CAD, modular molds, hot runners featured at Mold Expo.

New tooling materials, mold components, and design software that promise to trim lead times were a key theme at the second Mold Expo, held in September in Detroit. Among the highlights were a modular mold-building technique said to cut lead times for molds in half, and an easy-cleaning filter nozzle for hot-runner systems that purges in minutes. New developments in CAD software may cut valuable time in mold design and machining.

CAD SOFTWARE

A new Unix-based manufacturing-analysis software package from Cimlinc Inc.'s Advanced Manufacturing Technology unit, Troy, Mich., helps analyze CAD models for errors before machining begins. The AMT Design Analyst has been integrated with AMT's family of Tool Maker and Tool Designer software for mold design and machining. Design Analyst is said to quickly check the quality of surface geometry and translates the data into color-shaded representations that are easy to understand. Complex parts, even auto bumpers and instrument panels, reportedly can be checked in seconds for unmachinable undercut surfaces, programming errors that cause rippled surfaces, and improper draft angles. For example, the software can quickly color shade a model to identify obvious errors such as missing or untrimmed surfaces. Curvature analysis can evaluate surfaces for "saddle points" and directional flatness. Minimum draft analysis highlights areas on the model that have zero or negative draft. Similarly, minimum radius analysis highlights any areas of radius less than a specified value. And highlight analysis simulates shining studio fluorescent lights on a model to show up minute inflections and perturbations in the design surfaces. The software package starts at $2500.

A new surface modeling software package from Control Data Systems, Arden Hills, Minn., is said to eliminate many of the steps associated with traditional CAD surface modeling, helping to create surface designs faster and more accurately. The key to ICEM Surf software is that it allows designers to take raw data, organize it directly, and immediately begin to create and manipulate surfaces. The package bypasses intermediate steps such as digitizing point data from models and modifying the curve meshes.

MODULAR MOLD BUILDING

A new "modular" mold manufacturing process, developed by Advance Mold & Manufacturing, South Windsor, Conn., is said to reduce mold lead times by half. The system achieves lead-time savings by maximizing the use of standardized, pre-manufactured frames and components. According to company president Gerald Ludwig, the only limitation is that molded parts must fit within a pre-determined size--presently cavity blanks are available from 2 to 5 in., which Ludwig claims can accommodate about 75% of current applications for small parts. Typical lead-time savings range from 90% for preliminary layout discussions to 20% for fitting and assembling cavities, for a total estimated delivery time reduction of 50% over traditional mold-making methods. A series of 10 mold frames is available in two-plate, three-plate, and double-cam versions, with cavity blanks to accommodate one to 32 cavities. Max. molded part size currently ranges up to 4.25 in. diam. x 1.5 in. thick.

EASY-CLEAN FILTER NOZZLE

A new Reverse Flow filter nozzle designed for quick purging has been developed by hot-runner systems supplier Ewikon N.A., Schaumburg, Ill. Unlike conventional nozzles, this one does not have to be removed from the machine, and purging reportedly takes place in less than 5 minutes without the need to disconnect electrics. The nozzle contains a series of heavy steel disks inside its housing that filter particles down to 0.3 mm (0.1 mm filtration is available for easy-flow materials). During injection, melt flows from the center of the nozzle, through the filter disks, which trap impurities, to an outer annular flow channel, which leads to the nozzle tip. Purging involves retracting the injector carriage, inserting a "reversed-flow plunger" unit into the end of the nozzle, and then moving the carriage forward against the sprue bushing. This causes the plunger to push against a "changeover shaft" in the center of the nozzle, sliding back the shaft and engaging a new set of flow channels at the entrance to the nozzle. This reverses the flow path, sending melt first through the outer annular channel and then through the filter disks to the central nozzle channel, forcing contaminants from the disks and out the nozzle.

TOOLING

Two nozzle sizes are available: one for injection machines above 100 tons, another for below 100 tons. The nozzle is said to experience a lower pressure drop than other filter nozzles, and uses a 220-volt heater band driven by a standard industrial temperature controller. Price of a nozzle is approx. $2400.

OTHER HOT-RUNNER NEWS

In other news, Ewikon is offering its HPS hot-runner tips in multi-tip configurations. The company has supplied up to 12 tips in one 50-mm diameter nozzle, using one zone of temperature control.

Mold-Masters Ltd., Georgetown, Ont., is experimenting with new bimetallic hot-runner probe tips, consisting of a copper-alloy insert and titanium seal, for improved melt uniformity and better thermal separation.

A.L.B.A. Enterprises, Inc., Torrance, Calif., says that Enrietti's type D2D hot-runner nozzle, originally developed for quick color changes, is now being used also with semirigid PVC. The nozzle has a central core that shuts off on the cavity, and has no areas in which material may hang up and degrade. In other developments, Enrietti is machining its manifolds in two halves, which reportedly allows runners to be fabricated in smoothly curved channels, and is using Calrod heaters to provide uniform heat transfer.

For filling large parts, the series 1250 valve gate from Husky Injection Molding Systems, Bolton, Ont., offers gates up to 0.276 in. wide and melt channels of up to 0.630 in. The 1250 series, which complements Husky's 750 series, is available in nine different gating styles and two nozzle types: the VX nozzle for crystalline resins delivers heat to the gate area; and the VG nozzle for amorphous materials has a replaceable hardened-steel nozzle tip insulated from the surrounding cavity.

MORE MOLD COMPONENTS

D-M-E Co., Madison Heights, Mich., and D&L Progressive Components, Wauconda, Ill., have signed a distribution agreement to market D&L's Uni-Lifter undercut-releasing system for injection molds (see PT, May '91, p. 43). Both companies will market the system in North America, while D-M-E will be the exclusive source abroad. D&L also is expanding its Uni-Lifter line with smaller and larger sizes, and is adding to its lines of self-lubricated bushings, side locks, and side guides.

New lines of core-pin blanks and through-hardened ejector pins have been introduced by Royal Diversified Products, Warren, R.I. RQ-series core-pin blanks are fabricated from M-2 steel and heat treated to Rc 60-63 hardness. Featuring 60 |degrees~ head (RQA) and shoulder (RQB) types, they come in 0.001-in. diameter increments from 0.010 in. to 0.505 in. and lengths up to 8 in. The ejector pins, also made of M-2 steel, are available off-the-shelf in straight and 0.5-in. or 2-in. shoulder types within a tolerance of 0.0003 in. Non-standard decimal diameters and special shoulder lengths up to 4 in. are shipped in three to five working days.

NEW MOLD MATERIALS

A new grade of aluminum mold plate, CSM 7000 from Reynolds Aluminum, is being marketed by Crucible Service Centers, Camillus, N.Y. CSM 7000 is said to provide good dimensional stability to ensure close mold tolerances, as well as excellent surface quality. It also boasts good weldability and can be easily reworked. Also, Crucible has a new highly wear-resistant tool steel, CPM 15V derived from powder metallurgy, in addition to its current CPM 10V steel.

International Mold Steel, Erlanger, Ky., is marketing a relatively new chrome-moly PX5 steel grade that welds without pre- or post-heating. PX5 has a composition that suppresses cracks that commonly occur during welding. It also has a very uniform microstructure from surface to core that speeds machining (up to 30% faster than P20) and polishing, the company claims. It also has greater toughness than typical chrome-moly steels.