About Indicators and Its Product Range:
In various contexts of science, technology, and manufacturing (machining, fabricating, and additive manufacturing), an indicator is any of various instruments used to accurately measure small distances and angles, and amplify them to make them more obvious. The name comes from the concept of indicating to the user that which their naked eye cannot discern; as the presence, or exact quantity, of some small distance (example, a small height difference between two flat surfaces, a slight lack of concentricity between two cylinders, or other small physical deviations).
Many indicators have a dial display, in which a needle points to graduations in a circular array around the dial. Such indicators, of which there are several types, are often called dial indicators. Non-dial types of indicators include mechanical devices with cantilevered pointers and electronic devices with digital displays. Indicators may be used to check the variation in tolerance during the inspection process of a machined part, measure the deflection of a beam or ring under laboratory conditions, as well as many other situations where a small measurement needs to be registered or indicated. Dial indicators typically measure ranges from 0.25mm to 300mm (0.015in to 12.0in), with graduations of 0.001mm to 0.01mm (metric) or 0.00005in to 0.001in (imperial). Various names are used for indicators of different types and purposes, including dial gauge, clock, probe indicator, pointer, test indicator, dial test indicator, drop indicator, plunger indicator, and others. Probe indicators typically consist of a graduated dial and needle (the clock terminology) to record the minor increments, with a smaller embedded clock face and needle to record the number of needle rotations on the main dial. The dial has fine gradations for precise measurement. The spring-loaded probe (or plunger) moves perpendicularly to the object being tested by either retracting or extending from the indicator's body. The dial face can be rotated to any position, this is used to orient the face towards the user as well as set the zero point, there will also be some means of incorporating limit indicators (the two metallic tabs visible in the right image, at 90 and 10 respectively), these limit tabs may be rotated around the dial face to any required position. There may also be a lever arm available that will allow the indicator's probe to be retracted easily. A dial test indicator, also known as a lever arm test indicator or finger indicator, has a smaller measuring range than a standard dial indicator.
A test indicator measures the deflection of the arm; the probe does not retract but swings in an arc around its hinge point. The lever may be interchanged for length or ball diameter, and permits measurements to be taken in narrow grooves and small bores where the body of a probe type may not reach. With the advent of electronics and LCDs, the clock face (dial) and analog display has been replaced in some indicators with digital displays. Digital indicators have some advantages over their analog predecessors. Many models of digital indicator can record and transmit the data electronically to a computer, through an interface such as RS-232 or USB. This facilitates statistical process control (SPC), because a computer can record the measurement results in a tabular dataset (such as database or spreadsheet) and interpret them (by performing statistical analysis on them). This obviates manual recording of long columns of numbers, which not only reduces the risk of the operator introducing errors (such as digit transpositions) but also greatly improves the productivity of the process by freeing the human from time-consuming data recording and copying tasks. Another advantage is that they can be switched between metric and inch units with the press of a button.
