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 Geared Steam Engine by Joe Martin (Click on image to enlarge) |
Featuring Alibre Design 3D CAD Design Gallery |
Recent developments in 3D Computer Aided Design (CAD) have brought the price of programs down to where a home shop user can have access to design tools that rival that of the professional programs purchased by engineers and big companies. Programs like Solidworks, Pro/E, Catia, Inventor and SolidEdge cost many thousands of dollars. However, for the small business or home shop users, programs like Alibre Design offer all the important features to design sophisticated parts and assemblies for less than $200. We present here examples of clever work done entirely in the computer using 3D CAD programs. There are two categories: 1) Projects re-created in 3D from existing 2D plans and 2) New projects designed from scratch in the computer.
The old way vs. the new way to design and build parts—Computer Craftsmanship
The old way was to sketch out an idea on paper and then draw up a set of plans either on a drawing board or in a 2D CAD program like AutoCAD. Then a prototype would be built from the plans and parts fitted together. Once the inevitable mistakes were discovered and design changes were made, eventually you ended up with a corrected set of plans and an actual working prototype you could look at from any angle and move the parts to make sure it was what you wanted before going into production.
That has all changed with 3D design programs. Now the designer can start making parts right in the computer. He can rotate them around and visualize them from all angles on the screen. He can color them. He can build up assemblies of various parts to make sure they fit together. He can then apply constraints to the various parts so they move in the proper relationship to each other, and he can animate the whole assembly right on the computer screen. He can also easily convert the drawing into conventional 2D plans with dimensions, and he can create cross-sectional views and even exploded views with just a few simple commands. All of this is before the first part is even made.
Once the assembly is completed in the computer, there are two ways to translate that into a physical object you can hold in your hand. One is to use modern 3D printing technology. The drawing is sent to a 3D printer where it goes from a drawing directly to reality. Various technologies using plaster, plastic and even metal build a part in thin layers. Molds for the part can also be built in the printer so the part can be cast. The other method is to translate the information in the drawing into a text based language called G-code. This is the language modern CNC machines understand, and they can machine the design from a solid block of material (anything from foam to metal) to produce the actual parts exactly like the ones in the drawing. This is the way things are done now in the industrial world.
For those interested in learning what the Alibre 3D CAD program can do, CLICK HERE
Industrial Archeology—Recreating objects and assemblies from existing plans |
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Geared steam engine by Joe Martin. The mechanism features a planetary gear the circles inside a ring gear, keeping the connecting rod level. Plans: www.John-Tom.com |
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A small oscillating steam engines called "Millie" by Joe Martin Plans: From plans reprinted in Tabletop Machining by Joe Martin from a design by Ed Warren originally published in ModelTec magazine |
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Opposed piston steam engine by Joe Martin Plans: www.John-Tom.com |
Using the 3D design process to create new projects |
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Model R/C Airplane design by Jerry Nelson Jerry is an R/C flyer, retired hobby shop merchandiser and former user of SolidEdge 3D CAD software. The plans were taken from a full-size homebuilt airplane and scaled down to 1/4 size. Like the real plane, the model will be built using metal panels with fiberglass cowling, wheel pants and wing and elevator tips. In the drawing Jerry was able to confirm that fuel tanks will fit, linkages will clear bulkheads, etc. Working out problems in advance in the drawing assures perfect part fits the first time when the model is actually built. Jerry's design is based on is the Thatcher CX4, a VW-powered, single-place sport aircraft that has a wingspan of 24' and weighs just 520 pounds empty. NOTE: Jerry Nelson, along with Joe Martin, Bud Crane and Ed Shipe were the founders of the sport of Formula 1 R/C pylon racing in the 1960's. |