Project Details:
A Tier 2 automotive supplier needed a solution to print an interior bezel part for a major automotive manufacturer. The part would be molded in a multi cavity tool with tight tolerances for print location. This customer was an accomplished injection molder but had no previous pad printing experience.
Roadmap to solution:
First Attempt:
The initial customer request was for a standard solution with operators dedicated to the loading, unloading, and packaging of the parts. Our first quotation was for a single color machine with an optional turntable to increase throughput. With the turntable feature, this solution would have met the cycle rate requirements. The situation changed when the customer decided to allocate less operators to the workflow for this part, which led us to propose an automated solution.
Second Attempt:
The same print head that was recommended for the manual loading scenario was also a good fit for the automation, though the way the parts were presented to the head changed significantly. The part was molded in a multi cavity tool and the customer had decided to invest in a molding robot and end of arm tool that could pick the parts out and hand them off to our printing system with multiple drop points if needed.
Given the cycle rate of the molding machine and the travel time for the molding robot, our proposal included a staging table where the end of arm tool could drop the parts in nests that matched the pitch distances of the parts in the mold. The nests were situated on a two position dial table so that a four axis robot could load parts on a 16 station indexing carousel from the second table position. The carousel had locking stations and mechanical tooling for ease of loading/unloading by the robot while maintaining tight registration. This design allowed the printing system to keep up with the cycle rate of the molding machine without having to slow the process down for the handoff of parts between the molding robot and the printing system.
The printing system also included a vision system for the evaluation of print location, print quality, and completeness. The same four axis robot that was loading the carousel also unloaded the parts two at a time but maintained control over the destination of each individual part based on the pass/fail score of the vision inspection. Parts that passed went to a conveyor dryer for ink curing, while failing parts were directed to a reject bin. The HMI included an alarm that would notify the customer when a programmable number of rejects had been detected.
Synopsis or TL;DR:
We developed an in-line automated printing solution to match the cycle rate of the injection molding process for an interior automotive part with tight print location tolerances and high quality demands. The system reduced the need for an operator and delivered decorated parts that were verified for quality by a vision system.