as) United States
`a2) Patent Application Publication (1) Pub. No.: US 2007/0179656 Al
`(43) Pub. Date:
`Aug. 2, 2007
`Eshed et al.
`
`US 20070179656A1
`
`(54) RAPID PROTOTYPING APPARATUS
`
`Related U.S. Application Data
`
`(76)
`
`Inventors: David Eshed, Kfar-Saba (IL); Moshe
`Levi, Tel Aviv (IL); Eliahu M.
`Kritehman, Tel Aviv (IL): Hanan
`Gothait. Rehovot (IL); [gal Zeytoun,
`Avnei-Hefetz (IL); Dror Danai,
`Tel-Aviv (IL)
`
`(60)
`
`Provisional application No. 60/466,731, filed on May
`1, 2003.
`
`Publication Classification
`
`(51)
`
`(52)
`
`Int. Cl.
`(2006.01)
`G06F 19/00
`“WBWEL cossmexascenncnsosesiviies
`
`neceeemnnienes AUOELLD
`
`Correspondence Address:
`WOLF, BLOCK, SCHORR & SOLIS-COHEN
`LLP
`250 PARK AVENUE
`NEW YORK, NY 10177 (US)
`
`(21) Appl. No.:
`
`10/555,087
`
`(22)
`
`PCTFiled:
`
`May 2, 2004
`
`(86)
`
`PCT No.:
`
`PCT/TL04/00368
`
`ABSTRACT
`(57)
`Apparatus for producing an object by sequentially forming
`thin layers of a construction material one on top ofthe other
`responsive to data defining the object, the apparatus com-
`prising: aplurality ofprinting heads each having a surlace
`formed with a plurality of output orifices and controllable to
`dispense the construction material through eachorifice inde-
`pendently ofthe otherorifices; a shuttle to whichthe printing
`heads are mounted; a support surface; and a controller
`adapted to control the shuttle to move back and forth over
`the support surface and as the shuttle moves to control the
`printing headsto dispense the construction material through
`each of their respective orifices responsive to the data to
`form a first
`layer on the support surface and thereafter,
`sequentially the other layers; wherein eachprinting headis
`dismountable from the shuttle and replaceable indepen-
`dently ofthe other printing heads.
`
`§ 371 (c)(1),
`(2), (4) Date: Aug. 22, 2006
`
`36 _———
`
`Shenzhen Tuozhu 1008
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`Patent Application Publication Aug. 2,2007 Sheet 2 of 26
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`Patent Application Publication Aug. 2,2007 Sheet 11 of 26
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`Patent Application Publication Aug. 2,2007 Sheet 15 of 26
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`Patent Application Publication Aug. 2,2007 Sheet 16 of 26
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`Patent Application Publication Aug. 2,2007 Sheet 17 of 26
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`Patent Application Publication Aug. 2,2007 Sheet 18 of 26
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`Patent Application Publication Aug. 2,2007 Sheet 19 of 26
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`Patent Application Publication Aug. 2,2007 Sheet 20 of 26
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`Patent Application Publication Aug. 2,2007 Sheet 21 of 26
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`US 2007/0179656 Al
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`Patent Application Publication Aug. 2,2007 Sheet 23 of 26
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`Patent Application Publication Aug. 2,2007 Sheet 24 of 26
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`Patent Application Publication Aug. 2,2007 Sheet 25 of 26
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`US 2007/0179656 Al
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`Patent Application Publication Aug. 2,2007 Sheet 26 of 26
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`US 2007/0179656 Al
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`

`US 2007/0179656 Al
`
`Aug. 2, 2007
`
`RAPID PROTOTYPING APPARATUS
`
`RELATED APPLICATIONS
`
`[0001] The present application claims benefit of U.S.
`Provisional Application 60/466,731 filed May 1, 2003, the
`disclosure of which is incorporated herein by reference.
`
`FIELD OF THE INVENTION
`
`[0002] The present inventionrelates to apparatus, herein-
`after “rapid production apparatus”, for producing a 3-dimen-
`sional object by sequentially forming thin layers of material
`one on top of the other, responsive to data defining the
`object.
