TTH 3D Printing Handbook 3D Printing Handbook A Guide to Understanding and Applying the 3D Printing Process . ... As of 2012, the market for 3D printers and services was worth $2.2

TTH 3D Printing Handbook

A Guide to Understanding and

Applying the 3D Printing Process

In This Handbook

What is 3D Printing? 3

3D Printing History 3

3D Printing Types 4

Choosing the Best Process 6

3D Printing Design Tips 10

Developing with TTH 13

The technology and techniques of 3D printing and additive manufacturing have

drastically changed and improved over the years. These systems have changed

and evolved to become more sophisticated and at times complex. 3D printing

and additive manufacturing now offer more resources and solutions than ever

before. This handbook is a guide to help you understand the major 3D printing

and additive manufacturing techniques, as well as assisting you in choosing the

correct process for your specific needs.

440-248-3025 www.tth.com [email protected]

Page 2

The first 3D printer was created in 1984 by 3D Systems. The initial process was known as stereolithography (SLA). This process uses UV Lasers to cure photo-polymer resins layer by layer. In 1990, Strayasys developed the plastic extrusion technology fused deposition modeling (FDM). FDM is an additive manufacturing process where plastic fila-ment is extruded from a coil of material that builds parts layer by layer. These are two of the major processes that helped build the foundation for the 3D printing and additive manufacturing. Since this time, multiple other proc-esses have been developed. Machines and materials have expanded beyond hard plastics to include rubber and metal. Machines and materials are more readily available. Applications are as far reaching as ever which include archi-tecture, industrial design, automotive, aerospace, military & defense, medical, biotechnology, fashion, jewelry, food, consumer goods, and many others. As of 2012, the market for 3D printers and services was worth $2.2 billion

worldwide.

3D Printing is a process that makes a three dimensional solid object off a digital

model (CAD file). 3D printing is also known as additive manufacturing since

part layers are built on top of each other.

Page 3

What is 3D Printing and Additive Manufacturing?

3D Printing and Additive Manufacturing History



Page 4 TTH 3D Printing Handbook

Not all 3D printing machines fabricate parts in the same material. Materials range from rubber to plastic, and to metal. In addition, there are various sub-categories to these three materials. For example, metal parts can be printed in materials ranging from stainless steel, to aluminum, and to titanium. It is important to match the material to the needs of your part.

3D Printing Types


3D printed parts are used both in the industrial and commercial indus-tries. Depending on the part or application, you can tailor the process and mate-rial to their needs.

Typically, parts used on the industrial setting need to be durable and accurate

enough to withstand various tests in different settings and environments. Parts

used in the industrial setting are used primarily for fit and function testing, design

concept review, show models, and low volume production.

3D Printing is also used in the commercial industry. Hobbyists are able to

create parts to their specific needs. 3D printed parts in the commercial

industry are primarily used for customizable novelty items, simple design

concept review, and inexpensive show models.



It is important to match the prototype process to your application; otherwise

the prototype may not accurately reflect your product’s intention. The follow-

ing chart helps break down some of the major processes and their typical uses.

Once a part is designed, then you should prototype the design in order to re-view it. A prototype will allow you to view the design at different angles than viewing it on a computer screen. You will have a better understanding on part aesthetics and feel with an actual prototype.


Design Review

Choosing the Best Process for Your Application

This is a mobile phone cover printed in

SLA. This prototype allowed the customer

to better understand the look and feel of

their design.


Having the part in hand can allow you to learn more about the design and con-cept than what can be seen on a computer screen. A prototype can show the interaction between components better as well as how it will withstand its en-vironment.

Page 7

Fit and Function

This children’s lemonade stand was printed in SLA,

painted, and assembled. It was created to accurately

portray the production product, and was used in trade

shows and sales demonstrations.



Show Models are needed for a variety of purposes: sales demonstrations, trade shows, etc. The design or concept may not be finalized, so a 3D printed product can be the best avenue for you to accurately showcase their product without having to build production tooling.


