Thread design for fasterner used in medical device

The screw used for medical parts adopts special thread design due to the target material of the workpiece. Taking plastite alternative (plastic equilavent) screw as an example, it is the combination of trilobular thread and 60 ° or 48 ° angle. This combination is helpful to lock the plastic workpiece at a higher speed in practical operation and save the assembly operation of other nuts or washers. The PT screw is designed with special EJOT profile and 30 degree thin angle to achieve the same effect of cutting and locking.

The key to understanding the screw thread is to understand the failure mode of a system. For micro screws, the effective number of threads is very important because of their short length. Generally speaking, for nuts or screws, the first and last threads are generally incomplete and are functionally regarded as the leading part, so they are not regarded as effective threads. When you select screws with length ≤ 1 / 4 inch or 5mm, you need to pay special attention to the number of effective threads. Generally speaking, 5-6 effective threads can ensure the locking performance when drilling into hard materials.

Vibration failure is also the key to thread design. Even the screw is correctly locked into the workpiece, the failure caused by vibration is inevitable. Effective methods include using nylon patch or adding washers, nuts and other accessories to increase friction performance to prevent failure caused by vibration. Generally, the standardized nylon patch we provide is 90°-180° half cycle design. If you need special services, please contact us for consultation. Washers and nuts are recommended to be matched with standard products to improve the economy and time efficiency of procurement and installation.