Common Q&A for High Pressure Through-Spindle Coolant System

Our company uses plunger pumps, which have excellent vacuum sealing. There are no specific oil-water ratio requirements, and both oily and water-soluble cutting fluids can be used.

The filter precision required for the tool machine spindle rotary joint is 40 μm. Our company's plunger pump can also use a 40 μm filter precision, while the gear pump requires a precision of 5 to 10 μm; otherwise, the pump may be damaged. In comparison, using our pump can extend its service life. It is recommended to regularly clean the filter screen to improve clogging issues that may arise after a period of use.

For CNC milling machines, since the maximum allowable flow rate of commercially available high-speed rotary joints is only 30 L/min, increasing the pump flow rate cannot help maintain pressure. A stable pressure output can result in a smaller pressure drop with changes in aperture. In practical tests, our pump performs better than gear pumps; however, due to precision differences, only high-end brand centrifugal pumps perform similarly to ours, while other brands of centrifugal pumps perform worse. In the case of CNC lathes, centrifugal pumps generally perform better than gear and plunger pumps, but the difference is not significant for apertures below φ4.2mm.

High-pressure pumps compressing cutting fluid will also generate heat, and therefore long-term use can indirectly raise the temperature of the cutting fluid tank. It is generally recommended to use chillers or large water tanks, as these may help improve this issue.

Generally, regular oil changes are necessary, and users are advised to include the schedule for oil changes in their daily inspection items or to change the oil every month. If users forget to change the oil (which is a common situation in many small processing plants), it will directly affect the lifespan of the pump.