I agree that the burr may be from melting. If so, a magnifier will show
a smooth outer edge.

If so, we use a razor blade to "cut" it off. -Still pretty time consuming.

Could they use a short (automatic) blast of air during the start of the
drilling to stop the melting (if, indeed, melting is occurring).

Not the incognito plastics expert,
Pete Stanaitis
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