Johnson, who has been in the plastics industry for more than half a century, is retiring from his senior vice president of technical consulting role at Processing Technologies International (PTi) and reflected on his time in the industry, covering major innovations to key trends.
He cited PTI’s installation of its unique “dryer-less” twin-screw sheet extrusion production system in late 2011, as one example.
The firm was also awarded a US patent for its ratchet-activated height adjustment device which raises and lowers the cooling and polishing rolls relative to the sheet die exit for sheet performance in September 2012.
Another example was its manual roll gap adjustment device which features an integral ratchet positioning arm and can be operated up to full line pressure of 600 to 800lb per linear inch (pli).
Electronics development
The biggest innovation has been electronics but he cited screw design improvements and faster outputs as other developments.
“When I started analogue instruments were the norm, now everything has shrunk in size and all the programmable logic controllers (PLC) are now touch screen – the old analogue systems have been phased out in old plants, there are still some left but they are numbered.
“The key trend is more data and quicker troubleshooting makes it more scientific.
“Basic extruder outputs have grown two and threefold and there have been a lot of screw design improvements including square-cut screws and the mixing screw which led to 30% more output.”
Material use
Polyester is king in sheet extrusion applications because it is easier to recycle, added Johnson, but more polypropylene (PP) is being used as there has been a push for recyclable materials.
“The price of polypropylene has increased over the last two years and HDPE (high density polyethylene) has become a big player in sheet extrusion.”
He said companies, such as Walmart, are showing an interest in polylactic acid (PLA) as it won’t sit in landfill as long but drawbacks include its lack of compatibility with polyester in terms of temperature and degradation qualities.
He called for the industry to do a better job promoting the recyclability of plastic and the regrind so people understand and legislation does not come to “scary” measures such as plastic bag bans.
Half a century
The 51-year career spanned PTi, EDI, Davis-Standard, Reifenhauser USA, Johnson Plastics Machinery and for Rexall Chemical.
He was also the recipient of the Society of Plastics Engineers’ (SPE) Jack Barney Award in recognition of his major contributions to the plastic sheet industry in 2007.
Johnson started with Rexall Chemical in 1962 where he ran the blown film equipment, sheet equipment and described his first job in the plastics industry as a “great training ground” with testing on equipment due to the broad experiences.
He moved onto Johnson Plastics Machinery, which he described as the leading sheet extruder at the time, and his work as vice president of marketing and engineering involved dies and equations for analysing die flow.
He described the job for Reifenhauser USA as a “broad brush” of experiences working in the film and sheet markets alongside German technology.
Johnson also worked for Davis-Standard where he was involved in turning a fairly small sheet business into the number one or two in terms of volume in the US.
PTi role
However, he said the call from PTi in 2004 allowed him to get back into his “true love” – machinery.
Johnson said around 80% of PTi’s market was packaging-based with food packaging taking up a fair chunk due to the desire to find better packaging solutions.
Johnson will still be a part-time consultant for the firm several days a week.
“I am looking forward to more free time with the family and I may even improve at golf,” he concluded.