It is a challenging task to measure temperature/heat in the cutting/shear zone with accuracy. Most of the process adopted involve assumptions and is often termed as semi-quantitative method.
In our work we use thermocouples inserted in 0.5 mm from the tool tip. That worked quite well.
In our work we use thermocouples inserted in 0.5 mm from the tool tip. That worked quite well.
Thank you Daniel sir, Will you please send me the images if possible to me as I am newly starting work on this.
Indeed it is a challenging task. I agree with M. Madyira; the mounting of thermocouples (e.g. K-type), as close as possible to the tool's edge or the contact surface, in connection with a data acquisition unit, can give quite fair precision for temperature measurements. An other way to acquire thermal signatures in machining is the use of either infrared pyrometers or infrared thermography. Such methods have the advantage of providing fast and sensorless measurements but they are quite expensive and they don't actually measure the real temperature but the emmitted infrared radiation. This means that you have to be sure about the emmissivity of your material-target in order to achieve quite accurate temperature measurements; and even with a good emmissivity correction (something difficult for such reflective materials), IR thermographic measurements are usually characterized by a +/- 2% reading error, even for state-of-the-art equipment.
i think that the use of Thermo-camera is the best way to make this kind of measuerement without altering the measure and/or the process performances.
Measuring in the shear zone is very, very difficult. One possibility is with a termographic camera, but the measure have poor precision and you dont use lubricant. Turning better than milling, because the contact of the tool is constant.
Other possibility is with a termocuple 0,2mm under the cutting surface of insert. But this measure is "far" from shear cut.
well, using an IR camera is a better option. But using thermocouples won't disappoint us. the process is to insert a thermocouple into the cutting tool from the flank side and connect it to a wheat stone bridge apparatus to measure temperature changes using seebeck effect.
IR is very simple to install, can be interfaced easily with a computer. I think that is the best way.
Nevertheless, the technique of direct measurement by s has advantage before IR camera. Of course, we need to place it as close as possible within contact area. The optimal result may be achieved when cutting electroconducting surface used as as element of thermocouple. Serge
Measuring the temperature in the shear zone is a really difficult task. In many publications, the temperature is measured in the proximity of the rake face by radiation thermometry or thermos couples. Subsequently, the temperature at the shear zone can be estimated by FEA. However, one approach might be to measure the temperature in a linear planning process with a high speed infrared.
How fast are you trying to measure? For instance, what kind of bandwidth do you require in your measurements?
In other words, is it intermittent cutting line milling, or un-intermittent cutting like turning? It all depends on what you would like to do. Try first to determine the process and your objectives....
You can use a thermocouple type K on both the tool and the workpiece. For the later, I suggest to use an orthogonal cutting configuration to guarantee a plane strain state. this configuration will allow you to get more precise location of you thermocouple regarding the primary and the secondary shear zones. Orthogonal cutting can be performed on turning or milling machine. It will be easier to do these experiments using milling process.
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