Case Study: Solve The Problem of Overheat For The Spindle

Client: A Vertical Machining Center manufacturer in Taiwan

Issue:

The client made their own 10000 rpm spindle, while running at 10,000 rpm to the limit speed, the time was only within 30 min, the temperature of the front and rear ends of the spindle was exceeded 25 °C, and the machine was stopped automatically.

Analysis:

Detect spindle stiffness and it is 31kgf / μm (rigidity detection method: 1, press test, 2, frequency analysis method), after the spindle was disassembled, found that the European bearing used were 7014 series of bearing with large steel ball ( the machine maker used this type of bearing and had four bearing as set by QBC assembly , the limit speed was at 8000rpm when using)

Reason: 

1. the original rigidity was too large;

2. there was the error in bearing selection

Problem Solving:

Replace TIMG’s 10000rpm spindle bearing with large steel ball (ball diameter φ11.906mm, 21 rolling elements), and control rigidity at 18kgf/μm (TIMG can precisely control the spindle rigidity through calculation)

Solution: 

Use TIMG bearings and strictly control spindle rigidity, run the extreme speed till 10,000rpm, the temperature rise of the spindle at front and rear ends are just 12 ° C and 10 ° C, which has been greatly improved the performance of the spindle.