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After a shop decides on mist collector location, either indoors or outdoors, and on the appropriate capture hood size, it is time to determine the pick-up point location on the intended machine tool. Once that is accomplished, ducting and piping needs must be addressed to complete the installation.
The most common method of picking up mist is to connect the mist collector to a machining center enclosure. Many machine tool manufacturers provide a knockout plate or cut out designed specifically for mist collector connection. However, the locations specified by the machine tool designer are not always the best location, especially on older machines.
When selecting where to connect a mist collector to an enclosed machining center, the purpose of mist collection must be kept in mind. It should keep mist contained inside the machining center by pulling a negative pressure on the machine's enclosure. This prevents mist from leaking out the doors, around seals, and escaping through other open areas in the machine tool cabinet. Further, mist collection is for filtering the smallest and lightest amount of mist pulled into the mist collector. Cross-ventilation of the enclosed space makes this possible. So any open area - whether it's always open such as a chip conveyor, or sometimes open such as door will allow air into the machine and will sweep the inside of the enclosure free of mist.
The process is similar to how fresh air is drawn into a cave or mine: Before fresh air can move in, the old stagnant air has to be swept away. A vent hole is cut at the back of the cave, a fan pulls old cave air up and out of the vent hole, and fresh air enters through the entrance.
The location of the mist collector pick-up point on the machine tool cabinet needs to be well away from several other machine openings. These include openings for the chip conveyor, main access door, tool changer door, machine drive motors, and any other areas where plant air can enter the machine.
Good pick-up points are usually located high on the machine's enclosure walls or on the top to prevent excess mist and chips from being picked up. Two common locations are along the back wall of the...