Looking to the Future:
Dijital Technologies for Jewelry Design and Metalwork

Hiroko Sato-Pijanowski
Nicole Ann DesChamps

The University of Michigan School of Art and Design
2000 Bonisteel Boulevard
Ann Arbor, Michigan 48109-2069

c 1999 Hiroko Sato-Pijanowski and Nicole Ann DesChamps

All profits from the sale of this paper will go to The University of Michigan School of Art and Design Jewelry Design Department Fund. Make all checks payable to The University of Michigan.

Printed by Kolossos Printing, Inc., Ann Arbor, Michigan

I. ABSTRACT

Digital automated technologies have become practical tools for jewelry design and metalwork. Computer performance has increased while cost has decreased, and software for three-dimensional (3-D) freeform solid modeling has been perfected with user-friendly interfaces that reduce training time. Machines for automated fabrication of prototype models now provide high fidelity precision, smooth surfaces, and fine features.
In this paper, we evaluate three methods for producing jewelry prototypes: subtractive (carving) processes and additive (layered building) processes, both of which work from designer-created CAD (Computer Aided Design) files; and reverse engineering, in which a 2 or 3-D scan of an object produces a digital file that can be manipulated and transferred to automated fabricating machines, primarily of the subtractive type.
The subtractive process we examined used a Computer Numerically Controlled (CNC) Vertical Machine Center (VMC) to carve the prototype out of solid material. We also tested Micro-Droplet Fabrication (MDF), an additive process which uses a precision ink-jet technology. While both subtractive and additive processes had jewelry applications, the additive was best suited for true three-dimensional, solid freeform fabrication ability combined with precision, fine feature detail and excellent surface quality. Micro-Droplet technology yielded directly castable prototype patterns needing no further preparation. The CNC milling subtractive technology we researched was restricted, by tool articulation limits, to relief-type work. The third method, reverse engineering using 2 or 3-D scanning, in which a solid object is scanned to create a digital file containing its mathematical data, produced precise, finely detailed copies of the original object that could be manipulated, and reproduced at any scale, saving cost and labor.

II. BACKGROUND

Computer Aided Design (CAD), Computer Aided Manufacturing (CAM) and Rapid Prototyping and Manufacturing (RP&M) technologies are common in industry where three-dimensional (3-D) products are realized from graphic design data. Today, CAD used in conjunction with the manufacturing of 3-D parts and prototypes has entered the jewelry industry. Nowbeing introduced into art academia, it offers new avenues for student development and exploration by integrating computer design automation into the curriculum as a professional art tool.

Computer Aided Design (CAD) oftware

CAD systems aid in drafting, and also define or formulate geometric data. Computer Aided Design was first introduced in design drafting where its two-dimensional (2-D) drawing capabilities allowed easy modifications. Early 2-D CAD drawings consisted of simple lines, arcs and curves. Later improvements allowed for 3-D wire frame and surface definition, eventually including the ability to generate information for numerical control (NC) programming and rendering. These 3-D wire frames were limited because they did not provide data about the inside and outside of objects necessary for more complex modeling. This problem was solved with the onset of solid modeling that determined volumes trapped within surfaces. Several CAD software packages are now available for jewelry design including Alias, AutoCAD, Unigraphic, Pro Engineer, Solidworks, Rhino, Master Series, True Space, and JewelCAD, among others.

CAD File Formats

Computer Aided Design programs generate information that the fabricator, CAM (Computer Aided Manufacturing) and RP&M (Rapid Prototyping and Manu-facturing) machines understand or translate. In other words, CAD output becomes input information for CAM and RP&M machines. This input is formulated using surfaces, solids, points or even contours. The mathematical design data of the part is stored, then transferred to the fabricator. Most CAD systems generate designs in several different formats. However, the fabricator dictates which format it needs to produce the object. Five of the more common formats, or file types, are described on the attached definition page.

