I.          Background  

3D printing is a 30-year old technology that is currently entering the mainstream, to great fanfare. Despite the 3D printing industry’s double-digit (%) growth over the past year, the use of 3D printers has not yet become commonplace. The question is: Is something holding it back?  Conventional wisdom is that intellectual property has driven innovation by creating competition, which fosters advances in technology because of the need for IP workarounds. Our Founding Fathers here in the US were so committed to this idea that they built IP protection into the Constitution. Today, any big company will tell you that the limited monopoly of a patent or copyright gives them a head start and ultimately fosters innovation and competition.

Recently, some innovators have challenged the conventional wisdom, arguing that IP stifles innovation. Applying this thinking to 3D printing, they argue that patents have held back innovation in 3D printing technology and thus because companies are afraid of getting sued, they do not spend the resources to research and develop the technology. This minimizes competition, which keeps prices high and builds barriers to keep new entrants and affordable products out of the market.

Others argue that the only thing holding 3D printing back is the technology itself––printers are either too slow, too cumbersome or incapable of printing objects that people actually want, partly due to limitations in materials.  Regardless of where one stands in this debate, the threat of a lawsuit is certainly real and the 3D Printing Patent Wars, like the Smart Phones Wars, are probably not too far down the pike. For example, Formlabs, Inc. raised millions for its Form 1 3D printer through the crowd-funding platform Kickstarter. According to Formlabs, there were no low-cost 3D printers that met the quality standards of the professional designer, so “[a]fter a great deal of research, engineering, and experimentation, [they] figured out how to do it at a much, much lower cost, making this premium technology available to everyone.”[1]

In November 2012, 3D Systems sued Formlabs and Kickstarter in District Court in South Carolina, alleging that the Form 1 printer infringed U.S. Patent No. 5,597,520 (the ’520 patent) to Smalley et al. entitled “Simultaneous Multiple Layer Curing in Stereolithography.”  3D Systems alleged that both companies infringed at least claims 1 and 23 of the ’520 patent. Claim 1 recites:

1. An improved method of stereolithographically forming a three-dimensional object by forming cross-sectional layers of said object from a material capable of physical transformation upon exposure to synergistic stimulation comprising the steps of receiving data descriptive of said cross-sectional layers, forming said cross-sectional layers by selectively exposing said material to said synergistic stimulation according to said data descriptive of said cross-sectional layers to build up the three-dimensional object layer-by-layer, the improvement comprising the steps of: modifying data descriptive of at least a portion of at least one cross-sectional layer by copying said data from a first cross-section to a second cross-section; and using said modified data in forming said three-dimensional object.

The only substantial difference between claims 1 and 23 is that in claim 23 the data is modified by “shifting” instead of “copying” as in claim 1.  The ’520 patent expires January 28, 2014, and after settlement talks with Formlabs, the case was voluntarily dismissed on November 8, 2013.   On the same day, 3D Systems sued Formlabs in District Court in New York, this time alleging that the Form 1 printer infringed eight more patents.  These cases illustrate why many believe expiring patents will open the door to advancements in the technology: the inventions of expired patents are freely available for all to use, which may lead to new investment, innovation, and competition.

Many observers have pointed out that some of the early 3D printing patents have already expired.  For example, U.S. Patent No. 4,575,330 to 3D Systems’ Chuck Hull entitled “Apparatus for Production of Three-Dimensional Objects by Stereolithography,” which was dubbed by some as the “original U.S. stereolithography patent,” expired almost a decade ago.  Other early stereolithography patents also expired many years ago, including: U.S. Patent No. 4,929,402 to Hull, U.S. Patent No. 4,999,143 to Hull et al., and U.S. Patent No. 5,174,931 to Almquist et al.  It was the expiration of some Fused Deposition Modelling patents, such as U.S. Patent No. 5,121,329 to Stratasys’s Scott Crump, that apparently spawned a boom of growth in the consumer-level 3D printing industry.

Prior to the early FDM patents expiring, these printers cost thousands of dollars. A few years after expiration, FDM machines cost hundreds of dollars and the open-source community embraced the technology.  Whether the expiration of these patents drove this growth can be disputed, but the post-patent-expiration flood of low-cost, consumer grade 3D printers excites those who believe patents are holding the technology back.  The expiration of stereolithography patents may spark an even bigger boom in new 3D printers.

So is there a reason for the 3D printing startups to be excited now?  If you follow 3D printing closely, you already know that news of expiring patents has the community buzzing.   Several articles have mentioned “key patents” that will soon expire and allow the industry to explode.  What you probably have not seen is the identity of those patents and an explanation of the protected technology.  This article intends to highlight some potentially key patents that are set to expire soon.

