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Archive for the ‘Stereolithography (SLA)’ Category

Rapid Prototyping Helps Re-create the Face of a 2,000 Year-Old Mummy

Posted on: October 8th, 2013 by The Technology House

Issue:
The Ohio Historical Society wanted to learn a little more about the history of one of its most famous mummy residents. The mummy and its coffin were donated to the Ohio Historical Society in 1926 by Dr. J. Morton Howell, the first U.S. Ambassador to Egypt. The Ohio Historical Society partnered with the Department of Radiology at The Ohio State University Wexner Medical Center to apply the latest medical technology to learn as much as possible about the mummy’s past.

Rapid Prototyping in Action

Mummy History:

The team at the Wexner Center scanned the mummy with their state-of-the-art CT scanner, which revealed some interesting details about this mummy’s life. The CT scan revealed the mummy lived a full and comfortable life, which was unusual for the time period of 830 B.C. She was between 35-45 years at death and was 5 feet 2 inches tall. She had a symmetrical face and very straight teeth with only one being chipped. Her bones did not show wear typical of manual labor. She also appears to have died of natural causes.

The OHS curators gave her the name Amunet as a way for people to identify her as a person. Amunet means “the hidden one” which was thought appropriate since we do not know her actual name. It is pronounced “Ah-moon-net”.

Rapid Prototyping of Mummy Skull

How it was Made:
After the reveal of the CT scan, the Ohio Historical Society wanted to re-create the face of Amunet which is where Case Western Reserve University and the Technology House came into play. Case Western took the CT scan images of Amunet and re-built the skull to be able to run as a CAD file for rapid prototyping. The Technology House assisted Case with developing the quality of the 3D image to give an accurate prototype of Amunet’s skull.

Rapid Prototyping builds a 3D model

Once the 3D image was finalized we built prototypes through one of our rapid prototyping processes called Stereolithography (a.k.a. SLA). SLA prototyping builds a 3D model of a component using a vat of liquid ultraviolent-curable photopolymer resin and an ultraviolet laser to form one thin layer at a time.

TTH has had similar experience with fabricating SLA cases for the medical industry. In most of these instances, we recreate 3D models of body parts to help them to practice new equipment or surgeries.

For more information on Amunet visit www.ohiohistory.org/mummy.

Project Breakdown: SLA Prototypes Painted & Assembled

Posted on: September 19th, 2013 by The Technology House

Project Breakdown: SLA Prototypes Painted & Assembled

Issue:
Customer in the transportation business needed to showcase different versions of their new style of equipment. They requested painted SLA prototypes to be used as scale models at tradeshows and as sales samples for their reps, and they needed them fast!!!

Challenge:
All the SLA prototypes needed to be run, finished, painted and assembled complete 3-4 days from the receipt of 3D files. The challenge was that each 3D file needed engineering modifications done in order to build the SLA prototypes. On top of this, the scale models were fairly large (12” x 4” x 6”) and needed to be extremely detailed with hand finishing and multiple custom color matched painting. This was critical so that the customer’s design modifications to their equipment could be well noticed.

Solution:
1) File Review: After 3D files were received, our SLA technicians modified the .STL assembly files into manageable files that could be successfully built while still keeping all the exterior details. 3D files were then sectioned so that parts could run, be finished, painted, then assembled with greater ease.
2) SLA Prototyping Runs: Parts were orientated for the SLA prototype builds. Any parts that were small with a lot of detail ran on the 3D Systems Viper si2 High Resolution SLA Machine. Larger parts with less detail were run on the 3D systems SLA 7000 Machine.
3) SLA Finishing: By building the more detailed parts on the high resolution SLA machine, the SLA parts required less hand finishing so parts could make it to paint more quickly. Parts still required hand masking because most parts required multiple colors to be painted on each part.
4) Custom Painting: At first the customer supplied paint, but soon after we noticed that in order to save on time, we would do our own paint color matches for our own paint. This saved a lot of the dry time which was critical when painting multiple colors.
5) SLA Prototype Assembly: After all the parts were painted, the parts were then assembled and, if needed, modified due to revisions that happened on the fly in order for parts to fit and resemble the actual equipment.
6) Delivery: On average, a job like this would take at least 1 to 1.5 weeks, but this time around, each model was completed in 3-4 days.

Summary:
Projects like these cannot be done without very open and honest communication from customer to vendor to team and vice versa. This is why there is a dedicated project manager assigned to each and every project that comes in. The best way to be successful in the rapid prototyping industry is by working together to get the best possible model in the best possible timeframe. All projects are not like this one, but it sure is nice to have a project manager on hand when a project like this is needed as well as team of engineers, finishers, painters, and assemblers willing to do whatever it takes to make everyone successful.

Additive Manufacturing-Which Process is Best for You?

