Posts Tagged "Additive Manufacturing"

This post was originally created on December 8, 2016.

With all the buzz about Additive Manufacturing, or 3D Printing, in the manufacturing world today, there is a lot of mystery and confusion surrounding common practices and techniques. This week’s blog post will address a common type of 3D printing known as Fused Deposition Modeling (FDM).

But first, What is Additive Manufacturing?

Additive manufacturing is the process of creating a part by laying down a series of successive cross-sections (a 2D “sliced” section of a part). It came into the manufacturing world about 35 years ago in the early 1980s, and was adapted more widely later in the decade. Another common term used to describe additive manufacturing is 3D Printing – a term which originally referred to a specific process, but is now used to describe all similar technologies.

Now that we’ve covered the basics of 3D Printing, What is Fused Deposition Modeling?

It is actually part of a broader category, commonly referred to as a Filament Extrusion Techniques.  Filament extrusion techniques all utilize a thin filament or wire of material. The material, typically a thermoplastic polymer, is forced through a heating element, and is extruded out in 2D cross section on a platform. The platform is lowered and the process is repeated until a part is completed. In most commercial machines, and higher-end consumer grade machines, the build area is typically kept at an elevated temperature to prevent part defects (more on this later). The most common form, and the first technology of this type to be developed, is FDM.

The Fused Deposition Modeling Technique was developed by S. Scott Crump, co-founder of Stratasys, Ltd. in the late 1980s. The technology was then patented in 1989. The patent for FDM expired in the early 2000s. This helped to give rise to the Maker movement, by allowing other companies to commercialize the technology.

It should also be noted that Fused Deposition Modeling is also known as Fused Filament Fabrication, or FFF. This term was coined by the Reprap community, because Stratasys has a trademark on Fused Deposition Modeling.

What Are the Advantages of this Process? […]

With all the buzz about Additive Manufacturing, or 3D Printing, in the manufacturing world today, there is a lot of mystery and confusion surrounding the common practices and techniques. So, this week’s blog post will address a common type of 3D printing known as Selective Laser Sintering (SLS).

But first, What is Additive Manufacturing?

Additive manufacturing is the process of creating a part by laying down a series of successive cross-sections (a 2D “sliced” section of a part). It came into the manufacturing world about 35 years ago in the early 1980s, and was adapted more widely later in the decade. Another common term used to describe additive manufacturing is 3D Printing. A term which originally referred to a specific process, but is now used to describe all similar technologies.

Now that we’ve covered the basics of 3D Printing, What is Selective Laser Sintering?

It is actually part of a broader category, commonly referred to as a Granular Based Technique. All granular based additive manufacturing techniques start with a bed of a powdered material. A laser beam or bonding agent joins the material in a cross section of the part. Then the platform beneath the bed of material is lowered, and a fresh layer of material is brushed over the top of the cross section. The process is then repeated until a complete part is produced. The first commercialized technique of this category is known as Selective Laser Sintering.

The Selective Laser Sintering Technique was developed in the mid-1980s by Dr. Carl Deckard and Dr. Joseph Beaman and the University of Texas at Austin, under DARPA sponsorship. As a result of this, Deckard and Beaman established the DTM Corporation with the explicit purpose of manufacturing SLS machines.  And, in 2001, DTM was purchased by their largest competitor, 3D systems.

What Are the Advantages of this Process?

SLS is quick. It’s one of the fastest rapid prototyping techniques. Though, relatively speaking, most techniques are fast. SLS also has the widest array of usable materials. Theoretically, just about any powdered material can be used to produce parts. In addition, it can potentially be one of the most accurate rapid prototyping processes – the major limiting factor being the particle size of the powdered material.

Because parts are created in a bed of material, there is no need to use support structures like in other forms of rapid prototyping. This helps to avoid secondary operations and machining. Another advantage of the material bed is the ability to stack multiple parts into the build envelope. This can greatly increase the throughput of a SLS machine.

What Are the Disadvantages of this Process?

