Problem Analysis of Countersunk Head Phillips Self Dilling Screws
What is the reason why Countersunk Head Phillips Self Dilling Screws often appear slippery at the joint? Inappropriate selection of the hole diameter of the screw can easily cause slippage. The processing range of the major diameter d1 value of Countersunk Head Phillips Self Dilling Screws is 4.22~4.04mm, and the processing range of the small diameter d2 value is 3.10-2.95mm, so the value of the aperture of Countersunk Head Phillips Self Dilling Screws must fall between 4.22-2.95mm . In order to increase the occlusal force between the screw thread and the steel plate, and at the same time consider the influence on the screw penetration resistance with the increase of the thickness of the steel plate, the minimum value of the hole diameter is generally 3.1, and the maximum value is generally 3.5. When the matching hole is too large, the occlusion of the screw teeth and the steel plate is too small, and the slippery wire is prone to occur; when the matching hole is too small, the screw is not easy to penetrate, and the screw will break at the same time; therefore, for different thickness of steel plate, it is necessary to choose different The hole diameter of the screw can avoid the phenomenon of slippage.
The unreasonable design of the screw hole structure can easily lead to slippage. The screw hole structure can be divided into flat holes and flanged holes. Through research, it is necessary to use flanged holes for steel plates with a thickness of less than 1.0mm.
Structural defects in Countersunk Head Phillips Self Dilling Screws tend to cause slippage. The structural defects of the screw include substandard thread size and diameter, substandard thread pitch, substandard thread angle, unsaturated and incomplete thread, and reverse taper of the thread.
If the major diameter of the screw is too small but the minor diameter remains the same, it will affect the unilateral occlusion of the screw teeth and the steel plate.
The pitch value P of Countersunk Head Phillips Self Dilling Screws is 1.4mm. When this value is too large, it means that the helix is elongated, and the length of the screw "bite" into the steel plate is too short, which will also cause slippage.