North Brisbane Powder Coating is dedicated to ensuring the services we provide and the quality of every customer's job complies with all of the requirments of AS4506 - Metal Finishing - Thermoset powder coatings. Getting the quality and service experience right is the reason we established the business after years of suffering unacceptable service and quality from other suppliers for our other businesses. To this end we have set in place some pretty simple but detailed QA processes:-
Job materials receival and inspection
- Check the incoming customer job materials against the Purchase Order or materials list to ensure we have everything we are supposed to work with - we'll notify the customer of any discrepancies and amend the work order accordingly
- Inspect the materials for any issues that will impact on the final job finish and performance - when identified the customer will be contacted and the work order amended as required
- dirt, grease, print / ink labels
- whether the job requires a full blast back to raw steel allowing a primer coat application for longevity and rust resistance over time
- if we need to drill any holes to enable the item to be hung for all stages of the coating process
It is really important that the materials surface be well prepared to accept the powder and obtain a high quality end job - like painting any product, poor preparation will usually result in a substandard, short-life finish.
- We use a high pressure dustless water blasting system to remove any surface contaminants, dirt etc and to remove all rust, paint etc back to bare steel metal when required. Galvanised products are lightly etched, leaving close to all the existing galvanising in place.
- If a steel product requires an extensive blast clean and subsquent primer coating, we will advise you and sign off prior to proceeding further with your job
- Aluminium products go through a 4 stage preparation process
- light acid etching to remove any dirt, grease, mill scale to produce a bright appearance, prevent any streaking
- water rinse to remove any acid wash residual
- chromate free adhesion & conversion pre-treatment
- water rinse to remove any conversion chemical residue
- we use the very best European powder applicating gun equipment to ensure we have an even powder thickness which, when baked & cured, will deliver a finish that complies with AS4506
- Target powder thickness (in addition to any retained coating - e.g. galvanising) is to exceed the requirements of AS4506 - 60 - 80 microns
Baking & Curing
Baking & curing the applied powder is again crucial to the end job finish. The metal being coated needs to come up to the required temperature of approximately 200 degrees C, at which the powder begins to fuse onto the metal. Generally baking for 10 minutes at 200 degrees is required.
- We have a data logger device which sits in the oven during the baking process - it has 3 sensors which records temperature over time
- oven air temperature
- samples of the thickest metal items being coated / baked
- the data is downloaded at the end of each days production and readings are entered into the job file to ensure we have achieved the optimum oven temperature and time for the baking processes requirement
- After a job is removed from the oven and allowed to cool, a visual inspection is carried out to look for any obvious defects, which can sometimes include:-
- degassing "pimples" - in some steel products, gas can be relased from the steel products as a result of being heated to 200 degrees. This is impossible to predict prior to any stage of the powder coating process. It usually only appears in a few minor places on the metal. In many jobs the location of the "pimples" will not make any material difference, in other instances, the pimples will need to be lightly sanded back and recoated - in these instances we will take images of the problem, report it to the customer and receive their instruction on whether the item needs to be recoated
- Ink print bleeding is where the steel product has been printed with identifiying marks etc. When applying light colured powders (white, yellow etc), this ink printing may become slightly visible through the baked powder finish - in these instances we will take images of the issue, report it to the customer and receive their instruction on whether the item needs to be blasted back and recoated
For selected jobs, we undertake further QA tests includng:-
- Cross cut scratch tests - adhesion
- Coating Thickness measurements
- Cure test - solvent resistance to check curing has occured to target requirements
This test data is again entered into the job file for future reference. With our new IT system progressively being implemented, customers will be able to log in to retrieve individual job files which will include all job and QA data.