II.        Key Patents

Even though many of the early 3D printing patents expired long ago, many more exist that protect the basic technologies and 3D printer companies are filing new applications all the time, for important new ways of doing things and incremental advances. But many patents are expiring now and within the coming months.  Here they are, in chronological order based on expiration date, with those expiring soonest appearing first.[2]  Although many of these patents disclose one or more inventions, the following is intended to provide a general description of some of the claimed subject matter in each patent.  The metes and bounds of each patent is defined by its claims, so don’t rely only on this general description.

5,569,349– Expired October 29, 2013

Current Assignment Data Unavailable 

U.S. Patent No. 5,569,349 to Almquist et al. entitled “Thermal Stereolithography” discloses an apparatus of and method for providing 3D objects through the principles of stereolithography using flowable materials.  The patent also discloses the rapid substitution of materials throughout part building and the use of support materials that are easily removable from the finished part.  Using a CAD system, the apparatus directs the nozzle to selectively dispense material at appropriate areas to form the part.  The flow is then blocked, allowing the material to harden, and the next section is formed in the same manner.   For parts needing support, a second material (e.g., wax, thermoplastic, hot melt glue) can be used to fill voids.  By using a second material with a different melting point, the second material can be removed from the final part more readily.

5,587,913 – Expired December 14, 2013

Assigned to Stratasys

U.S. Patent No. 5,587,913 to Abrams et al. entitled “Method Employing Sequential Two-Dimensional Geometry for Producing Shells for Fabrication by a Rapid Prototyping System” discloses a method for producing 3D objects using a computer-generated specification of a solid object to interleave the planning and building phases of production on a slice-by-slice basis.  Because the method does not require an explicit evaluation of the entire shell of the object at the outset, it ostensibly reduces the total time required to generate a finished part.  The method can be operated with CAD and STL data and can also be employed to create non-planar objects.

5,597,589 – Expiring January 28, 2014

Assigned to DTM Corporation

U.S. Patent No. 5,597,589 to Deckard entitled “Apparatus for Producing Parts by Selective Sintering” discloses an apparatus for producing a 3D object from powder.  The apparatus comprises a means for successively dispensing a plurality of layers of powder onto a target surface, an energy source (e.g., a laser), and a controller for directing the energy source at locations of each dispensed layer of powder at the target surface to fuse the powder and form a cross-section of the desired object.  To avoid undesirable shrinkage of the object being produced, the apparatus further comprises a temperature control means (e.g., an exhaust) for moderating the temperature difference between the unfused and fused powder.

5,609,812 – Expiring March 11, 2014

Current Assignment Data Unavailable

U.S. Patent No. 5,609,812 to Childers et al. entitled “Method of Making a Three-Dimensional Object by Stereolithography” discloses a method of producing a 3D object from a medium that is solidifiable upon exposure to synergistic stimulation (e.g., UV or IR radiation).  The invention improves upon a known stereolithographic method that involves selectively exposing layers of material to a beam of synergistic stimulation in a pattern to build up the 3D object layer by layer, where the pattern includes paths of exposure defined by vectors.  The improvement disclosed in this patent comprises a method of identifying an endpoint of a first vector and a beginning point of a second vector, scanning the synergistic stimulation along the first vector at a fixed velocity, and shuttering (i.e., mechanically blocking) the synergistic stimulation when it reaches the endpoint of the first vector.  The method further comprises directing the synergistic stimulation in a pattern to the beginning point of the second vector, unshuttering the stimulation when it reaches the beginning point, and scanning the stimulation along the second vector at a constant velocity.

5,609,813 – Expiring March 11, 2014

Current Assignment Data Unavailable

U.S. Patent No. 5,609,813 to Allison et al. entitled “Method of Making a Three-Dimensional Object by Stereolithography” discloses an apparatus and method of producing a 3D object from a medium that is solidifiable upon exposure to synergistic stimulation.  The method involves applying a layer of flowable material, generating and sequencing a pattern of exposure paths for the layer corresponding to a cross-section of the object, and exposing the exposure paths to synergistic stimulation according to the sequencing to form a layer of the 3D object.  This process is repeated until the object is formed, but with the step of sequencing being altered with a different sequence of exposure on at least one subsequent layer.