Automated Fabrication

CAD (Computer Aided Design) information is used to fabricate final products via CAM (Computer Aided Manufacturing), or create prototypes via RP&M (Rapid Prototyping and Manufacturing). Using CAD in conjunction with CAM and RP&M is referred to as Automated Fabrication, a term coined by Marshall Burns, author of a book of that name. With CAD data, the CAM or Rapid Prototyping and Manufacturing systems' support software programs instruct the automated fabricators. These machines act like printers, importing CAD data to produce a 3-D hard copy rather than a printed one.
Automated fabricators may be divided into two types. One group uses sub-tractive methods, removing raw stock material until only the designed object remains. The other group uses additive methods, depositing layers of material to achieve the desired shape. Both methods are described below.

Subtractive Methods AM (Computer Aided Manufacturing)

CAM is a subtractive method of fabrication where the desired 3-D product is obtained by removing material. Subtractive methods include milling, lathe turning, grinding and planing, all of which can be computer automated and referred to as CNC (Computer Numerically Controlled) machines. The object file formats are input into a CNC computer, which then determines the milling operation. The main advantage of the subtractive method of fabrication is that the finished object can be produced directly by machining stock material (aluminum, brass, steel, wood, wax, etc.). Increasingly complex objects are made depending on the number of axes employed, though subtractive methods can not produce internal voids.

Additive Methods P&M (Rapid Prototyping and Manufacturing)

Rapid Prototyping and Manufacturing creates 3-D prototypes or models. RP&M systems function like 3-D photocopiers or printers that develop tangible objects for evaluation. Unlike subtractive fabricators, RP&M systems add materials€ usually intended for molding or casting ayer by layer to create the product. Like the CAM (Computer Aided Manufacturing) process, CAD (Computer Aided Design) information is imported by RP&M systems using a file type understood by the fabricator. The STL (Stereo-lithography) file format is common for additive manufacturing. A discussion of candidate additive methods elective Laser (Photo-curing) Apparatus (SLA); Laminated Object Manufacturing (LOM); Selective Laser Sintering (SLS); Fused Deposition Modeling (FDM); and Micro-Droplet Fabrication (MDF)ppears on the attached definition page.

III. INTRODUCTION

In 1996, The University of Michigan School of Art and Design began incorporating computer technology into its curriculum for jewelry design and metalwork. The exploration of CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) and RP&M (Rapid Prototyping and Manufacturing) began by researching the availability, compatibility, and appropriateness of hardware systems and software packages. After deciding on the type of CAM and RP&M machines that were conducive for jewelry making, we needed CAD software to produce mathematical information in a format accepted by automatic fabricators. We selected JewelCAD® software for its superior performance and ease of use. JewelCAD® creates slice files that are very compatible with the Sanders Model Maker II™ system. This eliminates the extra step of converting an STL file to a slice file, reducing the chance of conversion errors. JewelCAD® not only generates files required for MM-II, but also produces file types for CAM (Computer Aided Manufacturing) and other RP&M (Rapid Prototyping and Manufacturing) machines.
The subtractive system chosen was the CNC (Computer Numerically Controlled) Roland Digital Group CAMM-2 model PNC-2300 computer-aided engraving machine that produces models out of materials such as aluminum, brass or wax. The PNC fabricator is restricted to designs without undercuts, but the result is a very finely finished relief-type product. The PNC was within our budget and could be operated after minimal training.
Among the different RP&M (Rapid Prototyping and Manufacturing) additive processes, the Sanders Prototype, Inc., ModelMaker n™ 3-D Printer, which employs MDF (Micro-Droplet Fabrication), has several advantages. This technology applies tiny droplets of wax support material along with hot-melt materials to build the model. It is the system of choice of jewelry designersnd potentially metalsmiths ecause it yields the finest detail models in its class. This saves precious metals by fabricating thin-walled objects with hollow interiors if desired.
To test 3-Dimensional Reverse Engineering by Scanning, we used the Renishaw Cyclone Scanner, the PICZA 3-D scanner, and the Kreon® digitization system. The Renishaw Cyclone, which we accessed through a service bureau, records up to 1000 points per second as it passes continuously over an object. It produces a high-resolution data file compatible with a variety of CAM (Computer Aided Manufacturing) processes. Benefits of the Cyclone technology include rapid and precise reproduction, and the ability to produce mirror objects as well as changes in scale. We purchased the more affordable PICZA 3-D scanner so that we would have a convenient in-house capability. To explore contactless scanning, we tested the Kreon® system through a service bureau.

