Here is a brain dump of an idea I’ve been cooking up that I call the “Maslow Defender”.
I’ve ordered a @MakerMadeCNC kit that should ship in December 2018 and I have yet to build my Maslow frame. I’ve been going through the forum topics to catch up on what people are making and issues they are running into. I have found several different types of issues that Maslovians have experienced while cutting out a project (assuming calibration is dialed in):
- Excess heat & fire
- Z-axis depth not correct (depth different than specified in gcode)
- X,Y-axis movement not correct (movement different than specified in gcode)
When any one of these things happen there is a risk of:
- Damaging the work piece
- Damaging the equipment
- Injury or Death
- Damage to property
Since the severity of some of these consequences could be catastrophic, that seems to be the reasoning for recommending to stay and monitor the milling while in progress. While I plan to be there in person to monitor the milling process, I think I’ll be too slow to recognize and react to prevent anything but the more catastrophic consequences. This is where I think I could use the speed of computers to help enhance my ability to respond to issues and reduce risk to the work, tool, humans, and my property.
I envision a system that monitors the active milling task for anomalies and takes different actions based on risk and severity. I haven’t fully thought through what it would take to do all of the following but here are some of my thoughts so far.
X,Y,Z Position Issues
I imagine that several rotary encoders and wires could be utilized, in a similar configuration as the motors to move the sled, to calculate the current bit position. Example from amazon ->
That current position could then be compared to the expected position to see if the bit has been moved to where the gcode specified it should be. If it’s not within an acceptable range, the Maslow Defender could trigger Ground Control to pause or cut off power to the Maslow and the router.
I imagine having several different temperature sensors on the sled, router, and Maslow CNC motors. If temperatures go above an acceptable range, the Maslow Defender could trigger Ground Control to pause or cut off power to the Maslow and the router.
Abnormal Milling Vibrations or Sled Issues
I imagine having an accelerometer on the sled and router to monitor for abnormal vibrations or movement potentially indicative of issues with the milling end, feed rate, material, sled catching, sled coming free of one of the chains, etc.
Thoughts & Questions
If it all came together like I imagine, it would help reduce the number of ruined cuts while helping reduce some of the potential risks of running a CNC machine. I would create a dashboard view showing the status of all the sensors and acceptable ranges along with the current gcode line. This could enable sub second reactions as opposed to my sub minute reaction time.
I’m not sure how I would have this system get the same gcode that ground control is sending to the Maslow. I’m not familiar with the feasability of being able to recover a milling job after it has been paused or Maslow has had power cut to it.
Has this idea come up before? What do you think? Would there be a better way to accomplish this? Would it be worth the effort? What hurdles is this going to face?