How to manage cutting oil during long downtime of hmc machines
Cutting oil, commonly referred to as coolant oil in machine shops, is typically used in hmc machines to machine parts to the desired size and shape. During this machining process, a lot of heat is generated between the part and the tool due to friction. To provide lubrication and cooling effect, cutting oil is used.
There are two types of cutting oils for hmc machines:
(1) pure cutting oil
(2) Water-soluble cutting oil (WSCO)
Pure oil has good lubricity and is used for heavy machining applications such as gear cutting, broaching, etc. Water soluble cutting oil has good cooling effect and proper lubricity and is used for light to medium machining applications such as milling, turning, drilling, tapping, reaming, etc.
Pure oils are used 100% in hmc machines and usually do not require any maintenance activities. However, it is usually used in machines mixed in water at a rate of 5 to 10%. Normally, solutions containing water always require some maintenance, otherwise microorganisms from the water can destroy the properties of that solution. the same is true for WSCO. If the WSCO is in circulation or agitation, then there is not much problem. However, if the cutting oil is stagnant for a period of time, say a day or two (mainly during working holidays such as Saturdays and Sundays), then care needs to be taken to avoid WSCO breakdown. This is a manageable situation. However, if the downtime is very long, then we should take the necessary precautions to take care of WSCO to avoid a huge loss of hmc machines.
The following are precautions that need to be taken when you are running hmc machines with water soluble cutting oil (WSCO) for extended downtime.
(1) Keep the WSCO concentration (6 to 8%) higher than the recommended concentration (4 to 6%) to enhance its biological stability. This will keep the cutting oil healthy for a longer period of time.
(2) To avoid WSCO decomposition, remove impurities such as tramp oil, sludge and debris from the cutting oil tank.
(3) Circulate the cutting oil through the hmc machine for 30~60 minutes daily. This will prevent the growth of microorganisms.
(4) If WSCO has the smell of decomposition, please pour out WSCO from the machine immediately. fresh WSCO can be prepared after the downtime period is over.
(5) To avoid rusting on the machining bed and other expected machine surfaces (usually the internal areas of the machine), the same WSCO can be manually sprayed on these areas at a concentration of 10%. the same practice needs to be done regularly once or twice a week to keep the machine healthy from rusting.
(6) To avoid rusting of parts, apply rust preventive oil and cover properly to protect parts from contaminants such as dust and moisture.
(7) To avoid white corrosion of aluminum parts, make sure the parts are free of moisture and covered properly. If you suspect the presence of moisture, spray dry air or use a dehydrating solution via the dipping method to remove moisture from the part and cover it properly.
The above practices will help you to start your hmc machine trouble free after a long downtime. If you need more detailed information, feel free to contact us!