What is an appropriate calibration weight for a 4 ton weigh scale

Hi,



Hope you are doing well. I am an industrial engineer form Pakistan. I work as a production engineer. My question is:

1) What amount of calibration weight is necessary to calibrate a weigh scale with a maximum capacity of 4 ton?

2) Are there any relevant industry standards for this?

I am being told that i would need at least 1 ton of calibrated weights but that would be too expensive and impractical to carry out

I would be extremely thankful for a response

 

We weigh paper reels, which typically weight around 1200 kg to 2000 kg. Our tolerance is +/- 2 kg.

 

Paper rolls are by pound...I work in paper and plastic films these days.

My question would be the reliability of your tare weight (reel, core and wrap)...
The folks I work with have more than 2Kg uncertainty in tare...so a weighing tolerance of 2Kg is down in the noise...

For clarity...I see more than 2Kg uncertainty in what the core and reel weigh, not uncertainty in the gage...and you can't know the core weight until all the film is gone...by which time it's all moot.

 

The management is interested. We want to reconcile the input weight with the output. That's why we have installed weigh scales at both input and output. We sell with respect to packets to be produced from a reel.
So after having installed a weigh scale, now i am confused about the appropriate amount of calibrated weights required for calibration of the weigh scale

 

Basically we are weighing every thing. Gross weight of reel at input and weight of every single piece of output as well. But we are not able to reconcile perfectly due to the least count.
Anyways, do you have any standards regarding the appropriate amount of calibrations weights for calibrating a 4 ton weigh scale?

 

You aren't going to like this answer, just so you know...

You are weighing things because management is interested...no other reason (though it's a good reason).
There is no "standard" for doing this.
There is what works and what doesn't work in the scale range you desire...and Jen's comment and question regarding calibration are right toward this.
The appropriate amount of accuracy required (what makes calibration "pass" or "fail" is up to accuracy of data desired/demanded).

The more accurate you demand your scale to be, the more it will cost...so it becomes a cost/benefit decision by management (whose money it will be).
How accurate do they want, and how much cash are they willing to put out to get it?

 

Sorry for the late response.
The problem is that we are converting paper reels in to sheets. Since the grammage (GSM) varies in paper products, we almost never get the same output (in weight) as the input (in weight), even if we weigh every thing.
Personally speaking, it is quite frustrating since it is extremely unproductive to weigh every thing. But we are willing to accept a difference of maximum 2 kg between input and output, given that the weight of the reel is around 2000 kg

 

It is a platform scale. The trouble with covering the entire range of the load weight in calibration is that it would be too costly. Is there any other way out?

 

No. Can you share a link from where i can buy?