When you are inside the working envelope of a machine tool, tap testing its spindle, having to exit to do simple commands on the PC can be frustrating and exhausting. With a remote viewfinder on our safety glasses, we can now use voice commands and confirm they were executed from inside the machine. Pretty cool.
A little more on our AUGMENTED MACHINIST project. We are using a Surface Pro tablet with a magnetic back to attach to the machine's enclosure. Our new small USB adapter connects the hammer and accelerometer. The user sees the tablet's screen on their eyepiece and uses voice controls for the program's commands so they can stay at the spindle. When the tap-test is completed, a Dashboard is automatically generated showing stable speeds, surface accuracy and finish predictions. All relevant calculations and conversions are on the interactive Dashboard.
THE AUGMENTED MACHINIST
Frequency measurements of milling tools guided by a safety glasses mounted heads-up display. Instant AI-powered predictions of optimized spindle speeds, feed rates, cutting depths, surface finish and accuracy. Hands-free voice controls with augmented audio to detect chatter frequencies and calculate speed and feed corrections. SmartTools designed to exploit the proven science of Machining Dynamics.
Big news is coming. Stay tuned.
The top panel of the computer screen shown in this video shows the force of the tapping hammer's impact. The lower panel shows the tool's (or anvil's) response to that force as captured by an accelerometer attached to the opposite side of the hammer strike. It deflects, rebounds and then vibrates back to rest. After tap-testing tens of thousands of milling tools we have yet to see one with a response that was a flat line. They are all flexible and will deflect and vibrate from the forces of the tooth impacts. No physical object can be perfectly rigid. It's physics.
I just read this study from Ryerson University by Drs. Omar Garber and Seyed Hashemi.
“The aim of this paper is to present a semi-analytical stability technique, developed to incorporate the spindle’s dynamic behavior variations in the stability lobes diagram. The change in the spindle’s dynamic behavior, also referred to as aging, is generally caused by system’s bearings wear, translated through a reduction in the system’s natural frequencies.”
Since our new SpeedCast Dashboard is an automated and interactive visualization of the stability lobe diagram, it could be used to track a spindle’s condition.
An initial baseline tap-test of a tool assembly produces a Dashboard that is used to establish the program’s speed, width and depth of cut. Periodic tap-tests of that same tool will either; 1) verify the cutting parameters are still good, or 2) expose that the parameters, likely the speed, must be adjusted to maintain stability.
If 2 is true, the user has two choices. They can slow the speed and keep running parts or have the spindle serviced. When should they pick the latter? If the speed reduction, and the impact on productivity, is small, then probably not. A quick cost per cubic inch calculation will determine if the loss in revenue will justify fixing the spindle.
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