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Troubleshooting Common Powder Coating Problems

Posted on: October 28th, 2014 by byersbushblog

Powder coating is our specialty. At Byers Bush, we have been in the powder coating business for over 40 years, so over those decades we have learned to troubleshoot in order to keep our customers happy. These are a few of the most common troubleshooting issues that those in the powder coating industry often face and the easiest tips to help solve the problem.

Charging Troubles

Even though it is the ultimate goal of powder coating, some powder coaters have difficulty getting the powder onto the part. In many cases, the trouble comes from grounding. When you are painting, the substrate is targeted, but it could be insulated so it is difficult to get grounded. So, without good contact with the hanger, the powder will not adhere to the part. Here are a few solutions to prevent the problem:

  • Make sure the hangers are cleaned.
  • Look for a strong connection with the hanger for a good charge.
  • Use a megaohm meter to measure ground strength. Look for a resistance level that is less than one million ohms.
  • Pay attention to the recommended room conditions, so humidity is between 45 to 60 percent.
  • Be sure your power is working, especially if you regularly have problems with grounding.

Surging Power

Electricity can affect powder coating in a few different ways. Along with grounding issues, power surges can create problems for the typical powder coater. Since powder is forced from the gun with compressed air, power needs to be sent at a regular level and through an air-drying unit. The air quality that is working well has a specific oil content, dew point, and particulate matter of low levels. With the proper settings, power surges do not cause problems and coating guns work properly. However, if power surges to continue, these are a few tips to make them go away:

  • Be sure the hoses are not pinched.
  • Look for blockage in the hoses. To eliminate this problem, blow out the lines with compressed air after every shift.
  • Adjust fluidization if levels are off.

Penetration Trouble

If the delivery rate of your powder is too low, the powder will have difficulty penetrating. This can also happen with weak ground, a spray pattern that is inconsistent, as well as with incorrect voltage. When you have difficulty penetrating the part, you will end up spending more time and money than you originally intended as you or an employee will have to recoat the part. Penetration trouble often originates with the Faraday Cage, which is where the particles travel via the path of least resistance when they cannot reach the part. Fortunately, there are several ways to troubleshoot this problem, they include:

  • Trying different nozzles to find a specific spray pattern to improve penetration.
  • Reducing the gun target distance so the powder can reach the recessed area. It is easier to accomplish this with a manual application, but it can be challenging with the automatic application.
  • Turning up the spray velocity to increase the powder penetration. With more velocity the powder will avoid the Faraday Cage, but more powder will be wasted.
  • Turning down the voltage in order to achieve better penetration. You might need to reduce the voltage to 50,000 to 75,000 volts from 70,000 to 100,000 volts.

Back Ionization

This problem happens when the particles of powder in the air will not join with the part. As this problem builds and the powder builds on the part, the uncured surface texture becomes rough; this is called starring. When starring occurs, the powder cures but it looks lumpy like an orange peel and no customers want that look. Here are some tips to avoid the problem:

  • Reduce the voltage, but if you reduce it too low the coverage might adhere in another unacceptable fashion.
  • Set the gun-to-part distance to the proper length and keep the part grounded.

Try a grounding ring to keep the voltage at the proper setting.

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