What is really useful is very simple, so simple that everything is divided into two states.
For example, up and down, left and right, east and west, male and female... these two states have derived a rich and colorful world.
For example, the two forms of part features are either outer (shape) or inner (shape) to form the outer circle, inner hole, shape, inner cavity...
Similarly, tool radius compensation also has two compensation states, that is, G41 left compensation and G42 right compensation.
1. One left and one right for compensation, one outside and one inside for parts, how to choose G41 G42 when programming?
The essence is: look along the direction of tool movement, let the tool radius compensate to the left with G41, and compensate with the right with G42
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G41 is specified in the program, the operator inputs the tool radius value (positive value) in the machine tool radius compensation interface, and the tool will compensate to the left when viewed along the tool movement direction.
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G42 is specified in the program, the operator inputs the tool radius value (positive value) in the machine tool radius compensation interface, and the tool will compensate to the right when viewed along the tool movement direction.
2. There are 3 stages in the compensation process of CNC machine tools
1. Start compensation
2. Compensation status
3. Cancel compensation
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1. Start the compensation phase:
Let's look at the above program:
N1 block: Compensation has not started yet, that is, the center of the tool is at X=0, Y=0 (not the edge of the tool)
N2 block: G0G41X20.Y10.D1 start compensation, please note: X=20.Y=10. It is the coordinate point of the edge of the tool (not the coordinate point of the tool center)
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Because, from X=0, Y=0 to X=20.Y=10. The tool will gradually move to the left. (Because G41 is specified in the above program)
How much to move? The offset (positive value) is determined by the corresponding tool radius value input by the operator in the machine tool radius compensation interface
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For example, for a D10 milling cutter, if you enter the corresponding tool radius value of 5 in the radius compensation interface, it will move 5mm to the left. If you input 4, it will move 4mm.
Input 0, then it will move 0mm (at this time, the tool center is at X20, Y10, which means there is no compensation)
Enter -5, then it will move -5mm to the left, in other words, move 5mm to the right
Well, the above analyzes the process of establishing radius compensation. First, the tool radius compensation command must be specified in the program, and second, the operator inputs the compensation value in the machine tool radius compensation interface.
After analyzing this, please pay attention, you must pay attention to the sentence I said above:
From X=0, Y=0 to X=20.Y=10. The tool will gradually move to the left.
The two coordinate points from X=0,Y=0 to X=20.Y=10 are very important, that is to say, the X,Y values in the block before establishing radius compensation are the same as the X,Y values in establishing radius compensation value. At least one of the vertical distances between these two points is greater than the compensation amount in tool compensation.
Note: At the beginning of the compensation stage, it needs to be compensated in the state of G00 or G01, (it cannot be compensated under the command of G02 or G03, otherwise the machine will alarm)
2. Compensation stage
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In the compensation stage, the machine tool system will pre-read the following two blocks (namely N3 and N4 block), so as to judge the direction of the compensation vector.
Therefore, it is recommended that the two program segments following G41 or G42 compensation cannot have Z values.
Scale this example below:
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When radius compensation is established from segment N3, the CNC system can only pre-read the next two program segments, while both programs N4 and N5 are for Z-axis movement (the system cannot judge the vector direction of the next compensation, and the N3 segment program After execution, the tool path has changed, it is not the original P point, but P1 point (tool center point), and then moves to P2 intersection point (gradual compensation), so overcut occurs as shown in the above figure.
How to modify?
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3. Cancellation of compensation
The command to cancel tool radius compensation is G40, and it must also be in the state of G00 or G01, and cannot be canceled under the command of G02 or G03.
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Cancel radius compensation starts from block N7, (N7G40G00X0Y0)
From the end point of the N6 block to the end point of the N7 block X=0, Y=0, the tool center returns to (X=0, Y=0) point.
