Towards the automation of the die spotting process: Contact blue pattern decryption

Automotive die spotting is one of the most complex and least standardized processes in the tool making process. A spotting expert identifies local contact areas through a blue-paste pattern and the die/sheet contact is optimized by manual grinding. Research performed on the impact of tribology conditions and surface irregularities on die behaviour have demonstrated the critical importance of die/sheet contact. Therefore, correctly understanding, standardizing, and automatizing die spotting is of a great interest for the industry. In this work, the first step toward the die spotting automation is performed by decrypting the contact blue pattern. Different test procedures were followed in order to decrypt the relation between the blue-paste pattern and the contact pressure and gap appearance in the interface. Additionally, a numerical method for automatic contact pressure detection based on the blue pattern was developed and validated. The outcome of this study is presented as potential tool for objective decision making towards the automation of the die spotting process and die contact analysis, focused to decrease try-out loops and thus reducing production time and costs