Do not treat all electrical product coating as one category

When hearing about electrical product coating, many people may think of coatings on home appliance exteriors.

Refrigerators, washing machines, air conditioners, microwave ovens, and rice cookers are products consumers see every day. Attractive appearance, a clean impression, and harmonious colors are therefore important.

However, electrical products are not limited to home appliances.

They also include heavy electrical equipment, such as elevators, transformers, distribution panels, control panels, motors, and power generation and transmission equipment. Products such as communications equipment, electronic equipment, control equipment, plastic housings, and precision components require functionality as well as appearance.

Electrical product coating therefore cannot be addressed under one general category of “paint for electrical products.”

The following perspectives matter.

Where will the electrical product be used? What will it be exposed to? What functions must the coating film provide?

Selecting paint without checking these points can lead to appearance defects, rust, peeling, insufficient humidity or chemical resistance, and functional failures.

First establish whether the product is for indoor or outdoor use

The first point to check in electrical product coating is the installation environment.

Will it be used indoors or outdoors? In a factory? In a coastal area or a high-humidity environment? Will it be exposed to oil, chemicals, water, or heat?

These conditions significantly change the functions required of the coating film.

For indoor home appliances, appearance, a clean impression, and stain resistance are important. Outdoor distribution panels and equipment housings require rust protection, weather resistance, and humidity resistance. Factory equipment may need oil, chemical, and heat resistance. Communications equipment and electronic equipment may require electromagnetic shielding, conductivity, insulation, or other functions.

Even with the same type of metal housing, the required coating specification differs between products installed indoors and outdoors.

Appearance and a clean impression matter for home appliances

For home appliances, the appearance that consumers see directly is important.

Attractive color. Consistent gloss. Few dirt defects or inclusions. A pleasant feel to the touch. An appearance that fits naturally into a room. A clean impression.

These qualities directly shape the impression of the product.

A clean impression is particularly important for white goods. Refrigerators, washing machines, and air conditioners are used in homes for many years. Resistance to visible soiling, ease of cleaning, and resistance to discoloration are therefore also important.

Water resistance and alkali resistance also matter for products such as washing machines, which come into contact with water and detergents.

Alkali resistance is the ability of the coating film to resist discoloration, softening, and peeling caused by alkaline ingredients in detergents, soaps, and similar products.

Home appliance coating requires more than an attractive finish. It must also withstand dirt, water, detergents, fingerprints, and cleaning during everyday use.

Suitability for mass production also matters in home appliance coating

Home appliances are mass-produced products.

Their coating processes therefore require consistent quality and high productivity.

Even a high-performance paint is unsuitable for a mass-production line if it is difficult to apply, produces a high defect rate, or takes too long to dry.

The following points are important in home appliance coating:

• Can it be applied consistently?
• Are the drying and baking conditions suited to the line?
• Can film thickness be kept stable?
• Is uneven color or gloss unlikely to occur?
• Can dirt and inclusions be controlled?
• Can the defect rate be kept low?
• Is it easy for operators to handle?
• Is paint loss low?

In home appliance coating, ease of use in mass production matters alongside coating film performance.

When CoatureVietnam makes proposals to home appliance customers, it must check line conditions, workability, defect rates, and drying oven conditions as well as paint performance.

Long-term durability and corrosion protection matter for heavy electrical equipment

Heavy electrical equipment refers to products used in power facilities and large electrical installations.

Examples include transformers, distribution panels, control panels, elevator equipment, power generation and transmission equipment, and factory equipment.

These products require appearance quality as home appliances do, but long-term durability may be even more important.

Outdoor electrical equipment in particular is exposed to the following:

• Rain
• Humidity
• Ultraviolet light
• Temperature changes
• Dust
• Salt
• Oil
• Chemicals
• Factory exhaust

In such environments, the coating film needs rust protection, weather resistance, humidity resistance, and chemical resistance.

Heavy electrical equipment may be difficult to replace. Equipment downtime can also lead to major losses.

When considering a coating specification, therefore, it is necessary to consider long-term service, repairability, and maintenance intervals as well as the initial appearance.

Pay attention to edges, areas around holes, and welds on outdoor electrical equipment

On electrical equipment installed outdoors, check locations particularly prone to becoming starting points for rust.

