This question came via email this morning…
What is the effect of scale build up/rust build up on cooling channels?
The actual losses in efficiency are due to the difference in heat transfer from scale and the mold base material. Therefore, the more conductive the tool steel, the more the scaling will diminish cooling. So, for example, a 420-SS mold base will not be as greatly affected by scale as a BrCu core would be affected. In general, the excessive scaling will drop the efficiency 10-25% for steel.
Some people look at a 15% drop in cooling efficiency as a minor change. In most processes, this can result in a 10% increase in overall cycle time, resulting in a 5-10% drop in overall productivity, efficiency, and plant capacity. In today’s market where every penny counts, this is an avoidable drop in productivity which most companies cannot afford to bear.