October 2005 Issue

October 2005

No. 1 - Reciprocating-Screw Injection

A paradigm shift in injection molding machinery design began in the 1950s following the invention of the reciprocating screw.

Features

Featured articles from the October 2005 issue of Plastics Technology

1 Oct 2005

No. 42 - Underwater Pelletizing

When new plastics appeared, suppliers had to prepare them in a form handy for further processing.

Elastomers 1 Oct 2005

No. 20 - Thermoplastic Elastomers

The invention of materials that process like thermoplastics but imitate the properties and feel of crosslinked rubbers began in 1958-59 with the commercial introduction of thermoplastic polyurethane and styrenic block copolymers (SBCs). The attraction of simpler and faster processing plus the ability to reprocess scrap gained these materials a permanent market niche that has expanded enormously since.

1 Oct 2005

No. 12 - Parison Programming

The invention of the electronic parison programmer in 1958 helped to make extrusion blow molding a more efficient and productive plastics manufacturing process.

1 Oct 2005

No. 10 - Desiccant Dryers

Still considered the “gold standard” for drying hygroscopic resins—those that absorb atmospheric moisture—desiccant dryers first emerged in the late 1950s, when Carl Whitlock, founder of Application Engineering Corp. (AEC), developed the first regenerative dryer using silica gel as the desiccant.

1 Oct 2005

No. 28 - Multi-Material Injection

Injection molding of two or more materials or colors—or the same material in foam/solid or virgin/ regrind combinations—offers a wide range of opportunities to use materials more cost-effectively and/or combine materials for optimum functionality without the added cost of secondary assembly operations.

Automation 1 Oct 2005

No. 22 - Takeout Robots

Automated part takeout was said to originate in Japan in 1967 with Sailor Pen Co., one of the first manufacturers in the region to use injection molding presses.

1 Oct 2005

No. 48 - Film/Sheet Thickness Sensors

Film gauge control was of limited effectiveness before there was a means of online thickness measurement.

1 Oct 2005

No. 18 - Carbon Fiber

The pioneering efforts of Union Carbide scientists Roger Bacon and Leonard Singer led to the development of carbon fiber in 1963.

1 Oct 2005

No. 17 - Melt Indexers

The melt indexer originated with ICI in England as an adjunct to its work on developing LDPE in the 1940s.

1 Oct 2005

No. 8 - Ultrasonic Welding

In the early 1960s, there were a limited number of techniques to join plastics components.

1 Oct 2005

No. 13 - Structural Foam

Until the mid-1960s, thermoplastic molding processes had no presence in large, flat, structural parts such as pallets or furniture that were then dominated by metal, wood, and thermoset fiberglass composites.

1 Oct 2005

No. 31 - Hals UV Stabilizers

Hindered amine light stabilizers (HALS) can be considered the most important development in light stabilization for many polymers.

1 Oct 2005

No. 19 - Injection Molding Simulation

Until the late 1970s, the two tools molders employed to optimize mold filling were trial and error.

1 Oct 2005

No. 32 - All-Electric Injection Presses

One of the most significant and highly publicized trends in injection molding of the last two decades has been toward all-servo-driven electric injection presses.

1 Oct 2005

No. 4 - Polycarbonate

The modern era of engineering thermoplastics was launched in 1953 when Dr.

1 Oct 2005

No. 36 - Cavity-Pressure Sensing

The collection of real-time data from inside the mold first occurred through cavity-pressure sensing and marks the origins of closed-loop injection machine control.

sustainability 1 Oct 2005

No. 49 - Density Separation Of Mixed Waste

Plastics recycling is a tough business, and it would not have advanced this far without a cost-effective, automated way to separate mixed waste into relatively pure fractions.

1 Oct 2005

No. 45 - Auto Gauge Control For Blown Film

Automatic gauge control for blown film is relatively recent.

1 Oct 2005

No. 7 - Sheet Molding Compound

Bayer AG in Germany was the first to develop a process to produce thermoset polyester sheet molding compound (SMC) during the early 1960s, while Owens Corning Fiberglas was instrumental in bringing the process to the U.S.

1 Oct 2005

No. 37 - Spray-Up Composites

What used to be known as FRP (fiber-reinforced plastic) spray-up came on the scene in the 1950s as a more efficient open-mold laminating system that required less time and labor than hand lay-up for making large composite parts.

dies 1 Oct 2005

No. 46 - Auto Gauge Control For Flat Dies

Automatic thickness control of slot dies for cast film and sheet began in the 1960s.

