Using computer, Computer Aided Design (CAD) and modeling software; Not only we can visualize our design, we now can test, assemble and see how the parts fit before we start making them. Dramatically reduce error and bad design as a result. In this blog, we want to assist beginners by sharing our views on using these technologies, knowing the basics and transitioning your design from screen to a real part.
Welcome back readers
We hope you enjoyed the first two parts of introduction. For those who missed here are the links for Part 1 and Part 2. Visit our Flickr page for larger photos. Part 3 is about Computer Aided Design, drafting and producing your design. This blog is not a “how-to” as there are many tutorial sites covering software usage and machining. Here we hope to introduce these professional tools and provide a general guidance to our hobby community.
Beginner Tips on CAD/3D modelling
For a beginner, it is all about (2P & 2M) Patient, Practice, Math and Measure.
- You may need tools (i.e. Caliper, micrometer, height and depth gauge) to give you accurate measurement
- It involves basic mathematics, trigonometry, arithmetic and unit conversions
- Refer to Software Reference section at the end of this article
- Avoid frustration, please read software prerequisite, make sure your PC is capable of running the software
- Setup your CAD environment properly and stick with one unit of measurement
- Save and backup your work often
We recommend learn how to bring a part into a CAD drawing as a first step, grab a spare part from RC car or helicopter and get it digitized.
Carefully study the part you want to digitize. Very soon, you will run into questions like “How to measure distance between two screw holes?” or “How do I draw a hole tangent to cylinder?” Overcome challenges by read, ask, check on the Internet and see others are doing it.
First plan a dry run on how the part is going to be drawn, this process prompts you to look for features within software to complete the task. A good example will be (i.e. To draw a top view of a glow engine heat sink, are you going to measure and draw six bolt holes individually or use the pattern feature and complete in just a few clicks?) Read software manual on how to use each feature.
Properly setup your drafting environment, from unit of measurement to snap points, layers, commands and tool bars. Once your drawing is started, save your work often and make backups.
There are tons of drawing/3D model of parts, servos and glow engines being shared on the Internet, save time by using drawing made by others but make sure you double check their work and dimension. Consider subscribe to Thomas Register for official product information and CAD drawing of registered products.
Transitioning from drawing to making part (Machining)
Able to draw a part does not mean you can successfully making one in real life. However don’t be discouraged, for beginners try (2P & 2M).
Machining a part takes a different process, especially in manual machining where an operator needs to:
- Prepare stock material and secure it for machining
- Read and understand the drawing, plan how to machine the stock
- Machining multiple parts? Consider doing them all at once, it may be easier and faster
- Follow planned steps to mill, drill and tap the stock
- When everything is finished, a part is produced
A common misconception about CNC system, as seen from YouTube. It doesn’t really machining a part for you that magically.
CNC automates the use of machine tools and cut paths by means of executing a list of pre-programmed commands. Similar to running a batch file in a DOS. In short, machining concept and experience are still required. So you ask where are those commands come from? You can learn and write command yourself or use Computer Aided Manufacturing (CAM) to produce commands for you. Oh boy, another learning curve.
Now that you know CAD does drafting, creation of parts. CAM analyzes your CAD drawing and outputs a list of programmed commands (i.e. Change tool, cutting paths, feed rate). You feed the list to your CNC system, secure your stock, press “Begin” and watch it work. So, can you learn all that? Yes, of course. Can an “One-Man-Band” from hobby community handle all that? Yes, of course, just don’t complain you lose all your RC flying time! We have been warned, it can easily become a new hobby 🙂
Every application takes time to learn and master, eventually you will figure out the tricks to get things done faster. With popularity of free and open source software, we can easily try and start using these tools. Don’t hesitate to get started.
To learn more about Computer Aided Design software, visit Wikipedia for industrial standards and list companies.
Remember to support the industry, be legit and use genuine software. Get started by drafting in 2D. Dassault Systemses [Free CAD software] and Siemens [Free CAD software] both offer professional grade, industry backed, fully matured 2D CAD software for free. Take advantage for these offers and see if CAD drawing is for you.
Good Luck everyone, Team BTF
Lets talk electronics next! Stay tuned.