Today's KNOWLEDGE Share : Injection Molding – Cavity Pressure Instrumentation

 Today's KNOWLEDGE Share

Injection Molding – Cavity Pressure Instrumentation (Part 3)


How Many Sensors Do You Really Need?

Before answering that… let’s review the two real-world cases:


🔁 Post 1 – Crisis Control

PURPOSE

Recover a failing process and stabilize production using cavity pressure transfer.


WHAT WAS DONE

- Cavity pressure used to control machine switchover (transfer)

- 3 sensors per cavity installed initially for validation and redundancy

Final plan:

→ validate the best location

→ remove extras and redeploy


TECH SETUP

Strain gage (direct) sensors

Simple controller → single input → transfer signal to press


RESULT

👉 Crisis averted - assembly line uninterrupted

👉 Process stabilized

👉 Scrap eliminated

👉 Facility adopted new control strategy - seeing is believing


🔁 Post 2 – High Cavitation Recovery

PURPOSE

Save a 16-cavity tool from replacement by resolving chronic quality issues.


WHAT WAS DONE

- Strategic sensor placement based on quality data + short shot study

- 4 sensors total (not 16… just 4)

- Loadcells behind ejector pins (Indirect)

- Focus: capture imbalance, not measure everything


TECH SETUP

- Piezoelectric sensors behind ejector pins

- Charge amplifiers

- External process controller

- Defined monitoring limits


RESULT

👉 Zero customer complaints in 12-month period. Non-fill + flash issues eliminated.

👉 Tool returned to full production

👉 Indirect sensing performed reliably


COMMON MISCONCEPTION

Engineers often assume:

👉 “We need a sensor in every cavity… maybe even two (post-gate + end-of-fill).”


Maybe.

…but it depends on the objective.


CONSIDER THIS

- 16-cavity production tool

- 20 sec cycle

- ~7,000 production hours/year

- ~20 million parts made annually


Now ask yourself:

👉 How much of that is actually measured?


Current State

- Machine conditions are monitored

- Product quality is inferred

- Quality inspects 2 sample shots per shift (single shot)


CONCLUSION

👉 20 million parts produced

👉 0 parts measured in real-time at the cavity level



Quality is being judged based on:

machine behavior… not the plastic


WHAT IF…

We add just 2 cavity pressure sensors


NEW REALITY

- 2 cavities monitored out of 16

- Real-time process limits established

- Continuous validation of two cavities


📊 What That Means

- 12.5% of cavities directly monitored

- 2.5 million parts per year validated in real-time


🧠 THE SHIFT

We went from:

👉 0% direct measurement

to:

👉 millions of parts validated at the cavity level

👉 Every shot contained two validated parts


💡 THE POINT

You don’t need to measure everything to dramatically improve control.


You just need to measure:

👉 something meaningful

👉 in the right location

👉 with a sensing chain that will perform well over millions of cycles


🔥 FINAL THOUGHT

The biggest leap in process control

isn’t going from 2 sensors → 16


It’s going from:

👉 0 sensors → 1 meaningful measurement


Do you know what is happening inside your mold?


source : Rick Bujanowski

Comments

Post a Comment

Popular posts from this blog

Today's KNOWLEDGE Share : What Is Going Wrong in UK Plastics Recycling?

Image
Today's KNOWLEDGE Share What Is Going Wrong in UK Plastics Recycling? Biffa shut its Sunderland plant. Viridor walked away from Avonmouth and Rochester. Yes Recycling Fife collapsed within a year. All three were backed by major investments All three had buyers lined up for recyclate All three are now offline This is not bad luck It is bad structure Over the next four posts I will break down: 1. Why cheap virgin imports are undercutting UK recyclers 2. How weak policy enforcement is fuelling market failure 3. What volatile PRNs and cheap exports are doing to infrastructure 4. Why demand from brands is softer than their promises Let’s start with the first: **Cheap Virgin Resin = Broken Economics** Virgin PE, PP, and PET have been flooding the global market. New capacity in Asia and the US has driven prices down 30 to 40 percent. Meanwhile, recycled plastic costs more to produce in the UK than it can sell for. We are asking UK recyclers to compete with materials made in places with – ...
Read more

Today's KNOWLEDGE Share : Robotic 3D printing can compete with traditional boatbuilding

Image
Today's KNOWLEDGE Share “Robotic 3D printing can compete with traditional boatbuilding”, Simone Barbera and Mattia De Santis, Caracol V2 catamaran was printed in Italy at Caracol’s production center and headquarter in Barlassina, near Milan, with a Heron AM 400, Caracol’s robotic Large Format Additive Manufacturing (LFAM) platform. The lattest was specifically configured with a 7-axis robotic arm mounted on a rail, enabling the printing of parts up to 10 meters in length. How did the collaboration between V2 Group and Caracol come about? Simone Barbera : The collaboration between V2 Group and Caracol originated from a shared vision to revolutionize boat manufacturing through sustainable innovation. V2 Group, a Spanish-company specialized in nautical design and engineering, is seeking to develop electric vessels manufactured sustainably. On the other hand, Caracol, leader in robotic advanced manufacturing technology, had had years of experience working with Large Format Additive Ma...
Read more

Borealis’ new compounding line in Belgium offers premium recyclate-based polyolefins

Image
 Borealis is proud to announce that its new compounding line for recyclate-based polyolefins (rPO) is now fully operational in Beringen, Belgium. This milestone marks a significant step forward in helping customers meet their circularity and sustainability targets—without sacrificing performance and reliability. Using Borealis’ proprietary Borcycle M mechanical recycling technology, the line combines post-consumer and virgin polyolefins into rigid polypropylene (PP) and polyethylene (PE) compounds that meet the high standards required for demanding applications in mobility, consumer products, appliances, and energy. The Beringen facility is not only designed to process a wide range of recyclate flakes, offering exceptional versatility to meet diverse customer needs, but it also serves as a platform for collaboration—enabling customers to co-develop and test new solutions that bring recycled plastics into high-value applications. “This installation is more than just a technological ...
Read more