6 Control Features You’ll Find on the Best Gravimetric Blenders

6 Control Features you'll find on the Best Gravimetric Blenders
Blending

6 Control Features You’ll Find on the Best Gravimetric Blenders

Featuring the most advanced controls available in the industry, Conair TrueBlend® gravimetric blenders represent a dramatic step forward in ease of programming and use, simplified troubleshooting, comprehensive data collection and, of course, accuracy. Those are pretty hefty claims, but TrueBlend gravimetric blenders are not like other blenders you might be evaluating. Let’s take a close look at why.

What Makes a Gravimetric Blender the Best?

The critical component that will make a gravimetric blender stand out is its controls.

The latest SmartBlend SB-4 control from Conair sets a new standard for ease and precision in blender control for injection-molding and extrusion operations. Accessed through an enlarged and more vivid 7-inch color touchscreen display, the SB-4 control simplifies blending control with friendlier, more intuitive graphics, easier programming and more comprehensive monitoring and control features. It also sustains a best-in-industry dosing accuracy of 0.025% for the total batch dispensed, thanks to Conair’s unique “feed forward” dosing algorithm.

Here are 6 things the best gravimetric blenders do:

  1. Make set-up simple using an intuitive and feature-rich touchscreen display.

    SB-4The home screen display provides realistic graphics, showing current material levels and target-vs-actual dosing for each attached TrueBlend feed hopper, plus information about mixing-chamber material level and mixer blade rotation.The control can manage up to 12 ingredients, dispensed from 12 material bins. That’s 50% more than competitive blenders.

    Set-up is highly intuitive. The operator simply uses the touchscreen to identify the material types – any material can be assigned to any bin – and sets the feeding order. If regrind is a component, simply identify what percentage of the total batch size will be regrind. Then, the control automatically scales in the other materials in the batch to keep the ratio of all ingredients in line with the recipe. It will also reset the blend ratio if the regrind supply runs low or is depleted. Once a recipe is set, it can be stored in the expansive SmartBlend memory, which can accommodate up to 3000 recipes and up to 4000 resins and ingredients under custom names according to whatever system works best for the user.

    The control display supports 12 languages, making it possible for users to select whichever language they prefer for programming and operation. The language can be easily changed at any time, even from minute-to-minute as different employees interact with the system.

    The SB-4 blender control also includes a self-loading option, enabling users to add vacuum receivers to blender hoppers. After plugging them in to the SB-4, users enter parameters through the touchscreen to control up to 12 loaders, as well as 1 pump per blender, so that they can move materials to or from blenders, even using priority loading, if needed. The SB-4 shares the same loader control interface, so no extra operator training is needed.

  2. Increase dosing accuracy by incrementally dispensing in each batch.

    No gravimetric blender is more accurate than a TrueBlend blender thanks to a unique “feed-forward” learning algorithm at the heart of the SB-4 control. Instead of making a single dispense of each ingredient and adjusting for discrepancies in subsequent batches, the SB-4 uses incremental dispenses in each batch, continuously weighing the material and adding a little bit more until the target weight is reached. This approach ensures that all materials are accurate to 0.025% of the batch recipe. In other words, if the total batch is 1000g, it can dose any ingredient to within 0.25 grams of the target.

    The other major factor is seen in the order in which ingredients are dispensed. In most blenders, the dispensing order begins with regrind, then natural/virgin and then color or additive. The color/additive was normally done last so that it could be calculated to the proper percentage of the already weighed regrind/natural. However, Conair has rearranged the standard sequence. The regrind remains first in the sequence (since it is always a percentage of the total batch and already includes color and/or additive). Then, the minor ingredients are dispensed second, and weighed as accurately as possible, and then the natural is adjusted accordingly. By keying batch accuracy to the smallest component dispensed, rather than the largest, Conair’s dispensing sequence dramatically increases batch consistency and accuracy.

    Accuracy is further enhanced by using batch reports (about which more will be presented below) and process control to manage dosing centering and variability. The SB-4 SmartBlend control calculates both Cp, which measures the variability of dosing over time, and CPk, a value that indicates how well that variability curve is centered between upper and lower specifications. This ensures that materials are dispensed in a repeatable dosed amount and that that amount is well centered between upper and lower specifications.

