The gift that keeps on giving: a checklist for making your shop more productive and economical.

IN THE SPIRIT of the new year, I present some tips to help improve your production, cut down on reworks and increase shop floor satisfaction. Remember this checklist and 2005 may be kind to your bottom line.

Phototooling Densitometers measure both diazo phototool films (with selective filtration) and silver phototool films. Remember that a densitometer should be calibrated daily, and any time the unit is moved or bumped.

Review the calibrated density "standard" provided by the manufacturer; this small bit of film helps you verify and adjust densitometer readings. Holding the standard along its edges will prevent fingerprints or other contaminates from affecting readings. A densitometer measures the optical density of clear and opaque areas of a phototool film. Most units in the field are transmission densitometers; they measure the amount of light transmitted through different areas of the film.

Then there are the D-Min and D-Max numbers. The starting D-Min of a properly processed diazo phototool ranges between 0.08 and 0.11. That's the rating in the photolab before the film is sent to the production floor.

After the exposure and development of the diazo phototool, but before measuring the D-Max, it is imperative that photolab techs expose the film through the base side, not the emulsion side, at three times the original exposure time or units. This simple burn-back phase in which undeveloped diazo emulsion is burned away is important to avoiding false density readings. Technicians tend to expose and develop their diazo film, and then immediately take a reading instead of performing a burn-back.

Keep your densitometer free of dust and dirt and in a place where it won't be bumped or moved. Clean the reading head's glass filter monthly with alcohol. Glass cleaners often contain optical brighteners that compromise instrument readings. As for film replacement, that comes when you would need to increase the exposure time to your LPI/dry film soldermask to achieve the same step reading on your processed boards (panels). Depending on exposure energy, that is usually between 100 and 500 exposures.

Developer Operation. Like thedensitometer, the film developer plays a critical role in the production of diazo phototools. Proper maintenance keeps a developer productive for a long time:

* Keep your developer level to assure proper flow of ammonia.

* Locate this equipment in a well-vented area in a cool area (78[degrees]F or lower).

* On belt-driven models, monitor/adjust belt tension levels but do not over-tighten.

* Keep metering pumps and drain system tubing free of kinks and blockages.

* Don't cut corners with technical grade ammonia. For best results, use ammonia hydroxide in a strength of 26 to 30 baume.

* Maintain a 150[degrees]F to 160[degrees]F temperature range at the film plane.

Temperature variations may be the single biggest cause of poor quality film development. When a developer is too cold, film won't fully develop. If it's too hot you risk dimensional changes. Best advice: Never cold-start your developer. A 30-minute warm-up helps balance system parameters.

Film Handling. With the finer lines and spaces generated today by diazo and other phototools, careful film handling is more important than ever. Maintain a cleanroom mindset in your shop.

For best results, do your artwork/film on a generously sized and well-lighted flat surface that's free of grit or other foreign materials. Remember to store films emulsion to base, and not with emulsions exposed to each other, which can damage both films. Separate films using cleanroom-style paper.

The cleanroom model also applies to what technicians wear. Because the slightest scratch can cause a defect, techs should not wear watches or other jewelry and should avoid using hand lotions that can keep touch-up inks from adhering to film. Avoid clothing that sheds fibers. Wear hair nets, smocks, gloves and booties. Positioning tacky mats outside the film lab can catch dirt from shoes.

Because anything that unintentionally blocks light will cause a defect on the board, film touch-up and cleaning is vital to quality output. Be sure to clean films before, during and after use. Remember to apply a liquid cleaner to a cloth rather than squirting it directly on the film. Don't allow the film cleaner to smudge, smear or remove the ink.

Smart shops carry their film in Plexiglass boxes and stiff vinyl zippered pouches to prevent exposing film to nicks, bends and half moons. Make it a habit in your shop to remove film from folders carefully, inspecting them when you take them out and giving another once-over when you place them back into the folder.

Ed.: This column can be found in its entirety at www.pcdandm.com.

JEFF JARVIS is senior territory manager at InteliCoatTechnologies (www.intelicoat.com). He can be reached at [e-mail].