`
`BACKGROUND OF THE INVENTION
`
`[0003] Rapid production apparatus (RPAs) form objects
`by sequentially forming thin layers, hereinafter “construc-
`tion layers”, of a material one ontopofthe other responsive
`to data, hereinafter “construction data”, defining the objects.
`‘There are numerous and varied types of RPAs and different
`methods by which they form the thin construction layers
`they use to build an object.
`
`[0004] One type of RPA, conventionally referred to as an
`“ink-jet RPA”, “prints” each layer of an objectit builds. To
`form a given layer the ink-jet RPA controls. at
`least one
`dispenser, referred to as a “printing head",
`to dispense at
`least one construction material in liquid formin a pattern
`responsive to construction data for the object and then
`solidifies the dispensed material. At least one construction
`material, hereinafter a “building material” (BM), dispensed
`to formthelayeris printed in the shape of a cross section of
`the object. Building material in adjacent construction layers
`is printed in the shape of thin cross sections of the object that
`are displaced relative to each other by a small incremental
`distance along a same direction, hereinafter referred to as a
`“stacking direction”, relative to the object.
`[0005] For convenience of exposition, the cross sections
`of the object in whose shapes the construction layers are
`formed are assumed to be parallel
`to the xy-plane of a
`suitable coordinate system and the stacking direction is in
`the z-direction of the coordinate system. Optionally,
`the
`building material is a photopolymer, which is hardened after
`deposition by exposure to suitable electromagnetic radia-
`tion, typically UVradiation.
`
`For many construction objects, because of the
`{0006]
`complexity and/or shape ofthe objects, construction layers
`comprising only BM printed in the shape ofcross sections
`of the construction objects are not completely self-support-
`ing and require support during construction ofthe object.
`For such cases,at least one construction material, hereinafier
`referred to as “support material” (SM).is printed as required
`in suitable regions of each layer. to provide support for the
`building material in the layer. The support material and/or a
`shape in which it is formed, is such that upon completionof
`the object
`it can be removed from the object without
`substantially damaging the building material.
`In some
`embodiments, the support material, like the building mate-
`rial, is also a photopolymer.
`
`[0007] An ink-jet type of RPA typically comprises at least
`one ink-jet printing head comprised in a “printing head
`block”, which is mounted to a “shuttle”. Each printing head
`
`has an array of one or more outputorifices and is control-
`lable to dispense construction material from each orifice
`independently of dispensing construction material from the
`other orifices. The construction material comprises one or
`more types ofphotopolymer materials typically stored in at
`least one cartridge from which a suitable configuration of
`pipes transports the material or materials to one or more
`reservoirs in the printing head block from whichthe printing
`head receives the material . Optionally, to maintain appro-
`priate viscosity of the at least one photopolymer, a controller
`controls at
`least one heater, optionally mounted to the
`printing block, print head and/or reservoir,
`to heat
`the
`photopolymer to a suitable operating temperature. The one
`or more types of photopolymers may, generally, be dis-
`pensed in any combination, separately or together, simulta-
`neously or consecutively.
`[0008] During construction of an object, a controller con-
`trols the shuttle to repeatedly move over a support surface,
`hereinafter a “construction platform”, parallel
`to the xy-
`plane. As the shuttle moves, the controller controls each
`printing head to dispense construction material selectively
`throughits orifices responsive to construction data defining
`the object to print the construction layers from which the
`object is made onthe construction platform, one layerafter
`the other, one on top ofthe other. Mounted to the shuttle,
`adjacentto the printing head block are one or more sources
`of electromagnetic radiation, optionally UVradiation, for
`curing the photopolymer construction material printed in
`each construction layer. Also, optionally, mounted to the
`shuttle adjacent to the at least one printing head block is a
`“leveling roller” which levels newly printed layers of con-
`struction material to a predetermined layer height by remov-
`ing surplus material and/or peaks of material in the layer.
