Rust should have you seeing red

It went from an inconvenience to an infuriating problem. Rust was appearing every few days on a mold that was out of service for just one shift.

All the cool down/start up procedures were followed. A rust preventive was applied to the mold while the machine was offline for the night. The next morning the mold was cleaned and inspected. And there it was, light surface rust was appearing a couple of places on the mold.

What was happening? And what was the solution?

These inconveniences rob you of time and productivity. A part that tends to hang up, not ejecting cleanly. Cycle times that are extended just ever so slightly to accommodate a part that takes just a little longer to cool and eject. Flashing. A surface scratch that seems to have appeared from nowhere. The unexpected appearance of rust. This accumulation of seemingly small issues, when compounded day after day, really add up to lost productivity and lost revenue.

There is another underlying issue. Retaining legacy knowledge. The plastics industry is aging out talented, experienced mold techs and losing their expertise. These smart people with a depth of knowledge need to pass along their problem-solving skills to the next generation. They need to mentor the next generation and help them learn from their productivity and mold maintenance insights. If that knowledge is not on staff, where do you go for help?

So, there is this appearance of light rust. What was happening and what was the solution? An expert in mold care was contacted. And the recommendation was surprisingly simple. When the mold is cooling down, spray a short-term rust preventive that contained a light red dye. The visible dye would help highlight any parts of the mold that were missed when spraying the rust preventive.

It was the perfect answer. The mold went an entire week without showing any rust. The visible confirmation showing complete coverage of rust preventive ensured no surfaces were missed. An added plus was the rust preventive “flashed off” on the first cycle, so there was no part marking.

All it took was a little knowledge.