a2) United States Patent
`US 6,580,959 B1
`(10) Patent No.:
`Jun. 17, 2003
`(45) Date of Patent:
`Mazumder
`
`
`US006580959B 1
`
`(54) SYSTEM AND METHOD FOR REMOTE
`DIRECT MATERIAL DEPOSITION
`
`Jyoti Mazumder, Ann Arbor, MI (US)
`Inventor:
`(75)
`(73) Assignee: Precision Optical Manufacturing
`(POM), Plymouth, MI (US)
`
`(*) Notice:
`
`Subject to any disclaimer, the termofthis
`patent is extended or adjusted under 35
`US.C. 154(b) by 0 days.
`
`(21) Appl. No.: 09/575,857
`5
`Filed:
`
`May19, 2000
`
`(22)
`
`—
`Related U.S. Application Data
`(63) Continuation-in-part of application No. 09/522,671,filed on
`Mar. 10, 2000.
`(60)
`Provisional application No. 60/135,228, filed on May 21,
`1999, and provisional application No. 60/123,890,filed on
`Mar. 11, 1999.
`7,
`Int. Ch. cece seeseneeereneees GO06F 19/00
`9
`:
`.
`UWS. Ch eee 700/121; 700/166; 700/112
`Field of S
`h
`,
`700/121 166
`Field Ocriae.Tia.Ag.leo,en 119: 703/3.
`2
`206/46
`2
`2
`?
`?
`References Cited
`U.S. PATENT DOCUMENTS
`
`(51)
`(52)
`58)
`(58)
`
`(56)
`
`5,262,954 A
`* 11/1993 Fujino et al. oo... 700/112
`3/1994 Hutchins .......
`. 700/174
`5,291,416 A *
`
`6/1998 Meredith etal.
`... 118/665
`5,772,861 A *
`8/1998 Fiekiel ................0000008 702/122
`5,790,977 A
`
`
`
`3/1999 Moore oc. eee 345/835
`2/2000 Moukheibir
`.....
`33
`4/2000 Campbell etal. ...
`4/2000 Margery et al.
`............. 702/84
`
`5,877,961 A *
`6,021,404 A
`6,047,259 A
`6,055,487 A
`* cited by examiner
`.
`.
`.
`Primary Examiner—Leo Picard
`:
`Assistant Examiner—Kidest Bahta
`(74) Attorney, Agent, or Virm—Gifford, Krass, Groh,
`Sprinkle, Anderson & Citkowski, PC
`(57)
`ABSTRACT
`A system and method for remotely
`controlling the fabrica-
`y
`y
`iS
`tion of a product at a local manufacturing site. The product
`is fabricated by depositing successive material
`layers
`through a local
`laser-aided, feedback-controlled, direct
`material deposition system. The system is equipped with
`strain gages, optical sensors and acoustic sensors generating
`signals which are processed ina local computerto determine
`the temperature, strain and residual stress of the product
`during fabrication. A feedback controller interfaces with the
`local computer and with a numerical controller and operates
`to control the material deposition process. The local numeri-
`P
`Pp
`cal controller receives a file of a digitized description of the
`product from the remote computer, preferably via an Internet
`connection. The local computer sends temperature, strain
`and stress data to the remote computer, enabling a designer
`interfacing with the remote computer to monitor, control and
`modify the fabrication of the product in real time on line.
`The fabrication process is recorded by video or television
`camera and the shown in real-time on a screen display
`connected to the remote computer.
