Wednesday, February 3, 2016

Powder Curing Process Series: Bake Oven Designs

Bake Oven Designs and Energy Consumption


As a valued TCI Powder Coatings customer, we would like to ensure that you know which ovens are best for curing powder-coated materials. This way, our materials are being cured to their fullest potential, and your company is providing long-lasting products. The industrial ovens that you are using could be designed in various ways to expose powder coatings to heat. As you probably know, the heat helps the powder coating to obtain the desired properties inherent in its thermoset coating formulation. In order to cure TCI powder coatings, the heat within a bake oven can originate from one of several processes.

Oven Designs and Processes:
  • Convection Ovens: use transfer heat from circulation of heated air to cure powder coating.
  • Infrared Ovens: use radiant energy of several wavelengths to cure the powder coating.
  • Ultraviolet and Electron Beams: use available electric energy to harden solvent-free compositions.
  • Induction Ovens: primarily used to preheat parts prior to powder coating to elevate the film build.
Several of our coatings hold unique properties that already help to enhance the curing process, yet different oven designs and heating methods have their pros and cons. Here are a few of these positives and negatives of each type to have in mind:
Convection Ovens:
                                  Pros                                                          Cons
Better on complex, curved products
Some heat waste on underlying materials
Not as sensitive to reflective coating properties
Not as efficient as IR emitters on flat items
Lower cost
Large floor space

Infrared Ovens:
                                  Pros                                                          Cons
Can deliver heat to specific areas in exact amounts (line of sight technology)
Not as efficient for curved products
Reduce emissions of VOCs
Sensitive to reflective coating properties
Less heat loss
Higher cost
  
Ultraviolet and Electron Beams:
                                  Pros                                                          Cons
Reduced use of natural gas (uses available electric energy)
Need traditional solvent
Reduced floor space
Needs to be precise (ensure voltage is not too low or high)
Quick process
High equipment costs

Induction Ovens:
                                  Pros                                                          Cons
Focuses energy to the part only
Can be difficult to control
Lower hazard due to lack of flame
High costs
Faster and more energy-efficient than conduction ovens
Large floor space


Something to consider when curing powder coatings is the possible loss of heat. The oven’s heat can leave through wall loss, radiation loss, and conveyor loss. The net output (heat to lead) is often reduced because of these losses. See chart below for further heat loss details.
To ensure even heat distribution and less heat loss when curing, TCI has a technical team to perform audits on ovens and other curing machines using a program called Datapaq, which can be found here.

For additional information on TCI’S powder coatings, visit tcipowder.com. For more oven designs and troubleshooting information, click here to see the troubleshooting guide.

No comments:

Post a Comment