Steve Maguire, Founder and President, Maguire Products, Inc. in the Plastics Hall of Fame
- Machinery & Equipment
Steve Maguire is a prolific inventor who has transformed plastics raw material handling technology and revolutionized the way processors control the preparation and consumption of molding and extrusion compounds. As a self-reliant entrepreneur, he has drawn on his own early experience as a plastics processor to devise systems that addressnthe practical needs and preferences of processors, with an emphasis on simplicity, reliability, and ease of use.
Best known as the inventor of the Maguire Weigh Scale Blender, Steve Maguire has single-handedly developed the basic concepts, system designs, and manufacturing methods for this and other new forms of auxiliary equipment. Nearly all of these systems were radical departures from conventional equipment at the time of their introduction but eventually became industry standards. The company which he founded to commercialize his innovations, Maguire Products, Inc., is today one of the leading global supplier of plastics auxiliary equipment.
Having entered the plastics industry in the early 1970s, Steve Maguire at age 74 continues to work on developing new auxiliary equipment systems. His latest major invention, a new type of vacuum resin dryer for use by plastics processors, promises to have an effect on the industry as revolutionary as that of the Weigh Scale Blender. His three sons have joined him in the business.
Thus far 41 patents have been issued to Steve Maguire, 26 applications have been published, and 11 are pending. His chief innovations, presented in chronological order, include:
1977: Liquid color pump. While colorant is often the most costly additive in a compound, liquid colors are less expensive for processors than conventional bead concentrates. Until Steve Maguire’s invention of the Maguire peristaltic liquid color pump, however, there was no suitable device available for accurately metering liquid color into the processing machine. The invention was the basis for the formation of Maguire Products to supply dispensing pumps to liquid color manufacturers and their customers. In years to come, Steve Maguire would continue to develop innovations relating to liquid color (see developments in 2002 and 2015, below).
1980: Microprocessor control. Drawing on previous experience as a computer programmer, Steve Maguire pioneered the use of microprocessors in auxiliary equipment, starting with a controller and software developed for the liquid color pump. The microprocessor monitored the operation of the pump and automatically adjusted it to improve accuracy. Using digital input, the controller detected and compensated for changing cycle times, varying torque requirements, or fluctuations in plant voltage.
In developing other new types of auxiliary equipment, Steve Maguire subsequently expanded the role of computerization in raw material management. Among later innovations were self calibrating, self-adjusting controls for the Weigh Scale Blender; software enabling processors to network their blenders for plant-wide raw material management, operational monitoring, and job documentation; use of blender data for extrusion yield control; and translation systems enabling blenders to communicate with the microprocessor controls of all other processing equipment in a manufacturing plant.
These innovations in computer control have been put to work synergistically with the Internet via Maguire’s www.maguire.com website. Customers can use the site to download updates for their machine controllers, “test-drive” new control software, and troubleshoot problems with their Maguire equipment.
1989: Weigh Scale Blender. This system for metering and mixing pellet and powder ingredients enables processors to confidently blend in colors and additives that previously had to be pre-compounded, or to add regrind without the risk of erratic melt behavior caused by poor mixing. As a result, processors have eliminated over-coloring, reduced consumption of costly additives, and improved product quality and consistency.
When the Maguire Weigh Scale Blender was introduced in 1989, it immediately proved to be far simpler, less expensive, more accurate, and easier to use than the volumetric and “lossin- weight” gravimetric systems that were the only alternatives at the time. The first unit sold for $7,000, as against $35,000 to $70,000 for the alternative systems. In effect, the Maguire Weigh Scale Blender made sophisticated raw material management affordable and accessible to processors of all types. Today they are the predominant type of blender by far. Over 50,000 units from Maguire Products, Inc. alone are in operation around the world.
1996: Mini-central’ vacuum loader. The Maguire Clear-Vu loading system provides the advantages of a centralized system for loading pellets and regrind into processing machines while allowing flexible deployment in processing facilities. Each loader consists of a central unit with vacuum blower and dust filter; a microprocessor controller; and up to eight seethrough filter-less receivers for mounting over the hoppers of processing machines. Prior to the availability of this system, processors—particularly small companies—that could not deploy a large centralized system for loading multiple machines had to rely on integral-motor loaders. One of these conventional units, incorporating its own blower, filter, receiver, and controller in one large and costly package, had to be mounted on each processing machine.
1998: ‘Radial’ granulator. Completely different in design from conventional granulators, the Maguire Radial granulator yields greater throughput and higher-quality granulate and generates less dust. While the rotary cutting system in a conventional granulator turns on a horizontal axis at speeds as low as 200 rpm, the cutting system in the Radial granulator describes a circular path around a vertical axis at 1,750 rpm, creating far more centrifugal force to drive plastic scrap through the cutting knives and granulate through the screen. As a result, the rotor knives encounter the bed knives more often, yielding eight times as many cuts per minute. Introduced in 1998 as a beside-the-press system, the Radial granulator took up less space than conventional granulators and cost half as much.
1999: ‘Shuttle’ granulator. The first low-cost method for reclaiming large reject parts, purgings, and other bulky scrap, the Maguire Shuttle Granulator has a unique configuration based on the timeless concept of the carpenter’s plane. In a two-stage process, the granulator first literally planes scrap items into small pieces, then granulates them into high quality regrind. The system streamlines an operation that has been labor-intensive and costs an order of magnitude less than conventional size-reduction equipment for large parts.
