How to CNC machine a mold for hydroforming
Molds for deforming sheet metal by hydro-forming
Hoogovens Packaging Steel (after the merge with British Steel part of Corus, now Tata Steel Europe) are actively promoting the use of steel for packaging purposes. One of the developments is the shaped can: a can that has no longer just a cylinder shape, but a freeform shape instead. Hoogovens mentions the following advantages:"With infinite choice of products and an overload of commercials in the media, consumers are increasingly letting their decisions whether or not to buy a certain product depend on its packaging. They look for quality, convenience of use and transportation, a good environmental perception and, last but not least, attractiveness.
This is why shaped cans are the future in the packaging for food, beverages and products for personal care: they combine the traditional convenience and environmental attractiveness of cans with quality image and attractive styling, of both overall shape and surface aspects such as embossing, texturing and decoration."
Hoogovens started shaping cans in 1996 with the glass-shaped beer can shown below. This great looking can was immediately selected by the Dutch packaging industry as "can of the year".
The Hoogovens beer glass CAN and a few even more freeform shapes
Obviously for the manufacturing of these shaped cans a mold is needed. For these prototypes molds have been used machined in a special quality Cibatool (Renshape), on a desktop milling machine using DeskProto. Using these tools it was very easy to convert the Pro Engineer design into a set of two tool-halves, and within a few days the first series of prototype cans were ready. See the illustrations below, showing the milling of a tool-half.
Machining of one tool-half.
The actual production process uses water pressure from the inside, which is a type of hydro-forming.