`The surplus material removed fromthe layeris wiped off the
`roller by a “cleaning wiper” and gathered in a waste con-
`tainer comprised in the shuttle.
`[0009] Optionally, in moving the shuttle over the support
`surface during production ofa construction layer, the con-
`troller controls the shuttle to move back and forth along the
`x-direction. Optionally, at any one or more reversals of the
`shuttle along the x-direction the controller increments dis-
`placement of the shuttle in the y-direction, Following pro-
`duction ofa given constructionlayer, either the construction
`platform is lowered orthe shuttle raised, along the stacking
`direction by a distance equal
`to a thickness of a next
`construction layer to be produced over the just formed given
`layer.
`[0010] During construction of an object, excess cured
`photopolymer construction material has a tendency to accu-
`mulate on or between the at least one printing head in the
`printing head block and on the cleaning wiper. The accu-
`mulated material may result in total or partial blockage of
`output orifices, generating inaccuracies in deposition of
`construction material and/or damage to a printed layeras the
`printing heads and roller move over a printed layer. Often,
`functioning of a printing head block may be so degraded by
`accumulated photopolymer “debris”that the printing block
`must be replaced. Replacing a printing head block is gen-
`erally expensive, time consuming, and requires recalibration
`of the RPA so that deposition of polymer via the output
`orifices can be accurately controlled.
`(0011] Configurations of ink-jet type RPAs are described
`in U.S. Pat. No. 6,259,962, U.S. Pat. No. 6,658,314, U.S.
`
`28
`
`28
`
`

`

`US 2007/0179656 Al
`
`Aug. 2, 2007
`
`Pat. No, 6,569,373 and USapplications Ser. No. 10/101,089,
`USS, Pat. No, 09,484,272, Ser, No. 10/336,032, the disclo-
`sures of which are incorporated herein by reference.
`
`SUMMARY OF THE INVENTION
`
`[0012] An aspect of some embodiments ofthe invention
`relates to providing an inkjet type rapid production appara-
`tus (RPA) having improved operational characteristics.
`
`[0013] An aspect of some embodiments of the invention
`relates to providing an RPA comprising a shuttle having a
`printing head block for which each printing head thereinis
`dismountable and replaceable independently of the other
`printing heads in the block.
`
`In accordance with an embodiment of the inven-
`[0014]
`tion, the shuttle and printing heads are configured so that
`when a printing head is replaced it is automatically aligned
`by alignmentstructures comprised in the printing head block
`and the printing head. In accordance with an embodiment of
`the invention the printing head is associated with a memory
`comprising profile data that specifies operating characteris-
`tics of the printing head that is used by a controller in the
`RPAto control the printing head. In some embodiments of
`the invention the memeory is comprised in the printing head.
`
`[0015] An aspect of some embodiments ofthe invention
`relates to providing an RPA having an improved lamp that
`provides radiation for curing photopolymer construction
`materials,
`
`[0016] Photopolymer construction material along edges of
`construction layers formed by an RPA is often poorly
`polymerized resulting in edges that sometimes have rela-
`tively poor definition and may remain soft and sticky. A
`radiation lamp,
`in accordance with an embodiment ofthe
`invention provides a relatively large portion of its radiant
`energy so that the radiation is incident on construction layers
`at relatively large angles to a normal to their planes. The
`large incident angle radiation is relatively more efficient in
`polymerizing material along edges of a construction layer
`than radiationthat is incidentat relatively small angles. An
`aspect of some embodiments of the invention relates to
`providing an RPA having an improved cleaning wiper for
`removing photopolymerdebris that accumulates on surfaces
`of the RPA.
