Technical drawings without tolerances and ISO2768-1:1989 application

[toniriazor]

Hello Cove,
I am in doubt whether our business should use the ISO 2768-1:1989.
Below I’m presenting the case:
The company where I work receives aluminum and steel tubes from manufacturers in Asia. Some manufacturers are not specifying on the technical drawings tolerances for product characteristics. For example on the drawing we see inner diameter of tube should be ⌀50mm and there are no tolerances at all. However, when we measure the inner diameter of the tube, sometimes we could find that the inner diameter is ⌀49.95 (just an example), which means the product is not conform according to the drawing. We are working with suppliers to specify tolerances on the technical drawings, but this process takes time and it is not easy. In this case we can open a supplier quality claim since product is not according to technical drawing.

However, what worries me is that the team has found in internet a table from the ISO 2768-1:1989 with general tolerances for workpieces formed by metal sheet and has incorporated this table in one of the procedures. So when they measure and is out of tolerance, they refer to this table and use the tolerances from there to judge whether product is conform or not. However the company has not bought the standard, nor has received copyright permission from ISO to use it. I think this is 100% copyright violation or I am wrong? Also on the technical drawings is not specified to refer to this standard and for me this is incorrect method of work, but the team argued.

I am planning to ask ISO via official email, but first I wanted to hear your opinions and thoughts. Thanks.

 

[John Predmore]

the team has found in internet a table from the ISO 2768-1:1989 with general tolerances

The company where @tonirazor works buys tubes. The purchaser (the customer) has an obligation to state the requirements of the purchase agreement. Many times, the customer has design responsibility for the part, in which case they must state in unambiguous terms (typically a dimensioned part drawing) the technical requirements, including tolerances. Sometimes, a customer will purchase a commercial off-the-shelf item (COTS) based on the supplier's catalog or website, including their dimensions and tolerance, or sometimes the dimensions and tolerances are dictated by a national or international standard. But in either of these cases, it is the customer's obligation to make clear the terms of the purchase agreement, including technical details. The customer is the driver of the purchase agreement.

When purchasing from a supplier on a different continent, you should not be surprised to encounter language differences and common business practice differences. To facilitate a purchase transaction, in the absence of complete technical and contractual specifications by the customer, the supplier might make a reasonable attempt to provide the product they think the customer has sought. If the supplier's offering is not what the customer wanted, it is the customer's failing, who had the obligation to make clear their technical and contractual requirements.

Trying to blame the disagreement on a copyright infringement is a distraction from the customer's obligation. This is my take on the matter of international commerce.

 

[toniriazor]

Thanks for the answer. I understand your point and appreciate your feedback. The supplier should state the tolerances on the technical drawing. If there is no tolerance, it means their process is perfect and capable of producing each time the part with the exact dimension stated on the drawing without any deviation, which is impossible. As I said it takes a lot of time to work with suppliers and tell them to put the tolerances. Until this happens is the current decision adequate? The question is also can we use as an organisation the mentioned standard since there are no tolerances on the drawings and is the current situation copyright infringement? It is not a question to underestimate.

About the tolerances whether it is 50mm or 49.95mm in our case it is not critical at all. I want to address this in the most professional way and put it in order. To understand for myself the most correct way to approach such situations.