The glass bending
©Holger Jahns Produktentwicklung

C--C ELEMENTS by Holger Jahns Produktentwicklung

Holger Jahns was confronted with quite a challenge: The Berlin based Industrial Designer was invited to showcase c--c, his concept for an innovative architectural glass at trade fairs such as the Glasstec in Düsseldorf and BAU2015 in Munich. For the presentation at such events 1: 1 exhibits of the design are an obvious demand. Visitors simply need to touch and understand the dimensions of the product. Thus far however all that was available were drawings, digital renderings and 3D printed miniatures of the Design.

Posted 7 September 2015

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Hence a feverish search for a partner, who takes care of the production of prototypes began.
For the sake of limiting the expenditure – different from the industrial approach – elements should not get formed as endless strands from liquid glass, but rather get bent to shape from sheets of float glass.
A large number of suppliers was asked for a quote: Industrial glass producers and glass works, smaller
specialist vendors, as well as individual glass artists. None of them placed a bid for this work. After weeks of fruitless search, the Designer eventually decided to create the prototypes on his own – admittedly without ever having worked with warm glass before...

The usual strategy, to transform a float glass sheet by lowering, clearly was no option in this case - the work-piece shape in question was too complex. Yet it appeared possible to the Designer to help gravity out a little. After countless experiments a kinetic bending device which limits the transformation to just the portions actually needed was chosen and built from laser cut stainless steel.

c--c- elements: Actual 1:1 prototypes in glass were required. ©Holger Jahns Produktentwicklung

Bending process
©Holger Jahns Produktentwicklung


c--c bar glass ©Holger Jahns Produktentwicklung		Two of such devices populated with glass blanks were heated up, until they got ductile. Once the protruding portions on both sides of the device glass began to lower, they set two bending rolls into a semicircular motion. Their weight shaped the 6mm glass pane in the desired final shape, practically without human intervention. All what remained to do was letting the work-pieces cool down slowly. When separating the glass elements from the mould however, at some point became obvious that the chosen construction did not allow for greater precision: The more accurate the outcome, the more likely it de facto became to break the work-piece upon removal from the mould.

A first peek through a scuttle while heating up the furnace. Nothing has moved thus far.
©Holger Jahns Produktentwicklung

Glass bending process
©Holger Jahns Produktentwicklung


Thinking of brittle materials like glass the only solution would have been to use a bending apparatus with a divisible core, a measure which even got considered upfront but was waived in the sense of limiting cost and complexity of the overall procedure. Eventually – and with some good looking samples from Glass already at hand – it was decided to use acrylic glass for the longer elements needed in the actual exhibit. Acrylic in the process of bending turned out to be even more complex to handle than glass but precisely bent work-pieces could get easily separated from the bending device. With an exhibit with elements from acrylic glass and additional samples from glass one was equipped for public appearances. Product concept website: www.c--c.net Documentation on prototype creation: www.c--c.net/MakingOf More information: Holger Jahns Produktentwicklung Muskauer Straße 27 10997 Berlin, Germany +49 (0)30-60507373 www.konflux.net re@konflux.net		Mould creation © Holger Jahns Produktentwicklung