Yudo HOT RUNNER - System Startup and Shutdown; Startup

UH-02-Aug16-ENG P 18 / 21
4. S YSTEM S TARTUP AND S HUTDOWN
4.1. S TARTUP
4.1.1. Preparation for molding – Hot Runner system in general
- The injection unit stays attached to the mold during cycle.
- Connect power and thermo collective cable.
- Check, if power and thermo wiring do correspond by separately heating up each zone (for a short
period of time).
- A proper grounding at the injection molding machine must be ensured.
- The mold temperature recommended by the material manufacturer has to be observed.
- Please fix the YUDO type plate with the order number on the outside of the mold so that the Hot
Runner can easily be identified.
4.1.2. Start-up and filling of an "unfilled" Hot Runner system
- Mold and barrel should have reached the recommended temperatures.
- Switch on the manifold of the Hot Runner system and let the humidity from the heaters dry out at a
temperature between 100°C and 120°C for approx. 10 minutes. When the manifold reach his setting
temperature, switch on nozzles.
- Set processing temperature and heat system in even heat-up mode for 3 - 5 minutes, so that the
preload is ensured.
- Make sure that there is a sufficient barrel pressure. Without that leakage might occur between
machine nozzle and mold. Fill the Hot Runner with approx. 300 - 400 bar back pressure until plastic
emerges at the gates.
- When filling the Hot Runner system use natural non colored material and without additives,
especially if color changes are planned or if materials with flame retardant additives and glass fibers
respectively are used.
- Start molding process.
- If intense cooling of the mold is required, increase temperature by approx. 20°C - 25°C if necessary.
NOTE: Normally, the system is designed for a 2000 bar injection pressure
WARNING: You must follow the guidelines of the material manufacturer!
4.2. S HUTDOWN
4.2.1. Preparation for the end of production – Hot Runner in general
- With valve gate system and particularly with pneumatic drivers, we recommend to open gate before
switch off heaters.
- At the end of production, use natural material without additives, especially if color changes are
planned or if materials with flame retardant additives and glass fibers respectively are used.
- If flame retardant materials or materials with glass fibers are used, we recommends to purge the Hot
Runner system with natural material of the same type without additives or purging material after
finishing production. Thus the re-start of the system will become easier.