Dry-film Lamination with a Heated Plate Laminator

Materials / equipment needed:

• pouch laminator
• dry-film photoresist or soldermask
• plastic squeegee
• copperclad
• abrasive cleanser / copper brightener (scrub cleanser)
• abrasive scrub brush
• rubber gloves, safety glasses, and an old shirt or smock
• plastic cutting board (or 12" x 24" sheet of plastic)
• siliconized carrier
• Scotch® tape

Procedure

1. Place your laminator on a table (or any other stable horizontal surface) such that there is enough room behind the unit to accommodate the longest substrate (including carrier) that you intend to laminate. Make sure the tabletop is clean and ready to use.
2. Inspect the unit to ensure that the heat adjustment knob is set properly for your application. Most dry-film photopolymers (e.g. Think & Tinker photoresist and soldermask) work best if the lamination temperature is approx. 110°C (± 5°).
   
   If you are not sure what the proper temperature is, start at the minimum setting and work your way up until satisfactory lamination is achieved. It takes a lot longer for the laminator to cool down than to heat up, so start with a lower temperature setting and gradually increase it until the desired results are achieved. Always allow at least 10 minutes after changing the temperature setting before attempting to laminate your board.
   
   
3. Use the board as a template to cut out a piece of dry-film just large enough to totally cover the copper surface (cut two pieces for a double sided board).
4. Prepare the copperclad for lamination by carefully cleaning both sides.
5. Very slightly wet one side of the board using fine-spray plant mister. Remember-- you want the board moist, not dripping wet. If the water beads up from the surface, the board is not clean and you should return to step 4.
6. Peel off the dull (matte) release liner from one piece of dry-film to reveal the tacky adhesive side.
   
   Unless you have razor sharp nails, separating the thin polyolefin release liner from the rest of the film can be difficult at best. It is however, very easy if you use two pieces of sticky tape to pull the film apart. Stick one piece of tape to the peel sheet in one of the corners. Being careful not to touch the two pieces of tape together, stick the other piece of tape to the cover sheet in the same corner as the piece of tape you just attached to the peel sheet. You can then pull the two pieces of tape apart to delaminate (separate) the film.
   
   
7. Using a plastic putty knife, "roll" the film (adhesive side down) onto the moist copper surface, working out voids and air bubbles as you go along.
8. Working out from the center of the board, use the plastic putty knife as a squeegee to force out any voids or residual water. This should result in a uniform, void free pre-lamination.
9. For a double-sided PCB, repeat steps 5 through 8 for side 2 of the substrate.
10. Center the pre-laminated substrate into a siliconized carrier feed into the preheated laminator.
11. When the carrier has exited the rear of the laminator and has stopped moving, it is safe to remove. The carrier will often be held in place by spring-loaded cooling fins in the rear of the unit. It will be safe to handle as soon as it has stopped moving.
12. Remove the laminated copperclad from the carrier and inspect for voids and air bubbles. If small bubbles are present, they can often be removed by carefully scoring the center of each one with a new X-Acto knife blade and carefully working out the trapped air with your fingernail. Run the board through the laminator a second time to insure that the erstwhile bubbles are totally removed.
13. If the lamination is less than perfect, your board may still be usable if no defects occur at the same places as critical circuit elements. Simply inspect the laminated board through your PCB artwork to see if the board can be used.
14. Let the board sit for about 1 hour in a dark place (or inside a lamination carrier) to allow the dry-film to totally absorb any residual water before imaging.
15. The board is now ready for imaging and further processing.

Dry-films & accessories
Substrates & cleaning supplies