Patent Publication Number: US-2018050501-A1

Title: Apparatus and Method to Authenticate 3D Printer Consumables

Description:
FIELD OF THE DISCLOSURE 
     The present disclosure relates generally to identification and authentication of consumables and, more particularly, to an apparatus and method to authenticate 3D printer consumables. 
     BACKGROUND 
     Many types of 3D printers use a filament or other material as a consumable to print three-dimensional objects. A 3D printer that can identify markers in a particular filament or other consumable has many advantages over traditional 3D printers and filament. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of a 3D printer in accordance with the teachings of this disclosure. 
         FIG. 2  is a block diagram of a detector in accordance with the teachings of this disclosure. 
         FIG. 3  is a block diagram of an example extrusion head in accordance with the teachings of this disclosure. 
         FIG. 4  is a flowchart representative of example machine readable instructions that may be executed to implement the example 3D printer of  FIG. 1 . 
         FIG. 5  is a flowchart representative of example machine readable instructions that may be executed to implement the example 3D printer of  FIG. 1  in conjunction with the extrusion head of  FIG. 3 . 
         FIG. 6  is a block diagram of an example processing system capable of executing the example machine readable instructions of  FIGS. 4 and 5  to implement the example 3D printer of  FIG. 1 , the example detector of  FIG. 2  and the example extrusion head of  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION 
     Three-dimensional (3D) printers are capable of printing three-dimensional objects. These 3D objects can be used in a variety of commercial and/or non-commercial applications including rapid prototyping, end-use products, and collectibles among others. A wide variety of 3D printing technologies are available, each using a different type of consumable to create a three-dimensional printed object. It would be advantageous for a 3D printer to be able to recognize the type of consumable being used and to adjust the printer settings accordingly. Using improper settings for a particular consumable may cause a 3D printer to not print an object properly and could even damage the printer itself. 
     In addition, many manufacturers of 3D printers also sell consumables and the sale of these consumables represents a large portion of their income. If competitors are able to sell generic consumables that can be used with these 3D printers, the manufacturers of the 3D printers may lose this valuable source of income. In addition, an off-brand consumable might not work as well with a 3D printer and may even damage the printer. This can potentially lead to false warranty claims made by a consumer against the 3D printer manufacturer that should not be valid because an inappropriate consumable was used with the printer. As such, it is desirable for 3D printers to recognize generic consumables and only allow consumables provided by the manufacturer of the 3D printer or other authorized parties to be used with the printer. 
     Another object of the present invention is to allow a 3D printer to mark an object while it is being printed so that the object can later be identified as being printed by a specific printer. This can be done for a variety of reasons including security purposes or to allow items to be printed as collectibles. Another object of the present invention is to allow a 3D printer to mark certain areas of a 3D printed object. This allows for additional security on the object being printed as well as allowing for an artistic signature to be added to the object such that a user of a 3D printer can mark an object in a manner that no other user will. 
     The present invention can be used with consumables for a variety of 3D printer technologies including thermoplastic, photopolymer, powder and laminated technologies. One type of 3D printer technology is fused deposition modeling (FDM). In FDM, the consumable is a thermoplastic filament that is heated to its melting point and extruded through a nozzle. The object is built in additive layers using the filament material. The nozzle moves horizontally in two dimensions to extrude the filament in the proper locations based on the design of the object being printed. As the filament is extruded, it cools and hardens. After one layer is completed, the next layer is printed and so on until the entire object is printed. The printer may also have a separate nozzle for extruding support material to support upper layers of the object during printing. After printing the object, the support material can be dissolved or removed from the object. 
     There are a variety of different types of filament that can be used with 3D printers. Two of the most popular are polyactic acid (PLA) and acrylonitrile butadiene styrene (ABS) filaments. PLA, ABS and other types of filaments have different properties that are better suited for different types of printing projects. However, these different types of filaments often have different melting temperatures or other parameters that must be accounted for by the 3D printer. If a 3D printer does not appropriately adjust its settings to account for the type of filament being used, the object being printed will not print properly and the printer itself may be damaged. It is an object of the present invention to mark different types of filaments with an invisible marker that can be detected by a 3D printer that automatically adjusts its settings to account for the type of filament being used. 
