A foldable phone hinge consists of hundreds of micro-precision components. The liquid metal spindle, precision structural parts and micro-dose adhesives are highly process-sensitive links: liquid metal features low feeding volume and high specific gravity; air bubbles trapped inside will lead to shrinkage porosity and internal defects of parts. When micro-dose adhesives entrain air, curing strength will fluctuate, which directly undermines the consistency of hinge damping and folding service life. Bubble control during feeding is an easily overlooked factor in boosting the yield rate of precision parts.

Reported on October 26, Apple has placed a new order for around 30% more Foldable iPhone Duo units amid tight supply. Hon Hai is the exclusive assembler, while the core hinge bearing components are supplied by a joint venture between Hon Hai and Nissin Kogyo, with Amphenol as the secondary supplier. Industry insiders believe the core bottleneck limiting current output lies in insufficient bearing capacity plus high assembly difficulty. With surging orders and capacity constraints coexisting, the feeding and assembly processes for micro-precision parts need to be finalized before capacity expansion.

Precision component manufacturers and material suppliers usually confirm the mixing and defoaming window via actual feeding during verification, then transfer the process parameters to mass-production equipment. SIENOX engineers have recently received many inquiries from precision parts manufacturers, who want to complete sampling and verification of liquid metal and micro-dose adhesives on small-volume equipment.

The SIENOX MIX60 used for verification is a lab model for formula evaluation with a 300ml capacity, perfectly matching multi-formula assessment in small batches. Adopting planetary revolution-and-rotation structure, the machine combines shear force from rotation and stirring force from revolution to rapidly disperse high-specific-gravity feedstock and push air bubbles to the surface. Synchronous defoaming is carried out under a vacuum environment of -98KPa, with a maximum speed of 2000rpm; temperature control is available as a customized option. The small capacity supports parallel comparison of multiple feed materials, and verified process data can be seamlessly transferred to pilot and mass-production machines.

No visible bubbles remain in tested feed materials, with stable viscosity and fluidity across batches. During the capacity expansion of foldable devices, vacuum defoaming mixers are being added to the verification list by more manufacturers for precision component manufacturing. The adaptability of small vacuum planetary mixers for micro-feeding scenarios, as well as the supporting performance of silver paste defoaming machines in precision adhesive assembly, should be confirmed in advance at the capacity planning stage. The above analysis is compiled from public industry information; actual test data shall be subject to customer trials.