This is because when the feed is high, the load resistance imposed by {HEAD ~ the single crystal ingot} being sliced increases and causes the blade to wobble more roughly and thus the displacement of the blade is increased, and, on the other hand, when the feed is low, the load resistance decreases and causes {TAIL ~ the blade} to wobble less roughly and thus the displacement of the blade is decreased; as a result, the wafer will easily have an irregular surface 
This is because when the feed is high , the load resistance imposed by { HEAD ~ the single crystal ingot } being sliced increases and causes the blade to wobble more roughly and thus the displacement of the blade is increased , and , on the other hand , when the feed is low , the load resistance decreases and causes { TAIL ~ the blade } to wobble less roughly and thus the displacement of the blade is decreased ; as a result , the wafer will easily have an irregular surface
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