Bending Metal With Plastic: The Polyurethane Forming Die

The latest addition to our arsenal of press brake tooling is something a little different – a polyurethane forming die. It consists of a steel channel with a specially shaped piece of polyurethane inside. Watch the video below to see it in action bending 5mm steel with a 100mm radius punch.

There are a wide range of polyurethanes for different applications. The type used for press tooling like this would be an elastomeric variety which means it has elastic properties; this is why it returns to its original shape after pressing. You might notice in the video above that the punch is retracted relatively slowly – we intentionally configured the press to decompress slowly over a certain distance rather than just removing the pressure immediately. This is to avoid the ram being forcefully pushed back up when the polyurethane returns to it’s original shape.

You might be wondering why we’d use such a tool instead of a traditional steel die. The main reason is the flexibility it gives us when performing larger radius bends. We can use a single die to form a large range of radii by only changing the punch. The radius shown in the video above is 100mm and there’s plenty of room to go larger. Another benefit of the plastic die is the mark-free bends it produces. The relatively soft material and large contact area with the part means that there are no visible die marks on the outside of the bend. This is particularly helpful with aluminium or stainless parts where the aesthetics are important.

If you have any questions about our folding capabilities or would like us to quote on your next project, please don’t hesitate to get in touch.