Canton, Ohio (June 29, 2009) - Choosing the right steel for plastics
injection molding valves requires great experience and understanding of the issues and conditions with which injection molders deal daily.
Injection molding valve innovator Don Zeiger is a steel knowledge storehouse. President of Zeiger Industries, the leader in top performance screw-tip valves, Zeiger is the force behind the innovative Zeiger Z3 screw tip injection molding valve , a better-performing, more affordable
3-piece screw tip assembly for general applications.
Zeiger knows the right steels to select so a three-piece screw tip valve offers longer injection molding valve life, fewer breakdowns and better value. His advice helps plastic injection molders choose the best screw tip assembly for their jobs.
"Corrosion, abrasion, and heat on the wear surfaces of
front end parts create problems," he said. "Injection molders should specify wear parts steel with 60RC (Rockwell) minimum hardness to resist wear."
Zeiger advises avoiding nitrided steels, which are only coated on the outside, falsely raising the Rockwell rating. "Nitriding reduces corrosion resistance and polymers like ABS, nylon and PVC create corrosive byproducts," he said.
Zeiger said plastic injection molders working in low speed, moderately corrosive conditions gain performance and cost-savings with
screw tip valves made of D2 tool steel hardened to 60RC. His three-piece Z3TM is made with D2.
For high-speed, a four-piece
injection molding screw tip like the
Zeiger Z4 is required. Zeiger said the right steel is critical for high-speed processes. Molybdenum-based steel at 62 or 64RC is best for high speed, moderately corrosive conditions. Solid carbide-faced wear parts, warranted for life in the Z4TM, are excellent for ultra high speed, abrasive conditions.
Medical molding requires a four-piece screw tip assembly made with 440C or S90V stainless at 60RC. They perform well with corrosive polymers. Hastelloy and Inconel are best for ultra corrosive conditions.
Heat is a big factor. Zeiger tested front-seat and check rings, determining that unless screw tip assembly steel exhibits "red hardness" - meaning Rockwell is not diminished in red-hot heat - the application is not acceptable for rotating contact components.
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Zeiger Industries, inventor and
manufacturer of Zeiger Z4 and Zeiger Z3 screw tip valves, is known in the injection molding industry for top performance and quality. The Zeiger Z4 is the polymer industry's only screw-tip assembly that comes with a lifetime warranty.
Media Contact:
Jack Wollitz
330-492-5500