While the impact of quality-related cost factors are proportional to process throughput, efficiency contributors impose their costs or deliver their benefits over time by influencing process efficiency in various ways. Their impact is registered in the twin currencies of increasing up-time and reducing down-time, both of which readily contribute to bottom-line profit.
Flexible Material Handling
For most if not all plastics processors, operational flexibility is key. One way to keep flexible is to specify and select feeders capable of controlling the broadest possible range of materials possessing differing physical properties and handling characteristics. Feeder types and designs that are limited in this regard typically result in the costly and inefficient necessity to invest in multiple, ‘material-dedicated’ feeders.
No single feeder type, design or configuration can accommodate all materials, but when designed from the outset with material handling flexibility in mind, a feeder’s range of ‘handleable’ materials can be maximized. Modular design, easily interchanged feed elements optimized to handle various materials, hopper agitation and flow aid systems, selectable gear (speed) ranging, and other facets of feeder design all help add to the operational efficiency plastics processors require.
With or without a feeding system designed for material handling flexibility, material changeovers are a fact of life for nearly all plastics processors. Changeover costs are a function of changeover frequency and the time-based efficiency of the changeover operation itself. Clearly, a feeding system designed with material handling flexibility in mind also tends to pay off by improving changeover efficiency as well.
In addition to the design elements listed above that relate to material handling flexibility, other enhancements to changeover efficiency include features, options, and design attributes such as quick release clamps, single-tool changeover design, non-process-side access, material purging and supply transfer capabilities, control reconfiguration simplicity and the like.
Even apparently minor differences in the time-based efficiencies between alternative prospective systems will accumulate at each changeover and can become quite significant in the long run. Cost-conscious processors will carefully consider this dimension of the ongoing cost/benefit stream and include it in the purchase decision.
On the controls side of the equation, costs and benefits relating to the ‘human/machine interface’ are, by their nature, more difficult to identify. But, as the crucial point of contact between user and system, interface design and execution takes center stage in day-in, day-out operation, either boosting efficiency with full connectivity, attractive and well composed graphic displays, easy navigation and simple-to-use controls, or impeding it with poorly arranged, overly complex readouts and incomplete or disorganized information and outdated connection technologies.
While the subtleties of human-machine interplay may always remain subjective in the hard light of cost and benefit, there is no doubt that they leave their mark on the bottom line. When comparing alternative feeding systems it then falls to users themselves to gauge the extent to which a feeding system’s operational simplicity will affect overall efficiency and, in turn, the profitability of their process.
No one likes housework, but it’s a fact of life. At home we might be able to let things slip a bit now and then, but on the process line the stakes are much higher. Whether it’s material cross-contamination from less-than-thorough cleaning at changeover, a weighbelt that’s been left uninspected for too long, or any of dozens of other possible reasons, a failure to feed accurately immediately jeopardizes the entire operation.
A processor’s first line of defense is a program of regular monitoring, cleaning and preventive maintenance, formulated as the application requires. Thus, when evaluating feeding systems for purchase, particularly close attention should be paid to all suppliers’ cleaning and maintenance design features, recommended user practices, as well as what spare parts each supplier recommends be inventoried on site to enable immediate replacement of consumable or any other limited servicelife components.
Unplanned downtime or unanticipated process interruptions, whenever they occur, are painful and costly enough on their own. A single such event, if attributed to feeding system failure, could potentially incur costs that exceed any potential savings offered at initial purchase!
Don’t add to the pain by realizing too late that downtime may have been avoided in the first place. As part of any pre-purchase investigation, be sure to include cleanability and maintainabilty capabilities, issues and requirements as one of the many critical elements considered in the overall purchase decision.
An effective program of cleaning and preventive maintenance will certainly help minimize avoidable process interruptions and downtime, but such measures cannot guard against failures associated with an unreliable feeding system. As one of the true lynchpins of process operation, feeding system reliability is every bit as crucial to process operation as the reliability of any piece of ‘primary’ equipment.
Pre-purchase assessment of future operational reliability is problematic, in effect requiring the processor to ‘put the cart before the horse’ in attempting to predict which system will perform more reliably when put into service. However, telltale signs of future unreliability do exist, but it is up to the user to uncover them.
Here’s how: During pre-purchase equipment evaluation, inspect supplier offerings for the quality and robustness of design, the materials of construction, the quality of welds, mechanical fit, surface finishes, etc. The ‘devil’ may be in the details, but that’s where reliability resides as well. If possible, also visit each supplier for a tour of their production facility. Is it clean, well organized and efficiently run? And speak to prospective suppliers directly about your reliability concerns. Ask them for customer references you can contact and speak with. A little time spent before making the purchase decision will help assure reliable operation later on.
Pre- and post-sale support services provided by prospective suppliers (and their reps) play an especially important and continuing role in the successful application of any feeding system. It is only logical then to include this crucial dimension in the evaluation phase of the purchase decision.
Supplier support programs and services span a broad spectrum from initial application development, systems engineering, material analysis, and equipment selection and pre-purchase testing, to installation, commissioning, operations/maintenance training, and ongoing service, repair and spare parts programs.
Recognizing that the decision to select one feeding system over all others marks the beginning of a long-term commitment between supplier and customer, investigating each candidate supplier’s support services well before making a purchase decision enables a fair, fact-based comparison among available alternatives and will, in the long run, significantly improve the likelihood of a successful relationship.
Don’t be limited just to the efficiency contributors addressed above. If you can identify other ways a feeding system impacts the ongoing efficiency of your process operation, feel free to include them as well. As long as you can fairly detect and assess significant efficiency-related differences among candidate suppliers, it may be well worth the effort to include them even if you can’t attribute specific costs to each. See the next section for how to include elusive or intangible factors in your TCO decision.