What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The more complex inlaid embedded copper nut copper insert nut specification is M8, this copper insert nut is embedded in the injection molded part of the car, 5 twill embossing, 4 left twill embossing, 1 right twill embossing Knurling. Since there are multiple rolling patterns, double tool rests + double embossing rests are used, and 5 grooves and 2 chamfers are inserted at one time by a widening forming knife. The hot-pressed copper insert nut contains Reticulated and straight lines, the outer circle is conical, in the process of hot pressing to facilitate smooth introduction into the plastic hole.
Yueluo relates to a self-tapping screw according to the preamble of claim 1. A self-tapping screw is known from EP0623759B1, the ratio of the outer diameter to the smaller diameter of the self-tapping screw is about 1.25-1.5, the ratio of the outer diameter to the pitch lead is about 1.5-1.6 and the thread The flank angles of , are < 50° and ≥ 35°. EP0433484B1 proposes a self-tapping screw whose thread is provided with cutting teeth of approximately arcuate design, and the cutting edge and the thread crest are at the same horizontal position and are set in opposite directions. One purpose of Yueluo is to realize a general type of self-tapping screw so that it can be screwed particularly easily into holes drilled in concrete or other materials such as bricks and the like. According to Yueluo, this object is achieved by the features in the characterizing part of claim 1, and surprisingly, it has been found that the parallel arrangement of the flanks, ie with a flank angle of about 0°, will make screwing particularly easy when screwing in , especially if the diameter of the hole varies within an allowable tolerance. One reason may be due to the fact that there is no lateral pressure on the material screwed into the thread, even if threads of different depths are cut in concrete or other materials such as brick, chipped plywood, or hardwood. The thread cuts into the material over its entire width by cutting grooves. In particular according to the embodiment of claim 3 the material cut out when screwing in the screw can be discharged without any accumulation, the dependent claims reflecting many advantages of further embodiments.
rivet is a metal rod-shaped part with a cap at one end. During riveting, the rivet uses its own deformation or interference to connect the riveted parts. Commonly used rivets are semi-circular head, flat head, semi-hollow rivets, solid rivets, countersunk head rivets, blind rivets, hollow rivets, etc. At present, rivets are widely used in various backplane products and other stamping products. Since rivets are responsible for the functions of locking, positioning and bearing lateral force in the product, the degree of riveting and vertical have higher requirements. However, in actual production, there are often problems such as the failure of the rivet torsion to meet the requirements, the rivet being skewed by the rivet, the surface of the rivet being cut, the rivet placement being inaccurate and requiring manual repositioning, etc. Very high and very inefficient.
At present, in the process of injection molding, stamping, testing, etc., the product is usually positioned on the mounting plate or the positioning plate by pins. The general pin positioning method uses cylindrical pins with the same cross-sectional diameter for positioning. Because the product is easily deformed during processing, the pin positioning hole on the product is also deformed. With this kind of pin for positioning, the pin is often stuck. Dead products cause inconvenience in handling the workpiece, resulting in broken pins or scratched or even damaged products, with obvious defects.
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