As we enter the year 2100, this magazine will be 145 years old next month. I’ve been reviewing century-old issues to rediscover the trends and issues that were “hot” back in the days when metallocenes were the new thing in polymer synthesis and hydraulics still powered molding machines.

As we enter the year 2100, this magazine will be 145 years old next month. I’ve been reviewing century-old issues to rediscover the trends and issues that were “hot” back in the days when metallocenes were the new thing in polymer synthesis and hydraulics still powered molding machines.

I read an editorial from back then that mused about what injection molding was like in the days before reciprocating screws. Ironic, isn’t it? How many of you can remember when screws were used for more than specialty applications? People used to care so little about where energy came from or where it went. You probably learned in engineering school how plastics processing used to be a series of cycles of heating and cooling, melting and solidifying—first to make a pellet, then a shape, and if that shape was sheet, then one more time to form a part. Of course, that was before the Seattle Thermodynamic Directive of ’49 helped outlaw such absurd waste. I found a cover story from around that time, entitled “Back to the Plunger.” It celebrated the growing use of low-molecular-weight oligomers that flow like water until they are catalyzed in the mold to form full-fledged polymers.

Those back issues reveal a revolution in manufacturing—away from “re-shaping” technologies toward “shape-once” methodologies. Why use a mold when you can build up a shape from nothing via laser sintering or uv polymerization? But until the right materials became available, such techniques were used only for prototypes. In tool making, additive (sintering) technologies replaced subtractive (machining) methods in just a couple of decades. Can you imagine the waste involved in forming a slab of steel and then digging away most of it to make a hollow cavity?

In the next issue, I’ll tell you about the days before chemcycling, when they “re-cycled” plastics by sorting them by hand, chopping them with knives, and washing them—with soap and water!