The plate is crooked. The print job is no good. So what? It happens all the time. No problem. Just peel the plate off of the cylinder, reposition it (paying attention this time), whack it on to the stickyback, and give it another shot on press. Hey, we do this all the time. No big deal.
Yes big deal. Was any portion of the web wasted to figure out that the plate was mounted wrong? Was any operator time used to figure out which plate was crooked, remove the culprit from the press, go through the plate mounting process all over again, stick it back into the press, start up the machine and go through the makeready process one more time?
Yes, it is a big deal. If you’re paying for the wasted material, it’s money out of your pocket. If you’re paying the operator to stop the job to fix the plate, it’s money out of your pocket. You can do the math.
You also might consider purchasing a machine that helps your people mount plates accurately the first time. They’re called plate mounters.
“It’s amazing that there are still companies out there doing high-registration work and still mounting plates by eye,” says Rob Ireton Jr., vice president of IEC International, Dayton, OH. One plant he visited recently, part of a large converting corporation, employs four people who mount between 500 and 600 plates a day, “all by eye.” Ireton manufactures sophisticated plate mounting machines, and he was there to tell them that the plate mounting time on a multi-color print job could go from an hour down to five minutes with the right equipment, “and you don’t have to mess around with registration.”
Plate mounting devices range from the simple to the complex, and vary in price from under $1,000 into the low five figures. The models at the top end of the range allow the user to take advantage of video images of magnified registration marks to ensure accurate alignment, and to speed the mounting process. Some machines also can be used to produce inked proofs of plate images.
“All printing presses allow for registration adjustment across the web, which is lateral registration,” says David Cloud, vice president and sales manager of Conversource, St. Louis, “and along the web — lineal registration. But there is no way to correct for a plate that has not been mounted properly. The only solution is stopping the press, removing the print cylinder and remounting the plate. Using a plate mounter ensures properly mounted plates before they go to press. On multi-color jobs, it’s essential for all of the plates to be mounted identically.”
Plate mounters, Cloud notes, can be divided into two groups: bench mounters and precision mounters.
Bench mounters are designed to hold the print cylinder during the mounting process. Some have an integral straight edge to make the process easier. This type of mounter does not include a plate alignment mechanism.
Precision mounters, however, do utilize some method of accurate plate alignment. “Some use a precision grid, while the most accurate systems use video cameras and multiple image technology,” notes Cloud. “These mounters provide a precise method of aligning the plate before it is affixed to the mounting tape. Some precision plate mounters, such as the PM VideoMount, hold the print cylinder during the plate mounting process.”
|The AccuMount from Conversource|
Conversource markets four different plate mounters: The PM VideoMount, which combines Mark Andy’s mounter with Conversource’s video registration system; the AccuMount Video Plate Mounter; the Cortron Plate Mounter, and the Quali-Mount Plate Mounter.
“All plate mounters are capable of the same level of accuracy,” says Conversource’s Jeff Chosid. “Even the most basic bench mounter, a steel rod supported by two wood blocks, can be used to mount plates with precision. What one finds, though, is that the skill required is inversely proportional to the sophistication of the plate mounter. In other words, the more basic the mounting equipment, the more skill and experience is required to properly mount a plate. Precision plate mounters, especially those that utilize video viewing, require less skill and experience. Often, with video mounters, users can learn to accurately mount very complicated jobs with minimal training.”
According to Mike Polkinghorne, Propheteer International, of Lake Zurich, IL, manufactured the original video plate mounter in 1983. Polkinghorne, the company’s vice president, says that the first units utilized mirror optics, similar to that employed in a periscope. The next generation of that mounter is now in production from Propheteer.
“You can’t do the kind of printing most customers are looking for these days without some kind of vision-assisted plate mounting,” Polkinghorne says. “Some people are awfully good at lining plates up by eye, but for the print quality they need in order to shrink the traps, a plate that is a few thousandths of an inch askew will give you a nightmare on press.”
The Propheteer model, which sells for $10,600, is equipped with a monitor that features a split image, allowing for accurate alignment of registration marks located on either side of the plate.
|The Propheteer plate mounter.
||The Mark Andy PM Video Mount.|
Most of the plate mounters manufactured today come equipped with video cameras and monitors. The basic units, however, are still popular. The Conversource Quali-Mount, a tabletop mounter, offers ease of use. The print cylinder is held in position by a tapered shaft; mounting tape is applied and carefully cut in a butt joint with minimal gap. The operator then removes about an inch of the tape liner material, exposing the adhesive. Then a reference line is drawn onto the tape, along with a center line. The printing plate is placed onto the exposed adhesive, then wrapped around the cylinder. Alignment is checked by comparing images on the leading and trailing edges of the plates. After alignment, the liner is removed from the stickyback tape and the plate is smoothed onto the tape.
Quali-Mount units are available in several sizes from 7" to 20". The 10" model sells for $750.
The medium-priced Cortron mounter, manufactured by Cortron in Minneapolis, allows the plate to be in register and square with the print cylinder before contact is made with the exposed adhesive on the mounting tape. It does not require special register marks on the printing plate. The printing plate is aligned, face down, onto the precision grid. The print cylinder, with mounting tape, is lowered onto the printing plate. The grid table, which is mounted on linear bearings, is drawn forward, ironing the plate to the exposed adhesive on the print cylinder. The unit will accept all printing cylinders up to 18" in length, with a maximum cylinder diameter of 8".
