Thin to Thick Wall: Molder’s Misery part 2

Now let’s reverse the situation for mixed wall thickness as discussed in tip 183. We often see this situation in such parts as idler wheels, gears, impellers and so on. These parts have a thick outer rim with an inner “web” that has been made thin to save weight and...

Thick and Thin Wall: The Molder’s Misery

Many of our readers have read or been taught how important it is to design parts with constant wall thickness. I asked some of our consulting team, “When did you last see such a part?” Apparently they are becoming rare. We are now fining many more parts...

Stored Energy in Thin-Wall Filling

When pressing wine grapes with a bladder press, why do we pressurize it with water instead of air? If you were standing near the press when it burst, which would you rather have in it? 120 gallons of compressed air or water? I would go for the water. Why? Stored...

Thin Wall Molding: The Time Barrier

If you saw the film “The Right Stuff,” you may remember their concept of the “demon that lived out beyond mach 1.”† In thin-wall molding it may help to think of that “demon” as TIME. Time to freeze during fill or shortly after during pack.Parts made for packaging are...

Valve Gates and Thick Semi-Crystalline Parts

“You can’t use cavity pressure control of valve gates in semi-crystalline materials.”Or so I was told.I received this advice at NPE 2006. We were running Winzeler Gear’s “Gear Gizmo” mold. This had independent valve gate control in a family tool running Delrin. And we...