Efficiency improvements in coil processing don't have to start with a
May 12, 2009
The decision to upgrade a section or an entire coil processing line involves plenty of intelligence gathering from the shop floor if the right decision is to be made.
The decision to upgrade a section or an entire coil processing line involves plenty of intelligence-gathering from the shop floor if the right decision is to be made. Installation of this used leveler, for example, was the result of a significant investigatory process that determined the coil processor needed to improve quality for certain runs, but didn't have the financial means or the real estate to set up a new processing line complete with a leveler. After reviewing processes and deciding what made the most sense, the company purchased a reconditioned leveler for $35,000 and spent another $10,000 for engineering services that led to the creation of a base for the leveler and two adjustable idler rolls to move the leveler offline when it wasn't needed. The entire upgrade took three weeks. Afterward, the coil processor had the new capabilities to deliver higher-quality processing and adjust strip shape.
Because every coil processing line and each improvement project is different, only broad-based advice can be offered to companies considering changes on the shop floor. However, these five process applications can help any manufacturer make a dramatic change to improve efficiency. Moreover, each step is presented in order by estimated cost so that manufacturers can realize some benefit without exhausting all of their cash.
Internal processes should be scrutinized just like any other function within a business. Such feedback in an integral tool for fostering efficiency improvements.
Realistically, a proper review of the internal manufacturing process is the baseline by which 80 percent of rectifiable actions can be identified. The goal in these slow times is to find areas for improvement and efficiency and exploit them for the long-term growth of the company.
A comprehensive review of internal processes includes the following:
• Logistics (material movement,scheduling, and spares)
• Throughput (bottleneck identification)
• Organization (protocol, management, and communication)
• Planning (priorities, maintenance, and troubleshooting)
Many manufacturers have grown their businesses slowly over a long period of time. What can occur over the years is the creation of a material handling nightmare, as new lines and storage areas are added. Before the company realizes it, a considerable amount of time is spent moving coils to staging areas, transporting coils to saddles or conveyors, and loading and unloading scrap.
To start the process of improving the logistics of a manufacturing process, someone has to tabulate all material movements. This is the easiest and biggest payback available to any company. It requires little to no investment and can cut a considerable amount of time from the production process.
Performing a solid evaluation and comprehensive process time study will highlight areas requiring immediate improvement. At this stage, the goal is only to identify such changes; an action strategy can be performed at a later date.
Run schedules are always an issue with just-in-time processing. Outlining a changeover time study for each operation and setup in a process line can help the schedulers to better understand how to schedule urgent production runs.
Another area of concern regarding logistics are consumables. Many companies have their spares located centrally for ease of inventory and tracking, but this too can affect production efficiency. Centralized spares require that the tool cage attendants have an innate understanding of every part on every coil processing line. Categorizing consumables by process line is a simpler way to ensure that components are grouped for efficient retrieval.
Developing an accurate list of recommended spares for each piece of equipment in a process line is a long-term benefit for any coil processor. The recommended spares list, if not supplied by the OEM, can be refined over a period of time based on actual failures. Doing so results in a moderate reduction in spares inventory, while keeping critical components on the shelf.
This can be a time-consuming process, but it is a one-time investment. Refinement of the spares list is minimal once the overall list is compiled.
A chain is only as strong as its weakest link; similarly, a process is only as efficient as its bottlenecks. In manufac- turing, throughput is not limited just to the physical equipment and maintenance, but entails communication, receivables, deliveries, and tracking.
Organizing all incoming orders, requirements, schedules, safety cards, and maintenance actions is a major task. Again, the goal of the review process is to outline each step so that it may be addressed. This process can be handled with a traditional written list or with any one of many software packages aimed at process optimization.
When reviewing internal processes, a management team has to understand and focus the efforts of planning. This too can be a task unto itself, and creating a specific recipe to follow is difficult. Many good books on effective planning for manufacturers are available, so the team may want to read a few to determine what works best for their company's structure.
Reviewing internal processes is not an insurmountable task. The perseverance and tedium involved in identifying improvement areas can result in a solid foundation for greater changes. Again, this is the least expensive method to start the process of optimizing and improving any metals processing activity.
