H General Motors έχει δημιουργήσει ένα νέο πρωτότυπο εργαστήριο στο οποίο οι μηχανικοί της, με την χρήση ειδικών μηχανημάτων laser, μπορούν και κατασκευάζουν τα σχέδια του υπολογιστή, σε πραγματικά μοντέλα.
Το εργαστήριο βρίσκεται στο Warren του Michigan, εκεί όπου οι αεροδυναμιστές της GM χρησιμοποιούν τα μηχανήματα αυτά – τα οποία μπορούν να κάνουν και άλλα πράγματα – έτσι ώστε να δημιουργούν προφυλακτήρες, γρίλιες, αεροτομές, πλαϊνούς καθρέπτες κτλ για να τα υποβάλουν σε δοκιμές στην αεροδυναμική σήραγγα. Απώτερος στόχος είναι να δημιουργήσουν αεροδυναμικά εξαρτήματα ώστε να μειωθεί η κατανάλωση καυσίμων των αυτοκινήτων τους.
Παλαιότερα, οι σχεδιαστές για να κάνουν κάτι αντίστοιχο δημιουργούσαν, στο χέρι το εξάρτημα από ξύλο ή αφρό, πράγμα που εκτός του ότι απαιτούσε χρόνο, δεν ήταν 100% το σχέδιο του υπολογιστή. Με τα νέα laser μηχανήματα, η δουλειά γίνεται πιο γρήγορα, πιο φθηνά αλλά το σημαντικότερο είναι ότι τα πρωτότυπα εξαρτήματα είναι 100% ακριβής.
Περισσότερες λεπτομέρειες μπορείς να βρεις στο video και στο δελτίο τύπου που ακολουθεί.
[Πηγή: General Motors]
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Rapid Prototyping Creates Roadworthy Concept Parts
EN-V bodies fabricated in 3D Rapid Prototyping Shop at GM Design
WARREN, Mich. – Whether a futuristic concept like the EN-V or a contemporary family hauler like the GMC Acadia Denali, three-dimensional rapid prototyping accelerates the creative process and reduces the time and money spent on clay modeling and molding of expensive prototype parts.
Designers and engineers from General Motors studios and technical centers around the world are able to see and touch their creations faster and at lower cost because of the digital manufacturing capabilities at the GM Design Center.
Selective laser sintering (SLS) and stereolithography (SLA) techniques allow designers to quickly and inexpensively go from computer models to one-off parts for wind-tunnel testing so more iterations can be tested in less time. Aerodynamics engineers can put a current production vehicle into the wind-tunnel and skilled trade technicians can quickly swap body parts like bumper covers, grilles, spoilers and mirrors between test runs.
Before the parts are fabricated in the rapid prototyping shop, the computer models are tested for proper airflow using state-of-the-art computational fluid dynamics software. These pre-tested parts can then be replaced much more rapidly and with better repeatability than old-style clay models can be re-sculpted. More time is spent evaluating the changes than waiting for adjustments to be made. In fact, testing capacity has doubled in the past two years.
“Long before a full-size model or vehicle is built, rapid prototyping helps to improve the accuracy of the one-third scale models that are used for early aerodynamic testing,” said Aerodynamic Development Engineer Suzanne Cody. “Air-flow through the engine compartment and underneath the car is critical to both cooling the engine and lowering drag.”
In the past, modelers would carve a rough approximation of the front structure and the engine from foam or wood to evaluate the air flow through the engine bay. GM’s 3D prototyping lab can generate a fully detailed model including the engine, transmission, brake lines, drive-shafts, exhaust system, suspension and other components under the car.
“The end result is better correlation of air-flow measurements between the model and the full-size car or truck and fewer expensive changes are needed late in the program,” said Cody. “With the design of components like cooling systems locked in earlier, fewer prototypes are needed and vehicles can go from concept to production more quickly.”
Rapid prototype parts also speed up test track and on-road evaluations. When 80 pre-production Chevrolet Volts were being built in mid-2009, several interior parts were fabricated by the RP shop and installed directly in the test cars.
“In design, we work with conceptual ideas in preproduction. Early part iteration allows us to get hands on to see what works and what doesn’t at the point where people actually touch the car,” said Checo Pacheco, a lead creative designer in the Branded Component Studio.
Some of the most public applications of RP components to date have been the EN-V personal urban mobility concepts that were featured during the 2010 Shanghai World Expo and the 2011 Consumer Electronics Show. Three body styles were crafted for the EN-V at GM Design studios in Los Angeles; Melbourne, Australia; and Russelsheim, Germany. The RP shop in Warren fabricated the bodies and many of the components for the demonstration fleet.
