Our company produces bouncy balls, handles, decorations, caps and other rubber and silicone items for PLAY s.r.l., based in Lomagna (LC), which creates equipment for professional and amateur jugglers and some of the best-known circuses in the world.
In February 2019, “Davide from PLAY” proposed a new project: a hollow, translucent ball designed to hold a circuit board, which works in conjunction with a special application to change colour to the rhythm of the music. The ball must be closed with a silicone insert that contains and protects (IP65) the circuit board from the impacts of juggling. This insert is connected to a cap to keep it airtight and protected from moisture (IP65), in addition to allowing it to be opened and closed to recharge the battery.
Having obtained the dimensions and sketched a 3D design of the first circuit board we received, we began by cutting a PVC ball in half. We ran every step past the customer, reaching a joint decision on how deep the “undercut” needed to be to allow the cap to opened easily and keep the ball sealed during juggling.
Based on an annual sales estimate, we provided a quote for a 4-impression injection mould with two plates and a tangential hinged opening, allowing for easy extraction of the moulded piece. In light of its complexity, we decided to create a single-impression version of the final mould to allow us to modify the shape if necessary. The single-impression mould was finished in 3 weeks and tested after a few days.
Milk-coloured, platinum-catalysed 70SH high tear silicone was chosen for the cap material, as requested by the customer. The cap was moulded and positioned in its housing inside the PVC ball, having mounted the circuit board inside the ball. Everything went well until we started testing the balls in action, when we realised that the cap tended to open. We therefore decided to increase the undercut and use 80SH silicone.
The changes had the desired result, and the light-up balls could be put to work without the caps opening accidentally. We completed the other 3 mould impressions to the complete satisfaction of our customer and their users.
