Oil leakage in a numerical control milling machine can be divided into three categories: seepage, dripping, and flowing. Generally, seepage occurs at static joint surfaces, with one drop of oil every 0.5 hours, and at dynamic joint surfaces, with one drop of oil every 6 minutes. When one drop of oil occurs every 2-3 minutes at either a dynamic joint surface or a static joint surface, it is considered dripping. If there are more than five drops per minute, it is considered flowing. The general requirements for curing oil leakage in equipment are that there should be no seepage at static joint surfaces on the exterior of the equipment, slight seepage at dynamic joint surfaces is allowed, but it should not flow onto the ground. Some seepage is allowed inside the equipment, but it should not seep into the electrical box or transmission belt, and it can be returned to the lubrication box.
(1) Numerical control milling machine has poor oil return flow or no oil return channelTypically, oil accumulates and forms a certain pressure at the bearing area, causing oil leakage due to poor oil return flow. Some oil return holes are poorly designed and easily blocked by dirt. And some oil return grooves have a small capacity, causing oil to overflow from the grooves. Some have no design for oil recovery. After using the machine for a while, it was found that the slide had serious oil leakage, and the ground on both sides of the machine guide rail was covered in machine oil. After using the oil for a while, the oil becomes dirty and some iron chips will fall on the guide rail surface during the machining of parts, which are not easy to remove by the cutter.
(2) Castings have defects such as sand holes, air holes, cracks, and loose structure, but no measures are taken. These defects are often the root cause of oil leakage during the use of the equipment.
(3) When plastic or oil-resistant rubber products are used for oil pipes and pipe joints, they will become hard and brittle after long-term use, causing the oil pipes and pipe joints to break and cause oil leakage.
(4) After long-term use, especially for sealing rings in moving parts, the sealing performance is lost due to friction and wear. In addition, if the gap between the shaft and the shaft hole (sleeve) increases, it will also cause.
(5) Part machining accuracy errors and other reasons. For example: box body and box cover joint surface flatness deviation, surface roughness is too large, residual stress of workpiece is too large, causing deformation of workpiece, making the joint surface not tight. Or loose fasteners, etc., will cause oil leakage.
(6) Inappropriate selection or assembly of related parts often causes oil leakage.
(7) There are mainly three aspects of problems in the oil change of numerical control milling machine. First, for parts using high viscosity lubricating oil, if low viscosity lubricating oil is used arbitrarily during oil change, the sealing performance of corresponding box body, bore, etc. will be affected to a certain extent, sometimes greatly reducing the sealing performance of these parts. Second, if the oil tank is not cleaned during oil change, the dirt in the oil tank may enter the lubrication system and block the oil path or wear the sealing parts, causing oil leakage. Third, if the oil change volume is too large, especially in the parts with rotating parts, due to the stirring effect of the rotating parts, it is more likely to have oil overflow.
(8) Inappropriate selection and adjustment of lubrication system parts for CNC milling machine causes oil leakage. For example: when repairing, a oil pump with too high pressure or too large oil output is selected, or when adjusting the system pressure, the pressure adjustment of the overflow valve, safety valve, and pressure reducing valve is too high, and the flow rate of the machine tool lubrication system is too large, etc., which is not matched with the return oil system and sealing system, which will cause oil leakage.