Artwork Protection Films firm up; APF leads to new products, performance.

I LAST WROTE about artwork protection films last year. Since then, these products have emerged as real workhorses in phototool/artwork departments. Considering the substantial growth and popularity APF has enjoyed for the last year and a half, this seemed like a perfect opportunity to update you on the expanding APF market and revisit some basic techniques and approaches that can make your laminating jobs easier and result in better product quality.

So what does the APF market look like and where is it headed? Right now, according to the best available figures, the global market is pushing at least 30 million [ft.sup.2] of film each year, along with a very small amount of liquids. Asia has more production facilities than anyone. But the U.S. market is also gaining steam. Major domestic PCB operations are using APF for their inner/outer layers and in liquid photo-imageable soldermask departments. The expanding market is resulting in jockeying among suppliers. I know of one major manufacturer who recently appointed a large North American distributor with multiple locations to handle APF demand.

PCB manufacturers have come to understand how using APF can lower their costs on the production floor. Because the average usage of a piece of silver or diazo phototool film is increased at least six times, film costs are reduced by 600%--sometimes even more. Phototool rework is reduced considerably when 3.5 micron or 6 micron films are used to protect against scratches and chemical damage.

Another advantage: Cleaning films during the exposure cycle is much easier since virtually any style film cleaning solution can be used. Prototype shops are recording throughput improvements that translate into real cost savings while at the same time better managing customer lead time requests. Low material cost, no equipment obligations, reductions in the number of reworks and the amount of scrap--do the math.

As is the case for all industries where technology is advancing, increasing demand for APF is driving development of next-generation products capable of delivering enhanced performance and better specifications than predecessor versions.

This fall at InteliCoat, we're introducing a new ultra-low haze film with image resolutions that rival those of liquid types. By the numbers, that means with our new higher-grade polyester, we have successfully reduced film haze from about 8% to the range of 2%. This new material essentially offers the glasslike clarity of a liquid. Yet it's only one of the advances that will soon be available to users of APF in the months ahead.

Of course, nothing squanders the quality and cost advantages of technology advancements in film laminating more than inattention and disregard of fundamental processes in the lab. At the start of every shift--and before you laminate any films--visually check your unit's cleanliness. If necessary, wipe down the nip roller and wipe away any dust you see using a 50-50 solution of alcohol and water, or by vacuuming, then advance the tacky paper on the film cleaning system. Verify that there's an adequate supply of APF on the roll, and run a test piece of scrap film.

Cleanliness is critical at the lamination stage. You do not want to end up with dirt laminated between the phototool and the APF, which could translate into a panel defect. Check for wrinkles and proper alignment; look for a flat, smooth appearance. If a curl shows up, make a slight adjustment to the mandrels; loosen by a quarter-turn at a time to both the APF mandrel and the take up roll mandrel. Run another piece of film and check again for flatness. Once you have a flat piece of film, you should not need to make any further adjustments throughout the roll.

After plotting the silver master and making the necessary diazo duplicates, use a densitometer to verify the film's D-min and D-max. With a diazo phototool, you can perform a "burn back" or "out gassing" by exposing the film through the base side at twice the original exposure setting to ensure a stable D-min before lamination.

Inspect the artwork for pin holes, imaged on defects, scratches and other imperfections and apply touch up ink as required.

Clean the film with the appropriate film cleaner, making sure to remove all fingerprints and debris. Fingerprints will show up as tiny bubbles formed by the oils on our hands and fingers.

Line up your phototool film on the laminator. After the lamination, lay your film on a flat surface and remove the coated phototool film from the carrier material. Some shops will coat the entire piece of film, while others will leave a small space on the left and right sides for easier removal from the carrier film or paper. Either technique is fine--just remember that if you are not laminating the entire phototool film, you will need to leave a margin of at least 1" from the imaged area on your film. Place the film on a light box and check for any curling, bubbles or wrinkles.

You are now ready to send the finished laminated film(s) out to your production departments. Cutting corners only produces a poor quality product. Observing basic steps is paramount. Following the fundamentals is always your best bet.

JEFF JARVIS ([e-mail]) is SeniorTerritory Manager at InteliCoatTechnologies (Matthews, NC).