The Methods Of CNC turning Qualified Metric Triangular Thread
In most factories, one or more people are responsible for adjusting the machine, and then a special person is responsible for operating the machine. These people are collectively referred to as “Green Key” heroes. The formula, if there are any problems in the process of processing, can not be solved at all, the solution is very blind, plus a weak foundation, according to their own feelings to process the thread, this size is simply not guaranteed. On the contrary, if you thoroughly understand the formula, you will be able to know what you are doing during the CNC machining, and you will be able to handle the size well.
1. Thread parameters and process requirements for turning threaded workpieces
First, determine the large diameter and middle diameter of the thread:
The external diameter of the external thread for machining external threads (nominal diameter d), d =
Determination of the front diameter of the thread: generally it should be 0.2 to 0.4mm smaller than the basic size (about 0.13P)
Generally, it is 0.2mm smaller, because if you only cut to the large diameter, the thread is because the two sides of the tooth will be squeezed with the tool, which will cause the thread to not fit properly.
Before threading, you must know how to calculate the minor diameter of the thread. The minor diameter of the external thread is equal to the major diameter of the thread minus 1.3 times the pitch. Do not pull 1.0825 times the pitch here. These formulas are some empirical formulas. No matter how they are calculated, they can be banned. The detection of thread ring gauge is enough.
It does n’t matter if it ’s not counted. It ’s okay to know that it ’s the case. The calculation of this aspect is left to the “turner calculation”. In fact, it ’s more reliable. Why is the turner calculation too accurate? Sometimes It will confuse us, whose machine tool can achieve that precision.
Let’s take M24X3’s metric triangular thread as an example, use the empirical formula to calculate the thread bottom diameter, and write down the program by the way.
Before turning the thread, the big warp of the thread should be turned out with an external turning tool. What is the diameter of the M24X3 thread? Do n’t laugh, some people may not really know it. In layman ’s terms, the number followed by M is the diameter of the thread. With the diameter of the outer car, the number of the car ca n’t be exactly 24. Insiders ca n’t do lay things, right The method is to change the thread diameter to 0.1 times the pitch of the car, which is 23.7.
Knowing the major diameter of the thread, then the minor diameter (bottom diameter), the minor diameter of the external thread is equal to the major diameter of the thread minus 1.3 times the pitch. That is
24-1.3×3 = 20.1 The minor diameter of the thread is 20.1, that is, the tool will be retracted when the thread turns to X20.1.
I believe that the thread from such a car will be able to pass the inspection of the thread pass regulation.
Is the internal thread the same? Then you are wrong. You are wrong. The products are all scrapped. The boss asks you to settle the account in minutes.
We use M24x1 internal thread to calculate.
Where should the thread end? The only difference between internal thread calculation and external thread is that the minor diameter of the internal thread is equal to the major diameter of the thread minus 1 pitch. Note that it is double the pitch.
Then the prefabricated hole of the internal thread should be turned to 23, right, because it is internal thread, you turn the hole to 24 and return the thread, right? Let’s pay attention to it. Now it is calculated how big the thread bottom hole should be before thread machining.
Internal thread of M24X1. The threaded bottom hole should be 23 minus one pitch.
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