`
`[0017] There is therefore provide in accordance with an
`embodiment of the invention, apparatus for producing an
`object by sequentially forming thin layers of a construction
`material one on top of the other responsive to data defining
`the object, the apparatus comprising:
`
`a plurality of printing heads each having a surface
`[0018]
`formed with a plurality of output orifices and controllable to
`dispense the construction material through eachorifice inde-
`pendently ofthe other orifices;
`
`[0019]
`
`a shuttle to whichthe printing heads are mounted;
`
`[0020]
`
`a support surface; and
`
`controller adapted to control the shuttle to move
`[0021]
`back and forth over the support surface and as the shuttle
`moves to control the printing heads to dispense the con-
`struction material through each oftheir respective orifices
`responsive to the data to form a first layer on the support
`surface and thereafter, sequentially the other layers; wherein
`
`each printing headis dismountable from the shuttle
`[0022]
`and replaceable independently of the other printing heads.
`
`least
`[0023] Optionally, each printing head comprises at
`one registration structure that matches a registration strue-
`ture comprised in the shuttle and when a printing head is
`mounted to the shuttle its at least one registration structure
`contacts the corresponding shuttle registration structure and
`positions the printing head accurately in the shuttle. Option-
`ally, the orifices in each printing head are equally spaced in
`a linear array havinga first orifice located at a first end ofthe
`array. Optionally,
`the at
`least one registration structure
`comprised in each printing head and its corresponding
`shuttle registration structure position the printing heads so
`that their respectivelines oforifices are parallel. Optionally,
`wherein the lines of orifices are arrayed along a direction
`perpendicular tothe lines of orifices. Optionally, the at least
`one registration structure comprised in each printing head
`and its corresponding shuttle registration structure, position
`the printing heads so that the first orifice in each printing
`head is accurately positioned relative to the first orifices of
`the other printing heads. Optionally, projections on the
`support surface ofparallel lines through the centers of the
`orifices that are perpendicular to the lines oforifices are
`substantially equally spaced one from the other. Optionally,
`distancesof thefirst orifices from a same plane perpendicu-
`lar to the lines oforifices are located at distances from the
`plane in accordance with an expression ofthe form y(n)=
`C+n(d,/N). where y is the distance from the plane, C is a
`constant, N is a numberofprinting heads, d, is a distance
`between adjacent orifices in a same printing head and for
`eachof the printing heads,n is a different integer satisfying
`0Sn=(N-1). Optionally, the controller controls the shuttle
`to move along a direction perpendicular to the lines of
`orifices when construction material is dispensed from ori-
`fices in the printing heads during formation of a layer.
`Optionally, the distances y(n) are such that a printing head
`deposits droplets on a given line in the layer parallel to the
`lines of orifices at
`locations such that
`the droplets are
`substantially not contiguous with any droplets of material
`deposited previously on the given line by other of the N
`printing heads. Optionally, each droplet deposited between
`two closest, previously deposited droplets on the given line,
`is equidistant from the two previously deposited droplets
`
`In some embodiments ofthe invention,the at least
`[0024]
`one registration structure in each printing head comprises at
`least one registration pin that protrudes from the printing
`head andhasanend accuratelypositionedrelativetothe line
`of orifices.
`
`the corresponding shuttle registration
`(0025] Optionally,
`structure is a surface and whereinthe registration pin and
`registration surface are positioned so that when the printing
`head is mounted to the shuttle the tip of the pin butts up
`against the surface. Alternatively or additionally, the atleast
`one registration pin comprises three registration pins.
`Optionally, a line between the tips of twoof the registration
`pins is accurately parallel to the line oforifices. Optionally,
`the tp of a third registration pin is displaced parallel to the
`line oforifices and away from all the orifices by an accurate
`distance relative to the first orifice.
`
`In some embodiments ofthe invention, each print-
`[0026]
`ing head is associated with a memory. Optionally,
`the
`memory is comprised in the printing head. Additionally or
`
`29
`
`29
`
`

`

`US 2007/0179656 Al
`
`Aug. 2, 2007
`
`alternatively, the memory comprisesprofile data that speci-
`fies operating characteristics peculiar to the printing head
`that the controller uses to control the printing head. Option-
`ally, the profile data becomes accessible to the controller
`automatically when the printing head is mounted to the
`shuttle. Additionally or alternatively, each orifice is associ-
`ated withits own actuator controllable to control dispensing
`ofthe construction material from theorifice and wherein the
`profile data comprises data useable to control the actuator.
