What are the thermal expansion differences and tolerance issues with Performance Core Pins vs. standard steel core pins?
Performance Core Pins move heat much more rapidly than steel pins. This heat removal is done by conduction. Many times the core pin rests on a chill plate or is in contact with 70-80 degree Fahrenheit water. The most common problem is interference fit. For example, a .250 inch diameter Performance Core Pin has a tolerance applied of +.001/-.000. The corresponding Ejector Sleeve internal diameter (I.D.) has a tolerance of +0005/-.0000. Thus, the sleeve I.D. could be .0005 larger than the pin O.D. (outside diameter) or the pin could be .001 larger than the sleeve I.D.! This is a situation where galling will occur. Thus, the internal diameter of the ejector sleeve must be honed to accept the Performance Core Pin. At operating temperature the desired sliding fit between the two dissimilar materials should be .001/.0015. Beryllium-free copper alloy has a coefficient of thermal expansion of .0000097in./in./degree Fahrenheit. H-13 steel has a coefficient of thermal expansion of .0000058in./in
Related Questions
- What are the basic differences between the Digital Library Core Package and the standard, Print-only Core Publications Package?
- What are the thermal expansion differences and tolerance issues with Performance Core Pins vs. standard steel core pins?
- Can Performance Core Pins be used with standard steel ejector sleeves?