Optimization involves implementing actions to correct the shortcomings identified in the internal processes review. Optimization considers the following:
• Movements (material and personnel)
• Material handling (intraplant transport)
• Preventive maintenance
Movements throughout the plant are typically not scrutinized intensely enough to yield any profitable results. Earlier it was mentioned that a time study be developed to aid with scheduling. This same time study can be used to track movements throughout the plant.
A good place to start optimizing movements in a plant is by analyzing crane movements. Cranes are a vital part of material transport, equipment, and general maintenance, but one crane can do only one job at a time.
Of course, a coil processor can't have optimization with excessive downtime. Uptime is paramount, and a preventive maintenance program helps to deliver that.
The ability to plan maintenance around key indicators from the equipment will ensure that problems are rectified before they affect production. Recommended reading for company management includes guidance on developing a failure mode and effects analysis (FMEA). Such a report can help identify what areas of the equipment require the most attention.
A bit more cost is involved in optimization as most likely services will need to be contracted and equipment purchased. A full-service processor of coated coils theoretically could spend $75,000 to $100,000 optimizing operations, depending on the level at which it is pursued.
Getting the most from existing equipment is not as difficult as it may seem. Many companies, because of financial limitations, simply cannot install new equipment at every turn of the market. So to ensure the longevity of a process, it is necessary to upgrade the capabilities to obtain a competitive edge. However, understanding the equipment capabilities can be determined only after the other obstacles in the process are removed and the focus is on running production.
Factors in identifying equipment capabilities are:
• Downtime (looking at equipment failures)
• Performance (looking at equipment operations)
• Maintenance (examining equipment maintenance)
When equipment is down, obviously so is production. The big question is, Why does the equipment fail?
A preventive maintenance program based on the fundamentals of FMEA can help answer that question. It makes the physical process of fixing equipment more concise and allows the equipment to be analyzed for failures.
If equipment is failing because of a broken bolt or failed bearings, it could be possible that the equipment is not designed to handle a 10 percent to 15 percent increase in production. However, if the failures are linked consistently to drive faults and broken couplings, only a partial upgrade of the equipment may be needed.
Accurately determining equipment limitations requires observation and quantification. A sound strategy is to observe the past failures and correlate them to changes in material thickness, speed, metallurgy, and the age of the equipment. These associations, in conjunction with FMEA, will dictate what part of the equipment needs to be upgraded.
When identifying possible equipment enhancements, it is important to remember that maintenance requirements may change too. The maintenance kiosk may require different tools, a different FMEA, and a new list of consumables for spares.
All of these revelations about existing equipment come at a price. An assessment of the equipment and proposed changes requires engineering, design, and many review meetings. If these skills can be found in-house, the obvious cost associated with such work is greatly reduced.
The decision to move forward with any upgrade regardless of scale should not be taken lightly. A risk exists of signing off on a large expenditure and chasing an unattainable payback. A cost analysis after the proposals are in should be the ultimate deciding factor in pursuing potential upgrades.
Working with an engineering firm that has performed work of this nature can provide new observations and fresh input. An engineering study for a midsized project that includes 12 machines on a process line might cost between $75,000 and $125,000. A complete upgrade proposal at this level could cost from $120,000 to $200,000, which includes all drawings, calculations, concepts, and equipment proposals.
The actual task of undertaking an official upgrade will require a larger team to handle the specifics of each section of the process. Reviewing internal processes, which was mentioned earlier, will take place again as part of this process application, but this time all the details will have to be uncovered.
The four aspects that must be focused on during an upgrade are:
• Line overview
• Offline process/changeover (all prep work for product runs)
The team overseeing this upgrade should include a representative from every process section found in the coil processing line. With everyone contributing ideas, finding ones that make the most sense will be an easier task.
The line overview becomes the microschedule for the upgrade and begins with details for each piece of equipment on a punch-list. The easiest way to communicate the schedule is in a well-outlined spreadsheet or a document originating from some project management software.
One of the biggest areas of concern in any upgrade is changeover. Poorly planned and orchestrated changeovers can negate all of the hard work of an upgrade. Some upgrades deal with only changeover process and add value by reducing setup times and labor. The direction of an upgrade is ultimately based on a company's requirements.
To measure the success of a project, metrics need to be established. Milestones, cost, payback, and labor reductions are examples of factors that result in a good return on investment.
