When fitting the machining curve, there are two methods:
1. Linear interpolation
2. Arc interpolation
1. The more node data is processed, the smoother the curve will be. If programmed with software, the length of the program can be 100 times or even 10,000 times more than that of the macro program.
2. For some non-circular curved workpieces that are more complex and require higher shape accuracy, it is recommended to use smaller chord lengths for division (arc-circle fitting) to increase interpolation points and improve curve fitting. Accuracy.
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Dear friends:
Did you see the screenshot above?
This is a curve programming example
In this example (an ellipse is one of the most common curves), I used a little-known programming "secret"!
Without this skill, even if you can program, it will be difficult for you to become a qualified programmer.
Once you master it, the programs you write will be streamlined and efficient, and will make the workpieces processed by machine tool operators more "accurate"!
Come, let's think about it:
How to improve the processing accuracy of workpieces?
In addition to the workpiece clamping method, process, and tools you have to consider, what else should you consider when programming?
Let's look at the structure of any CNC program...
Mainly consists of two parts:
1. Instruction code
2. Point data
There are only a dozen commonly used CNC G command M codes, but the workpiece is composed of many point data. These data are connected with small line segments to form workpieces of different sizes.
The more these data are fitted and the denser they are (the data are connected with small line segments), the smoother the workpiece will be and the higher the accuracy will be.
This is the underlying algorithmic thinking of programming
However, there are two fitting methods for programming point data algorithms:
1. Linear interpolation (G01)
2. Arc interpolation (G02/G03)
For example, sometimes the program you see looks like this:
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(There are too many programs, some parts have been intercepted...)
Small segment linear interpolation (G01) is used for fitting...
For the programming of some more complex non-circular curve workpieces that require high shape accuracy, although such a program can process the workpieces qualified, the processing efficiency is low.
The consequences of such programming are:
1. For turning workpieces, the processing time is long and the tool dry wear is rapid.
2. For milling workpieces, the processing process is prone to vibration and the surface of the workpiece is rough.
Solution (one):
Use arc fitting
Say important things three times:
Use arc fitting
Use arc fitting
Use arc fitting
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For example, in the above example (O16 program), the N36 line block uses the (G02/G03) arc interpolation mode...
because:
The approximation error produced by circular interpolation is much smaller than that by linear segment approximation.
In other words, if the workpiece itself requires roughness and the accuracy is not high, and the resulting approximation errors are the same, then the segments can be divided very thickly when using arc approximation, thereby improving the processing efficiency of the program from the programming details.