     Example methods, apparatus, and/or articles of manufacture disclosed herein provide for authentication of 3D printer filament. In examples disclosed herein, filament for FDM 3D printers is marked by embedding ceramic, luminescent phosphors in the filament. In examples disclosed herein, a 3D printer contains a detector that detects the presence of the phosphors in the filament and only allows printing with the filament if the phosphors are present. In some examples disclosed herein, the 3D printer detects the presence of phosphors in a filament and adjusts the settings of the printer based on the detected phosphor. In other examples disclosed herein, a 3D printer mixes phosphor with filament as an object is being printed in order to mark the object with the phosphor. 
     Another type of 3D printer technology is photopolymer technology including stereolithography and digital light processing (DLP). In these types of 3D printer technologies, the consumable is a liquid plastic that hardens when exposed to a laser or other light source. In these 3D printers, an object is built in layers by exposing a liquid plastic to a light source at the appropriate locations according to the design of the object to be printed. Once the liquid plastic hardens, the printer does the same thing for the next layer and continues this process until all the layers of the object are complete. 
     Example methods, apparatus, and/or articles of manufacture disclosed herein provide for authentication of photopolymer consumables for 3D printers. In examples disclosed herein, photopolymers for stereolithography or DLP 3D printers are marked by embedding ceramic, luminescent phosphors in the photopolymer. In examples disclosed herein, a 3D printer contains a detector that detects the presence of the phosphors in the photopolymer and only allows printing with the photopolymer if the phosphors are present. In some examples disclosed herein, the 3D printer detects the presence of phosphors in photopolymer and adjusts the settings of the printer based on the detected phosphor. In other examples disclosed herein, a 3D printer mixes phosphor with a photopolymer as an object is being printed in order to mark the object with the phosphor. 
     Another type of 3D printer technology is powder technology including selective laser sintering (SLS), selective laser melting (SLM), and electron beam melting (EBM). In these 3D printing technologies, the consumable is a powdered material that is fused together to form a printed object when exposed to a laser, in the case or SLS or SLM, or to an electron beam, in the case of EBM. 
     Example methods, apparatus, and/or articles of manufacture disclosed herein provide for authentication of powder consumables for 3D printers. In examples disclosed herein, powder consumables for 3D printers are marked by embedding ceramic, luminescent phosphors in the powder. In examples disclosed herein, a 3D printer contains a detector that detects the presence of the phosphors in the powder consumable and only allows printing with the powder if the phosphors are present. In some examples disclosed herein, the 3D printer detects the presence of phosphors in powder consumables and adjusts the settings of the printer based on the detected phosphor. In other examples disclosed herein, a 3D printer mixes phosphor with a powder as an object is being printed in order to mark the object with the phosphor. 
     Another type of 3D printer technology is laminated object manufacturing (LOM). In LOM 3D printers, layers of paper, plastic or metal laminates are fused together with heat and/or pressure and cut with a laser or blade into the appropriate shape of an object being printed. 
     Example methods, apparatus, and/or articles of manufacture disclosed herein provide for authentication of laminate consumables for LOM 3D printers. In examples disclosed herein, laminate consumables for LOM 3D printers are marked by embedding ceramic, luminescent phosphors in the laminate. In examples disclosed herein, a 3D printer contains a detector that detects the presence of the phosphors in the laminate consumable and only allows printing with the laminate if the phosphors are present. In some examples disclosed herein, the 3D printer detects the presence of phosphors in laminate consumable and adjusts the settings of the printer based on the detected phosphor. In other examples disclosed herein, a 3D printer mixes phosphor with a laminate consumable as an object is being printed in order to mark the object with the phosphor. 
       FIG. 1  is a block diagram of a 3D printer  100  in accordance with the teachings of this disclosure. In the illustrated example, the 3D printer  100  is a FDM type printer. In other examples, the 3D printer  100  may be one that uses any other type of 3D printing technology including stereolithography, digital light processing, selecting laser sintering, selective laser melting, electronic beam melting, or laminated object manufacturing, among others. The example 3D printer  100  of  FIG. 1  includes a build material filament  102 , a support material filament  104 , a detector  106 , a control  108 , an extrusion head  110 , a build platform  112  and a sample  114 . 
