Hello everyone, the above picture is a mechanical product made of metal zippers. Metal zippers are formed by mechanically biting copper or aluminum wires onto the fabric tape. We usually refer to this machine as a dental alignment machine or a zipper dental implant machine. The high-speed operation of machinery results in high frequency of movement of sliding and swinging components, requiring high demands on related processes such as circuits, processing, materials, heat treatment, and assembly. Here, we mainly introduce the gap fit problem of the sliding plate device of this zipper machine (as shown in the figure below).

Common fits include clearance fit and interference fit. Here's a brief introduction: clearance fit refers to a fit where the tolerance zone of the hole is located above the tolerance zone of the shaft and has a clearance (including a minimum clearance of zero). Interference fit refers to a fit where the tolerance zone of the hole is located below the tolerance zone of the shaft and has interference (including a minimum interference of zero); Interference fit refers to the use of the interference value between the shaft and the hole to generate elastic pressure between the surfaces of the parts after assembly, thereby obtaining a tight connection.

The accessory highlighted in red in the above picture is the skateboard, with the skateboard groove below and the skateboard clamping block above. The clearance fit between the skateboard and the sliding groove, as well as the clamping block, is also required. The conventional clearance fit is generally 1-3 threads, which is 0.01mm~0.03mm. However, due to the high-speed operation of this zipper machine, it reciprocates about 700 times per minute. The friction and thermal expansion generated by high-speed operation also need to be considered. Therefore, based on our years of experience, the clearance fit of this skateboard is, When we process, it is generally safest to control the tolerance between 0.04mm and 0.06mm (the fluctuation of tolerance is closely related to the material and heat treatment) because long-term mechanical operation can also produce copper powder or other debris entering. So if the gap is too small, the machinery can easily get stuck and break.