how to measure temperature of a rotating drill bit 3

[khalchris]

I am trying to measure the temperature of a drill bit while drilling metals, I intend to pass the thermocouple through the one of its coolant holes , the problem is that the drill will be rotating and the thermocouple should send the temperature reading in a wireless way to the data logger ,is there such wireless method which I can use to capture the temperature while the drill is rotating. or is there any small wireless temperature sensors ?

I don't want to use a thermal/IR camera..

 

[khalchris]

Hi Guys thank you all for your answers , I have already found a way to measure the drill bit temperature when drilling but I am not sure if it will work 100% . I will use a wireless data logger that is connected with a thermocouple which is welded on the drill bit tip , this wireless data logger which is attached to the thermocouple can transmit the readings to a receiver connected to my laptop,

now the problem is that I am worried that when I attach the wireless data logger to the rotating spindle it wont be able to send the measured readings or even wont be able to record anything and send to the receiver due to the high rotational speed or the high vibrations caused while drilling the material ?!!! what do you think guys ? how possible is this to happen?

Thank you all for your comments

 

[MikeHalloran]

Survival depends on the particular design of the data logger, and how and where it's attached to the spindle.
So far I have detected no clue about which data logger you intend to use,
or which spindle you intend to use,
so I can't conjecture.



Mike Halloran
Pembroke Pines, FL, USA

 

[IRstuff]

Unless the data recorder is home-built, I don't see any problem. Commercial data recorders are used for shipping environment logging and on-vehicle environment recordings, which include massive shocks, and vibration environments so large that humans wouldn't stand it for more than a few minutes.

TTFN
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[MikeHalloran]

We still don't know the drill diameter or the nature of the material to be drilled.

As a point of reference, the optimum rpm for drilling a 1/4" hole in aluminum is somewhere near 18,000 rpm.
... so I wouldn't just assume that any old data logger will survive.



Mike Halloran
Pembroke Pines, FL, USA

 

[itsmoked]

I have already found a way to measure the drill bit temperature when drilling but I am not sure if it will work 100%

I hate to burst your bubble khalchris. Are you not realizing that NOTHING YOU DO will get you the correct temperature?

The temperature at the cutting faces is going to be different by hundreds of degrees from wherever you're sensing at. If you've somehow contrived to put the sensor right at the cutting edge in contact with the material you've completely invalidated its readings because it isn't cutting it's just rubbing.

As the tool cuts into the workpiece how the heat leaves the bit changes dramatically because the material starts changing its thermal coupling to the tool and the conduction cross section changes.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Skogsgurra]

@khalchris

Have you? (found a way to do that measurement)

What speed are you running the drill bit at?

Typical drills will not accept the unbalance that a transmitter causes. Or, the transmitter will not accept the forces caused by rotation.

So, what dimensions are we talking about? What speeds? What temperature are you interested in? The tip's temperature or the stem's? Or just about any temperature that you happen to read? Is this a real problem? Or something you just thought would be interesting to discuss in general?


Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[waross]

I like the idea of using the drill-work interface as a thermo-couple. That may be the best way by far to measure the temperature at the interface. The contact between a cutting drill and the material is intimate and the noise generated may be much less than expected. You may insert insulating material between the work-piece and the vise.
This is worth a try.
Why do you want to know the temperature??

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[DRWeig]

Regarding the transmitter but without comment on sensor placement:

Maybe not totally relevant, but this thread made me think of the pressure transmitters in my car's wheels. They survive an awful lot of shock while running maybe 1000-ish RPM, and report pressures on the road. They're about $50 per wheel.

Of course, you're not measuring pressure -- but a similar temperature device seems possible to me. A spinning drill seems like a calm environment compared to slamming a pothole at 70 mph on the I-85.

Best to you,

Goober Dave

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[VEBill]

Car wheel, ~1000 rpm, radius ~12.5 inches, ~355g.

Drill given 18,000 rpm (?), ~9200g per inch of radius.

I recommend safety goggles.

 

[DRWeig]

Well, I didn't comment on the mounting hardware... In the car wheel, the transmitter is contained. But I would wear safety goggles too!

Best to you,

Goober Dave

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[VEBill]

If it's a "wireless" (once upon a time, we used to call this "radio") system, the circular motion should impart a nice Doppler tone.

 

[PHovnanian]

You might want to look at WISP (wireless identification and sensing platform) technology. The drill bit thermocouple leads could be run back to the processor/transceiver module near the bit chuck. Since these tend to be very small devices, building an antenna loop and electronics into a mechanically balanced housing shouldn't be difficult.

The WISP module can be read with an RFID reader. The distances involved will be a few centimeters at most.

http://en.wikipedia.org/wiki/Wireless_Identification_and_Sensing_Platform

 

[ozmosis]

I'd take a step back and ask the question 'why?'.
Understanding the answer to that one might provide a little more background as to how to solve the issue.