Yintai linear guide model, MSA30LE overload type, sold in large quantities on Anang Mall

Yintai linear guide model, MSA30LE overload type, sold in large quantities on Anang Mall

PMI guide railThe rated lifespan and lifespan coefficient
PMI rail lifespan:
lifetime
When the PMI guide rail is subjected to load and moves, the surface of the ball track and the steel ball are constantly subjected to cyclic stress. Once the critical value of rolling fatigue is reached, the contact surface will begin to experience fatigue damage, and fish scale like flakes will peel off on some surfaces. This phenomenon is called surface peeling. The definition of lifespan is the total distance traveled by the surface of the bead and the steel ball until the surface peels off due to material fatigue.
2. Rated lifespan
The lifespan of PMI guide rails is highly dispersed, and even products manufactured in the same batch may have different lifespans when used in the same motion state; This is largely attributed to the inherent changes in the fatigue characteristics of the material itself. Therefore, to define the lifespan of PMI guide rails, the rated lifespan is generally used as the benchmark; Its definition is: the total operating distance that can be achieved by running a batch of the same products one by one under the same conditions and rated load, with 90% of them not experiencing surface peeling.
3. Calculation of lifespan
The lifespan of PMI guide rails may vary depending on the actual working load they are subjected to. The basic dynamic rated load and working load of PMI guide rails can be used to calculate their service life.
4. Life cycle coefficient
(1) Hardness coefficient (fh)
The hardness requirement for the bead contact surface of PMI guide rail is HRC58-62 at a certain hardening depth. If the hardness value cannot reach the required level, it will reduce the rated load and service life of PMI guide rail. At this time, the dynamic and static rated loads are the size table values multiplied by the corresponding hardness coefficient.
The hardness requirement for HIWIN's linear guide rails is HRC58 or above, so fh is
(2) Temperature coefficient (ft)
The system temperature will have an impact on the material of the PMI guide rail. When the temperature exceeds 100 ° C, the rated load and service life of the PMI guide rail will be reduced. At this time, the dynamic and static rated loads are the values listed in the size table multiplied by the corresponding temperature coefficient. Due to some accessories being made of plastic material that is less resistant to high temperatures, it is recommended to use them at temperatures below 100 ° C.
(3) Load factor (fw)
The load acting on the PMI guide rail includes not only the self weight of the device itself, the inertial load during starting and stopping, and the moment load generated by suspension, but also the vibration and impact load accompanying the motion. This type of load is not easy to calculate. Based on experience and the load condition and usage speed, it is recommended to multiply the calculated load value by the corresponding load coefficient