Emergency Stop Switch Installed

I haven’t had a need yet for an e-Stop switch, but I figured I should go ahead and install it before the need arises! I’m still amazed at how quickly I can model a part, create the CAM setup, and then create the part on the CNC machine. It took less than an hour to model the bracket, create the CAM setup and toolpaths, and produce a g-code file to bring out to my machine, all with Fusion 360. I cut the bracket from some scrap 0.25” plywood and mounted the switch on the front of the machine. One side of the switch was wired to pin 10 on the Gecko G540 breakout and the other side connected to ground on the power supply.

cnc e-stop switch

Overdue Update

I’ve been quite busy for the past few months. So busy that I haven’t posted any updates. I’m going to give a quick summary of what I’ve been up to and then follow up with some more detailed posts.

Since my last post I’ve done the following:

  • Added an emergency stop switch to my machine
  • Added a laser to my machine for engraving and cutting
  • Made my first cuts in Aluminum, using finish passes, resulting in +/-0.002” accuracy
  • Researched and purchased a few styles of home/limit switches to test (still in progress)
  • Wrote an eBook, Introduction to CNC Router Design
  • Performed a static rigidity test on my CNC machine
  • Created a Version 2 of my CNC design in CAD with some improvements that will make it easier for someone else to build a copy of this machine and to improve rigidity based on my testing
  • Started creating detailed drawings of Version 2 to be able to offer plans to others (still in progress)
  • Used my CNC router and laser for some small project requests

More details to come.

Introduction to CNC Router Project

Intro

I have always enjoyed learning new things and thinking about innovative solutions to a wide array of problems I encounter in life.  Many of the ideas and subsequent solutions have seemed viable, but would require resources that were not available to me to implement the idea.

In the back of my mind, I’ve always been intrigued by the thought of having a CNC machine at my disposal. This would help me to bring my ideas to life.  Seeing stories of other people building their own low-cost machines tempted me over the years to do the same.

After years of reading/dreaming about it and gradually learning, one day I decided to seriously research the options.  I looked at buying one of the hobby machines that have been popping up on the market in recent years, buying a diy kit, buying plans, or following one of the free open source projects to build my own CNC router.

In usual fashion, I spent a few months studying all of the specs, pricing out each option, and reading hundreds of forum threads, articles, and reviews.  It was quickly apparent that I could not afford to buy a machine, or at least a machine that had the performance I required.  Kits and open-source machines were not much better for affordability, but plans offered a lot of bang for the buck.

Researching CNC Router Plans

Quite a few plans were available, so I dug in to comparing them all.  In the process, I read many accounts of people who built machines based on the plans, those who modified the plans and those who upgraded their machines after not being satisfied with the initial results.  In addition, I happened upon people who designed their own machines altogether, which planted an idea in the back of my mind.

Once I had gained enough knowledge to evaluate different designs, features, and the resulting performance, I realized that none of the plans would satisfy my needs as-is.  However, they could probably be modified to do what I wanted at an acceptable price point.  After a lot more research (see the trend here?) I got to the point of feeling comfortable looking at any CNC machine, including the commercial models, and evaluating the design decisions and understanding their weaknesses.  It was then that I realized I could design my own machine and probably end up with a better product than anything currently available at a given price point.

A New CNC Router Design is Born

To confirm my thoughts, I made up a quick Bill of Materials and researched the prices of all the individual parts and raw materials that would be required.  This further cemented the idea that I could design and build a machine that would come in at the right cost, and likely with great performance too.

For the next 3 months, I researched CNC design, studied mechanical engineering, compared products, part manufacturers, parts suppliers, and started formulating a design.  I also knew that once I had a working CNC machine, I would have to learn CAD software to create the designs that the machine would produce.  I decided to jump in and learn solid modeling to design the CNC machine.  I compared all the CAD options and settled on Autodesk’s cloud based Fusion 360 software.  It was offered free to hobbyists and small businesses, and has comparable functionality (at least from a beginners view) to the industry standard SolidWorks, which I couldn’t afford.

In December 2015, I installed Autodesk Fusion 360.  Through reading the educational materials and following the tutorials I was able to quickly learn the software.  By the end of the month I had a rough conceptual model of a CNC machine, rendered beautifully and quickly in the cloud by Autodesk’s servers.  Over the following 6 months I went through many iterations of the design, gradually refining it and converging on an optimal solution to match my budget and performance requirements.

Once I felt the design was getting close, I learned to use the Simulation functions in Fusion 360 to perform stress analyses and deformation tests in order to find the weak points of my design.  It was a relief to see that the results of the stress analysis and cutter deflection simulations were in line with the calculations I performed during the initial design stages.  A few more tweaks to the frame components yielded a design that should meet the design goals and performance requirements.