Thread Tapping Process Problems, Reasons and Solutions or Correction Tips

2022.7.27

Tap is a tool for processing all kinds of medium and small internal threads. It is simple in structure and easy to use. It can be operated manually or on machine tools. Then in the process of thread tapping, what problems may occur, how to find the reasons and solutions?

Thread Tapping Process Problems, Reasons, and Solutions or Correction Tips

Tap tooth breakage

– Reasons: the front angle of the tap is too large; the cutting thickness of each tooth of the tap is too large, and the quenching hardness of the tap is too high. Because it has been in use for such a long time, the faucet has significant wear.

– Solutions: reduce the front angle of the tap appropriately; extend the length of the cutting cone appropriately; reduce the hardness appropriately, and replace the tap as soon as possible.

 

Tap is broken

– Reasons: The diameter of the thread’s bottom hole is too tiny, which contributes to the chip blockage, which is produced by ineffective chip removal; When the thread cannot be tapped because the drilling depth is insufficient, the cutting speed is too high, or the tapping speed is too quick; The sizes of the thread bottom holes are not the same as those of the taps that are used for tapping. The parameters for the tap grinding are selected incorrectly, which results in the machined item having an inconsistent level of hardness, the faucet has been utilized for an extended amount of time, which has resulted in severe wear.

– Solutions: Correctly select the diameter of the threaded bottom hole; Sharpen the inclination of the cutting edge or select spiral groove tap; The depth of bottom hole drilling shall meet the specified standard; Reduce the cutting speed appropriately and select according to the standard; When tapping, calibrate the tap and bottom hole to ensure that their coaxiality meets the requirements, and select floating tapping chuck; Increase the front angle of the tap and shorten the length of the cutting tap; Ensure that the hardness of the workpiece meets the requirements, and select the safety chuck; If the tap is worn, it should be replaced in time.

 

Tap wears too fast

– Reasons: cutting speed is too high when tapping thread; Improper selection of tap grinding parameters; Improper selection of cutting fluid and insufficient cutting fluid; The material hardness of the workpiece is too high; When the tap is sharpened, burns occur.

– Solutions: reduce the cutting speed appropriately; Reduce the front angle of the tap and lengthen the length of the cutting cone; Choose cutting fluid with good lubricity; Conduct proper heat treatment on the machined parts; Sharpen the tap correctly.

 

Excessive pitch diameter of the thread

– Reasons: the pitch diameter accuracy grade of the tap is improperly selected; Unreasonable cutting selection; The cutting speed of tapping is too high; The coaxiality between the tap and the threaded bottom hole of the workpiece is poor; The parameter selection of tap grinding is not appropriate; Burr occurs in the sharpening tap, and the cutting length of the tap is too short.

 

– Solutions: choose the pitch diameter of the tap with reasonable accuracy grade; Select the appropriate cutting fluid and reduce the cutting speed appropriately; When tapping the thread, the coaxiality of the tap and the bottom hole of the thread shall be corrected, and the floating chuck shall be used; Properly reduce the front angle and the back angle of the cutting cone; Remove the burrs generated by grinding the tap, and appropriately increase the length of the cutting cone.

 

The Thread pitch diameter is too small

– Reasons: the pitch diameter accuracy grade of the tap is improperly selected; The selection of tap grinding parameters is unreasonable, and the tap is worn; The selection of cutting fluid is inappropriate.

– Solutions: select the pitch diameter of the tap with appropriate accuracy grade; Appropriately increase the front angle and cutting cone angle of the tap; Replace the excessively worn tap; Choose cutting fluid with good lubricity.

 

Surface roughness of the thread is too high

– Reasons: the grinding parameters of the tap are not suitable; the hardness of the workpiece material is too low; poor grinding quality of the tap; unreasonable choice of cutting fluid, cutting speed is too high when tapping thread; the tap is worn out too long.

– Solutions: appropriately increase the front angle of the tap while decreasing the cutting cone angle; Utilize heat treatment, increase the workpiece’s hardness adequately, ensure that the cutting surface of the tap has a low surface roughness value, and choose a cutting fluid with excellent lubrication; adjust the cutting speed accordingly and replace the worn tap.