Ensuring Precision in Mold Processing

To ensure the accuracy of precision mold processing, the following work procedures are followed: cleaning the mold and applying mold release agent, placing the semi-finished product (oil seal skeleton and rubber ring), closing the mold by flipping, sending the mold into the vulcanizing chamber via rack and pinion drive, vacuum vulcanization, sending the mold out onto the carriage via rack and pinion drive, opening the mold, flipping, and ejecting the product.

Manufacturing of Two-Part Rubber Oil Seal Molds

The manufacturing of two-part oil seal molds involves processing monolithic components and then assembling them to fit precisely, ensuring excellent processing technology and convenient mold inspection. The single-cavity mold material is selected as Cr12, and the tie plate is made of 45 steel. During mold processing, in addition to strictly adhering to the mold drawings and ensuring cavity dimensions, the following points are crucial to maintaining mold processing accuracy:

1. Processing of the Glue Flow Groove:

Previously, the precision processing of the glue flow groove in oil seal molds was often neglected. The glue flow groove was frequently processed too far from the cavity or with difficult-to-control dimensions, complicating trimming and affecting product aesthetics. The two-part oil seal mold has improved these issues by aligning the inner end size of the triangular glue flow groove with the product's outer diameter (zero to zero). The upper and lower molds form a sharp cutting edge at this point, shearing off the excess flash during oil seal molding. This simplifies the trimming process and improves product appearance. Since the glue flow groove and the cavity outer diameter are located on different modules, there is no interference, making it easier to ensure accuracy.

2. Fit Processing of the Upper Mold and Upper Mold Core ：

The upper mold and upper mold core 1 use a tapered fit. Previously, a lapping method was used to achieve a contact rate of over 80%. This traditional method was not only difficult but also time-consuming, and it was still hard to achieve a flash-free effect. The new structure mold processing uses a slightly smaller taper angle for the tapered hole compared to the tapered shaft. This ensures that the upper mold and upper mold core are always tightly fitted at the parting surface, maintaining a gap-free fit and eliminating flash in this area, thus improving the mold's manufacturability.

3. Press-Fitting of Upper Mold Core 1 and Upper Mold Core：

The press-fit between upper mold core 1 and upper mold core 2 is key to ensuring the size and precision of the oil seal's secondary lip. Flash on the secondary lip significantly impacts its appearance. The new structure mold uses an interference fit between upper mold core 1 and upper mold core 2. After individual processing, they are press-fitted into one unit using thermal expansion, and then upper mold core 2 is securely fastened with screws from the top, effectively preventing any loosening at the secondary lip.

4. Connection Between Each Cavity Mold:

The connection between each single-cavity mold and the tie plate must allow for some floating to ensure precise and flexible opening and closing of the precision mold. Generally, the gap between the single mold and the tie plate is controlled within 0.50 to 1.0 mm. If the gap is too large, it may cause the mold to misalign during use, leading to excessive wear and reduced mold life. If the gap is too small, it may cause interference between the mold cavities during operation, making it difficult to operate.

The development of the two-part rotary shaft oil seal mold has changed the traditional three-part mold structure, ensuring the appearance and performance of the oil seal product and significantly improving work efficiency.