`
`21 Claims, 3 Drawing Sheets
`
`LOCALSITE
`
`205
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`200
`
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`REMOTESITE
`
` LAYER
`LASER-AIDED
`
`
`SUBSTRATE
`
`DMD SYSTEM
`
`
`
`
`
`COMPUTER
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`
`
`
`
`
`
`
`
`
`
`FEEDBACK
`
`LOCAL
`CONTROLLER
`
`
`70
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`1
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`Shenzhen Tuozhu 1004
`
`1
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`Shenzhen Tuozhu 1004
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`

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`U.S. Patent
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`Jun. 17, 2003
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`Sheet 1 of 3
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`US 6,580,959 B1
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`U.S. Patent
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`Jun. 17, 2003
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`Sheet 2 of 3
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`US 6,580,959 BL
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`internet
`
`ETB
`|
`|
`
`| Decompression
`
`DMD
`System
`
`Compression and Encryption
`
`FIGURE 2
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`3
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`~ ©SS
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`US 6,580,959 B1
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`FIGURE3
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`“a
`ws
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`9 —
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`U.S. Patent
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`Jun. 17, 2003
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`Sheet 3 of 3
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`4
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`

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`US 6,580,959 B1
`
`1
`SYSTEM AND METHOD FOR REMOTE
`DIRECT MATERIAL DEPOSITION
`
`REFERENCE TO RELATED APPLICATIONS
`
`This application claimspriority of U.S. Provisional Patent
`Application Ser. No. 60/135,228, filed May 21, 1999, which
`is a continuation-in-part of U.S. Patent Application Ser. No.
`09/522,671, filed Mar. 10, 2000, which claims priority of
`U.S. provisional patent application Ser. No. 60/123,890,
`filed Mar. 11, 1999. The entire contents of these and the
`following U.S. Patent Applications are incorporated herein
`by reference: Ser. No. 09/107,912, filed Apr. 10, 1997; and
`Ser. No. 09/526,631, filed Mar. 16, 2000.
`
`FIELD OF THE INVENTION
`
`this invention relates to lascr-aided direct
`In general,
`material deposition processes and, more particularly, to a
`system and method of monitoring, controlling and modify-
`ing such processes, preferably in real time, from a remote
`location.
`
`BACKGROUND OF THE INVENTION
`
`Advances in modem telecommunication methods, includ-
`ing the Internet, as well as advances in data acquisition and
`manipulation, allow the transfer of large volumes of data
`between distant sites in a relatively short time. The use of
`web browsers enable users to view not only text, but also
`video, graphics and audio files.
`Large data files may be compressed before their transfer
`by a variety of methods to speed transmission time. Con-
`nections between sites may be effected by high-speed links
`in asynchronous transfer mode (ATM)or using Ethernet and
`Fast-Ethernet in a Local Access Network (LAN) or Wide
`Access Network (WAN) environment.
`Interactive image and data transmissionis currently under
`development for various applications including medical
`examination, diagnosis and treatment of disease, as
`described in U.S. Pat. No. 6,021,404 (Universal computer
`assisted diagnosis), U.S. Pat. No. 6,055,487 (Interactive
`remote sample analysis system) and U'S. Pat. No. 6,047,259
`(Interactive method and system for managing physical
`exams, diagnosis and treatment protocols in health care
`practice).
`Another remote control application is related to remote
`access and exchange of data between a remote host and an
`instrument, such as the vector modulation analyzer (WMA)
`with resident control and data acquisition software, as
`described in U.S. Pat. No. 5,790,977.
`The need remains, however, for a system and method
`enabling a design team at a remote site to monitor, control
`and modify the fabrication process of a product at a local
`manufacturing site. Such tele-control would be particularly
`advantageous when the manufacturing process involves
`specialized and delicately calibrated or expensive
`equipment, which is either too costly to duplicate at many
`plants or simply not available at the chosen or required site
`of production.
`SUMMARY OF THE INVENTION
`
`This invention utilizes advances in telecommunication
`and fast data transfer to control the fabrication of precisely
`dimensioned and intricatcly-detailed products through an
`automated, feedback-controlled, laser-aided direct material
`deposition (DMD) process, as described in co-owned and
`co-pending U.S. patent application Ser. No. 09/107,912,
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`2
`filed Apr. 10, 1997, and in U.S. patent application Ser. No.
`09/522,671, filed Mar. 10, 2000.
