Preventive + Maintenance = Quality

Slitters and splicers play key roles during the printing or finishing of printed packaging, and it is imperative to keep them in good working order. To do so, many printers turn to preventive maintenance (PM) programs—structured maintenance schedules for specific parts of a piece of equipment. “A good PM program is absolutely necessary for any equipment in which the continued operation is critical to meeting customers’ demands for the products produced and/or converted on this equipment,” says R. Duane Smith, product manager, specialty winding, Davis-Standard, LLC, Converting Systems (www.davis-standard.com). Adam Wiecko, Rotoflex service coordinator, Mark Andy Canada, Inc. (www.rotoflex.com), adds, “It is important to consider involving the manufacturer in the development of any PM program. They are the ones who know the machine and know it best.”

Wiecko continues, “Damage can absolutely spread if maintenance issues are allowed to fester.” For example, he notes that failure to maintain a clutch will result in replacing an entire unit, and failing to replace bearings could mean a ruined shaft. “It is critically important to keep equipment updated and running smoothly to achieve optimal performance,” he asserts.

What wears out?

Knives are the parts that wear out the most in slitting systems, according to everyone who spoke with packagePRINTING. But these aren’t the only parts that need to be addressed.

Knives wear at varying intervals, with the top blade needing to be replaced before the lower knives. The interval, according to Smith, depends on the material being slit and the speed and percent of running time of operation. “This could be as short as one day or as long as one month,” he says. “The bottom slitter blades also need to be replaced on a routine basis, which is always much longer. This would typically be every three months to yearly.”

Brian Ivens, Arpeco (www.arpeco.com), offers, “The components that most often need replacing are the slitting knives, but I am sure that this is self-evident. After that, items related to the web transport are next, specifically nip rollers and nip roll gears.” Nip rollers, he says, wear depending on material type and width, and nip roll gears can be damaged during frequent, high-speed stops and starts, as well as during material wrapups. He adds, that in older machines, other parts such as brake and clutch friction discs and pads wear out. In general though, Ivens suggests that when it comes to maintenance, “converters should consider all areas of the machine that can affect web transport and processing accuracy.”

Kelly Hart, communications and advertising director, Martin Automatic, Inc. (www.martinautomatic.com), says the items that wear out on a splicing unit depend on the equipment, the material, and the process. “In butt splicers, for example, we might expect it to be the anvils or cutter wheels that have gone dull,” she says. “And here’s an important component of a splicing system that isn’t even part of the splicer: it’s the tape. Make sure you use a good tape and replace any that’s been sitting around too long.”

For manual splicing applications, Wiecko says “we have seen minimal components that require more than routine maintenance.”

Designing the program

There are several key factors to consider when developing a PM program—factors that are not necessarily germane to only slitters or splicers.

Peter Wood, slitting product manager, Tidland Corp.(www.tidland.com), says a PM program depend on the environment (heat, humidity, etc.), web materials (including chemicals), speed of the line, and run time.

“This is very specific to the type of equipment and the duty of the operation,” adds Smith. “The OEM supplier should provide a detailed list of spare parts for regular replacement, and suggested replacement intervals. These guidelines need to be followed for years of problem-free operation.”

Wiecko echoes Smith’s comments. “[The OEMs] should be familiar with any retrofits or upgrade details and intentions, as well as proprietary components including software,” he says. “A respected OEM will know what the latest technology is for the equipment and what can be done to maximize its value to the converter.”

He adds that the best course of action is to make a PM program routine, rather than a once or twice a year occurrence. “The program must be continual, resulting in the greatest long-term productivity from the [equipment].”

How comprehensive to make the PM program is also a consideration. Hart explains, “[The advantages] depend on the equipment, the material, and the process. And, it depends on what is meant by ‘comprehensive.’” She says that if “comprehensive” implies constant inspection, lengthy periods of downtime, and frequent replacement of parts, then that kind of program sounds like a disadvantage. She adds that maintenance to that extent also may be an indicator that an equipment upgrade is in order. “Preventive maintenance is helpful, but start with a well-designed, robustly built machine. The best splicers are those that follow the ‘KIS’ (keep it simple) principle. We have machines in operation for over 30 years. If you have a machine that’s built to last, then frankly, you shouldn’t need an exhaustive or costly PM program,” says Hart.

