Improving coating operations through film thickness, transfer efficiency, and paint consumption

Are you judging coating costs only by the price of paint per kilogram?

When considering coating process costs, the first point of attention is often the unit price of paint.

How much does it cost per kilogram?
Is it cheaper than the current paint?
Can switching to a locally sourced product reduce the purchase price?

The unit price of paint is certainly important.
However, unit price alone does not reveal the true cost of coating.

This is because not all purchased paint becomes a coating film on the product.

In a coating process, dilution, application method, film thickness variation, overspray, drying conditions, touch-ups, and recoating can substantially change the final cost.

Even if the paint is inexpensive, higher consumption to achieve the required film thickness or more defects and recoating can make the overall process more costly.

CoatureVietnam considers paint cost as the total cost of producing a coating film that meets the required quality, rather than simply the purchase price.

The real focus should be coating film cost, rather than paint price

Paint still in the can has not yet created value for the product.

It becomes a valuable coating film only when it adheres to the product surface at the appropriate thickness, dries and cures, and meets the required quality.

The following perspectives are therefore needed when considering coating costs.

• How much paint was purchased?
• How much paint was actually used?
• How much of that paint adhered to the product?
• Is the required film thickness being produced consistently?
• Are any areas too thin or too thick?
• Does the coating meet the required performance after drying?
• Are touch-ups or recoating required?
• What are the effects on booth cleaning, waste disposal, and the working environment?

In other words, buying paint cheaply is not the only way to reduce costs.

True cost improvement in a coating process means consistently converting paint into a coating film that meets the required quality with minimal waste.

A coating plan can be improved only when it is managed using numerical data

A coating plan is not complete simply because it has been drawn up.

Apply the coating under the planned conditions, check the results, and revise the conditions as needed.
Without repeating this cycle, coating quality and costs will not stabilize.

It is important to check the following numerical data on the coating shop floor.

• Target film thickness
• Measured film thickness
• Dilution ratio
• Viscosity
• Drying temperature
• Drying time
• Paint consumption
• Thinner consumption
• Defect rate
• Recoating rate
• Booth cleaning frequency
• Filter replacement frequency

Attempts to improve without recording these data inevitably rely on experience and intuition.

Shop-floor experience is certainly important.
However, experience alone can make it difficult to share an understanding of causes and achieve repeatable improvements.

Coating improvement requires both shop-floor observations and numerical data.

Film thickness directly affects both quality and cost

Film thickness control is very important in coating planning.

Film thickness is the thickness of the coating film formed on the product surface.
Industrial coatings require an appropriate film thickness to provide the required functionality and durability.

Insufficient film thickness can cause the following problems.

• Insufficient rust and corrosion protection
• Insufficient hiding power, allowing the underlying surface to show through
• Insufficient durability
• Effects on adhesion and functionality
• Failure to meet customer requirements

On the other hand, applying a film thicker than necessary is not necessarily better.

Excessive film thickness makes the following problems more likely.

• Increased paint consumption
• Greater likelihood of sagging and solvent popping
• Drying defects
• A greater tendency for solvent to remain inside the coating film
• Cracking and appearance defects
• Higher costs

In other words, both insufficient and excessive film thickness are problematic.

The key is to specify an appropriate film thickness for the required quality and reproduce it consistently on the shop floor.

Excessive film thickness is a paint loss that is difficult to see

Defects caused by insufficient film thickness are relatively easy to identify.
They become evident as inadequate rust protection, an underlying surface showing through, or failure to meet customer standards.

Losses caused by excessive film thickness, however, can be difficult to see.

A coating may look attractive even when it is thicker than necessary.
There may be no customer complaints either.

Nevertheless, extra paint is being consumed.
Drying takes longer, and the risks of sagging and drying defects also increase.

When a small excess in film thickness occurs every day, the loss per item may seem small, but it becomes a substantial monthly or annual cost.

Coating improvement requires checking not only for insufficient film thickness but also for unnecessary overapplication.

Consistent film thickness stabilizes quality and cost effectiveness

Looking only at average film thickness is not sufficient.

Even if the average is within the standard, thin and thick areas can create problems for both quality and cost.

Thin areas may provide insufficient rust protection, hiding power, and durability.
Thick areas are more prone to paint waste, sagging, drying defects, and cracking.

It is therefore important to produce the required film thickness as uniformly as possible.

Consistent film thickness is more than a quality-control issue.
It is fundamental to optimizing paint consumption, stabilizing drying conditions, and reducing defects.

The cost effectiveness of a coating process depends greatly on how uniformly the required coating film can be produced with minimal waste.

Paint consumption is not determined by area alone

Paint consumption is not determined simply by the area to be coated.