`The geometry of the product is provided by a computer-
`aided design system (CAD). The deposition tool path is
`generated by a computer-aided manufacturing system
`(CAM) for CNC machining having post-processing soft-
`ware for deposition, instead of software for removal, as in
`conventional CNC machining. The CAM software inter-
`faces with a feedback controller. For in-situ control of the
`DMD manufacturing process,
`the computer holding the
`CAD/CAM software, the CNC and feedback controller and
`the laser equipmentare all located at the local manufacturing
`site.
`
`For remote control of the DMDprocess, a design team or
`an individual designer is located at the “remote” site and
`operates, through a user interface, their “remote” host com-
`puter. The remote computer stores the description of a
`product to be fabricated. The description is preferably pro-
`cessed by a commercial Computer-Aided Design and
`Computer-Aided Manufacturing (CAD/CAM) software
`package, also residing at the remote host computer. This
`software generates a CAM file from whichthe tool path file
`will be created.
`
`Because the CAM file of the product description is large,
`it is first compressed by an efficient compression algorithm
`to enable its fast transmission, e.g. over the Internet, to the
`manufacturing site. The remote host computer is preferably
`equipped with two monitors, one with a graphical user
`interface and the other for image and video observation of
`the laser-aided direct material deposition process. The dis-
`play preferably includes zoom androtation capabilities to
`enable detailed and accurate view from variousangles of the
`product undergoing fabrication.
`When the designer perceives a defect, an abnormality or
`some other undesirable characteristic affecting the final
`quality of the product, or whenit seemsdesirable to improve
`the design, the designer may pause or abort the fabrication
`process by sending a commandto the controller of the DMD
`system at
`the “local”, ie.
`the manufacturing, site. The
`designer then edits the CAD file and transmits over the
`Internet the modified and post-processed CAM file, either in
`its entirety, or only a block ofit containing the modification.
`Optical sensors at the manufacturing site continuously
`monitor the composition, temperature, and dimensions of
`the product. Acoustic emission sensors and strain gages at
`the manufacturing site monitor residual stress development
`in the product. Some or all of the information from the
`sensors is sent via a communications system to the remote
`computer at the designer site to determine the need for
`corrective measures. The signals from the sensors are also
`sent to the local computer control system at the manufac-
`turing site, where they are further processed to determine the
`independent parameters controlling the DMD process,e.g.
`the laser power, the beam diameter and the powderflowrate.
`The feedback controller uses this information to control the
`
`laser deposition process on command from the remote
`computer transmitted to the feedback controller through the
`local computer.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a block diagram depicting important subsystems
`according, to the invention;
`FIG. 2 is a block diagram of information flow according
`to the invention with an emphasis on data type, sorting,
`compression and encryption; and
`FIG. 3 is an illustration of a NURBSinterpolation useful
`to the invention.
`
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`US 6,580,959 B1
`
`3
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`FIG. 1 is a block diagram which shows important sub-
`systems according to the invention. A remote site 200
`communicates with a local site 205 via a communications
`
`system 75, preferably including the Internet. The design
`group and design equipment and software are located at the
`remote site 200, while the manufacturing team and manu-
`facturing equipment and software are locatedat the localsite
`205.
`
`The local site includes a laser-aided, computer-controlled
`direct material deposition system 10, which is used to
`fabricate, repair or modify three-dimensional products by
`applying sequentially layers of material 20 on a substrate 30.
`The laser-aided direct material deposition system (DMD) 10
`is equipped with a feedback controller 80 for monitoring and
`controlling the dimensions and overall geometry of the
`fabricated product. The feedback controller is connected
`with a computer numerical controller (CNC) 90 which
`guides the path of the laser beam incorporated in the DMD
`system 10. The details of the laser-aided, computer con-
`trolled direct material deposition system can be found in
`US. patent application Ser. No. 09/107,912 and are notall
`explicitly shown in FIG. 1.
`The manufacturing system at the local site includes a local
`computer 70 interfacing with the fecdback controller 80 and
`receiving input data from one or more sensors outputting
`information representative to fabrication progress. Such
`sensors may include strain gages 40, acoustic sensors 50,
`optical sensors 60 and video or television camera 65. One or
`more cameras may bespatially calibrated enabling dimen-
`sions to be remotely determined from the remote location.
