DIFFERENCE BETWEEN ACCURACY & REPEATABILITY IN TERMS OF ELECTRIC SCREWDRIVER

DIFFERENCE BETWEEN ACCURACY & REPEATABILITY IN TERMS OF ELECTRIC SCREWDRIVER

Now we talk about the most confusing & most important topic of our industry that is what is accuracy & what is repeatability & what is the difference between them. These both the factor decides the working efficiency of any product or any process. It also decides the quality of the Product then the quality of work. So electric screwdrivers are clutch based mechanism, we set the torque through torque ring in them. They include a spring in their clutch assembly, when torque achieves then spring opens & pushes the pilot rod up then screwdriver shuts. So there is no sensor inside it who senses the force during fastening like in DC transducerized tools, they have the strain gauge to sense the force. So now first understand the accuracy then this mechanism will easy to understand.

ACCURACY

Accuracy is the correct working capability of anything, accuracy is hit near the goal all time in changed conditions also. Like we talk about DC tools if we set 15Nm (14-16Nm required) on soft joint and then result comes 14.5, 15.3, 14.2, etc. & then set 15Nm (14-16Nm) on hard joint and got the same result, so this is called good accuracy of the tool because here conditions were different one was soft joint & one was hard joint but tool adjusts itself & gave same result in the required band (14-16), hits near the target value always. So that’s why we always concerned about the accuracy of DC tools, we never talk about the repeatability, why let's discuss below.

REPEATABILITY

Repeatability is hitting the target in the same line means always hit a goal in the same way but only in an unchanged condition. Now we talk about the KILEWS electric screwdriver who has the high precise clutch assembly. If we required 15Nm (14-16Nm required) on a specific joint so first we will set the tool on 15Nm on static tester like KILEWS KTM tester, then run the tool on joint & if we are getting low torque because of losses in joint then we increase the tool torque, then again run & again check, and now if we getting the 15Nm, so our result comes like this 14.9, 14.9, 14.9 14.9. And now if conditions changed like joint changed or application changed so you will get different results may below be high, electric screwdriver can’t adjust itself according to the application , so it works better only in an unchanged condition. But it always hit the same target again & again.

So here is the big difference in accuracy & repeatability, somewhere repeatability is more important than accuracy. So electric screwdriver always have the repeatability, it always hits the same target in an unchanged condition.