Furthermore, the constant exposure of the steering rack to dirt and debris due to a faulty seal can cause premature wear and tear, necessitating costly repairs Furthermore, the constant exposure of the steering rack to dirt and debris due to a faulty seal can cause premature wear and tear, necessitating costly repairs
Copper and nickel are relatively inexpensive, while platinum is much more expensive but also much more durable and resistant to wear Copper and nickel are relatively inexpensive, while platinum is much more expensive but also much more durable and resistant to wearNotes
* JIS: Japanese Industrial Standard
✓: Compatible
✗: Incompatible
―: Not applicable
PTFE material is a perfect ingredient in making more reliable oil seals. These materials are used to make oil seals that can resist dry or unlubricated operations. PTFE oil seals, which are also called teflon oil seals, have a thermal strength ranging from -202 degrees Fahrenheit to 392 degrees Fahrenheit and an excellent chemical resistance. Oil seal PTFE is considered as the future of radial shaft seals.
As can be seen from the seal cross-section shown in Fig. 14.2, shaft seals are complex shapes that require advanced mold design and molding techniques (see Section 7.3 for discussion of fluoroelastomer molding). For some time, most shaft seals were made in the United States by compression molding. Injection molding of shaft seals is prevalent in Europe, and is being used increasingly in the United States. An advantage of compression molding is that preforms (usually rings cut from extruded tubing) are used that closely approximate the amount of stock required for the final parts, so compound waste is minimized. For injection molding, the amount of cured stock in the central sprue and runner (actually a thin sheet leading to the seal lip) is often large compared to the stock required for the final part, so the waste of high-cost fluoroelastomer may be high. Such waste is reduced in modern injection molding designs.