`Contact and non-contact metrological instruments may also
`be used to perform accurate measurements to monitor the
`fabrication process. The local computer 70 communicates
`with a remote computer 95 via the communication system
`75 and receives the necessary computer files defining the
`deposition tool path for the numerical controller (CNC) 90.
`The remote site includes the remote computer 95, which
`receives input
`form a computer-aided design/computer-
`aided manufacturing (CAD/CAM) software program 105.
`The geometry of the product to be manufactured at the local
`site 205 is provided by a computer-aided design program
`(CAD)whichis part of CAD/CAM 105 software. The CAM
`part of the CAD/CAM 105software generates the deposition
`tool path. ‘lo accomplish this, the conventional CAM soft-
`ware is equipped with post-processing software for
`deposition, instead of post-processing software for removal,
`as is the case in conventional CNC machining. For in-situ
`DMD manufacturing, the CAM software interfaces directly
`with the feedback controller 80. For remote-control DMD
`
`manufacturing, the deposition tool-path files generated by
`the CAM software reside in the remote computer 95 and are
`sent via the communications system 75 to the local computer
`75 which interfaces with the feedback controller 80.
`
`FIG. 2 is a drawing which emphasizes type of data and
`information flow. CAD/CAM data and sensor updates are
`preferably delivered to a data sorter and from there, to a
`compression/encryption platform. The information is
`decompressed and applied to the DMD system, with updated
`sensor outputs and other data being preferably compressed
`and encrypted prior to being sent back to the remotesite.
`The factors that affect the dimensions of material depo-
`sition typically include laser power, beam diameter, tempo-
`ral and spatial distribution of the beam,interaction time, and
`powderflow rate. Adequate monitoring and control of laser
`
`4
`power, in particular, has a critical effect on the ability to
`fabricate completed parts and products with complex geo-
`metric features and within control tolerances. Accordingly,
`the feedback controller 80 of the direct material deposition
`system typically cooperates directly with the numerical
`controller (CNC) 90, which, itself, controls all functions of
`the direct material deposition system, including laser power.
`The laser source (not shown) of the DMD system is
`mounted above the substrate 30, and a layer of material 20
`is deposited according to the description of the product,
`whichis incorporated in the deposition tool path. The laser
`source has sufficient density to create a melt pool with the
`desired composition of substrate or previously deposited
`layer and cladding powder. The cladding powder, typically
`metallic, is sprayed on the substrate preferably through a
`laser spray nozzle with a concentric opening for the laser
`beam, as described in U.S. Pat. No. 4,724,299, so that the
`powderexits the nozzle coaxially with the beam.
`The numerical controller 90 preferably controls all oper-
`ating components of the DMD system of FIG. 1, including
`the operating conditions of the laser, receiving direction
`from the remote computer 95 through the communications
`system 75 and the local computer 70 for building the part or
`product. The commands received depend on the design
`(CAD)files of the product, which have beentranslated to
`deposition tool path files for deposition by the remote
`computer 95 before they were sent to the local computer.
`Thetool path files enable the numerical controller (CNC) 90
`to prescribe a path for the laser nozzle across the substrate
`for material deposition.
`The numerical controller 90 also receives feedback con-
`trol signals from the feedback controller 80 to adjust laser
`poweroutput, and further controls the relative position of the
`substrate and laser spray nozzle. All these functions are
`coordinated by the local computer 70, which sends feedback
`data to the remote computer 95 and receives instructions
`from the remote computer 95 to control
`the deposition
`process and,if necessary, to alter the entire laser source path
`or parts of it.
`For real-time, on-line control of the deposition process
`from the remotesite, it is important that fast communication
`connections are used. The tool path files, which are gener-
`ated by the CAM program in the remote computer 95, are
`preferably transferred in seconds, and on line editing is
`preferably done in milliseconds. The tool path files are
`typically files of the coordinates of many points along the
`tool path and,for a realistic part or product, have size of the
`order of 100 MB. This is because CAM software models
`
`into short chords (straight-line
`contours (curved lines)
`segments), sometimes shorter than 0.0001 inch.
