Seeing Is Believing
By Jeff Reinke, Editorial Director
Just to review, 3-D printers operate similarly to an ink jet printer, as its roller travels back and forth dispensing material and binder in the manner directed by a CAD file in building up a part or prototype layer by layer. The simplicity of its core functionality is one of the reasons behind the usage growth. Another is its price, as 3-D printers are comparatively inexpensive when held up to other types of additive approaches. Most models now run under $50,000, with an FDM machine, for instance, costing hundreds of thousands of dollars.Getting back to the simplicity of these machines, their design also lends well in embracing the office environment, as opposed to the manufacturing floor. So current technology, with enhanced material usage, smaller footprint options and quieter operation, means these machines can be in the same vicinity as the design engineer using them.
Price and simplicity are only some of the core 3-D printer values, but they mesh well with the quicker turnaround and precision produced by these machines in providing a value-added option. Basically, there are more accurate ways to create a prototype, but some take longer and consume more floor space, and all cost more. Additionally, although there are some limitations when it comes to material choice and part size with a 3-D printer, they do allow for adding greater details and come out of the machine needing very little, if any, finishing work. This will depend on the type of model. Z Corp's units also allow for adding color.
The quick turnaround and in-house control of these printers have been key to their growth, as this naturally aids in gaining more feedback, more quickly - shortening the design and development process. In many instances, the accuracy of these units has also helped in identifying and eliminating unnecessary or inaccurate tooling, as well as other production-related issues.
Key to speeding these development times are the types of materials that can be used in building a prototype. Typically, 3-D printers will use some sort of high-performance plastic like acrylonitrile butadiene styrene (ABS), but more is being done in the areas of rubber and metal. "The market wants durable models produced in a variety of plastics or metals," adds Cobb. Dimension's Elite model features ABSplus, an updated ABS that is, on average, 40 percent stronger than standard ABS."
"The types of features that are being examined by Objet's technical team," adds Stephanie Checchi of Objet, "are focused on the mechanical properties of different materials. There is a huge amount of research and development being done to examine acrylic photopolymers and elastomers. This is a significant growth opportunity because it enables various combinations of materials to be altered in printing prototypes with different mechanical properties.
"For instance, if you need to print a tire around a wheel you can print the rubber-like material along with the hard acrylic wheel inside. With new technology being developed, this process will soon be available, eliminating the need to print two separate parts and then assemble them."This matrix of digital materials opens the door to many applications and material capabilities. It is virtually an endless number that can be combined, which allows for many different designs to be produced."
Z Corp.'s Kevin Lach adds, "We also are investing heavily in the development of new materials that will allow our customers to vary model properties like strength, color and flexibility to match the application. Versatility is important. Our customers know the hardware they buy today will get better with the materials we introduce tomorrow."
A big difference amongst the market's collection of printers and methodologies is layer thickness, or the amount of material being applied with each pass. This will be impacted by the type of material used, which will depend upon the project, the amount of time available for producing a finished prototype, and other project-related factors. In any case, looking at the type of material or materials that can be used by a given machine will be a vital component of the purchasing process, as will envelope size.
Lach explains, "Build size is certainly a factor in selecting a 3D printer. For example, footwear companies typically choose our largest printer (build size of 10" x 14" x 8") because it is capable of producing multiple copies of a full size shoe sole simultaneously. However, equally important considerations are throughput (how many models, and how often), color versus monochrome, user type (automated printers are better suited to novice users) resolution (higher resolution machines produce better graphics), and of course, price." Typical envelope sizes seem to range from about 650 to 2,600 cubic inches.
Cobb suggests that, "companies review their typical part sizes and base a decision on what size system can handle 80 percent or more of their typical parts, utilizing a single build." This would not include parts that are often "cut" and printed separately before being glued together in forming the final prototype.
It's A Small World
As is the trend with a multitude of other technologies, the next step for 3-D printers seems to be focused on decreasing the unit's overall footprint. With their new V-Flash™ Desktop Modeler (more product-specific information is available on page 6), 3D Systems has unveiled a unit that will physically fit on a desk and cost under $10,000. 3D's foray into the printer market comes after establishing a name for its selective laser sintering (SLS) machines.
"Desktop modeling enables a more modern process known as Iterative Prototyping - the integration of frequent prototypes into the design workflow," explains Nick Carter. "The technology that makes desktop modeling possible is actually an evolution of stereolithography. While the fundamental principal is the same, there are several key differences that address the speed and efficiency of the process. This new technology is called Film Transfer Imaging (FTI) and it is proprietary to 3D Systems. Both FTI and stereolithography cure a photopolymer layer upon layer to form a solid model. However, unlike the lasers found in traditional stereolithography, FTI uses a broader ultraviolet source to cure each layer in less time. The process creates stereolithography-like parts much faster, while maintaining the part's integrity and surface aesthetics."
3D also feels their new unit helps improve material consumption efficiency through greater precision, the recycling of unused material, and the use of fewer supports during the building process.
Looking ahead, smaller footprints will not be the only factor driving 3-D printer growth. Additionally, new applications should play a key role in the broader acceptance of this technology. "The first application for 3D printers was prototyping because mechanical design software made printable 3D data so available," states Lach. "What is exciting is the rate at which 3D data is emerging in every industry from architecture and electronic games to 3D mapping and medicine. Each of these applications will require a 3D output device to produce building concepts, entertainment avatars, 3D maps from geospatial data and physical models from CT Scan data. We see applications beyond prototyping as very promising."
Additionally, industry experts see a growing demand for 3-D printers in producing models that can be used for tooling and production fixtures, as well as in educational settings. Many companies also use 3-D printers in conjunction with SLA or FDM methodologies in producing prototypes, or for rapid manufacturing applications.
At the end of the day, 3-D printers are one of multiple options for producing prototypes. The key in deciding how or if to implement this technology will stem from assessing where your priorities are in terms of cost, time, precision and material usage.