     The example build material filament  102  of  FIG. 1  is comprised of a traditional 3D printer filament that has been embedded with ceramic, luminescent phosphors called taggant. In some examples, the build material filament  102  is a PLA filament. In some examples, the build material filament  102  is ABS filament. In other examples, the build material filament  102  may be any other type of filament compatible with the 3D printer  100 . 
     In the illustrated example, the build material filament  102  is a thermoplastic spool with a known melting temperature. During the printing process, the build material filament  102  is unspooled and passed through the extrusion head  110  where it is heated to its melting point. The melted build material filament  102  is then sprayed into appropriate locations by the example extrusion head  110  to form the shape of the example sample  114 . The melted build material filament  102  then cools and hardens into the appropriate shape. In some examples, the 3D printer  100  contains multiple filaments comprised of different materials. This allows the 3D printer  100  to print the sample  114  with a combination of different materials. 
     In the illustrated example, taggant is embedded into the build material filament  102 . Taggant consists of inorganic, ceramic particles that have the optical property of luminescence. Luminescence is the property of certain materials such that when they are illuminated by light at a particular wavelength (the excitation wavelength), they emit light at another wavelength (the emission wavelength). In the illustrated example, the taggant embedded into the build material filament  102  consists of inorganic, ceramic phosphors with a mean particle size of less than one micron in diameter. Accordingly, they do not interact with or change the properties of the example build material filament  102  and do not interfere with the normal operation of the example 3D printer  100 . In examples where the 3D printer  100  contains multiple filaments, different taggants with different excitation and emission wavelengths are embedded in each of the filaments. This allows the identification of each type of filament material that is used to print the sample  114 . 
     In the illustrated example, taggant is mixed with the build material filament  102  during the manufacture of the filament and is evenly dispersed throughout the build material filament  102 . In some examples, taggant is embedded in the build material filament  102  after the filament is manufactured. In the illustrated example, taggant is embedded in the build material filament  102  such that the filament has the same optical luminescent properties as the taggant such that the build material filament  102  emits light at the taggant&#39;s emission wavelength when it is illuminated by light at the taggant&#39;s excitation wavelength. 
     The example support material filament  104  is a material used to temporarily build support structures while the example sample  114  is being printed by the example 3D printer  100 . The example 3D printer  100  constructs the example sample  114  using an additive process by building each layer of the sample  114  from the bottom upwards. Therefore, for certain objects, certain portions of the example sample  114  may need to be supported until the entire sample  114  is printed. This is accomplished by using support structures which are produced from the example support material filament  104 . In the illustrated example, the support material filament is a different material than the build material filament  102 . In the illustrated example, after the sample  114  is finished being printed, any support structures made from the support material filament  104  can be broken off of the sample  114 . In some examples, the support material filament  104  is dissolvable in a certain liquid such that after the sample  114  is finished printing, the sample  114  can be placed in this liquid and the support structures will dissolve. In the illustrated example, the support material filament  104  does not contain taggant. 
     The example detector  106  detects the presence of taggant in the example build material filament  102 . In the illustrated example, the detector  106  illuminates the build material filament  102  with light at the taggant&#39;s excitation wavelength and detects the emission of light at the taggant&#39;s emission wavelength by the build material filament  102 . The example detector  106  is discussed in further detail below in connection with  FIG. 2 . 
     The example control  108  controls the operation of the example 3D printer  100 . In the illustrated example, the control  108  holds data about the sample  114  and communicates with the extrusion head  110  in order for the extrusion head  110  to print the sample  114  in the appropriate shape. The example control  108  also communicates with the example detector  106  to control the operation of the detector  106 . In some examples, the control  108  contains data about where on the sample  114  taggant should be placed. In some examples where the 3D printer  100  uses multiple filaments, the control  108  holds data about which filament to use for which portions of the sample  114 . 
