☛ nderstanding all the chemistry, following the manufacturing/production rules and standards

☛ when something is wrong with the raw materials:

☛ if sample is not good, call the raw material manufacturing company, and send back the materials

☛ when something is wrong with the final products:

☛ if sample is not good, keep hold of product and find out the problem by contacting the different departments

☛ solving the problem is hard; meeting with different departments to solve the problem

☛ tracing back to the processing stages of product