`
`In some embodiments ofthe invention, the appa-
`[0027]
`ratus comprises a temperature monitorthat generates signals
`responsive to temperature of the printing head. Optionally,
`the memory comprises calibration data that correlates a
`characteristic ofthe signals with temperature ofthe printing
`head.
`
`In some embodiments ofthe invention,the printing
`[0028]
`head comprises a heat source controllable to maintain the
`printing head at a desired temperature and wherein the
`memory comprises data useable to control the heat source.
`
`the
`In some embodiments of the invention,
`[0029]
`memory comprises data useable to determinethe position of
`the orifices relative to the orifices of other printing heads
`mounted to the shutile.
`
`In some embodiments ofthe invention, the con-
`[0030]
`struction material comprises a photopolymer. Optionally, the
`apparatus comprises a lamp that providesradiation to poly-
`merize the photopolymer. Optionally, the lamp provides a
`substantial portion ofthe radiation so that it 1s incident on
`the layers at substantially non-normal angles to their planes.
`
`in accordance with an
`[0031] There is further provided,
`embodiment of the invention, apparatus for producing an
`object by sequentially forming thin layers of a material one
`ontop of the other responsivetodata defining the object, the
`apparatus comprising:
`
`at least one printing head having a surface formed
`[0032]
`with at least one output orifice and controllable to dispense
`a photopolymer material in liquid form throughtheorifice;
`
`a lamp controllable to provide radiation that poly-
`[0033]
`merizes the photopolymer; and
`
`a controller adapted to control the printing head to
`[0034]
`dispense the photopolymer and sequentially form the layers
`and the lamp to irradiate and polymerize the dispensed
`photopolymer, wherein
`[0035]
`a substantial portion of radiation provided by the
`lamp is directed so that
`it
`is incident at a substantially
`non-normal angle on the layers.
`
`[0036] Optionally, the lamp comprises aradiation source
`and a reflector that reflects light provided by the source so
`that it is incident at a substantially non-normal angle on the
`layers. Additionally or alternatively, the magnitude ofthe
`angle is greater than 20° relative to the normalto the layers.
`In some embodiments of the invention, the magnitude of the
`angle is greater than about 30° relative to the normal. In
`some embodiments ofthe invention, the magnitude ofthe
`angle is equal to about 45° relative to the normal.
`
`In some embodiments ofthe invention, the reflec-
`[0037]
`tor comprises at least one parabolic reflector and at least a
`portion of the light source is located at the focus of the
`reflector. Optionally, the reflector is a polygonal reflector
`
`that approximates a parabolic reflector. Optionally, the angle
`ofincidenceis positive for a portionofthe light and negative
`for a portion ofthe light.
`[0038]
`In some embodiments of the invention, the radia-
`tion source is a discharge type bulb. Optionally, the bulb is
`an Hg or Xe discharge bulb.
`[0039]
`In some embodiments ofthe invention, the lamp
`comprises LEDs controllable to provide the radiation that
`polymerizes the photopolymer.
`[0040] There is further provided in accordance with an
`embodiment of the invention, Apparatus for producing an
`object by sequentially forming thin layers of a material one
`on top ofthe other responsive to data defining the object, the
`apparatus comiprising:
`[0041]
`at least one printing head controllable to dispense
`a photopolymer material in liquid form:
`[0042]
`a lamp controllable to provide radiation that poly-
`merizes the photopolymer; and
`[0043]
`a controller adapted to control the printing head to
`dispense the photopolymer and sequentially form the layers
`and the lamp to irradiate and polymerize the dispensed
`photopolymer; wherein
`[0044]
`the lamp comprises an array of LEDs controllable
`to provide the radiation that polymerizes the photopolymer.
