Earplug Scrap/Tear Issue Hears of Silicone Solution
Leading retail earplug manufacturer McKeon Products Inc. recently embarked on progressing its advanced earplug line. McKeon President/CEO Devin Benner commissioned technically advanced, multinational liquid-silicone parts molder Silcotech North America Inc. to lead the engineered production and product performance manufacturing challenges.
The key production issue stemmed from the fact that the product was a thin wall section membrane material which needed higher tear strength as the de-molding process generated high levels of scrap due to tearing. After prototyping five different molds, an automatic 16-cavity slide tool was chosen with thin wall sections for sealing flanges and thick wall sections for handle areas (small: 0.25 mil / thick: 5.0 mil).
Ultimately, the parts’ geometry and cavity had significant undercutstherefore, the loads on the material were high in part removal with parts breaking and remaining in the cavity which hindered the overall cycle time. Faced with the expensive option (70-100K) of again redesigning the tool to eliminate the undercut, Silcotech opted to seek out a superior material that had the sufficient mechanical strength properties to handle the part.
Silcotech NA President Michael Maloney contacted Shin-Etsu Silicones of America, Inc. to test its new KE2004-20 Series silicones which were stated to have the highest tear strength on the market. Additionally, relative to their low hardness and high tear strength, the KE2004-20 Series viscosity values also translated to physical property and processing advantagesincluding outstanding release properties which allowed for de-molding parts, particularly those with thin wall thicknesses, without tearing and creating scrap.
Shin-Etsu promptly sent Silcotech some test pails to run with the tool. According to Maloney, “In the final analysis, we needed a higher tear strength material and Shin-Etsu’s KE Series reduced our cycle time by more than one-half (60%) . . . it was a night and day difference.”