IV. FROM DESIGN TO MANUFACTURE CAD (Computer Aided Design) ewelCAD

The intent of using CAD (Computer Aided Design) software was to create objects that were either impossible or very difficult to construct from traditional metal-smithing techniques. JewelCAD® was the software chosen due to its direct correlation to jewelry, user friendliness, ability to make quick design changes, and its compatibility with the MM-II system. The JewelCAD® software was run on an IBM-compatible PC with the Windows® NT operating system. The design process on the software begins by creating curves. There are several different types of curve commands that create a variety of freeform lines, arcs, and even two-dimensional shapes like circles, squares and polygons. This is much like drawing on paper with rulers and stencils. The curves are then used in conjunction with surface commands to create 3-D shapes with volume, much like choosing a type of wire or gauge.
The curves and surfaces can then be altered by using the deform commands, allowing for quick adjustments, changes in scale (reducing or enlarging), or moving operations. Finally, the copy commands ensure quick replication of parts or pieces and are well suited for several reproductions of the same component, such as a repeating bead or bezel. More importantly, the copy command can create a mirror image of the entire piece ery handy in creating a pair of earrings. When de-signing, it is important to view the work in a variety of ways. The view commands allow the user to quickly display the three- dimensional designs in different formats ranging from wire frames to rendered images. Equally important are the different angles to view the work. The software is capable of displaying the work in the right, front, top and 3-D oblique views. These commands are very helpful for inspecting all sides of a piece, separately or at once. The success of the build is dependent upon accurate positioning. It is necessary to inspect where the segments join one another to ensure that contact is made. The zoom command magnifies these unions and aids in any adjustments. After all areas are inspected for contact, the parts must be unionized together with the misc. /union command. In a sense, this command tricks the computer into thinking all the parts are now one piece.
Some other attributes of the JewelCAD® software include a database that stores a variety of design examples, such as types of stones, metal and stone color, as well as background options. When the designs are completed, they must be stored or saved. The rendered image can be saved as a BMP (bitmap) file and printed directly from a color printer, or saved as a TIFF (Tagged Image File Format) file for making slides. The designs may be saved in a variety of hie types. For the PNC-2300 subtractive technology, JewelCAD® software can save the design as a DXF (Drawing Exchange Format) file and go directly to a CNC (Computer Numerically Controlled) machine. JewelCAD® can also make slice files for use directly with the Sanders ModelMaker II™ system. JewelCAD® software can produce IGES (Initial Graphics Exchange Specification) and STL files in addition to DXF file formats.

Delivering Designs to Automated Fabricators

There are several ways to export your design to fabrication systems, whether local or remotely located. If the CAM (Computer Aided Manufacturing) or RP&M(Rapid Prototyping and Manufacturing) machine is not networked directly to your computer, then the design data must be sent to a production facility by other means. The most common way is to save your file onto a diskette and hand-deliver or mail it to the facility. Often, however, design files are much larger than a regular 1.4MB diskette can hold. In that case, the data must be compressed with special software ("zipped" or "stuffed"), or hardware with greater storage capacity, such as Zip drives and disks, must be purchased. Using electronic mail is an equally viable method of sending data to the manufacturing facility. It is easily accomplished by sending the design file as an e-mail attachment. Once again, though, files may need to be compressed before e-mailing so as not to flood the receiver's in-box.

