A method for producing a multiplicity of fastener element molding cavities extending from a mold surface, for molding a plastic product having fastener elements integrally molded with and extending from a product base, and a mold so produced. The mold cavities are formed by depositing multiple layers of plating material on a workpiece in a predetermined pattern selected to produce a desired mold cavity shape, or by depositing a thick stratum of plating material over an array of fastener elements and then removing the fastener elements to leave shaped cavities within the plating material. The mold may be in the form of a roll or belt for continuous processing, or in any form for discrete injection molding. Molds having fastener element cavities defined by rigid cast materials are also disclosed.
This application is a continuation-in-part of U.S. Ser. No. 08/997,966, filed Dec. 24, 1997, now U.S. Pat. No. 6,099,289, which is a continuation-in-part of U.S. Ser. No. 08/920,188, filed Aug. 25, 1997.
A mold used to form a magnetic member includes a mold body having a mold opening, a mold support that supports the mold cavity, and a mold insert. The mold insert is disposed in the mold opening of the mold body to form a mold cavity. The mold insert is coated with a coating to protect the mold body from chemical attack and abrasive wear of the mold material. The coating comprises an electroless nickel layer formed on or over the mold insert, and a chromium nitride layer formed on or over the electroless nickel layer. The mold insert can be formed of beryllium-copper (Be--Cu).
A mold used to form a magnetic member includes a mold body having a mold opening, a mold support that supports the mold cavity, and a mold insert. The mold insert is disposed in the mold opening of the mold body to form a mold cavity. The mold insert is coated with a coating to protect the mold body from chemical attack and abrasive wear of the mold material. The coating comprises an electroless nickel layer formed on or over the mold insert, and a chromium nitride layer formed on or over the electroless nickel layer. The mold insert can be formed of beryllium-copper (Be--Cu).
Methods of rapidly prototyping microstructures such as HARMs are disclosed. A high precision process uses polymeric microstructure replication techniques and sacrificial layer etching techniques to mass produce high aspect ratio metallic and polymer micromold inserts. In one embodiment, after fabrication of an initial micromold insert, high aspect ratio replications are created by casting replication material, such as PDMS, directly onto the initial micromold insert. The replicated HARM is coated with a sacrificial layer and then electroplated to replicate another set of micromold inserts. After the electroplating process is completed, the sacrificial layer is etched away to release the replicated micromold inserts.
The invention relates to fastener molding. In one aspect, a molding apparatus for forming a sheet-form fastener product includes a first ring defining a plurality of voids extending inwardly from a circumferential surface of the ring. The voids are circumferentially spaced apart from one another by portions of the ring including recessed regions that partially define molding cavities. The molding apparatus also includes multiple plug members configured to be disposed within the voids. The plug members and the portions of the ring therebetween cooperate to define the molding cavities when the plug members are disposed within the voids. The molding cavities are shaped to mold, from molten resin forced into the molding cavities from a peripheral surface of the molding apparatus, an array of fastener elements having overhanging heads for releasable engagement with a mating fastener product.
An easy-to-grip diaper fastener tab has an array of hook-shaped fastener elements arranged in parallel rows, each fastener element including a stem and a crook extending from the stem in a predetermined direction to a distal tip. The array includes a plurality of rows of fastener elements arranged such that, in each row, all of the crooks face in the same direction and parallel to the direction of the row, with the crooks of adjacent rows facing in opposite directions. The longitudinal spacing between opposing tips of adjacent hooks of adjacent rows is greater in a first portion of the array than the longitudinal spacing between opposing tips of adjacent hooks of adjacent rows in a second portion of the array, such that the crooks of the hooks of the first portion are more exposed for engaging loops than the crooks of the hooks of the second portion. Methods and molds for forming such arrays are also provided.
