Since it was developed by a post-grad student in Kilkenny, Ireland–Jane Ní Dhulchaointigh–Sugru has been an indispensable tool for those looking to apply quick fixes to industrial design problems ranging from weak iPhone cords to sharp edges and protective bumpers.
The substance, which came out of Ní Dhulchaointigh’s goal of enabling people “to easily and affordably repair, improve or customize things they already own,” is made from a combination of moldable, self-adhesive and self-curing silicone caulk and talc.
Among some of the more impressive uses we’ve seen for the ‘wonder material’ is this recent project from Instructables user ‘andreasbastian’:
“As an experiment in improving the grip of the Raptor Hand, produced by a team of designers in the e-NABLE 3D printed prosthetics community, I designed a mold and modified the Raptor distal phalange to allow for Sugru overmolding. Sugru is an air-cured silicone material that is typically packaged in 5gram packets and is quite durable and grippy when cured. After molding and trimming, the Sugru fingertip is secured bonded to the distal phalange and provides some additional friction compared to the original PLA surface.”
Starting with a mold design created in Autodesk’s Fusion 360, the design is verified and tested before being sent to the 3D printer:
Mechanical joinery features–such as dovetails–were used to ensure a secure a bond between the overmold and the base part in the final printed design.
“After modeling the overmolding and the base part, subtract them from a block, offset all surfaces by 0.25mm (except the XY plane parallel surfaces– the sides of the phalange) to make for a nice fit with the base part, and mirror the block to make a two part mold. Add some tapered alignment pins (offsetting the negatives by 0.25mm) to make sure the mold registers properly.”
After lubricating the mold surfaces with oil–such as machine oil in this case–the Sugru packet is opened and kneaded to soften for being placed in the mold:
After applying the Sugru to the part and placing into the mold, pressure is applied to fill in the dovetail cavity and remove any excess material:
After immediately removing or letting cure for a day or two, the mold is removed and the final form is finished with an X-Acto knife or razor blade to achieve the final desired look:
For a more in-depth explanation as well as additional photographs be sure to head over to the project page over on Instructables.