Step 3 of 5
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Running forge dies: why this course exists
The same die, built to the same print and treated to the same spec, lasts 30K hits in one shop and 120K hits in another. The spread lives in four operator-controlled levers, and that gap is the subject of this course.
Step 3 of 5Lubrication as the second lever
Lubricant does two jobs at the die face. It carries away heat, and it provides a parting film between die and billet. A graphite-in-water lubricant dosed at 200 mL per cycle, sprayed through a clean nozzle hitting the engineered pattern, builds a 2-5 µm film in the impression and flashes the water off as evaporative cooling. The same lubricant dosed at 350 mL per cycle through a partially clogged nozzle puddles in the flash land, chills one region while leaving another dry, and seeds heat-check networks where the cooling is uneven. The chemistry on the drum does not determine the result. The application discipline shift over shift does. Lessons 5 and 6 cover lube chemistry and application separately because they fail separately. (Hawryluk repair-and-lifetime review; Materials MDPI 2021 dose-response study.)
Quick check
Two shifts run the same H13 die on the same job. Day shift logs a 200 mL/cycle lube dose through a nozzle inspected at start of shift. Night shift logs nothing and is later seen running roughly 350 mL/cycle through a clogged nozzle. The die comes off the press with localized heat-check on one side of the impression. What is the most likely chain of cause?