CNC (Computer Numerically Controlled) NC-2300 ubtractive Method

The GoldPro® PNC-2300 offers a refreshing venue for creating works of two-and-a-half dimensions (2-1 /2 D) and/or three dimensions. The PNC fabricator is restricted to designs without any undercuts and the end result is a very finely finished relief-type product. The PNC-2300 was within our budget and could be operated after minimal training.
CNC milling machines can be 2,3,4 or 5-axis operations. For example, a 2-D, 2-axis operation features 2 movements he X axis moves left and right, and the Y axis moves backward; in a 3-D, 3-axis operation the X and Y axes move freely, and the Z axis operates for depth. A 4-axis operation includes an index to hold and rotate cutting materials, and the machine moves along the X, Y, and Z axes, though it cannot tilt more than 160°. A 5-axis process includes the attributes of 4-axis, but the Z axis can tilt so that undercuts can be machined.
The PNC-2300 3-axis subtractive process carves the piece directly out of the desired material by controlling the X, Y, and Z axes. The CAD (Computer Aided Design) file is input into the Modella™ software, a driver for the CAMM-2, which generates the tool path and cut. The PNC-2300 has a maximum working area of 305mm by 230mm by 30mm for the X, Y, and Z-axes (12 by 9 by 1-1 /8 inches) and is capable of accorninodating tool shank sizes of 3.175mm and 4.36mm. The machine has the flexibility of cutting a variety of materials including wax, wood, aluminum, brass, and even plastics. Once all information is input, the tool path and cut can be generated to drive the PNC-2300.
Several JewelCAD® designs were created for the PNC-2300. Each one was carefully designed to avoid any undercuts. The designs were saved in a DXF 3D face file format by using the file/export command from the JewelCAD® tool bar.
Our PNC-2300 was connected directly with the host PC; therefore the files were opened directly from the Windows®-based driver for the engraving machine. Once opened the cutting parameters irection, depth, tool size and shape, material, and even the quality of the cut ere selected. The software can then generate a tool path and cut. Before cutting, it is important to set up the work area of the engraver by securely mounting the material, making sure it is level, and setting the milling bit starting coordinates. An additional parallel vice was purchased to hold small slices of wax and alurninurn securely. A rough cut is calculated and run first, followed by a finer cutting path. The cutting time varies greatly from one design to another depending on size, material and detail.

MDF (Micro-Drop Fabrication) anders ModelMaker II™ dditive Method

The MM-II system is supported by a software program called ModelWorks™ that accepts STL (Stereolithography) file data and slices it to create a layered build file. The Sanders MM-II system has the lowest acquisition cost of all RP&M systems researched, with an ownership cost of about US$3.00 per hour. However, acquiring a MM-II system was not within our current budget, so we sent our JewelCAD® designs to an industry service bureau as a practical short-term solution.
In preparation for the MM-II system, the JewelCAD® design was centered to zero on the X, Y, and Z axes, and oriented in a fashion that would allow for the least amount of slices. Slices are made from the bottom to the top, so generally laying the design on its side and positioning it where the height is the shortest is the best practice for shorter build time. This is all done in the front view. Next, the design is saved as a slice file. This is where the computer slices the design into a series of cross sections, much like cutting a loaf of bread into slices. By using the misc./cut into slices command, the user determines slice thickness, and chooses the dimensional output and input units of inches or millimeters. For greater detail of the model, select the thinnest slice thickness value. Keep in mind that finer layer thickness lengthens the build time.

After saving the file, the data is now ready to be transferred to the RP&M system. In this case the CAD slice file was compressed using the WinZip® software. Compressing a file in this fashion can decrease the size of typical designs to less than 5 MB. (The receiver must have compatible decompressing software.) The com-pressed files were then sent as an attachment via e-mail to the production facility.
Several designs were developed for fabrication on the ModelMaker H™ system. The Sanders MM-II system uses the JewelCAD® slice file directly (other CAD software capable of generating STL files is also usable). The STL file format is a triangular interpretation of the object surface that allows the RP&M system to slice the object into a series of parallel cross-sections, known as slice files. A final build file can be created with the slice file information. The thickness of the slices is usually determined by the fabrication machine parameters which depend on the material and method used. The slice files were then input into the Sanders Prototype, Inc. ModelWorks™ graphical user software that creates the build file. This build file was used to determine the placement of the ProtoBuild thermoplastic material as well as the ProtoSupport wax supporting material or substrate.