`[0045] Optionally the apparatus comprises a microlens
`that configures light from the LED into a cone beam of
`radiation having a relatively large cone angle. Optionally,
`the cone angle is larger than about 80°. Optionally, the cone
`angle is larger than about 100°.
`[0046]
`In some embodimentsof the invention,the array of
`LEDsis located relatively far from the layers and compris-
`ing a radiation conductor for each LED in the array that
`pipes radiation from the LED to a location relatively close
`to the layers from which the radiation illuminates regions of
`the layers.
`(0047]
`In some embodiments of the invention, the con-
`troller controls intensities of UVlight provided by LEDs in
`the array independently of intensities provided by other
`LEDs in the array.
`[0048]
`In some embodiments of the invention, the con-
`troller turns on and off LEDs in the array so as to reduce
`radiation from the array thatis not effective in polymerizing
`photopolymerin the layers.
`[0049]
`In some embodiments ofthe invention, the appa-
`ratus comprises a wiper and wherein the controller is
`adapted to moveat least one printing head over the wiper to
`clean the surface in which the orifices are formed.
`
`(0050] There is further provided in accordance with an
`embodiment of the invention, apparatus for producing an
`object by sequentially forming thin layers of a material one
`on top ofthe other responsiveto data defining the object, the
`apparatus comprising:
`[0051]
`at least one printing head havinga surface formed
`with at least one output orifice and controllable to dispense
`a photopolymer material in liquid form through theorifice;
`[0052]
`a wiper; and
`[0053]
`acontroller adapted to control the printing head to
`dispense the photopolymer and sequentially form the layers
`
`30
`
`30
`
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`

`US 2007/0179656 Al
`
`Aug. 2, 2007
`
`move the printing head over the wiper to clean the surface
`in whichtheorifices are formed.
`
`[0054] Additionally, or alternatively, the wiper comprises
`at
`least one cleaning blade having an edge that scrapes
`excess construction material from the surface when the
`controller controls the surface to move over the wiper.
`
`FIG. 2A schematically shows a bottomperspective
`[0064]
`viewof a shuttle, which is comprised in the RPA shown in
`FIG. 1 and has individually replaceable printing heads, and,
`in accordance with an embodiment of the invention;
`
`FIG, 2B schematically shows a bottom view ofthe
`[0065]
`shuttle showin FIG. 2.4;
`
`[0055] Optionally, the edge ofat least one cleaning blade
`contacts the surface whenthe surfaces moveover the wiper.
`
`FIG. 2C schematically showsthe shuttle in FIGS.
`[0066]
`24-2B with its printing heads removed;
`
`[0056] Optionally, the cleaning blade is formed from a
`resilient material so that the edge that contacts the surfaces
`resiliently contacts the surface. Optionally,
`the edge is
`scalloped and has a different scallop corresponding to each
`printing head ofthe at least one printing head.
`
`In some embodiments ofthe invention, the at least
`[0057]
`one printing head comprises a plurality of printing heads.
`
`[0058] Optionally, the cleaning blade is formed with at
`least one slot
`that partitions the cleaning blade into a
`plurality of teeth each having an edgethat contacts an orifice
`surface of a different one of the plurality of printing heads
`and scrapes excess construction material form the surface.
`
`[0059] Additionally or alternatively, wherein the at least
`one cleaning blade comprises at least two cleaning blades.
`Optionally, a cleaning blade ofthe at least
`two cleaning
`blades has an edge that does not contact the orifice surface
`ofa printing head but moves along and in close proximity to
`the surface whenthe controller controls the surface to move
`
`over the wiper. Optionally, when the surface moves over the
`wiper, regions of the surface move over the edge that does
`not contact the surface prior to contacting the edge that
`contacts the surfaces.
`
`In some embodiments of the invention, the appa-
`[0060]
`ratus comprises an obstacle detection system that detects
`defects in a layer that protrude from a surface of the layer.
`Optionally, the obstacle detection system comprises: a laser
`that provides a laser beam that contacts oris located close to
`the surface of the layer along a length ofthe laser beam; and
`a detector that receives light from the laser beam; wherein
`light that the detector receives from the laser is at
`least
`partially blocked by a defect that protrudes from the surface.