IEC International manufactures two mounters — one manual and the other fully automatic — that make use of its proprietary Snap-Fit Mounting System. “What makes our system different than any other mounter is the way we align the printing plates,” says Rob Ireton. “We use our patented PRR Plate — that stands for Physical Registration Record — to achieve alignment. The PRR plate is a female version of a common element in the printing plate, a pair of registration marks or, in most cases, a bearer bar. To align the plate, you simply place the marks on the printing plate into the marks in the PRR plate. There is a subtle click when the two plates lock together, similar to what you feel when you begin to close a Ziploc bag.” Once the plate is in place, Ireton says, vacuum is engaged to draw the plate down tight, after which it is automatically rolled onto the cylinder.
“You can accurately mount a plate in under 20 seconds with this system,” he says. The Snap-Fit NW22A, for narrow web plate mounting, can handle a maximum plate size of 25" x 25", and sells for about $14,000. “Another nice feature is that it’s fully modular: You can put video alignment on if you want it,” he says. IEC today is developing a color proofing system as a module for the mounter, which will feature color ink trays at the back of the machine, a drive that turns the cylinder, runs it through the ink, makes an impression, and allows for manual change of the cylinder. The company is also working on an automated tape applicator, and has developed a mounter for printers who make use of sleeves.
The manual version has been in production since 1996. The new version, introduced this year, features automated plate attachment.
|The Snap-Fit NW22A from IEC International.|
Through the lens
Video plate mounters take the operation into a dimension of greater precision. Popular models feature two cameras, each focused on a different edge of the printing plate. The captured images are then aligned on a monitor — or on two monitors, depending on the product — and the operator can manipulate controls to bring the plate into perfect registration prior to full contact with the cylinder.
E.L. Harley Inc., of Riviera Beach, FL, is well known in the industry for its stickyback tapes. The company also manufactures plate mounters for corrugated and flexible packaging substrates, and recently introduced its MVM-18, a Magnified Video Mounter for precision mounting and proofing targeted to the narrow web printer.
“We had not sold a mounter for narrow web in about eight or nine years,” says Brian Powell, Harley’s sales engineer. “Our early unit was a small, manually operated optical view machine, which was outgrown by video systems. We didn’t want to duplicate other video mounters this time, so the MVM-18 is different.”
With the Harley flat-bed system, the cylinder goes up and down for mounting and proofing. The plate is aligned via the dual cameras, which are focused on the cross-hairs, microdots or other identifying marks on the plates. After the plate is mounted, a handle is turned to make the cylinder go down. A gear locks, the cylinder is fully lowered, and the plate is pulled toward the operator to make the proof. Full control of plate impression is available. “With the next cylinder,” says Powell, “you use the same indexing spot, and the colors come out exactly on top of each other. It also has an anti-backlash gear on the gear rack. A lot of proofing machines have backlash, but this will not allow for any. These will hit dot-on-dot every time.”
Powell says that the basic 18" wide machine sells for $12,870. The MVM-18 was engineered, designed and built last year, and became available early this year.
“For years, press downtime didn’t cost a lot,” Powell observes, “and plates could be redone by eye, even two or three times. But on today’s eight- and 10-color presses, time is important. This will reduce downtime on press for sure.”
Focus Label Machinery, based in Bingham, England, also offers a dual camera plate mounter, which the company calls the PlateMate.
“One of the bigger advantages of the system is the clamp, which makes it more or less foolproof,” says Anthony Cotton, technical sales. “Others tend not to have the clamp.”
After plate alignment on the split-screen monitor is completed, “the operator closes the clamp, and twists its bottom jaw so that the plate is bang-on square,” Cotton says. “It also has a tape dispensing roller, so that the operator can cut off the exact amount of tape required, without waste.
“Once the plates are on an inline press of seven, eight or nine colors, the amount of time you’re saving equates to a lot of money a year, and you’re also saving money on the cushion tape as well. Our printers mount plates in literally 30 seconds sometimes. It depends on the quality of the registration marks.”
Focus Label Machinery, which also manufactures presses and other equipment, originally developed the mounter for use with its inline flexo press. “We took it to an exhibition to aid us with the press, and took a lot of orders for it,” says Cotton. The mounter sells for just over £5,000, or about $7,500, and is available in different widths.
Conversource offers the AccuMount Video Plate Mounter, which offers the speed and accuracy of a video-based viewing system at an affordable price — under $10,000. It can handle print cylinders up to 18.875" long.
The top of the line mounter from Conversource is the Mark Andy PM VideoMount System, available in 16" ($14,000) and 20" models. The systems combine the Mark Andy plate mounting hardware with the Conversource video mount system.
An upgrade package for those with earlier Mark Andy PM units is available, and features two high resolution CCD video cameras, a 9" split screen monitor, electronics package plus all mounting hardware.
Another tabletop plate mounter is the Mount-O-Matic, manufactured by AV Flexologic in The Netherlands and marketed in North America by Anderson & Vreeland, Bryan, OH. The system uses a zoom lens that magnifies register marks up to 8x. It accommodates cylinders up to 480mm (18") long and 628mm (24") in circumference.
The bottom line with plate mounters, say the manufacturers, is that you don’t have to mess around with registration by eyeball, or worry about long set-up times, plate fixes and scrap on press.
“The only problem we’ve had,” reports Anthony Cotton, “is persuading operators to use the new mounters. They’re used to the hand and knife for so long that it’s hard to get them to change their ways.”