     The example extrusion head  110  prints the example sample  114 . The example extrusion head  110  has two extrusion nozzles, one for extruding build material and one for extruding support material. In the illustrated example, the support material filament  104  and the build material filament  102  are unspooled and passed to the extrusion head  110 . The example extrusion head  110  moves in two dimensions in order to extrude the build material and support material in the appropriate locations in order to print the example sample  114  in accordance to the design stored in the example control  108 . 
     The example build platform  112  is the surface upon which the example sample  114  is printed. The example sample  114  is printed in layers starting with the bottom layer and then building subsequent layers in an additive process. After each layer of the example sample  114  is printed by the extrusion head  110 , the build platform  112  lowers so that the extrusion head  110  can print the next layer. 
     The example sample  114  is the object that is printed by the example 3D printer  100 . The shape of the example sample  114  is stored in the example control  108  along with the necessary instructions for printing it. The example sample  114  is printed using the example build material filament  102  which contains embedded taggant. Therefore, the example sample  114  will contain embedded taggant when it is completed. 
       FIG. 2  is a block diagram of the example detector  106  of  FIG. 1 . The example detector  106  includes an excitation source  200 , a photo element  202  and a filter  204 . 
     The example excitation source  200  emits light at the excitation wavelength of the taggant embedded in the example build material filament  102 . In the illustrated example, the excitation source  200  is a light emitting diode. In other examples, the excitation source  200  may be a laser or any other device or component capable of emitting light at the appropriate wavelength. In the illustrated example, the excitation wavelength of the taggant in the build material filament  102  is in the infrared portion of the electromagnetic spectrum. In other examples, the excitation wavelength of the taggant in the build material filament  102  may be in any other portion of the electromagnetic spectrum. 
     The example photo element  202  detects light at the emission wavelength of the taggant in the example build material filament  102 . In the illustrated example, the photo element  202  is a photodiode. In other examples, the photo element  202  may be any other device or component capable of detecting light at the appropriate wavelength. In the illustrated example, the emission wavelength of the taggant in the build material filament  102  is in the infrared portion of the electromagnetic spectrum. In other examples, the emission wavelength of the taggant in the build material filament  102  may be in any other portion of the electromagnetic spectrum. 
     The example filter  204  is an optical filter that blocks light at wavelengths other than the emission wavelength of the taggant embedded in the build material filament  102 . This prevents light at other wavelengths from interfering with the example photodiode  202  and its detection of the taggant&#39;s luminescent emission. 
       FIG. 3  is a block diagram of another example extrusion head  110  of  FIG. 1 . In the illustrated example of  FIG. 3 , the extrusion head  110  includes a build material extrusion nozzle  300 , a support material extrusion nozzle  302  and a taggant extrusion nozzle  304 . The example build material extrusion nozzle  300  extrudes build material to print the example sample  114  of  FIG. 1 . The example support material extrusion nozzle  302  extrudes support material to print support structures for the example sample  114  of  FIG. 1 . In the illustrated example of  FIG. 3 , the taggant extrusion nozzle  304  extrudes taggant while the sample  114  is being printed. In this example, the build material filament  102  does not contain taggant. Instead, taggant is extruded from the example taggant extrusion nozzle  304  simultaneously with build material being extruded from the example build material extrusion nozzle  300 . In this manner, taggant becomes embedded in the example sample  114  while the sample  114  is being printed. 