Show Models

This architectural model was printed in clear SLA, and stands 6 feet tall. The model had to be run in about 3 dozen parts. The

sections were cut in a way to allow the customer easy assembly. The model was use as a marketing tool at a trade show in Dubai.


Page 9

Low Volume Production

If your production quantities are low, then it may not be economical for you to product their product in traditional manufacturing processes. The setup or tooling costs may be too high to justify the low quantities needed. 3D Printing can help eliminate or reduce some of these costs. This is because parts are grouped together on a build, so you receive the benefit of economics of scale. Or lower cost tooling is used.

Snap Features

Some prototypes require more flex, mainly in order to snap into mating parts. It is nearly impossible to judge the flex of a part from a computer screen. Pro-totypes allow you to actually feel and understand the flex of their part.

Overmold Parts

In order for you to produce overmolded prototypes, you will need to utilize a process that can print multiple materials in the same setup. Overmolded parts allow you to have an accurate model and feel of the end product. You will be able to have a better understanding of how the materials of the product work together.

Urethane and Metal Casting Masters

When you wants to fabricate parts in either the cast urethane or metal casting process, then they need a master pattern to create the molds. 3D printing can allow you to create an inexpensive and dimensionally accurate master to be used in order to create the molds.




File Type

First and foremost, a CAD (computer aided design) model is required in order to build parts. 3D printers read CAD files in an .stl format.

File Accuracy

The CAD file must be as accurate as possible, since the fabricated part is built from this model. It is important to have a CAD file in a high resolution. This will help eliminate any facets being built in the part. It will also yield a smoother and more dimensionally accurate part.

This file does not have a high resolution, so the facets will be visible when the part is printed.

This file is saved at a higher resolution, so when printed its surface finish will be smoother than the previous file.

3D Printing Design Tips


Page 11

Hollowing Parts

Hollowing parts can help reduce your piece price. This is because less material is now needed to fabricate the part. Rather than running a part completely solid, it can be hollowed with a thick enough wall thickness to have the part still be durable. Although in 3D printing processes that use a liquid photopolymer, a drain hole must be added to the hollowed part. This is so that any resin on the inside can drain out of the part. If the resin is trapped inside, then it will harden when cured. Thus, the part will not save any material.


This file is solid, and has a cubic volume of 19.957. This part is hollowed with .080” wall thickness, and has a cubic volume

of 9.934. Since it is hollowed, it is saving 10.02 cubic inches of material.



Part Orientation

It is also important to orientate the part properly. For example, any round or cylinder pieces should be built upright in order allow for the most dimension-ally accurate piece. Parts built from 3D printers that extrude material can be

orientated in way to make the parts stronger. Finally, any show or critical sur-faces should be orientated so that they receive as little support as possible. This is because important features may be inadvertently removed when re-

moving support.

Parts that are built either flat or upright will have less “stair stepping”, than

parts built at an angle. “Stair stepping” is the build layers from the machine.

Stair stepping can make a part look less aesthetically pleasing. Although it

does not necessary cause any harm to the part, it may make it look unattrac-

Minimum Wall Thickness

3D printing processes require a minimum wall thickness of at least .025”-.030”.

This is because 3D printing machines need to trace over a feature a minimum

amount of times for the feature to build. Anything less than .025”-.030” may

not fully build. And even if it does, then the part will be very fragile.

The red circle highlights the stair stepping (build layers) of this part. If this cylinder feature was run upright, then the stair

stepping would not be present.


Page 13

Developing Your Product with TTH

3D printing technology has made leaps and bounds from when it was first created almost 30 years ago. It

is important to utilize the correct process for your product needs. We are here to help you get your prod-

uct to the market.

-Contact us at 440-248-3025, or email us at [email protected]. One of our project managers will work with

you to help establish your needs, and answer any of your questions.

-You may either email us any CAD data or drawings you have via email, or you may upload your data

through our ftp site.



mailto:[email protected]

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TTH 3D Printing Handbook 3D Printing Handbook A Guide to Understanding and Applying the 3D Printing Process . ... As of 2012, the market for 3D printers and services was worth $2.2