Search

The article discusses the success of the carbide cutting tools which was invented by trade machinist Jack Newberry and remained the secret of coating technologies specialist Micro 100 which combines the counteractive hardness and toughness of a tool. Topics mentioned include the cobalt binder prevents the penetration of vibration and heat, the characteristic of having transverse rupture strength (TRS), and the comment of regional sales Charlie Mersinas on its savings and benefit to tool life.

The article discusses the importance of drying hygroscopic resins to prevent possible loss of essential performance properties of polymers. It offers tips on how to determine the dryness of a resin before processing. It also provides information on resins that do not need drying and some polymers that are not susceptible to hydrolysis but may need drying.

The article discusses the emerging 5-layer polyolefin-dedicated (POD) blown film as a technology for non-barrier applications. The technology's specific formulation is intended to provide balanced in-use performance with maximum film extrusion output, outstanding optical properties for high-impact retail display and substantial downgauging potential. It notes that film processors can easily combine high throughput with outstanding film performance with the 5-layer POD coextrusion technology.

The article focuses on attaining uniform and balanced flow of material to each cavity in multi-cavity molding. It notes that minor temperature changes from one zone to another can create imbalances in filling within a matter of minutes. It explains the sources of changes in the hot-runner temperature.

The article discusses the die design procedure where the internal die configuration is molded to deliver polymer from entrance to the exit with the same pressure drop to have a balanced flow. It notes that changing the output can unbalance die flow and lead to a complicated analysis that can be simplified by assuming the process in the die is isothermal. It indicates that a die that cannot be thermally adjusted means the heating is not designed properly or the die is not suited to the polymer.

The article discusses how overfeeding can cause surges in the extrusion process of plastics. According to the author, the feed rate can exceed the melting capacity of the screw and create plugging in the melting section. The author notes that the melting rate is controlled by the shear stress in the film near the barrel wall, barrel temperature, the thermal and viscous properties of the polymer, and the design of the screw.

The article focuses on the effect of thermal properties of polymers on extrusion. Among the key polymer properties include specific heat, solid and melt density or their specific weights, and thermal conductivity. Data from a rheometer is needed in determining viscosity ranges of materials. Comparing polymers by their typical extrusion processing temperatures and estimating the relative power needed to process various polymers are explained.