Of the commercially available rapid prototyping machines, those that use the Selective Laser Sintering technique tend to have the largest price tag. This is usually due to the scale production these machines are designed for, making them much larger than others.

SLS can be very messy. The material used is a bed of powdered material and, if not properly contained, will get EVERYWHERE. In addition, breathing in powdered metals and polymers can potentially be very hazardous to one’s health; though most machines account for this, it is certainly something to be cognizant of when manufacturing.

Unlike other manufacturing processes, SLS limits each part to a single material. This means parts printed on SLS machines will be limited to those with uniform material properties throughout.

As materials aren’t fully melted, full density parts are not created through this process. Thus, parts will be weaker than those created with traditional manufacturing processes, although full density parts can be created through similar manufacturing processes, such as SLM.

In Conclusion

There are quite a few different ways to 3D print a part, with unique advantages and disadvantages of each process. This post is part of a series, discussing the different techniques. Thanks for reading!

With all the buzz about Additive Manufacturing, or 3D Printing, in the manufacturing world today, there is a lot of mystery and confusion surrounding the common practices and techniques. So, this week’s blog post will address a common type of 3D printing known as Stereolithography.

But first, What is Additive Manufacturing?

Additive manufacturing is the process of creating a part by laying down a series of successive cross-sections (a 2D “sliced” section of a part). This technology came into the manufacturing world about 35 years ago in the early 1980s, and was adapted more widely later in the decade. A more common term used to describe additive manufacturing is 3D Printing – a term which originally referred to a specific process, but is now used to describe all similar technologies.

Now that we’ve covered the basics of 3D Printing, What is Stereolithography?

Stereolithography is the process of building an object by curing layers of a photopolymer, which is a polymer that changes properties when exposed to light (usually ultraviolet light). Typically this causes the material to solidify, or cure.

This technique uses a bath or vat of material. An Ultraviolet Laser will cure a layer of photopolymer on a platform. The platform is then lowered into the bath, and another layer of material is cured over the top of it.

A variation on this technique, referred to as Poly or Multi-Jet printing, has a slight modification to the process. Instead of using a bath of material, Jet printing uses separate reservoirs of material, which are fed through a UV laser. The material reservoirs in this process are quite similar to inkjet printer cartridges, and function similarly to an inkjet printer. This technique was developed by Objet Technologies, which was acquired by Stratasys in 2012.

What Are the Advantages of this Process?

Stereolithography is fast. Working prototypes can easily be manufactured within a short period of time. This, however, is greatly dependent on the overall size of the part.

SLA is one of the most common rapid prototyping techniques used today. It has been widely adopted by a large variety of industries, from medical, to automotive, to consumer products.

The SLA process allows for multiple materials to be used on one part. This means that a single part can have many several different structural characteristics and colors, depending on where material is deposited. In addition, all of the materials used in SLA are cured through the same process. This allows for materials to be blended during manufacturing, which can be used to create custom structural characteristics. It should be noted, however, that this is only available with either the MultiJet or PolyJet SLA machines.

Of the all the technologies available, SLA is considered to be the most accurate. Capable of holding tolerances under 20 microns, accuracy is one of the largest benefits to this technique.

What Are the Disadvantages of this Process?

Historically, due to the specialized nature of the photopolymers used in this process, material costs were very high compared to other prototyping processes.  They could be anywhere from $80 to over $200 per pound. The cost of a machine is considerably large as well, ranging anywhere from $10k to well over $100k. Though recently, a renewed interest in the technology has introduced more consumer grade SLA machines, which has helped to drive down prices. New material manufacturers have also appeared in recent years (spot-A Materials and MakerJuice Labs), which has cut prices drastically.

Stereolithography is a process that requires the use of a support structure. This means that any part produced with this technique will require a secondary operation post-fabrication.

In Conclusion

There are quite a few different ways to 3D print a part, with unique advantages and disadvantages of each process. This post is the first part of a series, discussing the different techniques. Thanks for reading!

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