The following Corrective Action/Preventive Action taken to avoid Materiel chip off. 
1. Raw Material will inspect visually before issuing to production. If found any problem visually RM will be quarantined. 
2. Dia 8 end mill life calculated, informed to operators to monitor the tool life.and change the tool after as mentioned. 
3. Steel butting plates flatness inspection done before production starts. Taking all the above PA, rejections happened in material chip off. Out of 100nos production 5 to 6nos getting rejection. Due to customer requirement parts are manufactures with considering rejections.