Recently, astronaut Barry Wilmore discovered that the International Space Station (ISS) wasn’t quite as well equipped as his garage workshop, and lacked a simple but useful socket wrench. How did NASA solve this problem? They emailed him the CAD model and designs for the socket wrench parts, which he made using a 3D printer he had put together on board the station only a month before, then assembled the pieces into a working tool. While it’s easy to dismiss this as yet another futuristic NASA-exclusive technology, 3D printers and other automated manufacturing machines have become commonplace in the homes and hack-spaces of the DIY community. This innovative infiltration began with the advent of CNC (or Computer Numerical Control) machining.
Space Station 3-D Printer Builds Ratchet Wrench To Complete First Phase Of Operations
CNC machining platforms (including most commonly routers, mills, and lathes) are, in essence, “smart” motorized versions of their basic mechanical counterparts. Where 3D printers work based on an additive manufacturing principal (adding material to a piece to build it up), traditional machining tools like routers, mills, and lathes work based on a subtractive manufacturing principal (starting with a block of raw material and cutting away excess to reveal the final product). Both fundamental types of manufacturing have been implemented by humans since we had the tools to put clay and water together into pottery (additive) and carve wood or chip away stone to make sculptures (subtractive). Only since the introduction of motors, and shortly afterwards, computers, was it possible to automate these processes, providing huge savings in production time, labor, and cost.
Because CNC systems are dependent on computer processing for their automation control, their history and development parallels closely with that of the personal computer. The first rudimentary CNC systems (at that time, considered “NC” or Numerical Control machines) were developed and built from the 1940’s-50’s and began by running “programs” on tape and punch cards. These were typically monstrous assemblies, taking up entire rooms, not unlike computers of the time. Because of the recognized potential benefit of major cost, time, and labor reductions, as well as the ability to accurately recreate a part with finer precision, the US Army purchased over 100 early models and provided them to select manufacturers to help the idea take seed.
Image Credit: CMS North America
Pictured: Old CNC Machine
At that time, each manufacturer used their own language or protocol when creating the programs for their specific CNC system, which resulted in problems when attempting to make parts using programs from other manufacturers. Late in the 1950’s, about 1958, the MIT Servomechanisms Laboratory developed a language known now as g-code, which was standardized a few years later for most CNC use by the Electronic Industry Alliance and is currently the most prevalent CNC programming language. In the following decade, CAD (Computer Aided Drafting) and CAD/CAM (Computer Aided Manufacturing) programs began to replace traditional paper technical drafts, and helped cement the ease with which a design could be created using CNC.
A modern-day CNC machine usually consists of a machining head (which typically houses a tool bit and driving motor, though can be swapped out for laser cutting heads and other less traditional tooling options), positioned by an X/Y dual axis system. The components used to comprise this dual axis positioning system can vary greatly, with possible drive methods provided by belt and pulley, lead or ball screws, or actuators, and structural support provided extrusions, linear guides, or shafts, to name just a few examples. The motors driving the X/Y axes are usually designed for positioning (popular types include stepper and servo motors), and are controlled by signals generated from the processer translating the CAD/CAM design into positions, paths, and speeds for the tooling head to interpret, using the aforementioned g-code.
As industrial factory automation and machine components have become more readily available to the average consumer, and as computer processors have become exponentially more powerful in smaller and smaller packages, the ability for an individual to make sophisticated and compact CNC systems for home use has improved immensely. In addition, the convenience and depth of knowledge provided by internet communities devoted to Do-It-Yourself CNC like DIY CNC Cookbook (http://www.cnccookbook.com/CCDIYCNC.htm ), Build Your CNC (https://www.buildyourcnc.com/default.aspx/ ), and open-source/crowd-sourcing efforts allow for anyone with an internet connection to have access to and try to build their own CNC system. Finally, professionals, hobbyists, and enthusiasts alike can all come together at events like MakerFaire (http://makerfaire.com/ ) held around the country to share ideas, designs, and excitement for DIY projects, many of which have CNC to thank for as an introduction to home-manufacturing.
Carbide 3D Nomad CNC Mill designed with a rigid aluminum frame.
From empowering the individual maker in their garage workshop, to inspiring its latest technological ancestor in space, CNC machining has allowed modern manufacturing to improve by leaps and bounds. With the accessibility of the knowledge and experience of DIY communities online, making a CNC machine for home use has never been easier. And with machine components available in nearly limitless combinations and options, creating a unique design is within anyone’s grasp.
This is the first blog in a multi-part series focusing on CNC machining for at-home DIY solutions. Look forward to upcoming posts delving more in-depth into popular drive systems like timing belts and pulleys, ball or lead screws, and motor-driven actuators.
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