5,610,824 – Expiring March 11, 2014

Assigned to 3D Systems

U.S. Patent No. 5,610,824 to Vinson et al. entitled “Rapid and Accurate Production of Stereolithographic Parts” discloses an apparatus and method for producing a 3D object from a medium that is solidifiable upon exposure to radiation.  The method involves providing a container with the medium and generating a beam of radiation––having first and second intensities that differ from each other––at the medium to form cross-sections of the object.  The method further comprises scanning a first line on the material with the beam having the first intensity and scanning a second line on the material with the beam having the second intensity.  By using a beam with different intensities, the laser can be directed over portions of the material without curing any appreciable amount.  This can be particularly useful for large and complex objects, where a more powerful laser is required.

5,503,785 – Expiring June 2, 2014

Assigned to Stratasys

U.S. Patent No. 5,503,785 to Crump et al. entitled “Process of Support Removal for Fused Deposition Modeling” discloses a process for producing 3D objects having overhanging portions freely suspending in space.  The process involves dispensing a first, solidifiable material in a predetermined pattern to deposit multiple layers that define a 3D object and a separate 3D support structure.  The 3D support structure lies under the overhanging portions of the object, which require support during layer deposition.  A space is left between the underside of the overhanging portions of the object and the top side of the supporting structure.  A second, release material is dispensed into the space in a multiple-pass deposition process coordinated with the dispensing of the first material.  The second material is of a different composition than the first material so that a breakable bond is made with the first material.  This allows the support structures to be readily separable from the overhanging portions of the object, leaving only the object behind after removal.

5,637,169 – Expiring June 10, 2014

Current Assignment Data Unavailable

U.S. Patent No. 5,637,169 to Hull et al. entitled “Method of Building Three Dimensional Objects with Sheets” discloses methods of producing a 3D object using radiation.  One method involves dispensing a sheet of material capable of selective solidification onto a working surface and forming successive cross-sections of the object by selectively exposing portions of each sheet to electromagnetic radiation.  After portions of the sheets solidify, unexposed regions of the sheets are removed and the process is repeated to form the 3D object.  Two related methods are also disclosed, the main differences being that one incorporates sheets of insoluble material which become soluble upon exposure to electromagnetic radiation and the other incorporates sheets of material which are capable of selective cutting upon exposure to electromagnetic radiation.

5,639,070 – Expiring June 17, 2014

Assigned to DTM Corporation

U.S. Patent No. 5, 639,070 to Deckard entitled “Method for Producing Parts by Selective Sintering” discloses a method for producing a 3D part from powder.  The method involves dispensing a first layer of powder onto a target area and directing energy (e.g., a laser) at selected locations of the powder to fuse together a first cross-section of the part, leaving unfused powder remaining.  The next step involves dispensing a second layer of powder over both fused and unfused portions of the first layer and heating (e.g., with gas or a laser) the second layer of powder, but not all the way to its sintering temperature.  The method further involves directing energy at selected locations of the second layer of powder to fuse together a second cross-section of the part, while fusing the first and second fused layers together.  This process can be repeated to form the 3D part.

5,494,618 – Expiring June 27, 2014

Assigned to 3D Systems

U.S. Patent No. 5,494,618 to Sitzmann et al. entitled “Increasing the Useful Range of Cationic Photoinitiators in Stereolithography” discloses a process of stereolithography in which a 3D object is built up by polymerizing cationically polymerizable monomers by the catalytic action of cationic photoinitiators activated by a moving beam of UV light, such as an Argon ion laser.  The monomers comprise, e.g., vinyl ethers and epoxides, which make it possible to rapidly cure the vinyl ethers while leaving the epoxide largely uncured.  By post-curing the epoxides, any additional shrinking that occurs should not produce additional distortion of the object.  The process reduces the depth of cure and consequently enables production of thinner, more accurate polymer layers.

5,651,934 – Expiring July 29, 2014

Current Assignment Data Unavailable

U.S. Patent No. 5,651,934 to Almquist et al. entitled “Recoating of Stereolithographic Layers” discloses a method for forming a 3D object by adding subsequent layers to previously formed layers.  The method involves providing a volume of a building medium that is capable of selective physical transformation upon exposure to synergistic stimulation and forming a uniform coating over a previously formed layer of material, which includes sweeping a smoothing element over the previously formed layer to smooth the surface of the building material.  Synergistic stimulation is then applied to the building material to form the subsequent layer.  This process can be repeated to form the 3D object.  The patent also discloses an apparatus, which provides the means for carrying out the above method.

