. Chua, C. H. Wong, W. Y. Yeong: Standards, Quality and Measurement Sciences in 3D Printing and Additive Manufacturing, Academic Press, 2017, ISBN: 978-0-12-813489-4;

4. S. C. Ligon, R. Liska, J. Stampfl, M. Gurr, R. Mülhaupt: Polymers for 3D printing and customized additive manufacturing, Chem. Rev. 2017, 117, p.10212−10290, DOI: 10.1021/acs.chemrev.7b00074.

Buscar en la base del conocimiento

Introduzca una frase para buscar:

Buscar por

Texto completo
Palabras clave

Títulos
Extractos

Physical properties are available for a huge number of materials in the Total Materia database.

Data is available through official information from standards and also through Total Materia unique similar materials cross referencing functionality, adding another dimension to your search for physical properties data!

Enter the material of interest into the quick search field. You can optionally narrow your search by specifying the country/standard of choice in the designated field and then clicking "Search".

solution img

After selecting the material of interest to you, click on the Physical Properties link to view data for the selected material. The number of physical property data records is displayed in brackets next to the link.

solution img

Physical properties are displayed according to the origin of the data set. Official data from standards can be found under the official tab, data deriving from other sources for the material will also be displayed under its own tab.

solution img

The similar materials tab displays all materials that are similar to the original material and have physical properties inserted. This can be very handy when looking for equivalent materials!

solution img

The typical tab gives a generic overview of property data for the material for you to use as a useful starting point for further investigation.

solution img

For you’re a chance to take a test drive of the Total Materia database, we invite you to join a community of over 150,000 registered users through the Total Materia Free Demo.