How to adjust the error of CNC Swiss machine

1. Processing principle error

Processing principle error refers to the error caused by using an approximate blade profile or an approximate transmission relationship for processing. Processing principle errors often occur in the processing of threads, gears, and complex curved surfaces.

For example, the gear hob used for CNC Swiss-type lathes to process involute gears uses Archimedean basic worms or normal straight profile basic worms instead of involute basic worms to facilitate hob manufacturing, which causes errors in the gear involute tooth shape. For another example, when turning a modulus worm, since the pitch of the worm is equal to the pitch of the worm wheel, where m is the modulus and π is an irrational number, but the number of teeth of the replacement gear of the lathe is limited, when selecting the replacement gear, π can only be converted into an approximate fractional value for calculation, which will cause the tool to be inaccurate for the workpiece forming motion (spiral motion), resulting in pitch error.

In Swiss-type CNC lathe processing, approximate processing is generally used to improve productivity and economy on the premise that the theoretical error can meet the processing accuracy requirements.

2. Adjustment error

The adjustment error of a Swiss-type CNC machine tool refers to the error caused by inaccurate adjustment.

3. Machine tool error

Machine tool error refers to the manufacturing error, installation error and wear of a Swiss-type automatic lathe. It mainly includes the guide error of the machine tool guide rail, the rotation error of the machine tool spindle, and the transmission error of the machine tool transmission chain.

1) Guide rail guidance accuracy - the degree of conformity between the actual movement direction of the guide rail pair moving parts and the ideal movement direction. It mainly includes: ① The straightness Δy of the guide rail in the horizontal plane and the straightness Δz (bending) in the vertical plane; ② The parallelism (twist) of the front and rear guide rails; ③ The parallelism error or verticality error of the guide rail to the spindle rotation axis in the horizontal plane and the vertical plane.

2) The influence of guide rail guidance accuracy on cutting processing mainly considers the relative displacement of the tool and the workpiece in the error-sensitive direction caused by the guide rail error. The error-sensitive direction of CNC Swiss-type lathes during turning is horizontal, and the machining error caused by the guide error in the vertical direction can be ignored; the error-sensitive direction during boring changes with the rotation of the tool; which brands of domestic Swiss-type lathes are good? The error-sensitive direction during planing is vertical, and the straightness of the bed guide rail in the vertical plane causes straightness and flatness errors in the machined surface.