2002: ‘Pump-in-a-Drum’ liquid color system. More than a quarter century after developing the liquid color pump that gave Maguire Products its start in business, Steve Maguire designed this new system to eliminate the workplace mess and handling complications of working with liquid colors. Introduced in 2002 by Maguire affiliate Riverdale Global, the system centers on a metering mechanism whose pump is inside a standard-size drum that stays sealed from the moment it leaves the Riverdale Global loading dock to its return from the customer. During processing, the system meters color through a sealed tubing assembly, with automatic shutoffs preventing spillage. Changeover from empty to full drums is automatic, requiring no monitoring by the operator. By returning the drum to Riverdale Global, the processor avoids the problem of discarding it. Riverdale Global takes responsibility for pump maintenance, tubing replacement, and other color-handling logistics.
2006: Gravimetric color / additive feeder. Steve Maguire introduced the MGF feeder as an alternative to volumetric feeders, which Maguire had long produced. Unlike volumetric feeders, the MGF feeder monitors the consumption of colorant, using two load cells to track the loss in weight of colorant in the hopper as the material is fed into the processing machine by an auger. Because the feeder generates accurate data about how much of the material is actually consumed from moment to moment, it is able to adjust color metering far more accurately to account for process variations. The key to adjusting for such variations is Maguire’s loss-in-weight software in the feeder control. The system scans data on color consumption every half-second and automatically adjusts dispensing when a pre-determined amount of accumulated error is detected.
2008: Gaylord Sweeper. This device solved the vexing problem of how to completely empty Gaylord boxes without wasting operator time or resorting to cumbersome box tilters. The Sweeper continuously sweeps the length and breadth of the top level of resin in the container, reaching into every corner, as it uses vacuum to transfer the resin to a processing machine or dryer. It descends along with the level of resin in the Gaylord until the container is empty. Because The Sweeper removes resin from the Gaylord without unwanted interruptions, there is no need for operators to stand by to ensure that the processing machine does not run out of material or that un-dried material does not enter the process. As a result, the Sweeper reduces labor and material waste, saves energy and plant space, and avoids the high cost and safety issues of conventional tilt tables.
2013: New-generation vacuum resin dryer. Plastics technologists had long recognized that the use of vacuum to pre-dry resins was potentially much less costly and more efficient than the hot air and desiccant systems that were used exclusively throughout the industry. Steve Maguire’s initial achievement—the result of development work which he pursued through most of the 1990s—was to devise a vacuum-drying system that was simple, practical, and affordable enough for any processor to use. This was the LPD dryer, introduced in 2000. After rethinking vacuum dryer design, Steve Maguire introduced a radically different system, the VBD dryer, in 2013.
The VBD dryer relies on gravity to move material through vertically arranged stages of the drying process, with the discharge of material from one stage to the next controlled by slidegate valves. This eliminates most moving parts, in particular the three-station indexing carousel mechanism of the LPD dryer. It also does away with sealing gaskets, which can be worn and compromised by resin dust, and with perforated screens, which require cleaning.
The VBD dryer differs from conventional dehumidifying dryers in two ways: 1) instead of heating the resin and flowing dry air over the pellets to slowly draw the moisture out, the Maguire system uses vacuum to literally pull moisture from within the pellets; and 2) the VBD dryer carries out heating and vacuum drying simultaneously in separate vessels, making possible small batches while in effect transforming a batch process into a continuous one that keeps pace with the throughput of the plastics processing machine.
The Maguire VBD dryer is in commercial use in many parts of the world. Processors confirm that it provides large and immediate benefits as compared with conventional dryers: 60% less energy consumption; elimination of the possibility of overdrying; and reduction in startup time as a result of a batch drying cycle that is only one-sixth as long. In addition, resin is exposed to elevated temperature for as much as 80% less time than with the desiccant dryer, which means less processed-in stress.
2015: Gravimetric liquid color delivery system. The Riverdale Gravimetric Stand (RGS) added a new dimension to the “Pump-in-a-Drum” concept by providing liquid color metering with accuracy and control similar to that available with the Weigh Scale Blender. In the RGS, a liquid color drum with “Pump in a Drum” design is mounted on a self-calibrating loss-inweight scale that continually reports the weight of the contents to the controller as a means of ensuring that the target let-down ratio is maintained. Flow is modulated through an air-regulated actuator that is connected to the liquid color pump.
Gravimetric metering holds color-delivery tolerance to within 0.1%, preventing overcoloring and making it possible to reduce costs while maintaining target color levels. In injection molding, for example, the operator simply enters into the controller the target shot weight and letdown ratio. The controller automatically maintains accuracy after determining cumulative error over a number of cycles, eliminating the most costly cause of color waste—operator errors.
2016: Low-profile vacuum receiver. The LoPro vacuum loading system for conveying pellets and regrind from storage to single or multiple blenders is simpler to operate than standard systems and consists of autonomously controlled receivers that are fully 80% shorter than conventional material loaders and receivers. LoPro receivers protrude only 200 mm (8 in.) above the lid of a blender, providing a low center of gravity that minimizes potential sway on fast-cycling processing machines. Each receiver is self-controlled, with no central control required. Connection and installation is simple, with plug-and-play cabling and sequential linking of components. Receivers load on a first-in / first-out basis. Vacuum is supplied from a “mini-central” unit mounted on a portable floor stand or on the blender frame and is powered by a single-phase brushless motor that has been used in thousands of installed Maguire GSL vacuum loaders.
- A.M.SK, spol. s r.o.