Application case of silicone injection molding with in-mold implanted PCB board with battery

A key technology at WITTMANN BATTENFELD, the LSR (Liquid Silicone Rubber) process will be demonstrated by producing composite LSR parts on a servo-hydraulic injection moulding machine of the SmartPower series

A SmartPower 120/350 injection molding machine will be equipped with a two-cavity mold from Nexus, Austria, to produce a ready-to-use Drinky

SmartPower 120/350 LSR Injection Molding Machine

Drinky is a drink timer, also known as a drink manager, that reminds us to rehydrate every once in a while

From left to right: Finished Drinky beverage manager, PCB with battery

Dow's SILASTIC™ LTC 9400 series of LSR materials has received attention for its low temperature crosslinking properties, an important feature in the production of Drinky beverage managers, as the part will be embedded in a mold and overmolded, a PCB (Printed Circuit Board) with battery

Injection molding process for SmartPower 120/350 LSR: Two-cavity mold opens, embeds printed circuit board

Both electronic components and batteries have very limited temperature resistance, for example, batteries can only withstand thermal loads of about 120°C for a short period of time

Therefore, previous similar applications often involve embedding them in housings through additional downstream production steps

Drinky's innovation does not involve the beverage manager itself, but its production process

In this way, the assembly of the individual parts to the thermoplastic housing can be omitted, and the insert is overmolded directly in the mold and can be used after demolding without any further assembly steps

To facilitate setting or to speed up the crosslinking process, an accelerator is incorporated

Silastic LTC 9400-50 LSR and accelerator were fed into a SmartPower 120 injection molding machine using a Servomix X200 metering unit from Nexus

SmartPower 120/350 LSR injection molding machine with Servomix X200 metering unit

The injection unit with its open design facilitates the integration of the metering unit, which is connected to the injection molding machine via an OPC UA interface

The mold uses the latest cold runner technology with the FLOWSET needle valve control system, and an important feature inside the mold is the precise matching of the embossed edge to the circuit board and SMD components

Putting the insert in the correct position in the storage box, a powerful W918 robot uses its double gripper to pick up the insert

After removing the finished part, the robot places the electronic circuit board into a two-cavity mold

Injection molding process for SmartPower 120/350 LSR: parts are placed on a conveyor belt and fed to a packaging station

When the drink cup is placed on the Drinky, a pre-programmed timer is activated, which reminds us with a flashing signal every 10 minutes that it is time to add enough water