1 Oct 2005

No. 27 - Film/Sheet Coextrusion

U.S.

1 Oct 2005

No. 39 - PUR Thermal Insulation

Polyurethane rigid foam insulation for use in both the refrigeration and building/construction markets was in its infancy in 1955.

All Electric & Hybrid Machines 1 Oct 2005

Hybrid Prototyping Process Combines Casting and Machining

A new rapid-prototyping technique combines casting with CNC milling in a novel way to create prototype parts fas ter than conventional rapid prototyping approaches—and it all happens in one machine.

1 Oct 2005

No. 2 - Polypropylene

The invention of PP was nearly simultaneous in the U.S. and Europe.

1 Oct 2005

No. 23 - Pressure Forming

Thermoforming was re shaped when com panies like OMV Group in Italy and Brown Machine in Beaverton, Mich., developed positive-air-pressure thermoforming systems that gave parts improved detail and structural integrity along with an injection molded appearance.

1 Oct 2005

No. 24 - Rotary Thermoforming

The development of the rotary machine in the mid-1950s significantly increased production capabilities for U.S. thermoformers.

1 Oct 2005

No. 30 - Hindered Phenolic Antioxidants

Today we take it for granted that polymers can withstand high-speed processing at elevated temperatures and shear rates, and also can take exposure to heat on the job for extended periods without discoloring or embrittlement.

1 Oct 2005

No. 9 - Stretch-Blow Molding

Biaxial orientation makes plastic bottles clearer, stronger, lighter, and less permeable to moisture and gases.

1 Oct 2005

No. 15 - Accumulatorhead Blow Molding

evelopment of the first accumulator-head extrusion blow molder by Germany’s Kautex (later Krupp Kautex and then SIG Kautex) in 1963 enabled production of large industrial parts and storage containers with improved wall consistency, strength, and surface finish.

1 Oct 2005

No. 33 - Rotational Molding

Rotomolding is the simplest method of forming a closed, hollow part and the only cost-effective way to form very large hollow parts such as tanks holding thousands of gallons.

1 Oct 2005

No. 40 - RIM

Polyurethane reaction injection molding (RIM) technology, developed by Bayer AG in the late 1960s, has evolved into a range of rigid (“structural foam”) and elastomeric forms, as well as reinforced (RRIM) and structural (SRIM) composites.

1 Oct 2005

No. 41 - Foam Extrusion

Foam extrusion is a rare instance where the U.S. led the rest of the world in technology by at least a decade.

1 Oct 2005

No. 5 - Twin-Screw Extrusion

Twin-screw technology topped the experts’ lists as the most significant extrusion development of the past 50 years.

1 Oct 2005

No. 21 - Hot runners

Hot runners revolutionized the molding process by making part cooling the chief element dictating cycle time and not the sprue.

1 Oct 2005

No. 14 - Barrier Screws

Barrier screws were invented in 1959 as a way to increase throughput of single-screw extruders and to improve melt quality.

1 Oct 2005

No. 11 - ABS Resins

The addition of butadiene rubber as a third monomer to styrene-acrylonitrile resulted in development of a new range of widely used thermoplastics called ABS.

1 Oct 2005

No. 38 - Injection Blow Molding

While Plax Corp. and Owens-Illinois Glass Co. made significant contributions to the early development of injection blow molding, the process wasn’t of great commercial significance until the mid-1950s, when Wheaton Plastics Co. launched its first proprietary machine for high-volume production.

color 1 Oct 2005

No. 50 - Computerized Color Matching

Even 40 years ago, color matching depended on the trained eye and memory of an experienced technician.

Drying 1 Oct 2005

To Catch Trouble Early, Put Your Dryers on the Net

In the past, troubleshooting your resin dryer was a fairly straightforward procedure.

1 Oct 2005

No. 34 - Gas-Assist Molding

An estimated 15% to 20% of U.S. injection molders use gas assist to core out thick sections, reduce sinks and warpage, and mold larger parts at lower pressures.

1 Oct 2005

No. 3 - HDPE

The invention of the low-pressure process to make HDPE took place in both the U.S. and Europe at nearly the same time and centered around the development of types of catalysts that promoted ethylene polymerization at milder temperatures and pressures than were (and still are) used for LDPE.The first of these new catalysts was discovered in 1951 by Robert Banks and John Hogan at Phillips Petroleum (who were also pioneers in PP polymerization). In 1953, Prof.

1 Oct 2005

October 2005 Issue

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