What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The main purpose of the embedded nut is to replace the direct opening of screw holes on the injection molded parts, so as to improve the strength of the screw holes of the injection molded parts. Referring to FIG. 1 , in order to lock the workpiece 3 ′ on the injection molded part 2 ′, the screw 5 ′ passes through the through hole on the workpiece 3 ′ and is screwed into the screw hole of the embedded nut 1 ′ to fix the workpiece 3 ′. The embedding between the embedded nut 1' and the injection-molded part 2' generally includes two ways. One is to heat the embedded nut 1' and then insert it into the injection-molded part 2' by hot pressing; the other is to insert the embedded nut into the injection-molded part 2'. 1' and the injection part 2' are integrally injection-molded. In order to ensure the bonding strength between the inner nut 1' and the injection molded part 2', knurling is provided on the outer peripheral surface of the inner nut 1'.
A screw can be equipped with only one spring washer or only one flat washer, or it can also only be equipped with a two-piece combination of flower teeth. The national standard number of the combination screw is represented by GB9074. The commonly used cross recessed small pan head three combination screw national standard is GB9074.8. This .8 refers to the small pan head. That is, the size of the head of the pan head screw that is often said. Denoted by letters as PM. Professional combination screw manufacturers, the habitual expression method is three-in-one PM. The commonly used cross recessed large pan head combination screw national standard is GB9074.4. Professionally called large pan head combination screws. Or R head, or B head. That is to say, the head of this combination screw is larger and thicker than the head of the small pan head combination screw. There is also a commonly used external hexagon combination screw, which is a cross external hexagon combination screw. It is often called a socket hexagon combination screw. The national label is GB9074.13.
In the prior art, after the screw is screwed into the workpiece, rust inhibitor is dripped on the edge of the screw to prevent rust in the later stage, but this traditional dripping method of rust inhibitor often produces rust inhibitor during the dripping process. Difficult to penetrate, or the problem that the anti-rust oil cannot penetrate due to the tight contact between the screw thread and the thread groove. In terms of material saving, the traditional anti-rust of screws often causes a lot of waste of anti-rust agent, and cannot achieve a good anti-rust effect of screws.
In the prior art, there are two ways to feed the screws of the locking screw machine, the air blowing type and the air suction type. The air suction type is suitable for relatively small screws. If the screw size is larger than M2, smaller than M5, and the length-diameter ratio is larger than 1.7, the air-blown screw machine can be selected.
The above content is uploaded by Yueluo or the Internet. If there is any copyright issue, please contact [email protected].