“3D rapid prototyping is enabling the designers and engineers at Chevrolet, Buick, GMC and Cadillac to stretch the creative envelope,” said John Green, superintendent, GM Design Fabrication Operations. “We can bring more attractive, functional and aerodynamic vehicles to market in less time and at lower cost than ever before.”
3D Rapid Prototyping Fast Tracks GM Fuel Efficiency Gains
Finished parts for prototypes and concepts come from powder and liquid in just hours
WARREN, Mich.- Deep inside the GM Design building where future products from Chevrolet, Buick, GMC and Cadillac take shape and substance, an elite team fashions components, intricate sub assembles and entire scale model cars from highly specialized three-dimensional rapid prototyping manufacturing equipment.
In an already secure building, access to the RP Lab requires additional clearance because of the work performed there, Operating around the clock, the highly trained team of technicians is vital to the global base of GM designers, aerodynamicists and engineers who achieve huge gains in creativity, flexibility and accuracy along with dramatic savings in time and money.
The Rapid Prototype Laboratory features two fabrication processes – selective laser sintering (SLS) and stereo lithography apparatus (SLA). Both processes build up finished products from raw material in layers.
“Think of it as the reverse of slicing off cold-cuts at the deli counter, where each slice is created and joined back to the whole,” said Dave Bolognino, director of GM Design Fabrication Operations. “RP technology eliminates tooling plus it permits the production and testing of multiple iterations of a part or assembly with superb precision at little to no incremental expense. It’s a game-changer of epic proportion.”
Selective laser sintering (SLS) machines are used to fuse plastic, metal, ceramic or glass powders in cross- sections. A laser scans a pattern on the surface of the powder, fusing the particles together adding a layer four-thousandths of an inch thick. As each new layer of powder is added, scanned and fused to the previous one the part gradually takes shape within the 28-inch-cubed reservoir. To the naked eye, the plastic used in the SLS process looks much like powdered sugar with individual grains measuring just 550 microns or about two-hundredths of an inch across.
Technicians carefully position as many jobs as they can together within that space to maximize the throughput of each build request. The SLS manufacturing process is self-supporting, meaning un-fused powder cradles the part as it is being fabricated, often without need for additional finishing or trimming.
After it cools, the excess powder is shaken off and a portion is recycled with the finished part put to use immediately or joined with other components to make larger assemblies.
Stereo lithography (SLA) combines photochemistry and laser technology to build parts from liquid photopolymer resins. The parts are also built up in layers as a UV laser traces the section onto the surface of the resin, curing the liquid into a solid as it scans. Because the resin won’t support the parts being formed, a fine lattice-like structure is generated below each part during the manufacturing process. Highly specialized software from Materialise Inc. automatically calculates the required structure based on the original 3D model of the part so that it uses the least possible amount of material. When the parts are complete, the bottom plate rises out of the vat of resin and the lattice support is snapped off by hand leaving a ready-to-use part.
Both technologies were used on breakthrough vehicles like the pre-production Chevrolet Volt and advanced concepts like the Electric Networked Vehicle, known as the EN-V. In the case of the Volt, RP technology was used in areas ranging from design, development and validation of the battery cooling system to helping to lower its coefficient of drag.
3D rapid prototype technology has resulted in dramatic efficiencies in GM wind tunnel testing across GM’s entire car and truck lineup.
“Thanks to the rapid pace of production from the RP Laboratory, GM’s aerodynamics lab has been to double its capacity of testing scale models over the past two years, contributing to improved fuel efficiency on future GM vehicles,” said Bolognino.
Labor-intensive projects that used to take weeks or months to sculpt in clay and then cut and cast in molds are now produced in a fraction of that time and expense. From Brazil and China to Australia and Germany, as soon as the designer finishes creating a mathematical model in the Computer Aided Design (CAD) system, the digital file can be directly transferred to the RP Lab, which never sleeps. The lab manages a continuous flow of receiving, scheduling, manufacturing and express shipping of more than 20,000 components a year.
GM Design has been on the leading edge of rapid prototyping technology for nearly two decades and is highly regarded as a beta tester and innovator of new materials, formulas and processes by its supplier partners, 3D Systems Corp. and Materialise.
“It’s a way to reduce product development time, save costs, and give designers more options,” Bolognino said. “I don’t see any end sight for General Motors use of this technology.”
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