5,555,176 – Expiring October 19, 2014

Assigned to Jerry Zucker

U.S. Patent No. 5,555,176 to Menhennett et al. entitled “Apparatus and Method for Making Three-Dimensional Articles Using Bursts of Droplets” discloses an apparatus and method for producing a 3D object using successive bursts of flowable material.  The apparatus comprises a platform on which the droplets are placed, a material dispenser, and a dispenser positioning means for advancing the dispenser along a predetermined path.  The build material dispenser can be, e.g., a jet including a piezoelectric actuator.  In addition to the mechanical components, the apparatus further comprises a processor for controlling the dispenser and dispenser positioning means.  The processor can further comprise a burst control means for operating the dispenser to dispense a series of bursts of material or a corner forming means for constructing a corner of the object.  In contrast to a droplet-by-droplet approach, each burst in this apparatus is a plurality of successive droplets dispensed in relatively rapid succession to each other so that the material of the successive droplets combines at a target position.

5,572,431 – Expiring October 19, 2014
Assigned to Jerry Zucker

U.S. Patent No. 5,572,431 to Brown et al. entitled “Apparatus and Method for Thermal Normalization in Three-Dimensional Article Manufacturing” discloses an apparatus and method for producing a 3D object by re-solidifying build materials using a heat source.  The method involves dispensing a build material onto a platform to construct an object in layers which solidify after dispensing.  The object is then heated and melted such that it re-flows, and portions of the previously solidified building material are reshaped.  This process produces an object that more accurately reflects the predetermined coordinates and evens out surface irregularities.  The apparatus comprises a platform and dispensing means for jetting materials onto the platform.  The apparatus also comprises a heater, a body in connection with the heater, and position means for advancing the body along a predetermined path to heat the object and reshape the previously solidified portions.

5,529,471 – Expiring February 3, 2015

Assigned to University of Southern California

U.S. Patent No. 5,529,471 to Khoshevis entitled “Additive Fabrication Apparatus and Method” discloses an apparatus for producing 3D objects using additive fabrication techniques.  The apparatus comprises two nozzles for delivering fluid materials, two supply means for delivering fluid material to each nozzle, and two control means for moving and positioning the nozzles with respect to the object being produced.  An additional feature of the apparatus is the utilization of trowels, which enable rapid creation of smooth surfaces with better accuracy.  The trowels permit creation of various shapes using only the two trowels, instead of using a variety of tools needed in more traditional sculpturing and plastering.

5,733,497 – Expiring March 20, 2015

Assigned to DTM Corporation

U.S. Patent No. 5,733,497 to McAlea et al. entitled “Selective Laser Sintering with Composite Plastic Material” discloses a method for producing a 3D object by fusing powder materials.  The method involves applying a layer of composite powder on a target surface, where the composite powder consists of a polymer powder and a reinforcement powder.   After the powder is applied to the surface, energy (e.g., a laser) is directed at selected locations of the powder layer to fuse the powder and form a cross-section of the desired object.  This process is repeated and the unfused powder is removed, leaving the formed 3D object.

5,762,856 – Expiring June 9, 2015

Assigned to 3D Systems

U.S. Patent No. 5,762,856 to Hull entitled “Method for Production of Three-Dimensional Objects by Stereolithography” discloses a method of producing a 3D object from a material that is capable of solidifying upon exposure to radiation or synergistic stimulation.  The method involves providing a bath of a curable medium in a container and exposing it to heat or stimulation to form a lamina of an object.  As the previously formed lamina is lowered in the bath, a new layer of medium is then subjected to heat or stimulation to form another lamina.  This process is repeated to form the 3D object.

III.       CONCLUSION

Anyone who is interested in this technology should fully examine the specification and claims in each patent, as this article provides only a general description of some of the claimed subject matter.  Remember, the claims define the scope of the patent.

You can see that these patents cover some of the basic technology of 3D printing.  Whether the excitement over the expiration of these patents is met with an explosion or a dud is unknown.  Also unknown is when the major battles of the 3D Printing Patent Wars will begin.  New laws, evolving technology, and an unpredictable economy might affect 3D printing more than any of these patents.  Thus, it would be imprudent to say that the expiration of one or more of them is the key to growth because the market can dictate otherwise.  For now, we will need to wait and see.


[1] Kickstarter, “Form 1: An affordable, professional 3D printer,” http://www.kickstarter.com/projects/formlabs/form-1-an-affordable-professional-3d-printer (last visited Dec. 16, 2013).

[2] The expiration dates have been calculated for informational purposely only; they should not be relied upon in determining the rights of any party or patent holder.  The authors express no opinion on the accuracy of these dates.  The authors also express no opinion on the accuracy of the assignment data; patent ownership can change at any time.

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