Injection Molding Machine Shutdown Before Holiday
Professional guide on injection molding machine shutdown before holiday, covering rust prevention, power-off safety, mold protection, and smooth restart
Final, Proven Standard from a 20-Year Injection Molding Machine Manufacturer
This is not theory.
This is the shutdown method we use in our own factory, and the one we require our customers to follow before long holidays.
If you follow this guide exactly, 95% of holiday-related machine problems will not happen.
1. The Core Principle (Most Important)
An injection molding machine must be left in a:
Clean state + Pressure-free state + Dry state + Protected metal state
If any one of these is missing, problems will appear after the holiday.
Everything below serves this principle.
This guide explains the correct injection molding machine shutdown before holiday to prevent rust, pressure damage, and restart failure.
2. Raw Material & Barrel – The No.1 Risk Area
What operators care about:
“Will the screw get stuck after the holiday?”
Best-practice answer:
Plastic must NEVER remain in the barrel during a long shutdown.
Final standard procedure:
- Close hopper feed
- Empty hopper completely
- Purge until no plastic comes out
- Reduce barrel temperature gradually to 80–100°C
- Stop heating
- Shut down machine
Mandatory rules (non-negotiable):
- ABS / PA / PVC / FR materials:
→ Purge longer, never stop with material inside - Holiday > 3 days: Purging is mandatory
- Holiday > 7 days: Purging compound is strongly recommended
Why this is the best method:
- Prevents carbonization
- Prevents screw seizure
- Guarantees smooth restart
3. Mold Protection – Where Money Is Lost Fast
What managers care about:
“Why is the mold rusty after holidays?”
Best-practice answer:
Humidity + steel + no movement = rust (always).
Final standard procedure:
Short holiday (≤ 5 days):
- Clean cavities and runners
- Spray anti-rust oil
- Close mold slightly (no clamping force)
Long holiday (> 7 days):
- Remove mold (recommended)
- Clean cavity, core, sliders, ejector pins
- Apply anti-rust oil evenly
- Store in dry area
Critical note from experience:
More mold damage happens during shutdown than during production.
A professional injection molding machine shutdown before holiday reduces downtime and protects molds, hydraulics, and electrical systems.
4. Hydraulic System – Prevent Hidden Damage
What operators care about:
“Why does oil leak after restart?”
Best-practice answer:
Pressure must be fully released.
Final standard procedure:
- Stop pump
- Release system pressure completely
- Return cylinders to neutral position
- Check oil level
- Clean existing oil stains
Why this works:
- Protects seals
- Prevents internal stress
- Reduces post-holiday leakage
5. Cooling System – The Most Ignored System
What factories experience:
Poor cooling, leaks, corrosion after holidays
Best-practice answer:
No water must remain inside the system.
Final standard procedure:
- Shut off water supply
- Drain all cooling water:
- Mold
- Machine
- Chiller connections
- Blow residual water with air if possible
Mandatory for:
- Cold regions
- High-humidity environments
- Shutdown > 5 days
- Every factory should follow a standardized injection molding machine shutdown before holiday procedure.
6. Electrical Cabinet – Silent Failure Source
What happens after holidays:
Random alarms, sensor errors, unstable signals
Best-practice answer:
Moisture is the enemy of electronics.
Final standard procedure:
- Turn off main power
- Clean dust inside cabinet
- Close cabinet doors tightly
- Place moisture absorbers inside
Additional rule:
- Cabinet heaters should remain functional if installed
7. Mechanical Parts – Easy to Protect, Easy to Forget
Parts that rust first:
- Tie bars
- Platens
- Guide rails
- Ejector rods
Final standard procedure:
- Apply thin anti-rust oil or grease
- Avoid bare metal exposure
8. Restart After Holidays – Do NOT Rush
Best-practice rule:
Never restart at full speed.
Final restart sequence:
- Visual inspection
- Power on
- Heat barrel slowly
- Manual / low-speed operation
- Trial molding with simple parameters
Why:
- Protects molds
- Protects seals
- Prevents sudden failures
Final Statement (Manufacturer Position)
After 20 years, our conclusion is simple:
Machines do not fail because of holidays.
They fail because shutdown was careless.
A correct shutdown takes less than one hour.
An incorrect shutdown costs days of downtime and expensive repairs.
This is the best version, because it is:
- Proven in real factories
- Easy to execute
- Safe for all machine types
- Low cost, high reliability
