Order From Chaos
By Michael Legault, editor
To Chuck Morgan, tech center manager, Conair (The Conair Goup, 60, is represented in Canada by Stephen Sales Group, Markham, Ont., for injection, and Metaplast/Conair, Lachine, Que., for extrusion) th...
To Chuck Morgan, tech center manager, Conair (The Conair Goup, 60, is represented in Canada by Stephen Sales Group, Markham, Ont., for injection, and Metaplast/Conair, Lachine, Que., for extrusion) the question of how to cost-justify a centralized materials handling system is a moot point.
“If you want to ensure the integrity of your raw materials and prevent production interruptions resulting from lack of properly prepared materials, your only option is a centralized, automated system,” Morgan observes.
Maybe so, but tradition still holds a lot of sway with many smaller, custom molders who have been running press-side loading systems for decades. These processors usually need to be convinced with hard numbers that the investment in a centralized materials handling system is going to make their operations substantially more efficient and provide a reasonably quick return on their investment.
Len Miller, president of Nucon System Inc., Richmond Hill, Ont., (61), believes more small custom molders are seeing the advantages of centralized materials handling and slowly changing their attitude.
“In the past there was a misconception among some custom molders that it was easier to get back on line after a material change with an integral loader, compared to a central system,” says Miller. “In truth, a central system is a much more efficient way to run multiple materials, and it requires much less maintenance.”
Miller points out one of the main advantages provided by a central loading system is the use of one or two central pump units to move resin in place of many multiple, press-side pump and filter units required for an operation with integral systems.
“With a central system there are no filters to change on the loader when you change materials,” notes Miller. “All you do you at the press is blow out the screen on the vacuum receiver and you’re ready to run.” Miller notes that filters on a central blower/pump system are normally equipped with a timed, automatic blow-back, so the filter does not need to be manually cleaned. There is no chance of contamination because the air pull is directed away from the loaders on the press.
SYSTEMS GEARED FOR SMALLER PROCESSORS
Conair’s Morgan believes there are very few processors, large or small, which could not benefit from automating materials management in at least part of their operation. Whether the processor is running a large-volume, continuous-run operation or a smaller, customized molding operation requiring a few minor material variations, such as different colors or regrind percentages, the key materials handling objectives would be:
Protect resins from contamination
Prevent separation of blends
Achieve proper dryness and eliminate moisture
regain during conveying
Minimize energy consumption
Maximize use of floor space and manpower
Greg Reid, president, Dier International Plastics, Unionville, Ont. (63), Canadian representative of Motan Inc., sees manpower savings and energy efficiency as two of the key benefits arising from a centralized materials handling system.
“If you’re running 12 different materials, you can have all the materials on-line at the same time,” says Reid. “Because you’re creating a vacuum from one central blower, there’s no filters to change or motors to maintain. Essentially, one material guy can maintain the entire plant.”
Reid also notes that the energy savings in switching from many portable dryers to one or two central dryers can be substantial.
“The biggest energy use in a materials handling system is regenerating your dryer bed,” Reid notes. “You have to pump a lot of heat and energy into the bed to drive out moisture. Naturally, consolidating the number of dryers provides improved energy efficiency.”
Another advantage afforded by centralized drying and storage of raw materials is improved housekeeping, notes Mark Milligan, technical sales representative, Universal Dynamics, Inc. (64, Hamilton Avtec, Mississauga, Ont.; 68, Total Plastics, Delta, B. C.). Milligan says the requirement of custom molders to change materials frequently often challenges the housekeeping practices of even the most diligent of processors. An integral system based on loading material from gaylords consumes valuable floor space; creates heavy forklift traffic, clutter and material spills.
Morgan notes that a small custom molder can usually find some cost justification in centralizing even a portion of its materials handling system. For example, when a U.S.-based custom molder with about 50 employees and a dozen injection machines added four new presses to mold telecommunications connectors, it decided to create a highly automated manufacturing cell, complete with central materials management system, assembly and decorating operations. The company, Aimet Technologies Inc. (Raleigh, NC), purchased a Conair Central Distribution System. The company has configured the CDS to vacuum load resin from gaylords into four insulated drying hoppers served by a single dehumidifying dryer. A vacuum conveying system directs material from any of the drying hoppers, through a fantail distribution manifold to any of four molding machines. If necessary, two machines can be fed from one hopper. Loaders for all the dryers and machine hoppers are governed from a single location via a central control system.