The working area within the system is 12 x 6 x 9 inches (30.48 x 15.24 x 22.86 cm). Each layer is built by a patented ink-jet system that simultaneously builds the model and the support, one layer at a time, by depositing micro-droplets of material. One jet deposits thermoplastic material to build the actual pattern and the other jet delivers the droplets of wax that support the pattern cavities and voids during the build operation. The materials are hot-melt liquids that solidify instantly in position.

After the ModelMaker II™ system completes each layer, a milling subsystem mills away any excess vertical height; this aids in the accuracy of the design by controlling the layer thickness and hence, the surface quality of curved surfaces. The system's dimensional accuracy is 0.0005 in. (.013mm) over 9 inches in the Z-axis, and up to 0.001 in. (.025mm) over 3 inches in the X & Y axes. Micro-droplet size is 0.003 in. (.076mm). Once the build is complete, the model is removed from the substrate and immersed in a Bioact® solvent bath that dissolves away the wax support material. The model is then ready for molding or casting without any further post processing as required with many other RP&M systems.
After the models were returned to us, they were prepared for molding and casting. Several copies of each piece were ordered at once. This was cost-effective and granted us backup stock. The models can be either cast directly or molded. However, it may be necessary to seal the models with mineral oil or shellac because the thermoplastic is somewhat porous and water-soluble. When casting, it is important to know that the specific gravity of the thermoplastic is 1.25 and its melting temperature is approximately 90-113° C.

V. REVERSE ENGINEERING BY 2 AND 3-DIMENSIONAL SCANNING

The automated fabrication methods described up to this point have been based on CAD (Computer Aided Design) files created by the jewelry designer or metalsmith. The reverse engineering process is different in that it works from the data file created by a scanner tool for copying an existing 3-D object. This process optimizes the transfer of digitized data in the form of surfaces to a high-performance CAD/CAM software application. Among the many advantages of reverse engineering is the ability to reproduce an existing object precisely in far less time than it would take to recreate by hand. Scanning is also very effective at capturing textures. The data file can be manipulated to change the scanned object€ produce a mirror image, change scale, rotate through 360°, or invert (male to female). Dividing the scan file into separate files so that different parts of the scanned object can be reproduced in different materials is also easily accomplished. As with any data file that can be stored indefinitely, the object may be reproduced or altered at any time in the future.
There are two main kinds of scanners that are useful for jewelry design and metalwork: contact scanners, where a probe measures the 3-D object either point by point or by following a continuous path, and contactless scanners which pass a laser beam over the object to produce mathematical data.

Continuous Path Contact Scanning enishaw Cyclone

The Renishaw Cyclone scanner provides high-speed, high-resolution digitizing through continuous path scanning (rather than scarining point by point, which is slower and produces a coarser resolution). Amanmade ruby, ceramic or stainless steel scanning probe, ranging in size from .3 to 10mm, depending on the material and level of detail in the object to be scanned, maintains continuous contact as it passes over the object, recording measurements at the rate of up to 1000 points per second. The Renishaw Cyclone produces files compatible with a variety of CAM (Computer Aided Manufacturing) processes like CNC (Computer Numerically Controlled) milling machines. Recent developments enable the Cyclone, using a 4-axis system, to undertake increasingly complex designs, including simple undercuts, though it still cannot reproduce internal voids.
To test the benefits of the Renishaw Cyclone scanning system, a cherry blossom that had been created over the course of 200 hours using the traditional metal-smithing techniques of high-relief respousee and chasing was sent out for scanning. Several different scales of the model were ordered (the machine can enlarge, reduce or mirror the original). Each of the wax copies came out perfectly detailed, and each was produced in about seven hours (3.5 hours to scan, 3 hours to carve the front and .5 hours to carve the back). Because the cherry blossom was to be cast in three colors (platinum, yellow gold and green gold), the data file was divided into component parts to produce perfectly matching separate pieces for casting. In addition, the cost of materials dictated as thin a reproduction as possible, and the Renishaw Cyclone and CNC machine reached a thickness of only .8mm in wax for the first time when producing this piece.
The Renishaw Cyclone scanned the original and produced a model from it in seven hours, and with 4-5 hours of casting, polishing and assembly, it took approximately 11-12 hours to reproduce an object that originally took 200 hours to create using traditional methods. The labor and cost savings of this method are clear, though the price of the Renishaw Cyclone system made it more cost-effective for us to send out pieces to an industry service bureau.