`When a product demands precise contouring of intricate
`geometric features, many more and shorter chords are
`needed, and the tool path program becomes too long.
`Several commercial compression codes are available and
`can reduce the size of the files by compressing them before
`transmittal.
`In addition, some common sense rules and
`recent techniques have been developed to shortenthe size of
`the tool path files, especially for blocks of dense data near
`tightly curved geometric features. Such rules include:
`Eliminating non-essential characters, such as comments,
`especially since the design group at the remote com-
`puter will control the deposition process.
`Using the “tenths” rather than the decimal format, so that
`0.0003 is written as 3 in the language of the tool path
`code (G-code).
`Not repeating numerical control commands (G-code
`commands) on each line, since those commandsstay on
`until turned off.
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`US 6,580,959 B1
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`5
`Recent techniques for reducing tool path file size include
`circular interpolation and NURBS. Circular interpolation
`simply fits circular arcs of various radii to the coordinate-
`point data. A substantial program-size reduction is achieved,
`because an arc can represent a larger portion of a curve than
`a straight-line segment with comparable accuracy. Tool path
`files that have been converted to circular are files are
`typically 60 to 90 percent smaller than the original point-
`to-point
`files, according to Tom Beard, “Machining in
`Circles”, published in Modern Machine Shop, July 1996. A
`commercial software code NWDesigns MetaCut has been
`developed by Northwood Designs, Inc., (Antwerp, N-Y.).
`NURBS(Non-Uniform Rational B-Splinc) is a type of
`curve interpolation that uses spline curves, which are much
`more versatile than circular arcs. Recent CAM software
`incorporates a NURBSspline command into the tool path
`file by a single G-code command “G6.2”. The result is a
`single line of tool path programming instead of a dense
`block of file for a complex, curving tool path. Norwood
`Designs, Inc., and Delcam International (Windsor, Ontario)
`offer CAM systems that produce NC tool paths incorporat-
`ing NURBSfrom CAD files. FIG. 3 shows the extent of a
`typical NURBSblock replacing the linearized segments 310
`of an original curved contour 300.
`To control the quality of the product, strain changes in the
`deposited layers are monitored through several sensor sys-
`tems during the deposition process. Returning to FIG. 1, a
`mechanical strain gage system 40 includes conventional
`high-temperature strain gages attached to the back surface of
`the substrate 30. The strain gages 40 measure strain in
`predetermined locations and directions,
`typically X, Y
`directions, along and across the deposition path. These gages
`are attached on the back of the substrate with high-
`temperature solder or other temperature-resistant means to
`avoid damage from laser heat or stray reflection from the
`laser beam.
`
`Additional, non-purely-mechanical, sensors systems are
`incorporated, preferably acoustic sensors 60 and optical
`sensors 50. The acoustic sensors operate on the principle that
`during material deposition strains and other physical
`changes, such as phase transformation changes, or crack/
`defect initiation produce sound waves which can be picked
`up by the acoustic sensors 60. ‘The acoustic sensors 60 are
`typically piezoelectric. Currently miniaturized acoustic sen-
`sors are used for micro electrical mechanical systems
`(MEMS). U.S. Pat. Nos. 4,783,821 and 4,816,125,
`for
`example, disclose a miniature diaphragm pressure trans-
`ducer.
`The acoustic sensors, whether miniaturized or not, are
`basically micro-microphones or microphones, respectively,
`which convert sound wavesto electrical signals. The optical
`sensors 50 include a variety of devices, such as those
`operating on photovoltaic, fiber optic, and interferometric
`principles. Using an optical detector and an interference
`measuring technique, small strains can be measured with
`high sensitivity. The acoustic sensors and optical sensors
`must be calibrated against independent (mechanical) strain-
`gage measurements. The acoustic sensors,
`in particular,
`require careful calibration to distinguish strain from other
`sources of acoustic emission from the product, such as crack
`initiation, defect formation, and phase transformation, dur-
`ing the fabrication of the product fabrication through laser-
`aided material deposition.