In practice, the following factors affect it.

• Required film thickness
• Paint specific gravity
• Film-forming components in the paint
• Dilution ratio
• Application method
• Transfer efficiency
• Workpiece shape
• Operator application technique
• Spray gun settings
• Booth and exhaust conditions
• Fixtures and workpiece arrangement

Film-forming components, dilution, and transfer efficiency are particularly important here.

Paint contains components that remain as a coating film after drying and components that evaporate during drying.
If the proportion remaining as film is low, more paint may be required to produce the same dry film thickness.

Variation in the dilution ratio also changes viscosity, film thickness, drying characteristics, and finish.

To assess paint consumption correctly, it is necessary to check how much paint remains effectively as a coating film, as well as its unit price.

Dilution affects quality and cost as well as ease of application

On the shop floor, paint is diluted with thinner to make it easier to apply.

Dilution is a necessary operation.
However, if dilution conditions are not standardized, quality and cost will vary.

For example, when operators judge dilution differently, the following problems can occur.

• Unstable viscosity
• Unstable film thickness
• Changes in drying condition
• Sagging and surface roughness
• More application passes
• Higher paint consumption
• Differences in finish between operators

At factories in Vietnam in particular, high temperatures, high humidity, and changing working conditions make dilution conditions and viscosity control more influential on quality.

Thinner is not merely a diluting liquid.
It is an important auxiliary material that affects application, drying, finish, and film thickness control.

CoatureVietnam therefore checks the thinner and dilution conditions as well as the paint.

Transfer efficiency reveals the actual extent of paint loss

Transfer efficiency describes the proportion of paint used that actually adheres to the product.

In spray coating, some paint does not adhere to the product but disperses into the air or deposits inside the booth.
This is overspray.

Low transfer efficiency causes the following problems.

• Higher paint consumption
• A greater booth cleaning burden
• More waste
• A poorer working environment
• More appearance defects caused by paint mist
• A higher load on exhaust equipment
• A greater burden on operators

Improving transfer efficiency therefore affects the working environment, safety, and quality stability, as well as paint cost.

Before reducing the unit price of paint, it is important to examine how effectively the paint adheres to the product.

Overspray is both material loss and an environmental burden

Spray coating produces paint that does not adhere to the product.

This overspray is more than a material loss.

Paint that does not adhere to the product deposits inside the booth, loads filters and exhaust equipment, and becomes waste.
Cleaning work also increases.
The working environment is affected too.

Reducing overspray therefore improves paint costs while reducing environmental impact and the cleaning burden, and improving the working environment.

CoatureVietnam’s approach to coating improvement examines waste disposal, cleaning, and the working environment as well as paint consumption.

Paint consumption varies greatly with the coating method

Even for the same required film thickness, the amount of paint needed varies greatly with the coating method.

For example, air spray coating, electrostatic coating, and powder coating differ in dilution requirements, the proportion remaining as coating film, and transfer efficiency.

Generally, methods with high transfer efficiency increase the proportion of paint that adheres effectively to the product and make it easier to reduce material loss.

However, it cannot simply be said that a method with higher transfer efficiency is always better.

The appropriate method depends on workpiece shape, quantity, number of colors, required quality, workspace, equipment investment, maintenance, and color-change frequency.

High-mix, low-volume production with frequent color changes.
Coating large products.
A need for high appearance quality.
Applications suited to powder coating.
Situations where continuing solvent-based coating is more practical.

Each situation calls for a different decision.

The key is to assess the coating method together with the workpiece, required quality, equipment conditions, and operating conditions, rather than choosing the method in isolation.

Paint selection affects the whole coating plan, as well as quality

When selecting paint, compatibility with the required quality is important.

However, that alone is not sufficient.

It is also necessary to check whether the paint suits the shop’s coating method, equipment, drying conditions, production volume, and color-change conditions.

For example, even a paint with high performance is difficult to use consistently if its drying conditions do not match the available equipment.
If viscosity is difficult to adjust, differences between operators become more likely.
Even a cheap paint will not reduce total cost if poor transfer efficiency increases consumption.

Paint selection cannot be assessed in isolation.
It is a decision that affects the entire coating plan.

Coating equipment should be planned by working back from the workpiece

In coating planning, it is important to examine the workpiece first, rather than starting with paint or equipment.

The optimal coating method and equipment plan vary with workpiece dimensions, shape, quantity, material, and weight.

For example, the following relationships apply.

• For large workpieces, booth and oven dimensions are important
• For heavy workpieces, conveyor strength, fixtures, and safe loading and unloading methods are important
• For high volumes, processing speed, line arrangement, and drying capacity are important
• For multiple colors, color-change methods and ease of cleaning are important
• For heat-sensitive materials, drying temperature and curing method need to be reviewed
• For high appearance requirements, dust control and contamination prevention during handling are important

A coating line is not complete simply by installing a booth and a drying oven.

