Analysis of measures for determining the time of replacement of the manufacturing station

The time required for the automatic tool changer to complete all the actions. It is believed that the tool change time of the automatic tool changer is the sum of the time required for the automatic tool changer to complete all the tool change operations. For example, for the JCS? 018 vertical machining center, it is the sum of time required for the knife to turn over the knife, the knife, the knife, the knife, the knife, the knife, the arm reset and the knife cover. . In fact, the turning and turning of the knife sleeve can coincide with other movements of the machine tool, that is, the tool sleeve turning down motion can be completed at the same time or in advance when the machine tool is cutting or the coordinate axis is fed from the machining zone to the tool change position. The tool is in a state of waiting for exchange; and the tool cover flipping action can also coincide with the rapid moving action of moving the coordinate axis from the tool changing position to the processing area, and the coordinate axis movement time can be omitted. Therefore, taking into account the tool change time of the automatic tool changer will result in the calculated production tempo of the part being greater than the actual production tempo. Tool change time as specified in the ISO/DIS 10791-9 discussion paper In the ISO discussion paper on the tool change time of the automatic tool changer, the tool change time is defined as the "cuttocut" time. That is, the time interval from the reference position in the machining zone to the time when the next tool reaches the same reference position.

It includes the following time periods: the coordinate axis moves from the reference position PR to the tool change position PC; searches for the next tool; tool exchange; opens and closes the movable guard; returns the reference position PR from the tool change position PC. In the discussion draft, the reference position PR is defined as the intermediate position of each coordinate axis stroke for the vertical machining center; for the horizontal machining center, the X axis is defined as the middle position of the stroke, and the Y axis is at the lower limit of the stroke. In the interval of 4 strokes, the Z axis is the space point formed when the spindle end face is at the minimum distance from the work surface. It can be seen that the production cycle of parts calculated according to the ISO discussion draft is also more accurate. However, if the time required to move the coordinate axis is included in the tool change time of the automatic tool changer, it is unfair to the manufacturer of the automatic tool changer. Secondly, it can be known from the design and use of machine tools that for some automatic tool changers, the operation of searching for the next tool can be completed before the automatic tool changer implements the tool change. Therefore, this time period should not be included in the tool change time of the tool changer. Thirdly, this evaluation method takes into account the specific structural form of the machine tool too much, and the influence of the machine tool structure on the actual use is ever-changing, and is not involved in the structural form different from the discussion paper.

Before the "cut to cut" time was proposed, there was a similar "chiptochip" calculation method. The calculation method is as follows: after the coordinate axes of the machining center are moved from the intermediate position of the stroke to the tool change point by the rapid feed mode (G00 mode), the automatic tool changer completes the tool change to the middle position of the quick return stroke of each coordinate axis. time interval. Although it includes all the necessary time for the tool changer to change the tool, and can accurately calculate the production cycle of the part, it is “unfair” to the automatic tool changer itself, because it includes the coordinate axis rapid movement. Time required. In most cases, the time required for the rapid movement of each coordinate axis from the intermediate position of the stroke to the position of the tool change is difficult to completely coincide with the preparation time necessary for the automatic tool changer to place the tool in the tool change position. The position of each coordinate axis from the tool change position It is also difficult to completely coincide with the time required to return to the middle position of the stroke and the recovery time necessary for the automatic tool changer to return to the tool change position of the upper tool after the tool change. In summary, the current method for assessing the tool change time of the automatic tool changer has certain rationality, but it is difficult to accept the host manufacturer, the automatic tool changer manufacturer and the user at the same time. To this end, it is necessary to seek an evaluation method that allows the main engine manufacturer, the automatic tool changer manufacturing plant, and the machining center user to simultaneously recognize.

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