The invention belongs to the technical field of electroformed nickel molds. It specifically discloses a nickel mold for PDCPD material forming and an electroforming manufacturing process for the nickel mold. The mold features a surface resistant to sticking, uniform heat conduction, good smoothness of the product's A-side, and a long service life. Keywords: PDCPD Nickel Mold; Electroforming Manufacturing Process; Surface Properties; Service Life
I. Introduction
Polydicyclopentadiene (PDCPD) is commonly used to manufacture automotive components, such as bumpers, fender liners, instrument panels, and fenders. Its injection molding requirements are high. Traditional molds often have issues like insufficient smoothness of the cavity surface and a tendency for the material to stick, particularly resulting in less than ideal smoothness for Class A surface forming of automotive parts.
II. Structure of the PDCPD Nickel Mold
PDCPD nickel mold comprises matching upper and lower molds. The lower mold is equipped with a parting surface and internal flow channels. It also features a sealing groove surrounding the edge of the parting surface. The parting surface additionally has venting grooves, with the venting grooves and internal flow channels located on opposite sides of the parting surface. It is characterized in that: the face of the upper mold opposite the lower mold is provided with an electroformed nickel layer.
III. Electroforming Manufacturing Process for the DCPD Nickel Mold
The lower mold is cast from aluminum alloy and undergoes precision machining via conventional processes. The upper mold is manufactured using an electroforming process. The specific manufacturing process for the upper mold includes the following steps:
Create a master mold (electrode mold) according to the design parameters.
Clean the surface of the master mold and perform passivation treatment to form a passivation film on its surface, facilitating subsequent demolding.
Prepare an electroforming bath, fill it with electroforming solution, and place an electroforming nickel slab (anode, using sulfur-containing nickel) and the master mold (cathode) into the bath. Apply electric current to utilize electrolytic deposition. After energization, nickel ions in the electrolyte move towards the cathode under the electric field, gradually depositing on the surface of the master mold to form a nickel layer that exactly replicates the master mold's contour.
Continue deposition until the nickel layer reaches the required thickness (typically 2.5-6mm), thus forming the electroformed nickel layer.
Place the master mold coated with the electroformed nickel layer into a cleaning tank to wash away residual electroforming solution from its surface, then remove and wipe clean with water.
Install baffles around the perimeter of the electroformed nickel layer and fill with backing material (e.g., aluminum alloy, resin) to form the upper mold framework. This reinforces the electroformed nickel layer to prevent deformation during demolding.
After the backing material solidifies, perform demolding to separate the master mold from the electroformed nickel layer, forming the final electroformed nickel mold.
IV. Beneficial Effects
The electroformed nickel mold produced by the above method improves the performance of the cavity surface, resulting in high surface hardness and good wear resistance. The electroforming solution has a simple composition and stable components. The resulting electroformed nickel possesses good comprehensive mechanical properties, reduced internal stress, a tensile strength reaching 500 MPa, and an elongation rate of 25%. Subsequent demolding operations are simplified. Furthermore, due to the electroformed nickel layer on the cavity face of the upper mold, the surface is resistant to sticking during molding, heat conduction is uniform, the product's A-side smoothness is excellent, and the service life is approximately twice that of ordinary molds.
V. Conclusion
The PDCPD nickel mold and its electroforming manufacturing process provided by this invention effectively address the problems existing in traditional molds during PDCPD material forming. It improves product quality and production efficiency, demonstrating good application prospects. Additionally, electroforming technology can be applied in many industries.