Posted on: September 14th, 2013 by The Technology House

Additive manufacturing is a process that creates physical objects from digital models.  While traditional machining methods fabricate parts by cutting away at material, additive manufacturing builds the part up layer by layer.  Although the additive manufacturing process has been around since the 1980’s, there has been much excitement about it due to the numerous recent advancements in processes and materials. Companies are able to produce high-quality prototypes that come closer to the production piece.  For example, medical companies are exploring patient-customized implants that are fabricated through additive manufacturing.  But with the constant innovation, it can be difficult to stay informed on what will work best for you.  That is why we have compiled the following list to show how the different additive manufacturing processes can help you.

Stereolithography (SLA) Prototyping
SLA is available in numerous plastic materials (i.e. ABS-like, PC-like, PP-like, Water clear, and High heat) that simulate properties of actual plastics.  SLA is one of the most popular methods for initial prototypes because it is ideal for design review, and fit/function testing.  Accuracy and finish allow for SLA to be the best process for master pattern of urethane and metal castings.  In addition, SLA is favored for show models since it can be more easily sanded and painted compared to other methods.

SLA prototype golf ball

Click to see details about SLA Prototype Materials.

Fused Deposition Modeling (FDM)
Like SLA, FDM is a popular method for additive manufacturing.  A major benefit to FDM is that the materials offer excellent thermal and mechanical properties.  FDM is ideal for more “under the hood” applications.  Unlike, SLA where one will get a similar material to the plastic; FDM offers the actual plastic (i.e. SLA offers an ABS-like material, while FDM offers an actual ABS material).  FDM is one of the most used processes for production additive manufacturing.

FDM prototype golf ball

Click to see details about FDM Prototype Materials.

 

Selective Laser Sintering (SLS)
SLS builds rugged parts out of materials such as Nylon PA, Glass-Filled Nylon, or flame retardant Nylon. The parts can better withstand the wear and tear of functional testing.  They are a good choice for applications that require snap features, high heat, and chemical resistance. SLS is one of the most used processes for production additive manufacturing.

SLS prototype golf ball

Click to see details about SLS Prototype Materials.

 

Polyjet
Polyjet can fabricate parts in both shore A and shore D materials, as well as overmold parts.  It is a good alternative to urethanes when the timetable requires producing rubber-like parts within a few days.  Another benefit compared to urethane molding is that polyjet does not require any tooling.

Objet Prototype golf ball

Click to see Polyjet/Objet Prototype Materials.

Direct Metal Laser Sintering (DMLS)

DMLS produces metal parts by fusing metal powder layer by layer.  DMLS parts have mechanical properties equivalent to production materials such as steel, aluminum, and titanium.  They also have high detail resolution and excellent surface quality.  DMLS is ideal for small to medium sized parts that have highly complex geometry, as well as making direct tooling inserts.

DMLS prototype golf ball

Click to see Laser Sintering Materials.

Desktop 3D Printing

Desktop 3D printers are one of the most affordable additive manufacturing processes. Desktop 3D printing can fabricate plastic prototype pieces in a variety of colors. Parts fabricated from desktop 3D printers are ideal for design review. This process has been popular lately with individuals that want desktop and novelty parts.

Desktop 3D printed golf ball

It is easy to become inundated with the myriad of additive manufacturing news. But we hope this will help create a clear path on what will work best for you. This is an exciting time for our industry that will continue to see great advances in available processes and materials.

A Newer Twist in Additive Manufacturing

Posted on: April 24th, 2013 by The Technology House

No doubt about it, additive manufacturing is hot. Unlike subtractive processes, such as machining which make parts by removing material, additive processes build three-dimensional objects layer-by-layer from digital models. Solid objects can be “3D printed” to almost any shape. Over time, the technology’s range has expanded from mostly business-to-business to business-to-consumer. This has changed the face of industry, making many companies think differently about how they produce parts. Most companies used to associate “additive manufacturing” solely with “prototypes.”  Now, spurred by the rise of consumer resources such as MakerBot and MakerGear, firms are increasingly associating additive with “end parts.”

Although some firms are still stuck on using mill specs for production, it seems that in the last few years, more companies are thinking harder about when and how to use additive techniques. Stories such as the Navy using additive aboard ships to build replacement parts and NASA exploring the technology to create spare parts on spaceships crop up almost daily.

Fused deposition modeling (FDM) is the most common additive technique in industry because it prints parts using standard engineering thermoplastics — not the proprietary blends other techniques demand. Our company builds end parts using FDM, stereolithography (SLA) and selective laser sintering (SLS).

Additive manufacturing can be used to help in production in at least 2 popular ways. First, “3D printing” can be used to create fixtures. Currently, companies must design and machine-out fixtures from a metal or plastic material in order to make a production fixture. The FDM, and other additive processes, now allow companies to “print” fixtures and get the completed devices by the next day. The fixtures hold parts for assembly, painting or machining (for instance, post-op drilling.) Second, additive manufacturing can produce the end use part either for initial testing or for the actual production run. The medical-grade polycarbonate (PC-ISO) FDM material is popular in the medical device industry and Ultem is popular for many high-heat applications for the automotive and aerospace industries.

We see a lot of interest in additive techniques and feel that their use in industry will continue to grow.