Inside the Swiss-type lathe spindle cabin, the bar stock runs through and the tool post moves laterally. All dimensions refer to an invisible “side master line” — the parallel datum between the lateral movement (X-axis) and the spindle centerline. It directly determines the positional accuracy of the outer circle, end face and lateral holes. Once the side master line drifts, the long shaft will show taper, oval or hole-position offset — it is the micron-level “invisible spine” of the Swiss-type lathe.
II. Sources of Error
Casting stress: insufficient natural aging causes the side master line to deform slowly over time.
Assembly stress: uneven clamping force on the guideway leads to local bending of the side master line.
Thermal drift: long-term high-speed cutting causes a temperature gradient in the bed, making the side master line bow.
Impact load: accidental collision or heavy milling reaction force causes local sinking of the side master line.
III. JSWAY Compensation Chain ① Natural aging: the bed is placed in a constant temperature for several months to release casting stress and allow the side master line to “relax” into place. ② Pre-tightening calibration: during assembly, a laser interferometer scans the side master line, and the clamping force of the guideway is adjusted point by point to lock the error within the allowable band. ③ Thermal compensation: built-in temperature sensors in the bed read the thermal drift of the side master line in real time, and the CNC automatically compensates for the X-axis offset. ④ On-line recheck: use a wireless rotary axis calibration device to recheck the side master line every week, and alarm if the drift exceeds the limit.
IV. On-Site Identification at a Glance • Look at cutting: when the side master line is stable, the roundness of the long shaft outer circle is ≤ allowable value, and the chips are continuous ribbons. • Listen to sound: when the side master line is bent, the tool post shows periodic “click” impact sound. • Touch temperature rise: during thermal drift, the temperature difference between the two ends of the bed is obvious, and the side master line changes in a “bow” shape.
V. Maintenance “Two-Step Method”
Monthly: use a feeler gauge to check the gap of the guideway clamping block, re-lock if loose; use a laser interferometer to scan the side master line and record the drift curve.
Quarterly: re-tighten the guideway clamping screw, re-measure the side master line, and archive the data in the JSWAY cloud, and alarm if the trend is abnormal.
VI. JSWAY Service • The side master line curve is calibrated at the factory, and the laser scan report can be checked by scanning the code. • Provide on-site side master line re-calibration service to restore factory accuracy. • Common guideway clamping blocks are shipped within hours to reduce customer downtime.
One-Sentence Summary Treat the side master line as the “invisible spine” of the Swiss-type lathe, choose the right aging, standard pre-tightening, and real-time compensation—so that every lateral movement of the tool post is “zero drift, low noise, high rigidity”, which is another layer of accuracy insurance JSWAY provides for your long-shaft machining.
