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Minnesota State University, Mankato
Minnesota State University, Mankato

Applied Research

Page address: http://cset.mnsu.edu/met/research/

Minnesota Center For Rapid Prototyping

About Rapid Prototyping

Rapid Prototyping (RP) by definition is a technology for generation of physical parts (prototypes) directly from technical documentation, usually in an early stage of designing of new products. In practice however, it is much more. Effective use of rapid prototyping technology requires levering on a higher level use of computers, computer aided designing (CAD) and analysis systems(FEA), electronic means of communication across a company and among companies. Benefits from implementation the RP for everyday practice make manufacturing companies more competitive by introducing products to market in shorter periods of time. For years RP was a domain of big companies which could afford to invest in equipment and training. But now, we believe, it is time to introduce RP to small and medium in size industrial companies. This, along with providing training to the MSU students, will be a major mission for the RPC at MSU.

Location

The Rapid Prototyping Center is located in Nelson Hall 105 laboratory. This 2200 sq/ft recently completely remodeled area has all facilities needed for accommodation of the rapid prototyping equipment, pus room for teaching, industrial projects and applied research. Accommodations include adequate electric and air power supplies, Ethernet multi hub computer communication, air conditioning with clean air supply, secure area for a computer server, and technician supervision. This lab has also direct communication with two other important laboratories used in rapid prototyping: the machining cell with two full size machining centers, and designing (CAD) laboratory which has installed mechanical designing software.

Major Equipment

Two basic RP technologies are represented in the RP lab for training and research: numerically controlled machining (CNC) to produce a model (subtractive method), and building physical plastic models directly from a computer file or documentation (additive method). The selection and configuration of equipment is designed to provide a comprehensive training on all the important stages of prototyping from product design to production preparation for both subtractive and additive methods. The following pieces of equipment are installed and available for RP projects:

  • receiving network workstations (WindowsNT computers)
  • CAD processing workstations (Unix and WindowsNT computers);
  • reverse engineering station: Coordinate Measuring Machine and MicroScribe from Immersion Corporation;
  • prototyping mill: Roland;
  • two industrial HAAS machining centers: for turning and milling;
  • a model of flexible manufacturing system from Amatrol;
  • Acuta from 3D Systems, an additive type machine for building plastic prototypesfrom CAD files.

All pieces of equipment are computer controlled, and when needed can be connected to the Ethernet network for receiving or sending data, videoconferencing, or advance data analysis.

Computer Aided Design

  • AutoCAD r. 13, r. 14 and r. 2000;
  • Mechanical Desktop 4.0;
  • MasterCAM v. 7: Design, Mill and Lathe;
  • Coordinate Measuring Machine CADInspector for reverse engineering;
  • Design Space v. 5 from ANSYS for the fast engineering load-stress-thermalanalysis.

Rapid prototyping projects begin with introducing an idea of a new product or improvement of existing one. It can be a sketch, photo or a drawing. Commonly, a two dimensional drawing made with help of one of popular software systems is submitted as a hard copy or as electronic file over the Internet. Because there are different habits in documentation preparation and methods of sending files over the Internet the first step in teaching of RP is demonstrating the methods of conversion and standardization of files and preparing them for processing. Conversion between different CAD systems is an important part of the problem statement stage. Reverse engineering approach is a necessary step in RP when physical object exists, but must be redesigned and technical documentation has to be created. The coordinate measuring systems (CMM and the Measuring Arm) will be used for dimensional identification and inspection of the objects.

The next step in RP is creation of a computer solid model of the object. However it might be a time consuming operation but there are two major reasons to go on with solid models of prototyped objects. The first reason is that by viewing the model on the computer screen some important observations and evaluations of the object can be made before moving to the next stage which is building a physical model. The second reason is that the many RP processes, including tool path generation for subtractive methods or producing stereolithography files for additive methods, simply require solid models. In the lab we will use a powerful CAD system, Mechanical Desktop 2.0 for solid modeling.

From the two methods of building physical models the subtractive method of modeling will be used for the objects which can be created by a combination of milling and turning machining. The advantage of this method is ability of producing accurate objects with a variety of materials. The Roland prototyping mill, Haas Milling Center and Haas Turning Center driven by MasterCAM software will be used. The additive method of building objects is used when complex, hollowed parts must be built in a short period of time. Limitation is the size of the object and material used. Both processes can be repeated as many times as needed when the model goes through the designing iterations.

Once the model is made, it will be sent to the designing team for evaluation. Additional analysis will be available in the RP laboratory if desired, including computer stress analysis method from ANSYS, and physical stress/force/fatigue tests on prototypes.

One responsibility of the prototyping team is creation of technical documentation along with the physical model. That documentation will include "blue prints" needed on the shop floor, and electronic files including the 3D and solid models. One possible option includes files converted to the Internet format.

Rapid prototyping center will also offer practice on the next step, which follows prototyping which is production preparation. The Flexible Manufacturing System from Amatrol is a scaled down industrial installation, which can be used for study of material handing problems, fixturing, material storage and retrieval, production timing and other areas.

The Machining Cell which has two full size machining centers can also be used for production preparation studies as palletizing, designing of fixtures, efficient use of tolls, probes, selection of parameters of machining and other.

Conclusion

The objectives for the RP center are to use an advanced computer network technology to create a cross disciplinary approach to teach manufacturing students with cooperation with industry how to apply their knowledge they have from the program in situation when a "knowledge based" decision has to be made, and that decision can affect the performance of the whole team. The teaching goal are:

  • integration of students from different programs in problems solving situations;
  • transferability of instruction to other schools of different levels;