The Dial Indicator, some times called Prob Indicator, it is one of the few analog measurement instruments that allows the measurement of linear measurements directly (by measuring directly the desired) or indirectly (establishing the difference between the desired measurement and another known).
In this simulation you will learn the science of using this measuring instrument, interacting with the spindle or the contact tip ( see main components). In this learning object, you can also turn the 'display' (dragging and dropping the hoop in a circular motion) so that the line 'zero' align with the pointer after the called ' preload ', hide the measure provided (by clicking the eye icon) and cancel the spring effect of the instrument (by clicking the 'lock').
This instrument of measurement works fixed to devices devices such as bases, supports, or guides. Because of its fragility, we do not recommend its use in the operator's hand.
By definition, directly measurement (or indicator) occurs when the value of the wished measurement (mensuring it) is read directly in the device display of the measurement instrument. For example, when we determine a linear dimension with a paquimeter ( see the paquimeter simulator ), the reading that we obtained in the scale and it's vernier , not considering errors, is the efective measure of the object that we are submiting to measurement.
We use this dial indicator on this mode of measurement together with surface plate and(or) supports to measure the thick plates, for example, among other measures relatively small.
This method of utilization is seen in the Simulator and at figure 1. We submitted the instrument to a preload , we setted to zero mark (turning the counter), we moved the spindle mannually giving space to put the object to be measured in the axis of the instrument and return the spindle until the contact with the part that holds it. The dimension is read directly in the counter, by relative position (displacement) of the main pointer and of the turns counter.
On this case, by contrast, we have indirect measurement (indicator), when the read value in the display device of teh instrument it is not the value of the measure that we are mensuring. For example: when we use a barometer, or we measure the shadow, to determine the height of a building.
One of the possible uses of the dial clock compartator is to calculate the difference between a pattern and the one of we are mensuring.
Dimension of part = pattern dimension + (or) - value read in the instrument
We adjusted to zero the instrument with a pattern that dimension is known and we stablished the difference between her and of teh object that we are submting to measurement, algebraically -figure 2.
Using a dial indicator is one of the most easy tasks of metrology. We will understand the method using as example the simulator e you will get to use a lot of other models, with it's scales, ranges and resolutions. In general, they come with notes printed in the display showing your resolution and the nominal range (ex: 0.01 - 10.00mm or 0.001 - 1.000"). ( to interact with the Simulator of the Dial indicator in milesimal inch (1.000") click here)
One complete turn of the main pointer of our simulator it represents one millimeter of spindle. The display has ten numered divisions (from 0 to 90, ten by ten) and each of it is subdivided by ten, in a total of a hundred (100) dividions. This way each of the marks of teh display it represents to hundredeth part of millimeter (0.01mm) -figure 1. The nominal range of teh instrument of figures 1 and 2 is 10mm (to solve the limitations of the monitors resolution, the nominal range of this Simulator of Dial Indicator is 1.14mm - Click here and interact with a simulator of dial indicator with realistic path and nominal range of 10mm ); this carachteristic turns necessary that some device count the number of turns of the main poiter (number of integer millimeters to be added to the centesimal part).
figure 1 - dial indicator - direct measure
This step by step describes the procedures to the reading of figure 1. Observe thta the pointers are turning to opposite directions and the movement of the main pointer is the clockwise;
figure 2 - dial indicator - indirect measure
This step by step describes the procedures to the reading of figure 2, observe that the pointers are counter-rotating and the movement of the main is anti-clockwise. Do not forget that to indirect readings:
Dimension of the part =
Pattern dimension + (or) - Value read in the instrument
figure 3 -
dial indicator - aligning zero of the display
After stablishing the preload , the dial indicator it has a hoop that allow turning the display to, for example, align the zero of the Main Pointer to facilitate the reading, and for that it's needed to realease the screw that holds the hoop.
after interacting with the virtual dial indicator, I recommend that you solve this
list of exercises of reading and interpretation of the dial indicator in millimeter in centesimal resolution (0.01mm)
- turn the bigger display of the dial indicator
- click in the icon 'eye' to hide the measure
- click in the icon 'locker' to cancel the effect of the spring of the instrument
note: by limitations imposed by the resolution of the monitor, the distance runned by the the contact tip is not proportional to the indicated measure