Make sure nothing is in the path of the machine:
Obstructions will cause the machine to make a loud grinding noise while homing
Make sure clamps and material are not blocking the path in any way. In the case of Carvey check to make sure none of the clamps are hanging off the back edge of the work area table which moves during operation and can hit the back wall of the machine. Also, double check that no large debris is underneath the work area table that may prevent it from moving properly during operation.
- Homing cycle fails