Single Cavity Hot Runner System
Open Gate (Hot Tip)
Valve Gate System
Thermal Gate (Self-Regulated)
Core Components:
Hot Runner Nozzle – delivers molten plastic into cavity
Heater Coil / Band Heater – keeps material molten
Thermocouple – monitors temperature (so it doesn’t go rogue)
Mold Cavity – the actual product shape
Gate (Tip / Valve) – controls entry point
Sometimes:
Mini Manifold (for precise distribution, even in single cavity)
Types of Single Cavity Hot Runner Systems
1. Open Gate (Hot Tip)
Always open flow
Simple design
Small gate mark
Cheap, reliable, slightly imperfect finish
3. Thermal Gate (Self-Regulated)
Gate freezes naturally
No mechanical pin
Minimal moving parts, but less control
Heating Variants
Externally Heated Nozzle
Easy maintenance, slightly less efficient
Internally Heated Nozzle
Better temperature control, more complex
Advantages (Why people actually use it)
Zero material waste (no runner scrap)
Better surface finish
Shorter cycle time
Consistent quality
Less post-processing
Basically: less garbage, more profit.
Disadvantages (Reality check)
Higher initial cost
Maintenance needs skill (not “jugaad friendly”)
Temperature control is critical
Not ideal for very small production runs
Applications
Bottle caps (low cavity prototypes)
Medical parts
Automotive precision components
Electronic housings
Packaging prototypes
When to Use Single Cavity Hot Runner
Use it when:
Product is high precision / premium
Production volume is moderate but consistent
Material cost is high (so waste hurts your soul)
Avoid it when:
You’re doing cheap, low-volume jobs
Tooling budget is tighter than your patience
Practical Insight
Single cavity systems are like a sports bike.
Multi-cavity systems are like a bus full of passengers.
Single = precision, control, performance
Multi = scale, volume, efficiency
Pick based on your business, not your ego.