  3. Enable real-time troubleshooting with dispensing diagnostics and user-defined alarm parameters.

    The SB-4 Smartblend control makes it easy to diagnose blender problems in real-time. You can actually watch a batch being made. When it’s done, you can see the actual amounts that it dosed, the set and actual values in grams and as a percentage of the total batch. You can see the time it took to dispense each material and the number of dispenses it took to reach the final weight. From the control, you can also verify the accuracy of the blender. This is valuable in many situations. You can look at it live and see, for instance, if you have a valve problem or whether there might be some bridging in one of the material bins. And all this data is retrievable: every value for every component in every batch, along with the Cp and CPk data noted above. Just save it to a USB stick or share it over a network to other computers for more in-depth analysis.

    Of course, the SmartBlend control also recognizes other problems that can occur – such as a hopper low material signal – and generates alarms as needed to keep the blending operation running trouble-free. Alarms can be urgent, requiring immediate attention, or passive or merely informative. They can also be modified with user-defined parameters. The control can track and record up to 100 events (date, time, alarm type) and reports alarm date, time and error time.

  4. Verify blend quality and other KPIs with on-demand reporting.

    SB-4 reporting capabilities screenTransparency is one of Conair’s chief objectives in developing the data gathering and reporting functions of the SB-4 control. Each blender can develop a variety of reports that can be used to verify blend quality and consistency, track consumption of resins and other ingredients over a given period of time, track the amount of particular recipes over time, or record the materials consumed by a particular part or customer order. Any blender-specific report can be compiled on demand simply by pressing the ‘Run Report’ button on the control panel or run automatically on a user-defined schedule.

  5. Eliminate manual compilation of blender reports with SQL database queries.

    Until recently, obtaining a plant-wide view of blender operations required manual compilation of all blender-specific reports. But now, these reports can be exported directly from blenders to an SQL (Structured Query Language) server, via Ethernet connections from blenders to a network hub. This way, all the data discussed above flows straight into an SQL database. Once it’s automatically loaded and formatted into that database, you can use database queries created by Conair – or write your own – to run the reports you need. Queries can be structured to report on virtually anything – as general as how much polyethylene used plant wide in the past 90 days, or as specific as the amount of colorant processed in Molding Cell #5 during second shift on Monday.

    Learn more about SQL Reporting Software for Gravimetric Blenders ►

  6. Manage data on any device using the Industrial Internet of Things.

    When Conair’s SmartServices portal was first introduced at NPE 2018, one of the first families of equipment connected to it were the TrueBlend blenders. SmartServices is a web-based portal, supported by cloud-based data processing capabilities. It helps plastics processors manage data generated by dozens or even hundreds of pieces of plant equipment — blending, drying, temperature controls and more – and turn it into actionable information.

    Users can use SmartServices to do all the SQL reporting discussed above, including the resin totals, batch logging, Cp/CPk information, alarms and all the other data. All that is available to be run under the reports function in SmartServices. Because it is a web-based portal, you can use this anywhere you have an internet connection.

    One of the most useful features is the ability to establish Key Performance Indicators (KPIs) for connected equipment. For blenders, that might be batch hopper weight, how many pounds per hour the blender processes, or actual percentage of a particular ingredient dispensed. But there are as many as 60 different measurements that can be collected from each blender – all stored in the SmartServices cloud. You can also create alerts built around specific KPIs or custom performance thresholds, and tell the portal to notify designated team members (by phone or email) if variances occur.
    Gravimetric Blender KPIs on IIoT

    For instance, in a blow molding operation, the parison length may be very sensitive to how much regrind is introduced in the material mix. One of your KPI’s could be designated as regrind percentage, with high and low set points. If regrind percentage drifts outside the setpoint window, an alert would be generated and sent to designated team members.

    You can also control individual machines remotely simply by logging into the portal and clicking the ‘Machine Control’ button. If a problem occurs and a key set-up person is off-site, they can be alerted and can log into SmartServices from anywhere to make necessary adjustments, just as if they were standing in front of machine control panel.

Control systems are key when choosing the best gravimetric blender

Whether the SB-4 Smart Blend control system is used alone or augmented by the capabilities of SmartServices, it is the most significant differentiator for TrueBlend blenders versus competitive systems. It delivers not only the highest levels of accuracy, but also ease-of-use that is second to none, and data-collection and reporting capabilities – alone, through SQL databases, or with the SmartServices cloud – that give users a fully transparent view of everything going on with the blender so that they can operate at maximum quality and efficiency with minimal downtime.

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