Husqvarna 143AE15 Operator's Manual page 8

GENERAL SAFETY PRECAUTIONS
Cutters
Check the cutters. Never use cutters that are blunt,
cracked or damaged.
Ensure that the cutters are securely attached.
When the blade is manufactured it is sharpened using an
advanced method. This means that the blade cannot be
re-sharpened using conventional methods. Worn blades
must be replaced with new ones to ensure your machine
works satisfactorily.
8 – English