Like with the project, a successful equipment upgrade also requires feedback. Through the addition of instrumentation, this feedback on equipment status can be relayed properly to operations and maintenance.
Based on equipment feedback, a preventive maintenance program can be established, which should allow the company to go on the offensive in terms of maintenance issues. The goal is to be more efficient through predictability.
On the whole, equipment is dumb. Cylinders are either in or out, rolls turn or stop, sprays are on or off. The backbone of any successful upgrade is the addition or improvements to the control platform that runs the process.
Two basic architectures are employed in process lines: Level 1 and Level 2. Level 1 systems rely solely on the operator for set points and other system variables. This type of human-machine interface puts the adjustments in the hands of the operator. Level 1 control is typical with noncontinuous lines.
Level 2, on the other hand, is more standard with continuous process lines and uses a setup database that sends the set points to the equipment. This allows the operator to trim out the settings for a specific coil. Small manufacturers are using the Level 2 control for noncontinuous lines, too, because they allow information about the staged coils to be read and passed on to the line controls for quicker start-up.vDrive packages have changed dramatically in the past 10 years, and integrating new drives and feedback devices allow the equipment to operate with less energy and more accurate control.
The upgrade costs can become quite large pending project scale. It could be estimated that the upgrade will add another $200,000 to the cost of identifying the equipment capabilities. Of course, if new equipment is added to the mix, the investment figure could equal the sum of all the previous investments mentioned.
At this point, this investigation into an equipment upgrade has progressed to the point where a decision to press on with a fully capitalized project is due. That decision will depend on the information obtained from the equipment capabilities research and from the cost analysis.
The four key components of a capital project are:
• Commitment to a total process upgrade
• Possible new equipment purchases
• Possible facilities additions
• Commitment to training
Capital projects are costly, but have many redeeming qualities. Every process application discussed previously can be included in this type of project.
That's why it's called a total process upgrade (TPU). Without a doubt, projects of this size require a large and skilled team to be effective. When completed, a TPU can give any manufacturing process a much-needed facelift—increasing efficiency, removing cost, and reducing energy consumption—and set the course for future growth. On the contrary, a bungled project can be twice as expensive, with lost time and production headaches sometimes continuing for years.
New equipment purchases can be considered on a case-by-case basis and included in the TPU. What should be clarified is that integration of any new equipment may require that existing equipment be relocated, which may make upgrading existing equipment preferable.
Facility additions for new lines, shipping, and storage should follow the plan outlined in the initial review. If large growth is anticipated, time should be spent in determining the logistical layout of material flow.
Often considered as a price adder to the equipment, good training is invaluable to operations, management, and maintenance. More companies are requiring their employees to complete in-house training on their equipment for the sake of consistency.
Better material handling and equipment moving are only part of the benefit that can be realized from optimized movements. Allowing maintenance personnel and operators to stage the required tools at logical locations for routine adjustment and maintenance is a benefit too. Installing a maintenance kiosk at locations where adjustments are made routinely can eliminate excessive time spent looking for tools and parts.
Offline processes such as scrap handling, equipment staging, and waste removal are areas for improvement, but are often affected by varying real estate, line configuration, and available equipment issues. Implementing automatic scrap dumps, conveyors, magnetic jib cranes, and waste pumps can help get around some of these obstacles, but more than likely the optimization of these processes will require some financial investment in equipment and engineering services.
A team involved in investigating an equipment upgrade for a commercial food manufacturer was analyzing a tension stand in a push-pull operation on the line. The drag stand was a four-roll configuration using high-friction nylon rolls. During operation, everything was fine and operated as designed. The coil processor decided to take an order for some material that had a higher yield strength than the OEM specification. After consulting with the OEM, the company got the OK to run its new product range.
During this time the tension stand started to experience very high failure rates of its drives, motors, and couplings. After further study, it was found that the equipment had the capability to run the new product, but the drive train was not designed to handle the tension requirements, speed increases, and the line's tension transients. This resulted in redesigning the drive train from the couplings back to the drives.
This shows that even new equipment can be overworked just after installation.
Equipment performance is based on certain criteria designed into the equipment. Operation beyond the original intent needs to be reviewed by someone competent and capable enough to evaluate the upgrade request and see if it is feasible and cost-effective. The sad truth is, sometimes existing equipment needs to be reborn as a mailbox.