Contrary to widespread belief, many of the low cost "pouch" or "pocket" laminators currently on the market make adequate dry-film laminators. If the laminator is able to feed a standard piece of 0.062" FR-4, two layers of photoresist, inside a siliconized paperboard carrier without stalling, it will probably photosensitize your boards just fine. If you already own such a machine, and don't mind taking a chance of stripping the drive gears, try it out. A safe way to test the capability of your laminator is to gradually increase the thickness of a stack of paper inside the carrier that you feed through the unit until you can hear the clutch start to slip (usually a loud clicking sound), or the drive motor groans from excessive labor (something we can all sympathize with). If it easily passes a stack of paper that is as thick as the PCB you intend to fabricate, plus both layers of dry-film, you're in business.

If the drive mechanism does stall, you may be able to gently push the package out the back slot, in the normal direction of travel, without harm to the unit. Make sure the drive motor is ON when you attempt this so that it will help you move the bundle in the right direction. Under no circumstances should you attempt to withdraw the stack from a stalled laminator by pulling it back out of the machine against the normal direction of travel.

If you are in the market for a laminator, but cannot justify a full blown hot-roll machine (typically $900 to $5,000), consider one of the pouch laminators which are designed to accommodate thick substrates (usually limited to 0.125" or 3mm). These typically have some form of adjustable pressure rollers as well as a temperature adjustment to allow full control of the principal lamination parameters. The following assumes that you have one of these low-cost dry-film laminators, but the procedures described apply equally well to most machine of this class.

Safety First

Before using your laminator, review the safety notes at the beginning of this chapter.

Applying dry-films

The lamination process that you will use depends on the type of pouch laminator you have, a heated plate machine with unheated rollers, or a ModuLam laminator with internally heated rollers and optional footswitch.