Plastic injection mold maintenance is extremely important. Without proper care, your injection molds can suffer performance issues, produce defective parts, and require expensive repairs or replacement. In this comprehensive guide, as a professional plastic injection molding manufacturer, I’m going to walk you through everything you need to know about keeping your molds in tip-top shape.
Why Mold Maintenance Matters
Maintaining your injection molds should be a top priority. Here’s why:
Prevent Mold Damage
Injection molds are precision-machined tools that cost thousands or even hundreds of thousands of dollars. Like any piece of manufacturing equipment, they suffer wear and tear over time. Small issues left unaddressed can snowball into much larger problems. Proper maintenance keeps minor problems minor—saving you from costly mold repairs or replacement.
Ensure High Production Uptime
Unexpected mold issues force you to halt production. And downtime is hugely expensive in manufacturing. In fact, some estimates put the cost at around $260 per minute! Staying on top of maintenance keeps your molds running smoothly so you can avoid disrupting your production schedules.
Produce Quality Parts
When molds become damaged, they lose the ability to produce consistent, high-quality parts. Poorly maintained molds make bad parts. It’s that simple. Staying on top of maintenance ensures your molds remain capable of outputting perfect plastic components batch after batch.
How To Maintain Injection Molds: 8 Key Tips
Now let’s get into the nitty gritty of mold maintenance best practices:
1. Follow the Manufacturer’s Guidelines
Every injection mold is unique. So maintenance requirements can vary substantially depending on factors like:
- Mold materials used (e.g. aluminum vs. steel)
- Part geometries produced
- Types of resins processed
Luckily, most commercial mold makers provide maintenance documentation detailing optimal upkeep procedures for their specific molds. So step #1 is always to follow the manufacturer’s maintenance guidelines.
2. Perform Visual Inspections
Conduct routine visual inspections of your molds. Check for any signs of damage or wear, paying special attention to high-wear areas like:
- Parting lines
- Ejection system
- Venting
- Cavity and core
Also inspect cooling lines, moving components, plates, and hot runner systems (if applicable). Replace any damaged or overly worn parts as needed.
3. Clean Molds Thoroughly
Allowing dirt, debris, and excess plastic to accumulate causes all sorts of issues. Carbonized resin can lead to scorching. Metal chips floating around can score mold surfaces. Even cooling channels can become restricted.
That’s why regular, thorough cleaning is non-negotiable. Most molds only need basic manual cleaning using suitable solvents and tools. Soft brass or nylon brushes usually work well. Avoid anything that could scratch mold surfaces.
For more stubborn contaminants, consider dry ice blasting. The ultra-cold CO2 pellets blow away residues without damaging mold materials. Just be sure to lubricate components afterward, as dry ice cleaning can wash away protective lubricants.
4. Lubricate Moving Components
Reducing friction is hugely impactful for mold longevity. That’s why regularly lubricating moving mold components like ejector pins, slides, cams, and guide rods is critical. Use only lubricants specifically designed for injection molds to avoid compatibility issues.
Even something as simple as keeping ejector pins lubricated goes a long way. Cutting down on friction minimizes wear so you can keep producing good parts without pin breakage or sticking.
5. Maintain Proper Venting
Venting allows trapped gases to escape the mold during injection. Without adequate venting, the gases get trapped, causing defects like burn marks, welds, and short shots.
Poor venting also enables oxygen to reach metal surfaces, accelerating corrosion. What’s more, clogged vents reduce cavity pressure uniformity—outputting inconsistent parts.
So clearly, proper venting maintenance is essential. Routinely clear air vents of any obstructions. Wire brushing usually works. For stubborn buildups, use chemical cleaning agents (like vapor degreasing) to clear vents.
6. Monitor Cooling Channels
Cooling channels regulate mold temperature during operation. But over time these narrow passages can become fouled or blocked entirely. Restricted cooling translates directly into longer cycle times, reduced productivity, and poor part quality.
That’s why routinely monitoring, cleaning, and testing cooling channels is hugely impactful. Techniques like chemical flushing, ultrasound cleaning, and even abrasive flow machining all work to remove restricted cooling channel deposits effectively.
7. Protect Against Corrosion
Water, heat, plastic residues, and cycling all corrode mold materials over time. Unchecked corrosion pits surfaces, producing flawed plastic components that must get scrapped. It also accelerates wear—shortening useful mold life.
Shielding molds from corrosion is key for longevity. Nitriding treatments harden surfaces against wear and corrosion. Chrome plating also works. Just ensure protective coatings don’t interfere with plastic flow or release.
You should also store molds properly when not in use. Keep them dry, clean, and lubricated. Indoor, climate-controlled environments work best for preventing corrosion during downtimes.
8. Keep Detailed Maintenance Records
Like any effective maintenance program, keeping detailed records is invaluable. Track all inspections, repairs, lubrications, and parts replacements—noting dates performed and personnel involved.
Comprehensive documentation identifies chronic problem areas needing design modifications or helps determine optimal preventative maintenance frequencies. It also simplifies root cause analysis when issues do occur.
Essential Maintenance Tools & Equipment
Having the proper gear makes injection mold maintenance much easier. Here’s a quick rundown of must-have items:
PPE – Safety glasses, gloves, etc. protect against harm when cleaning molds or handling lubricants/solvents.
Brushes – Soft brass and nylon brushes clear residues without damaging mold surfaces. Stainless steel picks remove tough deposits.
Cleaning Agents – Suitable mold cleaners dissolve common plastic residues like polypropylene, ABS, nylon, etc.
Lubricants – Formulated greases reduce friction/wear on slides, ejector pins, and moving mold components.
Illumination – High-intensity LED flashlights spotlight cracks, wear, and other flaws needing addressal.
Magnification – Inspector’s loupes/digital microscopes inspect tiny flaws difficult to spot with the naked eye.
Precision Instruments – Calipers, micrometers, and indicators identify and monitor component wear over time.
Rust Protection – Anti-rust oils and storage bags shield molds when not in use. Desiccant bags also help by absorbing moisture.
Key Takeaways On Maintaining Molds
And there you have it—a comprehensive guide to injection mold maintenance best practices. Here’s a quick recap:
- Maintaining molds should be a top priority—not an afterthought. Poor maintenance causes major headaches down the road.
- Follow all maintenance instructions provided by your mold manufacturer. Requirements vary for different injection molds.
- Visually inspect molds routinely for damage/wear. Replace worn components before problems occur.
- Thoroughly clean molds of plastic residues, debris, etc. on a regular basis to prevent issues.
- Keep moving components (ejector pins, slides, etc.) well-lubricated to minimize wear and friction.
- Flush and test cooling channels regularly. Blockages drive down productivity and part quality substantially.
- Take steps to protect molds from moisture, debris, and corrosion when not in use for extended periods.
Staying on top of injection mold maintenance takes work. But considering the costs of new molds, downtime, and defective parts—it’s 100% worth every bit of effort.
Hopefully this guide gives you everything you need to start implementing an effective maintenance program for your injection molds. As always, let me know if you have any other mold maintenance tips/tricks by dropping a comment below!