     While an example manner of implementing the apparatus and method to authenticate 3D printer filament has been illustrated in  FIG. 1 , one or more of the elements, processes and/or devices illustrated in  FIG. 1  may be combined, divided, re-arranged, omitted, eliminated and/or implemented in any other way. Further, the example detector  106 , control  108  and/or, more generally, the example 3D printer  100  of  FIG. 1  may be implemented by hardware, software, firmware and/or any combination of hardware, software and/or firmware. Thus, for example, any of the example detector  106 , control  108  and/or, more generally, the example 3D printer  100  of  FIG. 1  of  FIG. 1  could be implemented by one or more circuit(s), programmable processor(s), application specific integrated circuit(s) (ASIC(s)), programmable logic device(s) (PLD(s)), microprocessor(s), hardware processor(s), and/or field programmable logic device(s) (FPLD(s)), etc. When any of the system or apparatus claims of this patent are read to cover a purely software and/or firmware implementation, at least one of the example detector  106 , control  108  and/or, more generally, the example 3D printer  100  of  FIG. 1  to authenticate documents of  FIG. 1  is hereby expressly defined to include a tangible computer readable storage medium such as a memory, DVD, CD, Blu-ray, etc. storing the software and/or firmware. Further still, the example detector  106 , control  108  and/or, more generally, the example 3D printer  100  of  FIG. 1  may include more than one of any or all of the illustrated elements, processes and devices. 
       FIG. 4  is a flowchart representative of example machine readable instructions for implementing the example 3D printer  100  of  FIG. 1 . In the example flowchart of  FIG. 4 , the machine readable instructions comprise program(s) for execution by a processor such as the processor  612  shown in the example computer  600  discussed below in connection with  FIG. 6 . The program(s) may be embodied in software stored on a tangible computer readable storage medium such as a CD-ROM, a floppy disk, a flash drive, a hard drive, a digital versatile disk (DVD), a Blu-ray disk, or a memory associated with the processor  612 , but the entire program and/or parts thereof could alternatively be executed by a device other than the processor  612  and/or embodied in firmware or dedicated hardware. Further, although the example program(s) is described with reference to the flowchart illustrated in  FIG. 6 , many other methods of implementing the example 3D printer  100  of  FIG. 1  may alternatively be used. For example, the order of execution of the blocks may be changed, and/or some of the blocks described may be changed, eliminated, or combined. 
     As mentioned above, the example processes of  FIG. 4  may be implemented using coded instructions (e.g., computer readable instructions) stored on a tangible computer readable storage medium such as a hard disk drive, a flash memory, a read-only memory (ROM), a compact disk (CD), a digital versatile disk (DVD), a cache, a random-access memory (RAM) and/or any other storage media in which information is stored for any duration (e.g., for extended time periods, permanently, brief instances, for temporarily buffering, and/or for caching of the information). As used herein, the term tangible computer readable storage medium is expressly defined to include any type of computer readable storage device and/or disk and to exclude propagating signals. Additionally or alternatively, the example processes of  FIG. 4  may be implemented using coded instructions (e.g., computer readable instructions) stored on a non-transitory computer readable medium such as a hard disk drive, a flash memory, a read-only memory, a compact disk, a digital versatile disk, a cache, a random-access memory and/or any other storage media in which information is stored for any duration (e.g., for extended time periods, permanently, brief instances, for temporarily buffering, and/or for caching of the information). As used herein, the term non-transitory computer readable storage medium is expressly defined to include any type of computer readable storage device and/or disk and to exclude propagating signals. As used herein, when the phrase “at least” is used as the transition term in a preamble of a claim, it is open-ended in the same manner as the term “comprising” is open ended. Thus, a claim using “at least” as the transition term in its preamble may include elements in addition to those expressly recited in the claim. 
     In the example of  FIG. 4 , the detector  106  determines whether the build material filament  102  contains taggant and only prints the example sample  114  if taggant is detected.  FIG. 4  begins when the example excitation source  200  of the example detector  106  illuminates the example build material filament  102  with light (block  400 ). In the illustrated example, the excitation source  200  illuminates the build material filament  102  for a particular length of time (e.g., 100 milliseconds). In other examples, the excitation source  200  may illuminate the build material filament  102  for variable amounts of time. In the illustrated example, if the build material filament  102  is authorized for use with the 3D printer  100 , it contains taggant with known excitation and emission wavelengths. In the illustrated example, the excitation source  200  emits light at a wavelength equal to the excitation wavelength of the taggant. If the example build material filament  102  is authorized and contains taggant, the taggant will emit light at its emission wavelength when it is illuminated by light at its excitation wavelength. If the example build material filament  102  is not authorized and does not contain taggant, it will not emit luminescence when it is illuminated. In the illustrated example, the excitation source  200  illuminates the build material filament  102  with light at one particular wavelength. In other examples, the excitation source  200  illuminates the build material filament  102  with light at multiple wavelengths in a particular sequence. This allows for the detection of multiple types of taggants. 
