New Zeiger Z3 Screw Tip Valve is Injection Molding Breakthrough by hcj



                  Injection Molding Screw Tip Assembly Performance
                          Depends on Selecting Correct Steels

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.

(View an RPM chart of Z4 screw tip valve steel options.)
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


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