Pulverizer/Mill Machine Spare Parts: Fixed Blades (24 PCS), which is ... be damaged, need to change about 3 months later. PVC Mill Machine Spare Parts: 1. Fixed Blade & Rotating Knife: according ... not the same. 2. In general, this kind of mill machine, knife can work about 3 months, also you can ... and reuse again, which is convenite to change. Plastic Pulverizer Machine Knife/PE Mill Machine Spare Parts