2.1 Spindle: Several problems can be refferred to the spindle. The spindle itself may become faulty due to the stress deriving from the normal work as well as from mistreatment. The most common problems are:
2.2 Bearings: Defective ball- or air bearings. This type of fault comes from the normal wear due to the high speed rotation of the spindles. The balls become worn out after approx. 5.000-8.000 hours of normal service, depending on the the coolant temperature, operator’s treatment and accidents during the normal work procedure. The air-bearings become defective due to the air-flow through the tiny passages inside the spindle and various other factors. The lifetime of the air-bearing spindles and modern ball-bearing spindles are quite identical, even though this has not been generally accepted by the PCB business. A faulty bearing is recoqnized by heating of the bearing and/or noisy operation (like a sharp, grinding noise). The heat can normally be felt most clearly in the lower part of the spindle, i.e. at the lower nose end of the spindle.
2.3 Collet: Another factor which can severely influence the quality of the work is the collet. The collet can influence the drilling accuracy, the laser measuring and the routing quality.
The collet must be cleaned at very regular intervals, especially if the machine is mostly routing.
2.4 Cooling: The spindles are cooled by a closed, re-circulating system which is cooled by a compressor pump and fed through the spindle by means of a recirculating pump. The cooling effficiency can be affected by biological particles in the coolant agent (slime and algaes in the water) or by insufficient cooling capacity due to low water level or obstructions in the water-pipes etc. |
