Coatings World - May 2011

The electrostatic powder application function of a UV-cured powder coating system and a thermoset powder coating system are the same. However, the separation of the melt/flow and the cure process functions is the differentiating characteristic between the UV-cured powder coating system and the thermal powder coating system. This separation enables the processor to control the melt/flow and cure functions with precision and efficiency, and helps maximize energy efficiency, improve material utilization and most importantly increase production quality.

Illustration of UV-Cured Powder Coating Application Process

UV powder coating’s time advantage

The “Faster” advantage of a UV powder coating system is the shorter process time, which equates to an increased finishing capacity and lower energy consumption. A UV-cured powder coating system can produce more product, uses less energy and increase first pass quality. Set-up times are shorter, thermal damage to substrate is virtually eliminated and process failures are greatly reduced.

Liquid finishing requires solvent flash-off and thermal curing requires 30 minutes or more. Although thermoset powder coatings do not require solvent flash, the cure temperatures are higher at 400°F), requiring an additional cooling period prior to handling. The UV-cured powder coating process significantly reduces process times, generating a number of process and efficiency benefits. These include less time waiting on daily start up and shut down; increased finish capacity; a reduced number of parts on the finishing line; and a reduction in defects and reworks.

Part Finish Time Based on Coating Processes

The short and fast process time for UV-cured powder systems
increases the daily finishing capacity and generates additional
marginal revenue for the user. A typical UV powder system can
finish 1,150 parts in an eight-hour production day. A compara-
ble solventborne thermal cure system has the capacity to finish
950 parts. The UV powder system will finish 200 more parts in
a day increasing productivity by 21 percent. For example, a fin-
ished product selling for $10 per part with 30 percent gross mar-
gin generates an additional $600 per day of marginal revenue, or
$150,000 per year.

Daily Finish Capacity for UV Powder and Thermal Cure Coating Systems

Value of UV-cured powder coating

UV powder coatings have many operating efficiencies that can be directly correlated to the value of the system, or the “Cheaper” part of the innovation challenge. A UV-cured powder coating has an applied material cost advantage compared to low solids solventborne coatings. A solventborne industrial coating is composed of 25 percent solids and has a 30 percent material utilization with a conventional spray application. A 1 mil dry film thickness has an applied cost of $0.28 per square foot. UV-cured powder coatings contain no solvents or liquids and are 100 percent solid with up to a 95 percent material utilization in the finishing operation. A UV-cured powder film build of 2 mils on a smooth substrate produces a continuous and uniform finish. The applied material cost of a 2 mil film thickness is $0.11 per square foot. Rougher substrates such as MDF require 3–3. 5 mils of powder finish with an applied material cost of $0.17 per square foot. The 2 mil UV powder finish is 60 percent cheaper than the 1 mil solvent liquid finish. The user will save $170,000 per year finishing one million square feet using the UV powder system.