Timing of a major trade show is like the weather: Everybody talks about it, but can't do anything about it. Each show fits into the broader economy. Psychology and expectations have a major impact, too.

Take K 2010, which just ended on a high note, coming on an upward economic curve, and NPE 2009, held in the slog of the Great Recession.

K 2010, the huge, eight-day show that just ended in Germany, came at the best possible time, as the global plastics industry rebounds from the grueling recession. The mood at the show was upbeat and optimistic, looking to the future. The show drew more than 220,000 visitors. That number's down by about 9 percent from the last K show, in 2007 — not bad, considering the industry and global economy were booming back then.

In 2007, many machinery executives reported shortages of basic components such as castings and motors. How great it was.

Then the bottom fell out in late 2008. Fear of a global financial collapse brought capital spending, investment in new plants and new product development — the life-blood of any international trade show — grinding to a halt. NPE 2009 got hit hard. The show's organizer, the Society of the Plastics Industry Inc., reported 44,000 registrations, down 28 percent from the previous NPE, in 2006. Holding NPE 2009 at all was a moral victory.

K 2010 came on an upward swing. Plastics industry leaders said business has come back sharply. “K 2010 took place at the right point in time and has provided all areas of our industry with new impetus,” said Ulrich Reifenhäuser, chairman of the K 2010 Exhibitor Council and chairman of VDMA, the German Plastics and Rubber Machinery Association.

At K, machinery makers said lead times are extending. Some even talked about potential shortages of components — if the steep demand growth continues well into 2011. Of course, some parts of the world never really slowed down. Chinaplas 2010, held in April in Shanghai, drew 81,435 people, posting a 17.5 percent jump from the 2009 show. And that came in the midst of a volcanic ash cloud that cut back visitors from Europe!

So now the talk in trade-show circles turns to NPE 2012. SPI has moved the show to Orlando, Fla., leaving its longtime home of Chicago. It's a major step that brings a new set of questions, chiefly: Will all those people from plastics processing in the powerhouse Midwest who used to drive to Chicago now fly down to Florida for a trade show? We won't know for sure until 2012. But one thing is clear: The economy is the biggest question.

 The number of K 2010 visitors from the United States and Canada held steady at about 6,800, about the same as the figure from K 2007. On the exhibitor side, 112 U.S. companies showed their products this year, 49 of them at two special U.S. pavilions.