`
`Anaspect of some embodiments of the invention
`[0061]
`relates to providing new construction materials for use in a
`jet-ink RPA, which when used to construct an object results
`in the object having improvedstructural strength relative to
`that which it would haveif produced using priorart ink-jet
`construction materials,
`
`BRIEF DESCRIPTION OF FIGURES
`
`[0062] Non-limiting examples of embodiments of the
`present
`invention are described below with reference to
`figures attached hereto, which are listed following this
`paragraph. In the figures, identical structures, elements or
`parts that appear in more than one figure are generally
`labeled with a same numeral in all the figures in which they
`appear. Dimensions of components and features shownin
`the figures are chosen for convenience and clarity of pre-
`sentation and are not necessarily shownto scale.
`
`[0063] FIG. 1 schematically shows a rapid production
`apparatus (RPA) in accordance with an embodiment of the
`present invention:
`
`FIG. 2D schematically shows a printing head,
`[0067]
`accordance with an embodiment of the invention;
`
`in
`
`FIGS. 2E and 2F schematically showperspective
`[0068]
`and cross section views respectively of a system for pro-
`viding construction material to printing heads in an RPA, in
`accordance with an embodiment of the present invention:
`
`FIG. 3A schematicallyillustrates lines along which
`[0069]
`different output orifices of the printing head dispense con-
`struction material to form a construction layer of an object,
`in accordance with an embodiment of the invention:
`
`FIG. 3B showsa portion of FIG. 3A enlarged for
`[0070]
`convenienceof presentation;
`
`FIG. 4A schematically illustrates a method ofdis-
`[0071]
`pensing construction material
`to produce a construction
`layer, in accordance with prior art;
`
`FIG. 4B schematically illustrates a method of dis-
`[0072]
`pensing construction material
`to produce a construction
`layer,
`in accordance with an embodiment of the present
`invention;
`
`FIG. 4C schematically shows a shuttle configured
`[0073]
`to dispense construction material as illustrated in FIG. 4B, in
`accordance with an embodiment ofthe present invention;
`
`FIG. 5 schematically shows a bottom view of
`[0074]
`another shuttle, in accordance with an embodiment ofthe
`present invention;
`
`[0075] FIGS. 6A-6C schematically show a perspective
`partially cutaway view and cross sectional views respee-
`tively of a lamp that provides UVlight for polymerizing
`construction material, in accordance with an embodiment of
`the invention:
`
`FIG. 6D shows a graph that graphs relative inten-
`[0076]
`sity of light from a UVlamp that
`is reflected from a
`construction layer being formed by the RPA shown in FIG.
`I as a function of height above the layer of the aperture
`through which the lamp provides the light;
`
`(0077] FIGS. 7A and 7B show schematic cross sectional
`views ofother UVlamps, in accordance with embodiments
`of the present invention:
`
`FIG. 8 schematically shows UVlamps comprising
`[0078]
`LEDs, for providing polymerizing UVlight, in accordance
`with an embodimentof the present invention;
`
`[0079] FIGS. 9A and 9B schematically show perspective
`views ofa shuttle having UVlampsthat comprise LEDs that
`are located relatively far from construction layers that the
`shuttle is controlled to form, in accordance with an embodi-
`ment ofthe present invention;
`
`[0080] FIGS. 104 and 10B schematically show a perspec-
`tive and cross sectional view respectively of a shuttle
`
`31
`
`31
`
`

`

`US 2007/0179656 Al
`
`Aug. 2, 2007
`
`undergoing maintenance cleaning in accordance with an
`embodiment of the invention:
`
`FIGS. 10C-10D schematically show variations of
`(0081]
`cleaning blades used to clean a shuttle, in accordance with
`an embodiment of the invention;
`
`FIGS, 11A and 11B schematically show perspec-
`[0082]
`live and cross section views of another cleaning blade
`configuration,
`in accordance wi