How to Know if You Need “Smart” Size Reduction Controls

How to know if you need "smart" size reduction controls
Size Reduction

How to Know if You Need “Smart” Size Reduction Controls

“Smart” equipment controls and the future of Industry 4.0 are definitely hot topics in the plastics industry right now. But, according to my colleague Alan Landers, realizing the vision of Industry 4.0 – the seamless exchange and processing of data using intelligent machines that can self-adapt and optimize processes autonomously – is very much in the future.

That’s true not only for primary processing equipment, but also for many pieces of auxiliary equipment, including size-reduction equipment.

How do you know if you need a “smart” size-reduction control?

Whether a piece of equipment requires digital controls that can monitor performance and trigger alarms for unusual conditions today, or that can self-adapt equipment behavior in response to changing process conditions tomorrow, really depends on how critical the equipment is to your operations.

In the case of granulators or shredders, your need for digital controls – and for future Industry 4.0 capability – probably comes down to whether your granulation and shredding operations are in-line – integral to your ongoing operations – or offline.

Today, for example, if your operators simply toss scrap into bins and then granulate it offline when they have time, you may not see the value in a granulation system with sophisticated digital controls, sensors, or alarms. You need a granulator that turns on, runs, and processes scrap when needed.  Should the throughput of that granulator decline due to blade wear or the need for maintenance, you can live with the delay.  The accumulation of ungranulated scrap isn’t slowing your operations or costing you essential production materials.

Who are the processors that typically need smart size-reduction equipment controls?

Users of size-reduction equipment who need and value the information provided by more advanced, PLC-based controls, and who may be looking forward to what Industry 4.0-capable controls might bring include:

  • High-volume film producers. If you’re running film lines at 3,000 to 4,000 lbs per hour, you need in-line granulating processes because those lines are generating a lot of edge and trim scrap and there’s no good place to put it.  Some of these processors literally put a granulator in the basement—directly below the line – to capture and granulate that scrap so that they can live-blend the material back into the process.
  • Thermoformers. Like film producers, thermoformers who make containers from continuous sheet constantly generate scrap in the form of “skeletons,” start-up scrap and off-spec product.
  • Recyclers. For a recycling operation, maintaining high throughput is everything. So you can’t afford to have unexpected downtime, or find yourself needing to take a key shredder offline for major repairs.

Processors like these must rely on size-reduction equipment to be available and ready when needed. So, smart control features, monitors, and alarms are important for tracking performance and keeping ahead of maintenance problems.

What equipment functions/factors are most commonly monitored by smart controls?

For some time now, makers of size-reduction equipment have been monitoring key factors of equipment performance, such as amperage, heat, and vibration using PLC-based control systems. These data – and a lot of practical experience – show that when any of these factors start moving beyond normal or baseline levels, then something is likely going wrong.

So, advanced granulator controls offer alerts or alarms when motors are drawing above-normal amperage, cutting chambers are getting hotter, or internal vibrations are higher than usual. The problem could be that the hardness of the material you’re granulating has changed and is taxing the capacity of the granulator more than usual. Or, the alarms could signal that the blades are getting dull or that lubrication and belt adjustments are needed.

For critical shredding equipment equipped with PLC controls, the most common things to monitor are motor amperage for the shredder shaft and hydraulic pressure in the feed mechanism that pushes material into the shredder. You’ll find that when the shredder blades are new, motor amperage is going to run in a baseline range, such as 30-40 amps.

If you see an alarm that motor amps are rising suddenly, you can use digital controls – manually or automatically – to temporarily reduce the hydraulic pressure in the feed mechanism until the amps come down. Then, higher feed pressure can resume.

However, if motor amps are consistently running in a higher-than-baseline range, say 40 to 50 amps, it’s a good indication that either new blades or other maintenance is required.

Smart, PLC-based monitoring functions like these weren’t really developed with Industry 4.0 in mind, but rather because processors with critical size reduction challenges need to know how their equipment is performing and want to know about any potential problems as early as possible, so they can schedule troubleshooting and maintenance and avoid outages or throughput problems.

What will it take to develop Industry 4.0-capable controls for size-reduction equipment?

We are having internal discussions at Conair about what future granulators and shredders will look like and how they will operate.  As you would expect, there’s a great deal of focus on what the controls should be like and what they should be able to do.

But, to be clear, there’s a huge difference between where we are today — with individual computerized controls that can monitor things like temperature, amperage, and vibration on a piece of equipment and indicate when those changing more than expected — and a whole class of equipment and controls with the capability to scan real-time sensor data, actively predict or identify a problem based on those changes, and then go on to recommend that people take some corrective action.

The difference is that it takes the collection and analysis of a huge amount of data over a long period of time, followed by the development and testing of computer algorithms, to make a control with such predictive capabilities.  But that is where the future of Industry 4.0 lies.

I know that such predictive capabilities will be very important for some categories of plastics auxiliary equipment, but, as I explained earlier, I’m not sure how broadly such “smart” or Industry 4.0 controls will be adopted in granulators and shredders.

The processors who need them will know and be willing to invest.  And those controls will be available. But there will always be a lot of processors who want grinders that they can buy, turn on, and forget about.  For them, the added cost of the controls, the alarms, or the predictive capabilities aren’t justified.

When I think of the smart granulator control that would be perfect for them, I think of an inexpensive plug-in module that that would simply indicate when blade changes or adjustments were needed. I think that would be a feature that virtually every processor would find valuable, regardless of the size or complexity of the machine.  But alas, it doesn’t exist today.

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