Alternative Title: Master Your EBM Production: A Troubleshooting Checklist for Plant Managers

1. Introduction: When Production Stops, Costs Go Up

I know the sound of a profitable factory floor. It is a steady, rhythmic hum. When that hum stops, the stress starts.

For a plant manager, silence is not golden. It means downtime. It means lost profit.

Troubleshooting isn’t just about fixing a machine. It is about getting your business back on track. This guide focuses on Extrusion Blow Molding (EBM) technology. We will look at fixes for both continuous and accumulation type machines. These tips work best for containers made of HDPE, PP, and PVC.

I am writing this based on my experience at LEKAmachine. With a total shipment volume of over 1000 units, we provide engineer on-site assembly and remote engineer maintenance guidance. We have seen almost every problem a blow molding machine can have.

Here is how to fix the most common ones.

2. Safety First: Critical Precautions for EBM

Before you grab a wrench, you need to be safe. These machines use high heat and high pressure.

• Lock-Out/Tag-Out (LOTO): Never touch the extruder or clamp without locking out the power. This is mandatory.
• Heat & Pressure: The die head gets very hot. Also, hybrid machines might have leftover pressure in the lines. Be careful.
• Emergency Stops: Check your E-Stop buttons every single day. You need to know they work before you need to use them.

3. Parison Troubleshooting: The Heart of EBM

The parison is the tube of melted plastic. If the parison is wrong, the bottle is wrong.

Problem 1: Parison Curling (“Banana Effect”)

The tube curls to one side as it comes out.

• Diagnosis: The die temperature is not even. Or, the die bushing or mandrel is dirty.
• Fix: Clean the die lips. Check your heater bands to make sure they are all heating evenly.

Problem 2: Parison Sagging (Draw-down)

The tube stretches too much under its own weight. The top gets thin.

• Diagnosis: The melt temperature is too high. Or, the extrusion speed is too slow for how heavy the material is.
• Fix: Speed up the screw RPM. You can also lower the temperatures in the barrel zones.

Product Spotlight: Different materials behave differently. You need a machine that can adapt. Our FORMA Serisi is born for versatility and diversity. It is a stable and reliable production partner designed to handle diverse production demands easily.

Problem 3: Parison Swinging/Instability

The tube swings back and forth like a pendulum.

• Diagnosis: The die head isn’t centered. Sometimes, air drafts in the shop push the plastic.
• Fix: Center the die head. Look for fans or open doors near the machine and block the wind.

4. Wall Thickness & Container Weight Issues

Customers want strong bottles. They do not want to pay for wasted plastic.

Problem: Uneven Wall Distribution

One side of the bottle is thick, the other is thin.

• Diagnosis: The die mandrel is not aligned with the bushing.
• Fix: Mechanically adjust the bolts on the die gap to even it out.

Problem: Thin Corners

This happens often in square items like jerry cans or tool cases. The corners blow out and get weak.

• Diagnosis: Your Parison Programming Profile is flat.
• Fix: Use the parison controller. Optimize the servo points to make the plastic thicker in the areas that will stretch into the corners.

Product Spotlight: For big industrial containers, you need stability. The TITAN Serisi is synonymous with strength and scale. It delivers unparalleled power and stability for large products like chemical drums and automotive parts.

5. Flash & Trimming Defects

Flash is the extra plastic you cut off. It should come off easily.

Problem: Tough Flash (Won’t Separate)

The flash sticks to the bottle.

• Diagnosis: The plastic is still too hot. Or, the “pinch-off” metal on the mold is worn out.
• Fix: Check your mold cooling channels. If they are blocked with scale (dirt from water), the mold stays hot. Clean them out.

Problem: Excessive Flash Thickness

The flash is too thick and hard to cut.

• Diagnosis: The mold is not closing tight enough. The air pressure inside blows the mold open slightly.
• Fix: You need more clamping force. Ensure your machine tonnage matches the size of your product.

For example, using a machine like the TITAN H30L (which creates 30L containers) ensures you have the power to seal tightly.

6. Leak Testing Failures

A leaking bottle is a rejected bottle.

Leak Location: Bottom Pinch-off

• Fix: Increase the clamping pressure. You can also increase back pressure on the extruder. This mixes the plastic better so it fuses stronger.

Leak Location: Neck Finish

• Fix: The blow pin might be crooked. Or the shear steel (the part that cuts the neck) is damaged.
• Tip: Calibrate the blow pin. It must match the neck height exactly.

7. Surface Defects: Appearance Matters

Even if the bottle holds water, it has to look good.

Defect: Black Specks/Carbon

• Cause: Plastic is burning inside the extruder. Or there are “dead spots” in the head where old plastic sits and burns.
• Maintenance: You need to purge the machine. Clean the screw regularly.

Defect: Die Lines (Vertical Streaks)

• Cause: There is a scratch or a piece of dirt on the die lip.

Defect: Bubbles/Splay

• Cause: Moisture. Water in the plastic turns to steam and makes bubbles. This is very common if you use recycled materials (rHDPE).
• Fix: Check your hopper dryer. Make sure the material is dry before it enters the screw. We know clients are pushing for more recycled materials, so this step is vital.

8. Optimizing Cycle Time & Output

Time is money. Slow machines kill profitability.

Hydraulic Performance

Check: Look at oil temperature. If the oil is too hot, pumps work poorly. Carriage movements get slow.

Cooling Efficiency

Check: Water flow rates. EBM needs cold water to set the plastic fast.

The High-Speed Upgrade

• Scenario: Sometimes your old machines are just slow and break down, causing bottlenecks.
• Çözüm: Look at the AERO Series. It is the wind-fast solution for producing small to medium containers. We designed it specifically for rapid, fluid motion and high-volume production.

9. Electrical & Servo Systems

Modern machines use smart tech.

Temperature Alarms

If a zone is cold, check the heater band. It might be burnt out. If it reads “999”, your thermocouple (sensor) is broken.

Servo/Motion Errors

Our Hybrid and Electric models are precise. They need stable voltage.

Tip: Often, a simple sensor calibration resets the system.

10. Preventive Maintenance Checklist

Don’t wait for a breakdown. Do these checks.

• Daily: Lubricate toggle pins, check air pressure, and visually check the parison flow.
• Weekly: Inspect gearbox oil levels and check that heater bands are tight. Loose bands burn out.
• Monthly: Clean water filters and inspect hydraulic hoses for cracks.

Service Note: If you get stuck, we can help. LEKAmachine offers remote engineer maintenance guidance to guide your team through these checks.

11. Conclusion: Fix It or Replace It?

Systematic troubleshooting saves time. It stops you from guessing.

But sometimes, a machine is just too old. If you are spending more time fixing than running, let’s talk.

Do you need a spare part?

Or are you looking to expand capacity with a versatile FORMA or a high-speed AERO machine?