Generally, the method adopted for hard-facing worn parts like press screws in the palm oil industry does not give the expected life span as it fails to identify the wear factors.  It can be compared to a doctor who first tries to understand a disease by diagnosis and then attempts to get rid of it by medication.  Likewise, the palm oil mill engineer must understand the reasons for the wear before he can plan and take necessary action to address the problem.  The major wear are press worm screws, press cages, digester arms and shaft, digester liners, wear plates and conveyor scrolls.