Such questions do not make any sense. it would help if you gave sintering variables used in sintering, such as - what temperature sintered, time at the temperature, and also in ball milling -high or low speed, how long, type of ball used. Without stating these sintering factors, your question is like a joke.
There is also one answer if the sintered parts are ball milled at low speed, then the parts have any burr, they are removed by tumbling in tumbling or ball mill and are used in the powder metal fabricating, casting, and stamping industries regularly if there are any burr on the surface of the parts. The process is called deburring.