Rotational molding: The challenges ahead

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In May 1995, Plastics Custom Research Services published a report covering the North American rotational molding business. Later that year, in August, Plastics News published the results of its inaugural survey of rotational molders based in the United States, Canada and Mexico.

PCRS has revisited this business roughly every three years, and Plastics News has produced its rotational molding rankings issue every year since 1995. These are the two most comprehensive sources of data and insights relating to the regional rotomolding business over the past 23 years.

At the end of 2018, PCRS released its eighth and final report, providing a review of the past and prescriptions for the future of this unique process. The long-term growth of aggregate sales revenue in this business has been impressive. Rotomolders have managed to penetrate every segment of the plastic structural plastic part marketplace — agriculture, automotive, building and construction, material handling, medical, toys and tanks — with its ability to produce structurally strong and aesthetically pleasing hollow and semihollow parts.

In this new report, PCRS throws a candid and compelling spotlight on issues regional rotomolders need to confront going forward. The first issue is the recent slowdown in aggregate sales. From 1995 through 2013, the average annual growth rate was 5.2 percent; that rate ratcheted down to 3.1 percent from 2014 through 2018. This was reflective to some extent of the weak, "new normal" U.S. economic growth rate of the post-recession years.

The second issue addressed is productivity. Sales per employee grew fairly consistently from 1995 through 2008, but then in the wake of the Great Recession, the trend in this measure of productivity flattened and actually declined to 2017. Sales per machine occasionally dipped, but the trend of this metric over the past 23 years has generally been "uphill" (3.7 percent on average).

The recent weakening of sales per employee is noteworthy since rotational molding is a much more labor-intensive process compared to injection molding, industrial blow molding and industrial thermoforming. In fact, the labor/capital ratio (i.e., the average number of employees per machine) in regional rotomolding has been rising — this at the same time robotics and other forms of labor-saving automation are spurring the productive efficiency of alternative plastic structural part processing methods.

The third issue is one rotomolders around the world have struggled with for a long time, and that is their reliance on various grades of polyethylene; in the North American market, this resin accounts for over 90 percent of part output. The original resin of choice, vinyl plastisol, holds a minor share of the market today, and some of the more enterprising companies have mastered the art of processing nylon, polycarbonate, and a few other engineering resins. However, the rotomolders have yet to add ABS to their material menu, and they have been ambivalent in their commitment to polypropylene — a resin that vastly improved the market reach of injection molders and industrial thermoformers.

Ultimately, the issue the regional rotomolding community has to face is the need for new blood. On the one hand, the number of new entrants into the regional rotomolder ranks has tapered off since the turn of the century. On the other hand, rotomolders have perennially found it challenging to attract new plant operatives and retain existing plant operatives. It all goes back to the need to make the process more productive and the work environment more appealing. Solving this issue would help restore the former pace of growth and development of the regional rotomolding business.

Peter Mooney​ is president of Plastics Custom Research Services in Advance, N.C.

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