Although the future of 3D printing continues to look bright, what is still needed is a new file format for 3D print data. Being very mindful of that fact, Autodesk, HP, Siemens, Stratasys, 3D Systems, and some others have come together to form the 3MF Consortium that espouses to get behind a truly ubiquitous file format for 3D printing. It’s really an industry partnership working toward the goal of finding a better, universally applicable 3D printing file format known as the 3D Manufacturing Format (3MF)—a file format originally developed by Microsoft, also a member of the Consortium.
The consortium admits that there is a problem that the 3D manufacturing must resolve – the current file formats used for 3D printing are in serious need of an upgrade. I totally agree.
Typically, data is passed from computer to 3D printer in STL (stereolithography) or OBJ (object) files, common 3D printing file formats. The 3MF Consortium, which now includes the research wing of General Electric, say STL and OBJ are outdated and clunky file formats with interoperability issues when used by some of the newer 3D printers, as well as contribute to 3D printing failures.
3MF Consortium Introduction
Thus, one of the driving forces behind 3MF, an XML-based open format, this new file type could contain information on the texture of a 3D print, the color of the print, and other complex characteristics. If that sounds familiar, that’s because it is—the Additive Manufacturing File Format (AMF), which has been around since 2011, solves many of the issues STL files have, and 3MF and AMF are in many respects pretty similar file formats, but let’s take a closer look.
Like it or not, since the mid-1980s, the STL file format has been the de facto industry standard for transferring information between CAD programs and additive manufacturing equipment. However, the STL format only contains information about a surface mesh, and cannot represent color, texture, material, substructure, and other properties of a fabricated object.
As additive manufacturing technology has evolved from producing primarily single-material, homogenous shapes to producing multi-material geometries in full color with functionally graded materials and microstructures, there has been a growing need for a standard interchange file format that could support these features. A second factor that prompted the development of a new standard was the improving resolution of additive manufacturing machines. As the fidelity of printing processes approached micron scale resolution, the number of triangles required to describe smooth curved surfaces resulted in unacceptably large file sizes.
The Additive Manufacturing File Format (AMF) was introduced as an alternative to the STL file format to address many of the shortcomings of the popular file format. STL files introduce errors such as leaks and inconsistences, and also does not support color, material The choice, or orientation. STL files also rely on triangle subdivision to account for curvature. As the STL file scales in size, retaining resolution means introducing significantly more triangles. For example, a 10cm sphere at 10 micrometer resolution requires 20,000 triangles. Scaling up the 10cm sphere at the same resolution would significantly increase the amount of triangles, resulting in a much larger file. AMF seeks to address these issues by redesigning the way a 3D object is digitally stored.
Since the dawn of 3D printing, a little over three decades ago, there has been one file format that has dominated communicating with 3D printers — STL. Love it or hate it, and even with its limitations and shortcomings, STL has remained the de facto standard for the 3D printing industry. That may finally be changing, though, with the advent of more contemporary and robust file formats for 3D printing, such as AMF and 3MF. Over the next couple weeks we’ll be discussing the evolution, advantages, and disadvantages of 3D printing file formats, starting this week with STL.
So What Exactly Is An STL File?
Essentially, an STL file stores information about 3D models, but this format describes only the surface geometry of a 3D object without any representation of color, texture, or other common model attributes.
As it has been for three plus decades, the STL file format is still by far the most commonly used file format for communicating with 3D printers.
The true meaning of the file extension .STL has always been somewhat of a mystery. I’ve always considered it be an abbreviation of the word STereoLithography, although sometimes I have also heard it referred to as Standard Triangle Language or Standard Tessellation Language. Which is correct? Probably all of them.
Introduction To The STL File Format
The main purpose of the STL file format is to encode the surface geometry of a 3D object using tessellation. Tessellation is the process of tiling a surface with one or more geometric shapes with no overlaps or gaps. Having no gaps is especially important, as an object must be watertight to be printed. A good real life example of tessellation is a tiled floor.