`The acoustic sensors 60, optical scnsors 50 and strain
`gages 40, send their strain measurements during the depo-
`sition process to the local computer 70 in the form of
`electrical signals. A rough estimate of stresses may be
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`obtained through linear stress strain relations and elementary
`beam theory, but a complete residual stress history requires
`the incorporation of finite element codes, such as those
`commercially available for linear and nonlinear systems.
`The local computer 70 is programmed to offer both of these
`options: a rough calculation for experimental purposes dur-
`ing product design and development, and a full-fledged
`finite element analysis for more accurate prediction during
`actual production.
`The computer program comparesthe results of the stress-
`strain calculation with pre-determined failure criteria which
`incorporate a safety factor. The simplest criterion is to
`compare the maximum tensile stress with the yield stress
`and require the ratio not to exceed a given value. For ductile
`materials and multi-axial stresses, more sophisticated failure
`criteria may be incorporated in the stress analysis computer
`program, such as the von Mises or maximum strain energy
`criterion, or even crack initiation and propagation theories
`may be applied. Based on the results of the failure analysis,
`the local computer issues a warning/alarm signal for a
`humanoperatorat the local site, or sends an electronic signal
`to the remote computer for online control, or sends appro-
`priate commandsto a feedback controller 80, which inter-
`faces with the numerical controller 90.
`The numerical controller initiates corrective action, such
`as termination of the deposition process, adjustment of the
`deposition rate or laser power, and changes in the cooling
`conditions. ‘he data from the sensor systems 40, 50, 60 are
`processed by the local computer to produce real-time
`temperature, strain and stress data during the fabrication
`process. The sensor data are transmitted through the com-
`munications system 75 to the remote computer 95 for remote
`control of the process, or for modification of the product
`design, in its entirety or in part, and for replacement of the
`original CAM file with a new edited CAM file or CAM-file
`block to be transmitted back to the local computer 70.
`In addition to the sensor systems 40, 50, 60, a video or TV
`camera 65 records the laser-aided DMD process and trans-
`mits the images to the local computer 70, which then sends
`the images together with the associated temperature, strain
`and stress data to the remote computer 95 to be displayed
`preferably on a TV screen or shown on the remote computer
`monitor as streaming video (display screens not shownin
`FIG. 1).
`The temperature, strain and stress data, visual images or
`metrological information collected at the local manufactur-
`ing site 205 are all processed through the local computer 70,
`which communicates with the remote computer 95 and the
`numerical 70 and fecdback 80 controllers. All the data-
`
`processing is done locally at the manufacturing site 205 and
`only processed information of actual temperature, strain and
`stress, as well as physical dimensions, composition and
`appearance of the product
`is transmitted to the remote
`computer 95. Modification of CAD and CAM files, as well
`as generation and compression of the tool path files is done
`at the remote site 200 using the remote computer 95.
`In the preferred configuration, only the new or edited
`compressed tool path files are transmitted to the local
`computer 70. The reason for this is that, according to the
`invention, the control of the manufacturing process lies with
`the remote site 200 that houses the design team. If there is
`a need to transfer control to the local site 205, the CAD files
`are simply transmitted to the local computer 70, and a
`backup package, which is stored in the local computer and
`includes CAM software and post-processing software for
`generating tool path code, is used instead. This latter mode
`of operation is intermediate between in-situ and remote-
`control direct material deposition process.
`
`7
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`

`US 6,580,959 B1
`
`7
`
`I claim:
`1. Aremote control manufacturing system, comprising:
`a remote computer system for generating and editing a
`design description of a product;
`a local manufacturing system for fabricating the product
`in accordance with the design description using a
`laser-aided direct material deposition (OMD) process
`interfaced to a numerical controller, the DMD process
`being characterized in that the laser is used to create a
`melt pool into which powder or other feed material is
`delivered to create three-dimensional objects; and
`a communicationslink facilitating the electronic transfer
`of design, manufacturing and control
`information
`between the remote computer system and the local
`manufacturing system,
`thereby enabling the remote
`computer to monitor, control and modify the fabrica-
`tion process at the local manufacturing system.
