FOCUS ON COIL PROCESSING
using the type of folding and cutting that you do in origami . I played with the concept and developed a full-sized model in cardboard . When I showed it to my associate , Jonas Nyvang , he shared my excitement . We decided to form STILRIDE to take the idea forward , winning a grant from Sweden ’ s innovation funding agency , Vinnova .”
A chance encounter with an Outokumpu specialist introduced Tue to the possibility of working with high-strength stainless steel . It was not something he had considered as the material usually needs powerful tools to bend and form it into shape .
“ The Outokumpu specialist told us about a research project that used localised heat treatment to selectively soften sheets of temper-rolled stainless steel to make them easier to form . After connecting with Outokumpu ’ s research and development manager , Hans Groth , he shared some advice and gave us access to research papers . We used that insight to explore ways to create scooter bodies , for example by folding a section round onto itself and welding it to form enclosed beams that are strong enough to support a rider ’ s weight , as well as being lightweight and durable . Having worked with stainless steel before , I already knew that it is beautiful , does not need painting and is long-lasting , making it ideal for a low-cost scooter .”
Developing the LIGHT . FOLD technique
When researchers at Outokumpu first developed the concept in 2000 , they called it blanc forming . However , STILRIDE has carried out further development covering the entire value chain from digital design tools to production , ultimately developing a new process for designing and manufacturing that it calls LIGHT . FOLD .
The technique is based on using lasers to apply highly localised heat treatment to temper-rolled stainless steel , focused on dehardening key areas where the material will need to bend . The approach is similar to using a knife to score card to control the location
STILRIDE founders ; industrial designer Tue Beijer and CEO Jonas Nyvang .
VIDEO
STILRIDE industrial origami
A stainless steel formed part for the MK3 model .
and extent of folds . By scoring a card multiple times in a fan shape , the card can be formed into a cone . LIGHT . FOLD achieves similar results with stainless steel , using robots to provide control and accuracy to form the sheets into complex 3D shapes .
When working with stainless steel in this way , it is important to start with temper-rolled sheet as it has been hardened during cold rolling . Temper-rolled sheets are often used by industrial engineers in pressure vessels and chemical storage tanks or to build escape tunnels for oil platforms . However , bending and forming the high-strength sheet is challenging . Therefore , de-hardening selected areas allows large sheets to be bent and formed more readily .
The intense laser heat reverses the process of cold working , softening the material enough to allow forming with narrow , well defined bending radii . The final forming reapplies the work hardening to some extent so that the structure partially regains the strength of the original flat sheet .
Paul Janiak , Outokumpu ’ s R & D manager for design and fabrication , explained : “ When you temper-roll a duplex stainless steel , such as the Forta 301 that STILRIDE is using , it becomes so hard that it is difficult to bend . In the early 2000s , we developed the method of blanc forming using local heat treatment of 600-800 ° C concentrated into narrow lines to selectively change the material ’ s formability . The interesting thing about using a laser is
that you can focus its beam to influence the bending radius . For example , if you want a tightly defined bend , you could have a 1mmwide beam but you can use wider , defocused beams or oscillating patterns to create bends with larger radii .
“ We ’ re always keen to promote the use of stainless steel , so we were pleased to share our experience to help STILRIDE take the blanc-forming concept forward .”
Planning for 2022 launch
STILRIDE MK3 model .
According to STILRIDE ’ s estimates , its innovative technique and the digital value chain LIGHT . FOLD has the potential to save manufacturers and metal fabrication workshops 20 to 50 per cent on material and 25 to 45 per cent on labour costs . This gives it potential for much wider adoption .
However , the current focus is to prove the concept by launching the e-scooter . Having secured its grant in November 2019 , STILRIDE has been making steady progress in spite of the COVID-19 pandemic . The team is planning to carry out type testing and start accepting orders before the end of 2022 and then ramp up production in 2023 . Until then , it is continuing to refine the design .
“ In a typical scooter , you will find hundreds of components and design details , as well as a wide variety of materials . All these need time and attention during design and manufacture , as well as sourcing , procurement , test and qualification of components . And any of them could go wrong and need replacement during the scooter ’ s lifetime ,” said Tue .
“ We ’ re using fewer materials , components and production steps . That makes our scooter less costly to produce . We ’ re confident that our scooter will be lighter and more rigid than its competitors , thanks to LIGHT . FOLD . We ’ ll know exactly how much lighter once we have fine-tuned our bending technique and optimised the design to select the ideal sheet thickness to give us the strength that we need .”
26 | sheetmetalplus . com | ISMR April 2021