Wiecko cites peace of mind as an added benefit to having a comprehensive program. “A comprehensive PM program gives converters the comfort of knowing that their equipment is updated and tuned to run at peak performance,” he says. “Many PM programs include a maintenance agreement, guaranteeing a set number of visits throughout the contract. The converter is secure in knowing that the equipment will be appropriately and fully maintained throughout the contract.” More importantly, to Wiecko, is the current economic situation. “The converter will experience reduced costs, including a reduction in downtime and waste, and increased speed and high quality,” he relates.

Ultimately, the equipment owner and supplier should discuss exactly what the PM items should be and the interval in which these items need attention, according to Smith. “Then,” he says, “be sure that this program is undertaken and maintained on a continuous basis for the life of the equipment, which hopefully will be for many decades.”

Some things to include in your PM program for slitters, according to Wood, include cleaning linear rails, checking for bearing wear and lubrication requirements, checking carriage movement, cleaning cable management, and checking air supply and filters for pneumatic systems and knifeholders.

On the splicing side, knives are equally as important to Smith. “On a splicing operation, changing out the transfer knives on a routine basis is also a good preventive maintenance action item,” he says. “A missed transfer can be very costly.”

Clear advantages

Properly maintained machines will stand the test of time. Ivens says that regular preventive maintenance will reduce the overall cost of repairs to a machine because problems are discovered and corrected before they get a chance to damage other parts. “Machine downtime can be scheduled instead of occurring at the worst possible times,” he says. “As well, machines, which are in good condition will perform better and provide higher productivity.” Ivens adds that Arpeco works with customers that run equipment from the 1970s, but cautions that, “I have also seen equipment that was not maintained and was considered scrap after only 10 years of operation.”

On the splicing side, Hart asks, “what is the cost of a missed splice—the cost in downtime, wasted material, lost profits, late shipments, depressed morale, etc.?” She says that if equipment is engineered and constructed well, and if operators are trained to use it properly and inspect it regularly, a simple maintenance regiment is all that’s needed.

“Implementation of a PM program can prolong the life of the equipment indefinitely,” claims Wiecko. “Slitting/splicing machines from reputable manufacturers are built to last a long time, as long as they are well maintained. Of course, technology always plays a role and as OEMs find ways to improve speed, waste, accuracy, productivity, etc., an older machine may become outdated. But that is the risk with any industrial equipment. With proper PM programs, appropriate upgrades and retrofits will be recommended as appropriate.”

The bottom line

If investing in a PM program isn’t going to have a good ROI, then companies will probably be less inclined to give them a shot, but Wiecko says the benefits far outweigh the investment. “PM programs vary in cost, but the converter may expect to spend hundreds of dollars per year for [PM on] a typical slitter/rewinder,” he says. “By keeping the equipment in good condition, the PM program becomes a consistent, predictable, and relatively small expense.” In terms of monetary savings converters can expect after implementing a PM program, Wiecko says it will vary depending upon the converter and aspects of its business, including applications being run, cost of labor and materials, opportunity costs of capacity, etc. “However,” he says, “this small investment will invariably provide a handsome payback for most any converter.”

Costs for PM programs for splicers are hard to pinpoint, according to Hart. “There are so many different kinds of splicers that it is hard to give a rule of thumb on cost,” she asserts. “Generally we would expect lap splicers running paper or butt splicers in the narrow-web segment to be on the lower end. Heat seal splicers or splicers in the liquid packaging industry would likely be more.”

Ivens says, “Preventive maintenance on a standard Arpeco machine would normally be in the range of $2,000 to $3,000 per year. Replacement cost of this equipment is probably in the $40,000 to $50,000 range.”

“Monetarily,” Ivens says, “a customer would have to take into account not only additional parts costs, but also unplanned downtime, improved productivity, and the overall equipment lifetime to determine the savings it would enjoy from establishing a PM program.”

In the end, use the KIS concept when considering whether to implement a PM program. Quite simply, the quality of your jobs could take a hit without such scheduled maintenance. “Costs for not implementing a PM program add up quickly,” cautions Wiecko. “Downtime (especially unplanned), material waste, speed limitations, labor costs—all of these contribute to lost productivity, which means lost profits. Another cost to consider is quality. If equipment is not running at peak performance, quality suffers.” pP