Sumitomo (SHI) Demag plans to team up with several key partners at NPE2015 to “meet or beat” the world-record the company set for water bottle cap production in 2014. Exhibiting in NPE booth W-623, Sumitomo Demag will run an El-Exis SP 420 molding a 29/25 water bottle cap with tamper-evident band molded by mechanical slides.
The high-precision, 96-cavity hot-runner mold is being supplied by Plastisud (W-7550). The lightweight 1.3-gram HDPE caps are designed for still (non-carbonated) water. The mold was specially designed and built by Plastisud, France, to achieve consistent high-precision parts at an ultra- high-speed cycle while still using the conventional, proven method of part ejection utilizing clamp and ejector stroke.
For the demonstration: the water-cooled chiller will be supplied by Frigel North America (W-7991); the hot-runner temperature control will be supplied by SISE Plastics Control Systems (W-4053); and the mold dehumidification system will be supplied by Eisbär Trockentechnik GmbH (S-24138).
To verify the process stability and repeatability of the El-Exis SP, and to permit a 100%-check of all screw caps, the production unit will also be equipped with an IMDvista optical inspection system from IMD.
"There are a variety of challenges to molding this type of part with precision and repeatability at such a high speed,” said Mike Uhrain, technical sales manager – packaging. “At cycles this fast, it is difficult to consistently maintain the caps’ essential physical properties related to sealing function, opening/closing torque, tightness after drop test or temperature variation and prevention of over winding. For example, managing shear heat within the melt stream and fast decompression of the hot runner can both be difficult, plus a very fast ejector is required to ensure the caps fall properly from the mold. While the El-Exis SP is uniquely designed and equipped to handle all of these challenges, this speed can only be achieved if there is a perfect match between the mold and the machine. Mold engineering, as well as machine performance and precision, is key.”
Available in model sizes from 165 to 825 U.S. tons, the El-Exis SP is a “true hybrid,” combining: ultra-high-speed injection via hydraulic accumulator and servo-valve; an energy-efficient electric screw drive for maximum plasticizing capacity and parallel recovery; and a clamping unit with AC servo drive and hydrostatic transmission for fast, energy-efficient mold open/close.
“The original El-Exis machine was introduced 15 years ago, and the El- Exis SP of today is the result of continuing technological development and the ongoing exchange of ideas with leading global packaging companies over that time period,” Uhrain said. “This machine series continues to prove its standard-setting combination of speed, energy efficiency, precision and long-term reliability for closures and thin-wall packaging applications that require ultra-high-speed processing.”