     After the example excitation source  200  of the example detector  106  illuminates the example build material filament  102  with light (block  400 ), the example photo element  202  of the example detector  106  detects light emitted by the example build material filament  102  (block  402 ). Any luminescent emission by the build material filament  102  will pass through the example filter  204  and illuminate the example photo element  202 . If the example build material filament  102  contains taggant, it will emit light at the emission wavelength of the taggant. Light at this wavelength will pass through the example filter  204  and be detected by the example photo element  202 , which is sensitive to light at this wavelength. The example photo element  202  determines the strength of the luminescent signal emitted by the example build material filament  102 . 
     After the example photo element  202  detects the light emitted by the example build material filament  102  (block  402 ), the example control  108  determines whether additional the example build material filament  102  should be illuminated additional times (block  404 ). In the illustrated example, the excitation source  200  illuminates the build material filament a predetermined number of times and the photo element  202  measures the luminescent response after each such illumination. In some examples, the excitation source  200  illuminates the build material filament once. In other examples, the number of times that the excitation source  200  illuminates the build material filament  102  depends on the luminescent response measured by the photo element  202 . If the example control  108  determines that additional illuminations are needed, control returns to block  400 . If the example control  108  determines that additional illuminations are not needed, control advances to block  406 . 
     After the example control  108  determines that additional illuminations are not needed (block  404 ), the control  108  determines whether taggant is present in the example build material filament  102  (block  406 ). In the illustrated example, the control  108  determines that taggant is present if the luminescence detected by the photo element  202  is above a threshold. In other examples, other methods of determining whether taggant is present in the example build material filament  102  may be based on the luminescence detected by the photo element  202 . In some examples, the control  108  also determines the type of taggant detected based on the luminescence detected in block  402 . If the example control  108  determines that taggant is present, control passes to block  410 . If the example control  108  determines that taggant is not present, control passes to block  408 . 
     After the example control  108  determines that taggant is not present in the build material filament  102  (block  406 ), the control  108  alerts the user that the build material filament  102  is not authorized to be used with the printer (block  408 ). In the illustrated example, the user is alerted through a visual display. In other examples, an audio alert or other methods of alerting the user may be used. When the example control  108  determines that the example build material filament  102  does not contain taggant and is not authorized to be used to print, the example 3D printer  100  will not allow the example sample  114  to be printed with the un-authorized build material filament  102 . Therefore, the example of  FIG. 4  ends at this point. 
     After the example control  108  determines that taggant is present in the example build material filament  102  (block  406 ), the example 3D printer  100  prints the example sample  114  via its normal operation (block  410 ). This ensures that authorized filament prints normally. In some examples, the 3D printer  100  prints the example sample  114  after the control  108  adjusts the settings of the 3D printer  100  based on the taggant detected in block  406 . The example of  FIG. 4  then ends. 
       FIG. 5  is a flowchart representative of example machine readable instructions for implementing the example 3D printer  100  in combination with the example extrusion head  110  of  FIG. 3 . In the example of  FIG. 5 , the extrusion head  110  of  FIG. 3  is used in the 3D printer  100  to mix taggant with filament while an object is being printed. This allows an object to be later identified as being printed by a specific 3D printer. 
     The example of  FIG. 5  begins when the extrusion head  110  is moved into position to begin printing the sample  114  (block  500 ). The position in which to move the example extrusion head  110  is determined by the design for the particular shape of the example sample  114  stored in the example control  108 . 
     After the example extrusion head  110  moves to its initial position to begin printing the example sample  114  (block  500 ), the example control  108  determines whether support material or build material is needed at this location based on the design for the sample  114  stored in the control  108  (block  502 ). If support material is needed, control passes to block  504 . If support material is not needed, control passes to block  506 . 