These include the following:

• Edges
• Corners
• Areas around holes
• Areas around bolts
• Welds
• Cut surfaces
• Areas where water tends to collect
• Joints around doors and covers

Compared with flat areas, these locations tend to have insufficient film thickness and are more easily scratched.

Even when film thickness on flat areas is sufficient, a thin film at an edge can allow rust to start there. Inadequate surface preparation around holes or welds may cause blistering or peeling later.

On outdoor electrical equipment, inspect defect-prone locations closely as well as the flat areas that are easy to measure.

Communications and electronic equipment may require functional coating films

Coating films on communications and electronic equipment may need to provide functions beyond appearance.

One example is electromagnetic shielding.

Electromagnetic shielding reduces the effects of electromagnetic waves from outside the equipment or limits the escape of electromagnetic waves generated inside it.

A metal housing itself may provide electromagnetic shielding. A plastic housing, however, may not provide the same shielding effect as metal.

Conductive paint may therefore be used to give the plastic surface an electromagnetic shielding function.

For this type of coating, an attractive appearance alone is insufficient.

The required checks change as follows:

• Is the film thickness appropriate?
• Is conductivity stable?
• Is the coating film uniform?
• Are there any pinholes?
• Is adhesion sufficient?
• Will the function be maintained after assembly?
• Are the necessary inspection criteria in place?

Visual inspection alone cannot assure the quality of a functional coating film. How the required film functions are measured and controlled is important.

Greater use of plastics also changes coating conditions

Plastic components are widely used in electrical products for their low weight, moldability, cost, and design flexibility.

Coating plastic components requires different precautions from coating metals.

The main checks are as follows:

• What type of plastic is it?
• Is any release agent left on the surface?
• Is there oil or dirt on the surface?
• Could the paint solvent cause cracking?
• Could the drying temperature cause deformation?
• Is a primer required?
• Is adhesion sufficient?
• Is surface hardness sufficient?

Solvent cracking requires particular attention.

Solvent cracking occurs when solvents in paint or thinner affect the plastic and cause the substrate to crack.

Although it may look like a coating defect, the actual cause may be incompatibility between the paint and plastic substrate.

For plastic components, identify the specific substrate material rather than treating all of them simply as “plastic.”

Motors and coils require a different approach from ordinary surface coating

Some electrical product components cannot be addressed through ordinary surface coating alone.

Motor coils are one example.

For coils, insulation, moisture protection, heat resistance, and secure fixing are more important than an attractive surface finish. Impregnation may therefore be used to allow paint or resin to penetrate the gaps inside the component.

Impregnation is a treatment that allows paint or resin to penetrate the interior.

Ordinary coating forms a film on the substrate surface. Impregnation, by contrast, fills internal gaps with resin to improve the performance of the component as a whole.

The purpose of coating or surface treatment for electrical components thus varies significantly with the product.

Coating to protect a surface. Coating to improve appearance. Coating to provide electrical functions. Treatment to penetrate the interior.

A suitable proposal requires identifying which of these purposes applies.

Waiting time after surface preparation can cause poor adhesion

Surface preparation is also very important in electrical product coating.

Metal components undergo processes such as degreasing, washing, chemical conversion treatment, and drying. However, carrying out surface preparation does not automatically guarantee a satisfactory result.

If components are left for a long time after surface preparation, dust, oil, or moisture may settle on the surface again. Hot, humid conditions can also cause reoxidation or moisture-related effects.

Coating the surface in this condition can cause poor adhesion, blistering, peeling, or rust.

In Vietnamese factories, components may be stored temporarily after surface preparation. Storage in dusty or humid areas, or where operators touch them with bare hands, creates a risk of recontamination.

In the surface preparation process, it is important to control not only the treatment conditions but also the time between surface preparation and coating, and the storage environment.

Common problems in electrical product coating

Electrical product coating can develop various problems depending on its use.

The following defects are concerns for home appliance exteriors:

• Uneven color
• Uneven gloss
• Dirt and inclusions
• Poor stain resistance
• Susceptibility to scratching
• Yellowing
• Discoloration caused by detergents

The following defects are concerns for outdoor electrical equipment:

• Rust
• Blistering
• Peeling
• Chalking
• Color fading
• Edge corrosion
• Deterioration caused by rainwater

The following defects are concerns for communications and electronic equipment:

• Uneven film thickness
• Pinholes
• Insufficient conductivity
• Insufficient electromagnetic shielding performance
• Poor adhesion to plastic
• Solvent cracking
• Foreign matter contamination

Even within electrical products, the types of defects vary with the application.

