Material and equipment companies partnered at NPE 2015 to mold Make-A-Wish wrist bands from liquid silicone rubber.
The bracelets were offered to NPE attendees for a small donation to the Make-A-Wish Foundation's North Central chapter. The organization fulfills the wishes of children with life-threatening medical conditions.
The NPE partners gave more details about the technologies involved in making the wrist bands.
Boy Machines Inc. of Exton, Pa., molded the bands at its booth, on a Boy injection press with 27.5 tons of clamping force. The press was specially configured to mold the LSR parts.
Shin-Etsu Silicones of America Inc. supplied the material, KEG-2000 LIMS (liquid injection molding system). The two components, mixed in a one-to-one ratio, give higher viscosity under low shear stress during pumping and shutoff, and lower viscosity under the high shear stress of injection. That gives faster mold filling with minimal flash, according to Akron, Ohio-based Shin-Etsu Silicones.
GDSI, based in Barberton, Ohio, provided the silicone color dispersions.
Thermal Care Inc. of Niles, Ill., supplied the chiller.
Graco Inc. of Minneapolis premiered its Fluid Automation F4-5 two-component silicone pumping system on the bracelet project. The technology replaced two previous systems. Graco said it offers better ratio control for mixing two-component LSR and two-additive color streams at ratios of 0.5 to 5 percent. According to the company, the dosing system provides seven times the measurement resolution of the previous models.
The cold-runner mold came from Kipe Molds of Placentia, Calif. Kipe also premiered its MD 125 Micro Injection Unit system, featuring a patented Microdeck technology. That system has offered highly repeatable automatic molding for parts as small as 0.003 grams, according to Kipe. It also features a servo-actuated micro plunger with fully controllable injection parameters—which eliminates the need for runners the same size as the micromolded silicone parts.
The injection unit can be used as a second barrel, for molding two-component parts.
A robot from Yushin America Inc. of Cranston, R.I., removed the wrist bands from the mold.