How to implement glue into production? Adhesive standard DIN 2304

The DIN 2304 standard was introduced in March 2016. It is related to the ISO 9001 quality management system and applies to all industrial sectors where adhesive bonds are used. This standard is comparable to the well-known DIN 6701 standard designed for the railway sector. The purpose of the standard is to create standards that will enable the preparation and implementation of repeatable and reliable bonding processes. In addition, the standard facilitates process identification, error analysis, and strengthens employees' quality awareness. Implementation of testing and research techniques.

This standard describes the state of the art for the organization of the correct execution of processes related to the gluing technique in the plant. Glued joints within the meaning of DIN 2304 are material joints made using adhesives, with the basic function of transferring mechanical loads, regardless of the strength and deformation properties of the adhesives used. At the same time, the load-carrying function guarantees, throughout the entire life cycle of the product, its operational efficiency and safety.

According to this standard, gluing is a special process. "Special processes" are production steps, product units or products that cannot be tested with non-destructive testing with 100% certainty. This means that it is impossible to reliably predict how long the joint and product will last. The adhesive joint is one of these types of processes because without tearing and aging tests that destroy the joint and the product, it is impossible to determine the durability and strength of the adhesive and the entire connection.

The reason for this is the fact that the gluing process and the parameters achieved are affected by a number of variables. In addition, each factor can have a decisive influence on the entire connection, which can determine the success of the entire production process. The situation is not helped by the fact that most of the industrial adhesives used are plastics that are subject to aging, e.g. under the influence of moisture. Aging, on the other hand, weakens the adhesion and cohesion of the adhesive.

It is assumed that 90% of errors in gluing processes are caused by application errors, not a defect in the product itself.

Gluing is the most comparable to welding technology. As part of their technology, welders have a hierarchical, product-independent personnel qualification system formalized and certified by international standards. Employees involved in the welding process at every stage are trained and aware of their duties and responsibilities. For gluing processes, a similar system has been created with hierarchical levels of responsibility for the process, starting from the execution level, through the level of supervision / management, to the level of technical decision-making. These are internationally recognized degrees, compliant with ISO 17024, independent of industry and product. Harmonized guidelines for Europe: European Adhesive Technician - EAB, European Adhesive Specialist - EAS, European Adhesive Engineer - EAE.

The ISO 17024 standard describes the state of the art for the organization of the correct implementation of processes related to the gluing technique in the plant.

Safety requirements for glued joints

Classification of glued joints in terms of safety requirements is carried out by the constructor or the person responsible for a given manufactured element. The potential consequences of breaking the bonded joint are assessed.

The consequences of disconnection are divided into:

S1 – high security requirements

Breaking the connection leads to direct or indirect to unavoidable threat to health and life. Breaking leads to loss of functionality, the consequence of which is a high probability of unavoidable threat to health and life.

S2 - medium security requirements

Breaking the connection can lead to a direct threat to health and life. Breaking the connection leads to the loss of functionality, the consequences of which may be related to damage to people or serious damage to the environment.

S3 - low security requirements

Failure of the glued connection leads to a loss of functionality, the consequences of which are not expected to cause damage to people or serious damage to the environment.

Breaking leads to the loss of functionality, the consequences of which are associated at most with loss of comfort or performance.

Such a breakup probably does not involve any higher capital costs.

S4- no security requirements

Breaking the connection leads to a loss of functionality, the consequences of which, under foreseeable conditions, are not related to damage to people and the environment.

Breaking involves only a loss of comfort and efficiency, and does not involve major property damage.

According to Professor Andreas Groß from Fraunhofer IFAM, the DIN 2304 standard is a very helpfultool in the event of legal disputes for damages. It specifies the ISO 9001 quality standard, defines the rules of the art of gluing. The implementation of this standard allows for the reduction of errors during gluing, which translates into lower costs. Companies applying the above standard additionally increase their prestige and trust of contractors and recipients.

Who is responsible for compliance with DIN 2304?

The gluing process is the sole responsibility of the user of the product. Responsibility cannot be transferred to the adhesive supplier. The task of the adhesive manufacturer is to deliver products in accordance with the specifications contained in the technical data sheets, in appropriate conditions (e.g. temperature), as well as to prove the desired quality of its products. However, after delivery to the customer, the manufacturer has no further responsibility, as he has no influence on the application and use of his products. It can only advise certain solutions, but cannot make decisions and bear responsibility for them. The manufacturer/supplier should not engage in dubious legal constructions aimed at circumventing the responsibility assigned to the recipient clearly in the standard in question.