An impossible object is a type of optical illusion. It consists of a two-dimensional figure that is instantly and subconsciously interpreted by the visual system as representing a projection of a three-dimensional object.
In most cases the impossibility becomes apparent after viewing the figure for a few seconds. However, the initial impression of a 3D object remains even after it has been contradicted. There are also more subtle examples of impossible objects where the impossibility does not become apparent spontaneously and it is necessary to consciously examine the geometry of the implied object to determine that it is impossible.
The unsettling nature of impossible objects occurs because of our natural tendency to interpret 2D drawings as 3D objects. With an impossible object, looking at different parts of the object makes one reassess the 3D nature of the object, which confuses the mind.
Although possible to represent in two dimensions, it is not geometrically possible for such an object to exist in the physical world. However, some models of impossible objects have been constructed, such that when they are viewed from a very specific point, the illusion is maintained. Rotating the object or changing the viewpoint breaks the illusion, and therefore many of these models rely on forced perspective or having parts of the model appearing to be further or closer than they actually are.
Below is the Penrose triangle (an impossible object) that was first created by the Swedish artist Oscar Reutersvärd in 1934. The mathematician Roger Penrose independently devised and popularized it in the 1950s, describing it as “impossibility in its purest form.”
A 3D-printed version of the Reutersvärd Triangle illusion, its appearance created by a forced perspective.
So what does all this have to do with MCADCafe? (more…)
Last month at the RAPID + TCT event, many new things were presented and among those was GE Additive’s setting a target of growing its new additive manufacturing business to $1 billion by 2020, and selling 10,000 metal 3D printing machines in 10 years, building upon acquisitions it announced last year.
“It’s a big number,” said Tim Warden, senior sales director of GE Additive. “That’s why they’re investing heavily,” he said, referring to GE.
GE controls Concept after agreeing last October to buy an initial 75% stake in the German company, with plans to acquire the rest over an undisclosed number of years. The GE Additive turned to Concept Laser after a previously announced deal with SLM Solutions fell through.
The company estimates that it ultimately can expand additive manufacturing into a $10 billion business. GE owns more than 70% of Arcam but doesn’t have full control of the Swedish company.
The following video shows GE Power’s advanced manufacturing facility in Greenville, SC to learn about GE Additive’s metal 3D printing process for creating a gas turbine component that is used to power homes.
GE Additive and the Power of Additive Manufacturing
For now, “We’re concentrating on Concept where we can do what we want to do,” Warden said. “We’re going to support Concept in every way possible.”
The spring season seems to be the time of year when many companies and professional organizations hold their annual conferences, and this spring was no exception. I’ve attended several events in the past few weeks and noted striking differences of two of them — divergence at RAPID + TCT 2017 and convergence at LiveWorx 17 — and that’s how I want to wrap up our spring 2017 trade event tour (although I have one more next week).
Divergence at RAPID + TCT 2017
Diverge (dih-vurj, dahy-): Tomove,lie,orextendindifferentdirections fromacommonpoint;branchoff. To turn aside or deviate, as from a path, practice,or plan.
3D printing/additive manufacturing (AM) are about making something digital into something analog. Although the technologies are 30+ years old, many things are still being done as they were in the beginning, such as building 3D models, exporting STL data, etc. However, several aspects of AM are diverging from its historical roots.
For example, the first AM materials were polymers, and they still account for ~85% of all materials used, but metals are coming on strong and now account for about 14% of the materials used. The range of materials being used, though, is constantly increasing — everything from ceramics to composites to food to living tissue.
Panel Discussion at RAPID + TCT 2017
Volume quantities are also diverging from one-offs or small quantities for rapid prototyping to real production quantities where the costs can be justified when costs go down and production speed goes up.
It’s not often (thankfully) that I cover two major conference events in the same week, but this week was exceptional (in a good way) — Siemens PLM Connection and RAPID + TCT 3D Printing & Manufacturing.