`2. The remote control manufacturing system of claim 1,
`wherein the manufacturing system interfaces with a feed-
`back controller.
`
`3. The remote control manufacturing system of claim 1,
`wherein the local manufacturing system includes one or
`more sensors to collect temperature, strain or stress data for
`transmission to the remote computer system.
`4. The remote control manufacturing system of claim 1,
`wherein the manufacturing information includes visual
`images of the product being fabricated.
`5. The remote control manufacturing system of claim 1,
`wherein the remote computer system includes software for
`generating a deposition tool path file from the description of
`the product.
`6. The remote control manufacturing system of claim 5,
`wherein the remote computer system includes software for
`minimizing the size of the deposition tool path file.
`7. The remote control manufacturing system of claim 1,
`wherein a uscr interfaces to the communications link
`
`through an Internet browser.
`8. A remote control manufacturing system, comprising:
`a laser-aided direct material deposition (DMD) system for
`fabricating a three-dimensional product by depositing
`successive material layers on a substrate, the material
`deposition system comprising:
`a plurality of sensors providing outputs;
`a local computer receiving and processing the sensor
`outputs to generate fabrication progress information;
`and
`
`a feedback controller interfaced to the local computer
`and a numerical controller, the feedback controller
`being operative to control the material deposition
`process; and
`a remote computer system, comprising:
`a computerized description of the product;
`a software package for creating a file of a deposition
`tool path for the fabrication of the product; and
`a communications system for sending the tool path file to
`and receiving the fabrication progress information from
`the local computer, so that the fabrication of the product
`can be monitored, controlled and modified from the
`remote computer system through the local computer in
`real time on line.
`
`10
`
`5
`
`20
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`8
`9. The remote control manufacturing system of claim 8,
`wherein one of the sensors is an acoustic sensor.
`10. The remote control manufacturing system of claim 8,
`wherein one of the sensors is an optical sensor.
`11. The remote control manufacturing system of claim 8,
`wherein the fabrication progress information includes prod-
`uct temperature, stress or strain.
`12. The remote control manufacturing system of claim 8,
`wherein the fabrication progress information includes the
`height of the deposition layers.
`13. The remote control manufacturing system of claim 8,
`wherein the deposition tool path file is compressed to reduce
`its size at the remote computer system.
`14. The remote control manufacturing system of claim 8,
`further comprising a video or television camera recording
`the fabrication process and transmitting the images to be
`viewed on a screen display situated at the remote computer
`system.
`15. The remote control manufacturing system of claim8,
`wherein the communications system connecting the local
`and remote computers includes an Internet browser.
`16. A method associated with the remote-control fabrica-
`
`tion of a product, comprising the steps of:
`a) generating a file of a deposition tool path at a remote
`computer, and sending the file to a local computerat the
`manufacturing site;
`b) transferring the deposition tool path file to a numerical
`controller interfaced to a laser-aided, direct material
`deposition system to fabricate the product on a sub-
`strate by depositing successive layers having a height;
`c) collecting in the local computer real-time strain and
`temperature sensor data of the product during material
`deposition;
`d) sending the strain and temperature data to the remote
`computer via a communications system; and
`e) sending control commands from the remote computer
`to the local computer to control the material deposition
`process.
`17. The method of claim 16, further comprising the steps
`
`of:
`
`inputting the strain data into a finite-element program in
`the local computer to calculate residual stress data for
`the product; and
`sending the stress data to the remote computer via the
`communications system.
`18. The method of claim 16, wherein the file of the
`deposition tool path is compressed to reduceits size.
`19. The method of claim 16, wherein the direct material
`deposition system of step b) includes a feedback controller
`for controlling the height of each deposited layer.
`20. The method of claim 16, comprising the additional
`step of using a video or television camera to record the
`fabrication of the product and sending the images to a
`display connected to the remote computer.
`21. The method of claim 16, comprising the additional
`step of:
`editing the file of the deposition tool path in the remote
`computer and sending the edited file to the local
`computer.
`
`8
`
`