Material selection for LSR molds directly affects durability, surface finish quality, and overall tool life. Premium grades like P20, 718HH, or H13 are commonly chosen based on expected cycle counts and operating temperatures. Corrosion resistance is vital given LSR's platinum catalyst sensitivity to certain contaminants.
Hardened steels offer extended service life but require stress-relief treatments to prevent cracking during EDM or grinding operations. Pre-hardened options simplify machining while delivering adequate performance for moderate-volume applications. Selection criteria include thermal conductivity, polishability, and weldability for repair purposes.
Surface treatments enhance mold performance further. Nitriding improves hardness and wear resistance particularly in high-abrasion scenarios involving glass-filled LSR compounds. Chrome plating adds corrosion protection and facilitates easier part release. Advanced coatings like TiAlN or CrN provide exceptional hardness and dry-film lubricity reducing maintenance intervals.
Balancing material cost against anticipated longevity yields optimal return on investment. Early consultation with metallurgists and coating specialists ensures compatibility with intended LSR formulations and processing conditions. Periodic evaluation of worn molds informs future material choices leading to continual improvements in mold design practices.
