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can handle up to 26 cars. Between the two plants, Impact Plastics employs about 100 people; approximately 60 are involved in manu- facturing. Each manufacturing facility is equipped to handle both custom and proprietary applications. Companywide, operators typi- cally focus on specific lines, though they are cross-trained so they can work on any setup. Products currently range from 8 to 250 mils, with the majority of the business focused on 10-90 mil roll stock. Eight of the nine sheet lines were furnished by Gloucester Engineering (now part of Davis-Standard, Pawcatuck, Conn.). NEW PUSH TO PP The newest line was installed in the fall of 2016. Furnished by Graham Engineering Corp., York, Pa., this single-layer Welex line is significant for a number of reasons, notably that it aims to support Impact Plastics' focus on high-value PP sheet. "Our company's early growth was built on selling PS into various thin-gauge packaging markets, but within the last five years we have directed much of our mar- keting and development efforts towards polyolefins, with a focus on polypropylene," states MacVarish. Interestingly, around this same time, Impact Plastics began to ramp up its investments in R&D; related to its customers' application demands. Among sheet extruders—particularly those serving pack- aging—it might be considered unusual not to have APET capacity. But at Impact Plastics, that's by design. Burke explains the philosophy: "We made a decision about six years ago that we could not create value in the marketplace providing PET sheet. We asked ourselves, 'What would we add?' We answered, 'Not a lot.' While we are a custom extruder, we don't try to be every- thing to everyone. We made the determina- tion that PET was commoditized, and that a better path for us was to focus on high- value niche applications like thin-gauge PP." As Burke explains, PP offers a significant density reduction over PS and PET. In ther- moforming, this lower density often trans- lates to a higher yield and a lighter part for the customer. In addition, there's a gap in the market for high-clarity, microwavable food packaging, and the thermal characteristics and high heat resistance of polypropylene make it an ideal material. Impact Plastics produces a range of PP sheet for packaging, including high-clarity sheet utilizing NX UltraClear PP additive from Milliken Chemical, Spartanburg, S.C., as well as calcium carbonate-filled and talc-filled PP sheet. Additionally, the new Welex line, engineered specifically for PP, is being utilized for an undisclosed medical-device applica- tion where even the slightest variation in thickness can result in a critical misdiagnosis. The product was developed jointly by the medical OEM and the thermoformer, which, having worked with Impact Plastics on other projects, turned to the sheet processor specifically to develop a 15-mil product where gauge control is critical to the success of the application. The gauge tolerance to meet the requirements of the application is ± 0.33 mil (or 0.00033 in.), with an acceptable gauge range of 0.01470–0.01530 in. With the help of the new Welex line, Impact has been able to successfully hold the gauge tolerance to ± 0.25 mil (or 0.00025 in.) generating a yield of 98%. "We've always prided ourselves in maintaining tight gauge control," says Burke. "We are always in pursuit of the perfect gauge. But running so thin at high rates is not easy." The Welex Evolution line was delivered on Labor Day 2016. Line components include a 130-mm extruder, XSL Navigator inte- grated controls, Cloeren die, specialized hydraulic roll stack with auxiliary cooling rolls and a jumbo winding system. While automatic gauge-control dies are fairly common tech- nology in sheet extrusion, Impact Plastics opted for a manually "We made the determination that PET was commoditized, and that a better path for us was to focus on high-value niche applications—namely, thin-gauge PP." Auto dies for sheet are common, but Impact Plastics prefers manually adjusted dies to give operators true control over the process. 48 JANUARY 2018 Plastics Technology PTonline.com Impact Plastics On-Site