Working back from the workpiece, required coating film, production volume, quality standards, and safety, it is necessary to design the coating method, drying capacity, handling, loading and unloading, working positions, and staffing.

Paint cost issues that are easily overlooked at factories in Vietnam

The following paint cost issues can be found at factories in Vietnam.

• Comparisons based only on paint unit price
• No understanding of actual paint consumption per product
• No comparison of theoretical and actual consumption
• Checks for insufficient film thickness but not excessive thickness
• Dilution ratios that depend on operator intuition
• Insufficient viscosity measurement
• Uncontrolled thinner consumption
• Excessive overspray
• A heavy burden of booth cleaning and filter replacement
• High losses during color changes and small-lot production
• More touch-ups and recoating despite switching to cheaper paint
• Equipment and fixtures that do not suit the workpiece

These may appear to be separate issues, but in practice they arise from the interconnection of coating planning, materials, equipment, working methods, and people management.

Checks for reviewing paint costs

The following checks are useful when reviewing coating costs.

Film thickness checks

• Is the required film thickness clearly defined?
• Is measured film thickness recorded?
• Are both insufficient and excessive film thickness checked?
• Are there film thickness differences between operators?
• Does product shape cause uneven film thickness?

Paint consumption checks

• Is daily and monthly paint consumption known?
• Is paint consumption per product known?
• Is the difference between theoretical and actual consumption checked?
• Are losses during color changes and cleaning known?
• Is the amount of discarded paint recorded?

Dilution and viscosity checks

• Is the dilution ratio standardized?
• Is the thinner appropriate?
• Is viscosity measured?
• Are there adjustment rules for temperature and humidity?
• Do dilution conditions vary between operators?

Transfer efficiency checks

• Is overspray excessive?
• Are spray distance and gun angle standardized?
• Are air pressure and paint delivery rate controlled?
• Do fixtures and workpiece arrangements allow easy application?
• Is booth exhaust too strong or too weak?

Coating method and equipment checks

• Is the reason for choosing the current coating method clear?
• Does the coating method suit the workpiece shape?
• Is there scope to switch to electrostatic or powder coating?
• Does oven capacity suit the paint conditions and production volume?
• Are the time and material losses associated with color changes and cleaning known?

How CoatureVietnam can help

CoatureVietnam supports cost improvement across the coating process, as well as supplying paint.

Paint Optimizer

We consider switching from imported or existing paints to locally sourced products or alternative candidates.
The assessment includes quality, ease of application, paint consumption, and defect rates, rather than simply replacing the paint with a cheaper product.

Thinner Streamer

We check thinners and dilution conditions suited to the paint, and support improvements in application, drying, and film thickness stability.
Thinner is treated as an important element supporting coating quality, rather than merely an auxiliary material.

Coat Visioner

We make film thickness, paint consumption, operating conditions, defect trends, and equipment conditions visible and identify improvement priorities.
We clarify opportunities to improve coating costs using shop-floor data and observations rather than intuition.

Coat Systemizer

Working back from the workpiece, required quality, production volume, and safety, we design the entire process, including the coating method, booth, drying oven, handling, fixtures, and layout.

Coating the Future with Science and Care

Science is needed to improve coating costs.

Film thickness, solids content, dilution ratio, transfer efficiency, paint consumption, and defect rates must be made visible and assessed across the entire process, rather than looking only at paint unit price.

Care is also needed when improving coating costs.

Reducing paint loss reduces the cleaning burden on operators.
Reducing excessive film thickness and recoating eliminates unnecessary shop-floor work.
Increasing transfer efficiency also improves the working environment.

CoatureVietnam aims to make coating processes visible through a scientific approach and improve quality and cost together while reducing the burden on the people working on the shop floor.

Summary

Paint cost cannot be judged only by the unit price per kilogram.

What matters is how efficiently purchased paint adheres to the product and becomes a coating film that meets the required quality.

Is film thickness stable?
Is there loss from excessive film thickness?
Are dilution conditions standardized?
Is transfer efficiency appropriate?
Is overspray excessive?
Does the coating method suit the workpiece?
Are touch-ups and recoating consuming extra paint?

These checks reveal the real improvement priorities in a coating process.

If a factory in Vietnam faces issues with paint costs, paint consumption, quality variation, or the touch-up burden, checking film thickness, transfer efficiency, and paint consumption is the first step toward improvement.

CoatureVietnam examines coating processes from the 4M perspective and supports coating cost improvements that cannot be seen from paint unit price alone.