Saturday, December 6, 2014

Image collection of test coater for coating team

Although this is only a 12" coater it could be used for development of the next generation materials at a cost less than we might pay at a commercial coater.

  1. Made by Modern Metal Craft in Midland, Michigan.
  2. Built in 1990.
  3. Weighs ~1200 lbs.
  4. Nip and doctor blade
  5. Unwind and rewinds
  6. Variable speeds
  7. Pump
  8. Heated roller (may be used cold)
  9. Designed for paints, but can be used for coating other low viscosity materials.

DOW BENCH BLADE COATER (excerpt from manual)

Basically, the bench blade coater consists of side plates, a backing roll, two idler rolls, two unwind stations, a rewind station, a doctor blade holder, doctor blade, and variable speed gear motor which drives a chrome plated or stainless steel drum (12" diameter by 12" wide), which may be heated by recirculating a 50/50 blend of water and glycol.  Some users like to substitute peanut oil when operating at temperatures above 212 degrees F but less than about 250 degrees F. For high temperature applications (greater than 250 degrees F) it is recommended that Dow Corning Silicon Oil 710R be used.

The coating is applied to the paper from a puddle via a trailing blade. Blade pressure is accomplished via sliding weights attached to the hold-down arms. Coat weights are controlled by coating solids and the placement of the sliding weights on the hold-down arms (additional weight may be added to further reduce the coating weight if desired). Machine speed is dictated by color solids, coat weight, and drum temperature. Speeds of 30 to 40 feet per minute are typical for a 62% T.S. color dried at 195 degrees.

The coater requires 12" wide rolls of base stock wound on standard 3" diameter cores with a maximum roll diameter of 12". Colors of 10,000 cps or less can be easily handled, and in normal practice, a minimum of 10 grams of coating is placed in the nip and the machine started. The coater may be left running until all the coating has been used, thus avoiding messy clean-up. Much larger quantities of stock may be coated by continuously replacing the coating as it is being used. Plastic squeeze bottles (4 oz.) with eye dropper nozzles are suggested as a means of placing the desired amount of coating in the nip. The semi-dried coating film remaining on the doctor blade is removed with a single-edge razor blade.

The coated sheet, dried by the heated drum, and the IR Dryer and/or Hot Air Dryer if they are used, is fed out at the rear and wound into a roll. Coating two sides as well as double coating can be accomplished by proper placement of the coated windup roll in the secondary unwind station, which rotates in either direction. The paper supply shaft will rotate in either direction too.


Larry Kellogg said...

Nifty! Was that an eBay find? I suppose this is a silly question but you have to operate this thing in the dark, no?

Bob Crowley said...

Yes, ebay. But we can operate this in daylight, since we are not coating emulsions. That's left to the film suppliers. We do need to coat receiver sheet, and that has been a problem, so I thought we had better bite the bullet and get a small coater.