From the United States, we awaited the arrival of the coronavirus with great trepidation, watching as countries overseas battled what would eventually become a global pandemic. Manufacturers raced to postpone normal operations, keeping workers safe and distanced, but many jumped at the opportunity to produce much-needed equipment and personal protective equipment (PPE).
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Risks and challenges
Issues that are not addressed properly during changeovers can introduce risk to the manufacturing process and can cause longer startup cycles, more rejected product and increased machine malfunctions. In addition, manufacturers have to be cognizant of the effect a new process has on equipment failure, as well as the limited knowledge base of the workforce in manufacturing that new product. “Both of these factors will slow down production and increase rejected product, resulting in high operator costs and increased safety concerns,” warns Ranbir Saini, director, digital product management, GE Digital.
“When manufacturing liquids such as alcohol production to sanitizers, companies require a repeatable recipe that they will produce in batches,” explains Saini. “Batch-execution-management software enables recipe scheduling and execution, as well as rapid sequencing of batches by not requiring modification of the PLC code. By leveraging a model-based system, manufacturers can easily build and deploy recipes to run on any equipment of a certain equipment type and gain greater agility.”
Initially, changeovers will equate to nonproduction time with many labor hours spent cleaning, adjusting and verifying machine setup, notes Saini. “The key to manufacturing success is maintaining an agile environment by leveraging robust software solutions that ensure all processes are moving, and moving quickly, to address the changing needs of the current climate.”
When making a factory changeover in times of need to a wholly different product there are many major challenges to consider, but Jim Davis, director of advanced solutions & technical support, Allied Electronics and Automation, believes there are three that are illustrative of the overall process. One is the physical layout of your factory. If for instance, you have been producing cars, 2-ton, 12-foot-long products and now you need to produce ventilators, a much smaller item, there are some challenges to overcome. In addition to the physical scale issue, you will have challenges around the electrical systems from workstations to sensors used in the build process. And lastly, you are likely to need completely new control program to handle whatever the new production task may be.
“To create efficiency around your existing physical plant space, you need to find ways of using the installed conveyance and material management systems,” explains Davis. “This could be done using jigs that would fit on current systems and hold the new parts. While jigs and adapters can incur some cost to fabricate, they will also help keep other costs from mounting. A second advantage of using the installed equipment is that when reverting to normal production, much of your prior physical setup is still in its pre-transition place.”
Another challenge that must be addressed if a facility wants to maintain efficiency in output using the assembly-line approach is the electrical infrastructure of the plant. “Utilizing existing workstations allows for the use of the same power for new tooling and eliminates the need to change lighting in the building,” explains Davis. “Making an effort to use the same sensors and other field devices in use for normal production can also help keep the timeline and cost of transitioning down.”
Control systems are a major hurdle since many manufacturers have spent decades refining their production programs, notes Davis. “Keep in mind PLCs and distributed control systems were developed to be flexible. You can store code away from the controller so that when it is time to revert to normal production that will be a much easier process,” he says. “When altering production controls for the temporary new products, you likely won’t need to start totally from scratch, but just alter the timing and flow to get the new desired effect. After the safety systems are in place, you can then begin production.”