Contact Scanning ICZA 3-D and Microscribe-3D™

On the other hand, the GoldPro® PICZA 3-D Digitizing Scanner, though less sophisticated, is more affordable. The PICZA produces DXF (Drawing Exchange Format) files from 3 dimensional scans of objects with one flat side and no undercut. The PICZA software has the ability to alter the scale or produce mirror images of the scanned object, and the DXF file it creates is compatible with almost any CNC (Computer Numerically Controlled) machine that produces models by the subtractive method. For example, the PICZA scanner can be connected to the GoldPro® PNC-2300 3-Axis CNC milling machine, which carves wax, aluminum, brass, wood, plexiglas, etc. The combination PICZA scanner and PNC-2300 automated fabricator creates a cost-effective system for reproducing relief-type designs, but is limited in its application to 3-D objects. Solid 3-D can be done with the PICZA / PNC-2300 combination only with great difficulty.
If, for example, an asymmetrical three-dimensional design is desired, PICZA scan DXF hies can be transferred to Rhino or comparable software. We chose Rhino because it is very user-friendly and many of its commands are similar to JewelCAD®, which by itself isn't sufficient. Rhino can be used to create 3-D, adjust or increase the complexity of the design or even to merge imported PICZA scan files with other scanned images to create an entirely new model. Rhino files can be sent to CNC (Computer Numerically Controlled) or RP&M (Rapid Prototyping and Manufacturing) facilities, depending on the design.
The Microscribe-3D™ scanner is an affordable, truly 3-dimensional system that produces model with any additive RP&M technology. Unlike either the Renshaw or PICZA scanners, using a 3-D scan from the Microscribe™ and Rhino software, it is possible to actually change the form of the scanned object.

Contactless Scanning aser

Kreon® digitization systems are based on laser plane projection by sensors which sweep the surface of the component (instead of contacting it) at the rate of 600-15,000 points per second. The points are scanned ten times faster than with a standard acquisition process, and definition of digitization traces is four times as fast as with previously existing systems. It provides stereoscopic visualization of digitized points at several levels of detail, from all angles, and without shadow areas. Resolution is in the range of 10 microns. Because there is no contact between scanner and scanned object, complex, soft, fragile, elastic, and even hot or live parts can be scanned. One of the most complex forms was successfully scanned and produced using the Kreon® system.
The system is operated by the Kreon Reporter® software program which treats the information collected by the sensors, visualizes and digitizes points and generates a cloud of tri-dimensional coordinates. The software is free-standing and modular, and provides real-time control. Convenient access to the Kreon® tactless laser scanning system is through industry service bureaus.

