Machine shutdowns during holiday periods: why a clean shutdown leads to a better startup
For many plastics processors in both the injection moulding and extrusion industries, planned machine shutdowns during holiday periods, maintenance activities, or production breaks are a normal part of operations. However, what happens before the machine is switched off can have a major impact on how efficiently production starts up again.
Residual material left inside the barrel, screw, or hot runner system can degrade during downtime. When production resumes, this degradation may lead to contamination, black specks, unstable processing conditions, increased scrap rates, and longer startup times.
A shutdown should therefore not be viewed as the end of a production run, but as the first step towards a successful and cost-effective startup.
What happens during machine downtime?
Even when processing the same material every day, small amounts of residue gradually build up inside processing equipment. During an extended shutdown, these deposits remain exposed to heat and time, increasing the risk of material degradation and carbon formation.
The result can be:
- Material degradation
- Carbon build-up
- Colour contamination
- Black specks in production
- Reduced process stability
- Longer startup and cleaning times
These issues often only become visible when the machine is restarted, leading to unnecessary downtime, material waste, and additional labour costs.
The Dyna-Purge shutdown philosophy
At De Monchy, we believe every shutdown should create value for the next production run. Use every shutdown to improve startups, extend equipment life, and enhance machine performance. A structured shutdown procedure helps reduce startup costs, protect processing equipment, and maintain operational efficiency.
Instead of simply switching off the machine, we recommend a shutdown strategy that combines thorough cleaning, proper machine shutdown practices, and equipment protection during idle periods.
A practical shutdown procedure
Step 1: Thoroughly purge the machine
Before shutting down the machine, run Dyna-Purge® through the system to remove residual resin, colourants, degraded material, and contamination.
Continue purging until the material leaving the machine is clean and consistent. This step helps eliminate deposits that could otherwise degrade during the shutdown period.
Step 2: Shut down the equipment correctly
Once the machine has been thoroughly cleaned, follow the manufacturer’s recommended shutdown procedure.
This may include:
- Reducing temperatures in stages
- Correctly shutting down heating zones
- Relieving system pressure where required
- Preparing the machine for an extended idle period
After purging, fill the system with Dyna-Purge® and then switch off the machine according to the manufacturer’s shutdown procedure. Keeping Dyna-Purge® in the system during the shutdown period helps protect the barrel, screw, hot runner, or extrusion system from contamination, oxidation, and material degradation.
A proper shutdown procedure helps protect critical components and ensures the machine is ready for a smoother startup.
Step 3: Seal and protect the system
For longer shutdown periods, additional protection measures can further improve startup performance.
It is recommended to leave Dyna-Purge® inside the barrel, screw, hot runner, or extrusion system after the cleaning process has been completed. By remaining in the system during the shutdown period, Dyna-Purge® helps protect processing components from contamination, oxidation, and material degradation.
This approach is suitable for both injection moulding and extrusion applications and can significantly reduce cleaning requirements when production resumes. As a result, processors can often achieve a faster, cleaner, and more stable startup.
Step 4: Protect the machine during downtime
Whether the shutdown lasts several days or several weeks, a clean and properly prepared machine is less susceptible to contamination, carbon formation, and startup complications.
Protecting equipment during idle periods helps preserve machine condition and contributes to a more efficient restart.
Step 5: Restart with confidence
When production resumes:
- Inspect the machine and processing components
- Bring the system back to operating temperature
- Perform a short startup purge if required
- Resume production with a clean and stable process
Because contamination and degraded material were removed before shutdown, startup is typically faster, cleaner, and more predictable.
How Dyna-Purge supports better shutdowns and startups
Using Dyna-Purge® as part of a planned shutdown strategy can help processors:
- Reduce startup scrap
- Minimize downtime
- Lower startup costs
- Improve process stability
- Reduce carbon build-up
- Protect screws and barrels
- Extend equipment life
- Improve overall operational efficiency
Rather than spending valuable production time cleaning contaminated equipment after a shutdown, processors can start with a cleaner machine and focus on getting production back up to speed.
Need help choosing the right Dyna-Purge grade?
The De Monchy team is happy to help you select the most suitable Dyna-Purge® product for your application and provide step-by-step guidance for implementing an effective shutdown cleaning procedure. Whether you’re planning a short maintenance stop or an extended holiday shutdown, we can support you in developing the right cleaning and shutdown strategy for your equipment.
Contact: jwiechmann@monchy.com
Request a free sample and discover how Dyna-Purge® can help improve your machine shutdown and startup performance.
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