Powder coating is a vital process that allows sheet metal fabricators to deliver a complete manufacturing solution.
Following fabrication processes such as laser cutting, forming and welding, sheet metal components can be finished with powder coating to achieve a smooth, durable and resilient surface finish.
To ensure maximum quality, powder coating starts by passing all components through a pre-treatment process. The aim of pre-treatment is to clean and prepare the sheet metal surface to allow better bonding of the powder paint to the metal, to enhance resistance to weathering and corrosion and to ensure long-lasting performance.
As with any painting process, preparation is the most critical stage. Almost all sheet metal materials used in sheet metal fabrication, including aluminium, stainless and mild steel, can be pre-treated and coated to a high standard at a competitive cost.
Two types of phosphates widely used in powder coating pre-treatment are iron phosphate and zinc phosphate. However, many metal fabricators now adopt an alternate phosphate-free technology, Oxsilan. Here are just some of the benefits of using Oxsilan pre-treatment during the powder coating process.
Powder coating is a type of paint applied either through automated coating systems or manually with powder coating guns, as a free-flowing, dry powder. Unlike liquid paint, powder coating does not require a solvent to keep the binder and filler together.
The powder is a mixture of ground particles of resin and pigment which is applied electrostatically to the metal part. Once applied, the coated metal component is cured by heating to between 200C and 240C to creates a paint 'skin'.
Powder coating delivers a high-quality, durable and consistent paint finish that complies with environmental policies and offers a good level of resistance to scratches and corrosion.
Powder coated components can move directly into the curing oven after application and therefore it is a quick and cost competitive finishing solution.Find out more detail on What is powder coating.
Oxsilan was introduced to the UK as an alternative powder coating pre-treatment in 2006. It is a hybrid-polymer composed of Zr-hexafluorid, Siloxan-polymers and additives. Before this, the majority of metal fabricators had used phosphate pre-treatments such as iron and zinc phosphates.
The introduction of the new Oxsilan technology was driven by factors such as increased environmental awareness, the need to reduce CO2 emissions, new legislation and increasing costs of raw materials. Leading metal fabricators like KMF are adopting the new pre-treatment technology for their powder coating process.
Oxsilan application relies on chemical bonding and involves a rinse water system with the following stages:
-1: Cleaning with a highly alkaline for steel alloys and zinc-coated steels
-2: Cold rinsing from the main water supply
-3: Rinsing with demineralised water
-4: Oxsilan 9810 liquid pre-paint treatment
-5: Single ring rinsing with demineralised water.
Oxsilan 9810 not only out-performs equivalent zinc and iron phosphate pre-treatments for corrosion resistance but also offers additional environmental and process benefits.
-Excellent paint adhesion and corrosion resistance that meets and, in some applications, exceeds the performance offered by alternative phosphate treatments.
-Eco-friendly solution that does not contain any phosphate or hazardous heavy metal ions such as Ni, Cr and lowers risk for safety, health and the environment.-Support for thin and functional coatings
-Multi-metal capability as the technology is suitable for all metal and multi-metal substrates
-Delivery improvements to process times as multiple stages of the pre-treatment can be removed e.g. activation and passivation.
-Requires a simple wastewater treatment and demands less maintenance that phosphate processes
-Low energy and water consumption
Provided by Chemetall:
The table above displays figures provided by Chemetall for average process reductions for Oxsilan pre-treatment compared to zinc-phospating. Process reductions include C02 emissions, water usage, electricity and maintenance costs.
KMF is the UK's leading metal fabricator with extensive in-house powder coating facilities that employ Oxsilan pre-treatment. Its complete powder-painting facility includes GEMA automatic powder coating equipment and a high-efficiency curing oven, F8 Sidetrack conveyor system and multiple QCS4 Magic Cylinder fast colour change booths. The automated system incorporates manual powder gun facilities to ensure even coverage and high-quality results with even the most complex fabrications.
Powder coating services are available for a broad range of sheet metal materials, including steel, stainless steel, aluminium, chrome and galvanized steel and can be applied in all RAL colours as well as a large selection of matte, satin, gloss and metallic colours.
If you want an innovative metal fabricator who can deliver high-quality and reliable sheet metal fabrication and CNC machining services, including powder coating, please contact one of our experts today.