Nucon’s Miller argues that even a molder with as few as two machines can benefit from a centralized system. “A centralized system provides a custom molder with the flexibility to expand.” Miller notes that additional machines can be accommodated simply by “daisy chaining” electrical cable between machines.
Nucon compliments its own line of equipment with off-the-shelf wiring, PLCs and other componenets from major suppliers to offer molders an integrated materials handling package that is customized to the user’s operation and needs, says Miller.
CUSTOMIZING YOUR SYSTEM
Whether a processor has a large captive operation or a small custom molding business, specifying an automated materials handling system needn’t be guesswork. The key to success, suppliers say, lies in proper planning. A materials handling system should never be an afterthought.
Richard Hamilton, president, Hamilton Avtec Inc., Mississauga, Ont. (65), points out that there are no fixed formulas to determine whether or not a processor should or should not consider automating their materials handling.
“Over the years we have automated material flow in companies that process as little as a few thousand kilograms of material a week to those that process a million kilograms a week,” says Hamilton.
In helping a processor design a centralized or automated system, Hamilton says there are a number of fundamental considerations for processors to weigh (Table 1). After obtaining a basic plan of the type of system the processor wants to install, Hamilton suggests going through a cost savings work sheet with the processor to estimate cost savings as a result of materials bulk purchasing and automated materials handling. Factors considered in such a cost savings estimate include savings on bulk over small-lot materials purchasing, savings on floor space, savings on labor for maintenance and materials handling, savings on colorant usage if blending, etc.
Hamilton Avtec features a comprehensive line of auxiliary equipment, from silo systems to weigh blenders and loaders, for customizing an integrated materials handling system.
Much of today’s equipment for materials handling is designed to be modular and easily incorporated into a pre-existing system set-up to provide centralized capability. The modular Turbo line of pneumatic loading systems from Walton/Stout Inc., Lithonia, GA, (66) provides good production flexibility with a reduced floor space requirement at an economical cost. The system maximizes loading capacity in an operating envelope half the size of other designs, according to the manufacturer. An integral filter configuration reduces maintenance while pumps are energy efficient and quiet. The base syste
m consists of two vacuum pumps, controller, frame, filter and canister.
Maguire Products’ Micro-Blender gravimetric blenders with the company’s Clear-Vu vacuum loading system is ideal for companies that run multiple small processing machines (67, Nucon Systems Inc.). Clear-Vu vacuum loading systems provide the advantages of a central system at prices equivalent to those of conventional integral loaders, according to Stephen Maguire, president of Maguire Products. “In essence, ours is a ‘mini-central’ system that combines affordability with the efficiency of an automated, multi-station network,” says Maguire.
The AF-II additive feeder from Mould-tek, Scarborough, Ont. (69) is designed to provide highly accurate metering of pelletized color concentrate or other free-flowing materials into the main flow of resin. The AF-II utilizes Automatic Speed Control that eliminates the manual adjustment of motor speed associated with volumetric units. Under precise microprocessor control, the AF-II measures the screw recovery time of each cycle, totalizes the auger revolutions and calibrates to the exact meter rate of requested set value. Color metering occurs uniformly over the entire screw recovery cycle. All settings are made via an easy-to-use remote mounted control panel.
Blending is another facet of a centralized materials handling system that is catching on with many processors, says Nucon’s Miller. “Today’s gravimetric blenders are highly accurate and the cost has come way down,” says Miller. “Processors can do their own compounding and coloring at the machine. They don’t have to have 50 different pre-colored resins in stock.”
Says Dier International’s Reid: “We’ve noticed greater interest in centralizing raw materials handling in Canada. These aren’t new companies but existing companies looking to scrap their old integral systems and install a centralized one.” CPL