VI. CONCLUSION

The worldwide jewelry market is highly competitive esign creativity, time-to-market, conservation of precious metals, product cost, and profitability are major issues. Jewelry design and fabrication as an ancient art form, traditionally performed by skilled artisans, is rapidly being augmented by computerized methods. Advances in computer technology, application software and automated fabrication methods are key factors in the jewelry design revolution. The chief benefits of automation to the jewelry industry are ease of design and modification, rapid prototyping of first article, design fidelity, process repeatability, faster time to market and reduced cost.
Our exploration of computer technology began with the excitement of tapping a new resource: exploring ways to enhance and expand traditional metalsmithing techniques, and creating works of art difficult or impossible to produce by traditional means. We chose the computer hardware and software applications best suited for our needs, but of course the best solutions will ultimately be discovered and explored by each individual.
For the past several decades, we as a society have witnessed a wide range of technological advances and developments. These range from ATM banking interfaces that allow us to do banking errands at any hour of day or night and computerized checkouts at the grocer's that expedite shopping, to the automated rover on the planet Mars. Some of us embrace these automated systems as easily as watching television, but for others these technologies are foreign and even threatening. Do we initiate these developments for convenience, time, continuing knowledge, or perhaps all of these reasons? Our lives seem to be dictated by the never-ending battle to expedite all of our tasks. Is this by choice or by need? Do the demands of today's world require these technologies or do they spring from our quest for inspiration? No matter how we choose to answer these questions, rapid technological change is an unarguable fact.
We don't view digital CAD (Computer Aided Design), CAM (Computer Aided Manufacturing), RP&M (Rapid Prototyping and Manufacturing) and Reverse Engineering as replacements for traditional jewelry design and metalsmithing methods, but as new tools that we can use where appropriate. Broadening the interface between skilled designers and the world of automated production is especially important, since the current rapid rate of technological growth is likely to accelerate well into the foreseeable future.

VII. REFERENCES

Burns, M., Automated Fabrication: Improving Productivity in Manufacturing, Prentice Hall, Englewood Cliffs, New Jersey, 1993. Chang, T./C, Wysk, R.A., and Wang, H.P., Computer Aided Manufacturing, 2nd
Edition, Upper Saddle River, New Jersey: Prentice Hall, 1998. Hastbacka, A., "Ink-Jet Rapid Prototyping Machine, Final Report," NASA/
MSFC, SBIR Contract No. NAS8-97022,1998. Hastbacka, A., "Precision Ink-Jet Rapid Prototyping," Technology 2007 Conf.,
Boston, 1997. Hastbacka, A., "Advances in Ink-Jet Rapid Prototyping," RPMAConf., Dearborn,
MI, 1996. Machover, C, The CAD/CAM Handbook, McGraw Hill, New York, NY, 1996. Stoddard, R.D., "Drop-on-Demand Ink-Jet Prototyping," Prototyping Technology
International, UK & International Press, London, UK, p. 242-246,1997.

Acknowledgments

This exploration of CAD/CAM and RP&M was funded with grants from the following University of Michigan offices and departments: the Office of the Vice President for Research, the Undergraduate Research Opportunity Program, and the School of Art and Design & Information Technology Division Partnership. The authors also wish to acknowledge the support and contributions of the Sanders Design International Sales Manager Rolf Hubert and Senior Electrical Engineer Robert D. Stoddard, ITW Illinois Tool Works Division of Paslode Senior Design Engineer Walter Taylor, and Edwards Industries Manufacturing Engineer Michael D. Ottaviano.

Special Thanks

The authors are especially grateful to the following individuals for their assistance with this project: Steven Archangell, Kathy Arhangelos, Scott Balaban, Roland Benke, Fred Betlach, Ross Carl, Craig Chaffee, Ann Doyle, Debaish Dutta, Michael Farman, John Forsythe, Joseph W Fournier, Timothy Gornet, Doug Hagley Jo Ann Heap, Chris Hubert, Scott Johnson, James Knackstedt, Keith Ketchum, Mark Krecic, Victure Luciere, Bill Manspeaker, Anne Marson, Jeff Mead, Joy Melzian, Linda Mills, Tim Myer, Paula Neuroth, Kimberly O'Donnell, Scott Paulinski, Eugene Pijanowski, Anna Regulyant, Todd Rolack, Keiko Sato, Yasuo Sato, James Sheriden, Rob Small, Betty Smith, Ken Steele, Ruth Taubman, Karen Thomas, James A. Turner, and Theresa Woodiel.