This is why the product’s use and installation environment must be checked first.

Points to watch in Vietnamese factories

When coating electrical products in Vietnam, pay attention to the following:

• Poor drying caused by high temperature and humidity
• Increased humidity during the rainy season
• Recontamination after surface preparation
• Appearance defects caused by dust
• Insufficient identification of plastic substrates
• Variation in coating conditions between operators
• Poor temperature distribution in the baking oven
• Rust caused by outdoor storage
• Salt damage in coastal areas
• Inconsistent repair criteria

For home appliances and electronic equipment in particular, even small appearance defects can lead to complaints. For outdoor electrical equipment, however, rust or deterioration after several months or years may be more problematic than the initial appearance.

In Vietnamese operations, it is important to manage humidity, dust, storage, and operator training together.

The 4M perspectives CoatureVietnam checks

CoatureVietnam uses the 4M perspective when considering electrical product coating.

Material: materials

• Is the paint suited to indoor or outdoor use as required?
• Is it for metal or plastic?
• Is rust protection required?
• Are humidity, weather, or oil resistance required?
• Are stain resistance and cleanability required?
• Are functions such as electromagnetic shielding required?
• Are surface preparation chemicals and primers suited to the substrate?
• Is the thinner adversely affecting the plastic or appearance?

Method: methods

• Is waiting time after surface preparation controlled?
• Is the film thickness suited to the application?
• Are baking requirements followed?
• Is the drying temperature appropriate for the plastic components?
• Is there an inspection method for functional coating films?
• Are appearance inspection criteria for home appliance parts clear?
• Are repair-coating conditions standardized?

Machine: equipment

• Does the surface preparation line provide sufficient cleaning performance?
• Is booth cleanliness stable?
• Is the temperature distribution in the baking oven appropriate?
• Can the powder coating equipment handle color changes?
• Is inspection equipment available for functional coating films?
• Is the drying equipment suitable for plastic components?
• Can the coating equipment achieve the required film thickness on outdoor components?

Man: people

• Do operators understand how the product will be used?
• Do they understand the different quality criteria for home appliances and outdoor equipment?
• Do they understand the precautions for handling plastic components?
• Do they understand the risk of recontamination after surface preparation?
• Do they understand that functional coating films cannot be assessed by appearance alone?
• Do managers communicate the installation environment to the shop floor?

The Management perspective is also important.

For electrical product coating, the product category, installation environment, customer requirements, inspection criteria, and warranty conditions must be clarified and incorporated into the coating specification.

Questions for customer visits

For electrical product coating projects, sales and technical team members can use the following questions:

• Is this product for indoor or outdoor use?
• Will it be installed in a factory, in a home, outdoors, or in a coastal area?
• Will it be exposed to water, humidity, oil, chemicals, detergents, or heat?
• Which has greater priority: appearance quality or durability?
• Are the components metal or plastic?
• For plastic components, has the specific material been identified?
• How much time passes between surface preparation and coating?
• Is dust or oil settling on the surface again?
• Are baking temperature and time stable?
• Are there functional requirements such as electromagnetic shielding or conductivity?
• Are functional inspections carried out in addition to visual inspection?
• Have past complaints concerned appearance, durability, or functionality?

These questions help identify risks that paint selection alone does not reveal.

Conclusion: start electrical product coating with the installation environment and required functions

Do not treat all electrical product coating as one category.

For home appliances, appearance, a clean impression, stain resistance, and suitability for mass production are important. Heavy electrical equipment and outdoor installations require rust protection, humidity resistance, weather resistance, and long-term durability. Communications and electronic equipment may require thin films, electromagnetic shielding, conductivity, insulation, or other functions.

For electrical product coating, the product’s use and installation environment must therefore be checked first.

Where will it be used? What will it be exposed to? What is the coating intended to protect? Which matters most: appearance, durability, or functionality?

After checking these points, coordinating materials, methods, equipment, people, and management helps prevent coating problems.

CoatureVietnam views coating as a process that supports product value and reliability, rather than simply a surface finish.

Coating the Future with Science and Care.

Putting this into practice, we will support practical coating improvements suited to each electrical product’s use and installation environment.