     After the example control  108  determines that support material is needed at the current position of the example extrusion head  110  (block  502 ), the example support material extrusion nozzle  302  extrudes a portion of the example support material filament  104  (block  504 ). After the example support material filament  104  is extruded, it will eventually dry and harden into the support structure needed to print the example sample  114 . Control then passes to block  508 . 
     After the example control  108  determines that support material is not needed at the current position of the example extrusion head  110  (block  502 ), the example build material extrusion nozzle  302  emits a portion of the example build material filament  102  and the example taggant extrusion nozzle  304  simultaneously extrudes a small amount of taggant (block  506 ). The example build material filament  102  will eventually harden around and dry around the extruded taggant to become the example sample  114 , which will subsequently contain taggant itself. The example sample  114  can later be identified as having been printed by the specific example 3D printer  100  by detecting the presence of the embedded taggant. Control then passes to block  508 . 
     After the example extrusion head  110  extrudes support material filament (block  504 ) or build material filament and taggant (block  506 ), the example control  108  determines whether additional printing is needed (block  508 ). If the example sample  114  has not been completely printed, then the example control  108  determines that additional printing is needed and control returns to block  500  and the example extrusion head  110  is moved to the next location required to continue the printing of the sample  114 . If the example sample  114  is completely printed, then the example control  108  determines that no additional printing is needed and the example of  FIG. 5  ends. 
       FIG. 6  is a block diagram of a processor platform  600  capable of executing the instructions of  FIGS. 4-5  to implement the example 3D printer of  FIG. 1 . The processor platform  600  can be, for example, a server, a personal computer, an Internet appliance, a DVD player, a CD player, a Blu-ray player, a gaming console, a personal video recorder, a smart phone, a tablet, a printer, or any other type of computing device. 
     The processor platform  600  of the instant example includes a processor  612 . As used herein, the term “processor” refers to a logic circuit capable of executing machine readable instructions. For example, the processor  612  can be implemented by one or more microprocessors or controllers from any desired family or manufacturer. 
     The processor  612  includes a local memory  613  (e.g., a cache) and is in communication with a main memory including a volatile memory  614  and a non-volatile memory  616  via a bus  618 . The volatile memory  614  may be implemented by Synchronous Dynamic Random Access Memory (SDRAM), Dynamic Random Access Memory (DRAM), RAMBUS Dynamic Random Access Memory (RDRAM) and/or any other type of random access memory device. The non-volatile memory  616  may be implemented by flash memory and/or any other desired type of memory device. Access to the main memory  614 ,  616  is controlled by a memory controller. 
     The processor platform  600  also includes an interface circuit  620 . The interface circuit  620  may be implemented by any type of interface standard, such as an Ethernet interface, a universal serial bus (USB), and/or a PCI express interface. 
     One or more input devices  622  are connected to the interface circuit  620 . The input device(s)  622  permit a user to enter data and commands into the processor  612 . The input device(s) can be implemented by, for example, a keyboard, a mouse, a touchscreen, a track-pad, a trackball, isopoint and/or a voice recognition system. 
     One or more output devices  624  are also connected to the interface circuit  620 . The output devices  624  can be implemented, for example, by display devices (e.g., a liquid crystal display, a cathode ray tube display (CRT), a printer and/or speakers). The interface circuit  620 , thus, typically includes a graphics driver card. 
     The interface circuit  620  also includes a communication device such as a modem or network interface card to facilitate exchange of data with external computers via a network  626  (e.g., an Ethernet connection, a digital subscriber line (DSL), a telephone line, coaxial cable, a cellular telephone system, etc.). 
     The processor platform  600  also includes one or more mass storage devices  628  for storing software and data. Examples of such mass storage devices  628  include floppy disk drives, hard drive disks, compact disk drives and digital versatile disk (DVD) drives. 
     The coded instructions  632  of  FIG. 6  may be stored in the mass storage device  628 , in the volatile memory  614 , in the non-volatile memory  616 , and/or on a removable storage medium such as a CD or DVD. 
     Although certain example apparatus, methods, and articles of manufacture have been disclosed herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all apparatus, methods, and articles of manufacture fairly falling within the scope of the claims of this patent.