Siemens PLM Connection
The Siemens PLM Connection event in Indianapolis was a first timer for me and I got a lot out of it.
The major theme I came away with was Siemens’ push for what it calls the digital enterprise hub based on a digital twin.
There are many definitions of the digital twin, but for Siemens, a digital twin is a set of computer models that provide the means to design, validate and optimize a part, a product, a manufacturing process or a production facility in the virtual world. It does these things fast, accurately and as close as possible to the real thing – the physical counterpart. These digital twins use data from sensors that are installed on physical objects to represent their near real time status, working condition or position.
Siemens supports digital twins for product design, manufacturing process planning, and production through the Smart Factory loop and via the Smart Product.
A deployment of a digital twin includes three pillars: in product design, in manufacturing process planning and in feedback loops.
1. In product design. A digital twin includes all design elements of a product, namely: (more…)
Clean up after anything is not usually an especially enjoyable endeavor, even where subtractive or additive manufacturing processes are concerned. This is where post processing comes in.
The Problem with CAD In Subtractive Manufacturing
To cut parts using a CNC cutting machine, it has to be programmed with the path of the desired shape or nest of shapes. Most parts are designed with a CAD program where they are saved in a CAD drawing format, such as DWG, STEP, or several others.
But you can’t just take the CAD file and send it to a cutting machine. It has to be interpreted first, so the CNC on the cutting machine can understand it. The problem with CAD file formats is that:
They usually contain a lot of information that the CNC cutting machine doesn’t need or would find confusing, such as title blocks, Bills Of Material, dimension lines, borders, welding symbols, etc.
They usually have multiple layers, some of which are useful to the CNC and some of which the CNC needs to ignore.
They sometimes have many parts in one file, some of which might need to be cut on the CNC cutter, and some might need to be machined, cast, or sent to an EDM.
They don’t have all of the information needed by a CNC machine. Machines need to be told when to turn a process on and off, how to lead-in and lead-out from a part, etc. All of this information is referred to as the process technology.
Last week marked the 50th edition of one of the world’s biggest technology spectacles – CES 2017 – showcasing the connected future of technology. With more than 3,800 exhibiting companies and exhibit space of more than 2.6 million net square feet, CES 2017 hosted some the world’s biggest companies in addition to hosting more than 600 startups. More than 175,000 industry attendees, including 55,000 from outside the U.S., convened in Las Vegas to discover the latest and greatest in many segments of the technology industry.
Probably one of the big trends at CES 2017 was Amazon’s Alexa assistant integrated into all sorts of gadgets everywhere, including cars! Not to be outdone, at this year’s CES, though, no fewer than 56 exhibitors were under the 3D Printing banner – many that you’ve heard of and a few that you probably haven’t. Although there were some basic retreads on previously released products, there were significant developments presented, and the ones that caught our eye were in the areas of materials (metals and ceramics) and affordability (sub-$500 machines).
It’s almost the end of November, so with just over a month left of this year, it’s not too early to start thinking about what we’ll be covering in 2017. The calendar below reflects what we perceive as some of the most important topics today, as well as feedback from our readers and other supporters.
The main theme for each month will be covered in an extended article or series of articles so that the topic can be covered in a more comprehensive way. We’ll also be covering some of the major MCAD events throughout the year, reporting what we see and hear from vendors, partners, and attendees.
We’ll also be covering some of the major MCAD events throughout the year, reporting what we see and hear from vendors, partners, and attendees. All of the events we attend will include daily written coverage and Tweets throughout event days, as well as video and audio interviews.
If you have any thoughts of topics you would like to see covered in 2015, feel free to contact me at email@example.com or 719.221.1867.
We look forward to an exciting 2017and providing you with the MCAD content you want most for improving your design, engineering, and manufacturing processes.
Keep MCADCafe.com your source for all things MCAD because 2017 is going to be a great year!
2017 MCADCafe Editorial Calendar of Monthly Topics
January 2017 – CAM Trends
February 2017 — Cloud Computing with MCAD Applications