Stabilize quality in the coating process.
Reduce operator workload.
Create a process that does not depend on experienced operators.
Reduce material loss.
Reduce hazardous work.
Address labor shortages.

These objectives may lead a factory to consider automatic coating machines or coating robots.

Automation is a powerful way to improve coating operations.
Successful implementation can stabilize film thickness, reduce material consumption, improve the working environment, and increase productivity.

However, automatic machines and robots do not deliver stable quality immediately simply because they have been purchased.

Even a high-performance robot cannot be used effectively unless the conditions of the workpiece to be coated are clearly defined.

Which surfaces will be coated?
Which surfaces will remain uncoated?
What film thickness is required?
What level of appearance is required?
Is the workpiece geometry simple or complex?
How will fixtures hold it?
How many part numbers are there?
What is the production volume?
Which coating material will be used?
Can the booth and drying oven accommodate the process?

Installing a robot without defining these conditions can leave the factory with equipment that is difficult to use.

Introducing automatic coating machines and robots should not start with robot selection.
It should start with defining workpiece conditions.

1. A robot system can be designed only after what it will coat is defined

A coating robot does not make spontaneous, flexible application decisions like a person.

From what position, at what angle and distance, at what speed, and with what material output will it coat?
Define these conditions in advance.

This first requires an accurate description of the objects to be coated.

Workpiece geometry.
Dimensions.
Weight.
Coated surfaces.
Uncoated surfaces.
Holes.
Recesses.
Edges.
Back surfaces.
Hanging positions.
Conveying orientation.

Without this information, robot motion cannot be defined.

The first consideration is not which robot to buy.
It is deciding what to coat, to what quality, and under what conditions.

2. Workpiece geometry determines the difficulty of robotic coating

The difficulty of robotic coating changes greatly with workpiece geometry.

Coating paths are relatively easy to create for simple shapes such as flat panels.
Complex three-dimensional shapes, recesses, internal surfaces, edges, or products with many holes make application conditions more difficult.

Complex shapes make the following problems more likely.

• Missed areas
• Uneven film thickness
• Excessive buildup at edges
• Insufficient deposition in recesses
• Variation in gun distance
• Constraints on gun angle
• Robot arm interference
• Interference with fixtures
• Increased teaching time

A manual operator can observe and adjust while coating.
A robot follows motions taught in advance.

Robotic coating of complex shapes requires a thorough understanding of the geometry and defined conditions for each surface.

3. Clearly define coated and uncoated surfaces

Before introducing a robot, clearly define where coating is and is not required.

This may seem obvious, but it is extremely important in practice.

A robot path cannot be created if coated surfaces are unclear.
Uncoated surfaces require consideration of masking, fixtures, gun angle, and application sequence.

Check the following items.

• Is the whole product coated?
• Is only one side coated?
• Are internal surfaces coated too?
• Is back-surface coating required?
• How far must coating extend over edges?
• Is coating inside holes required?
• Are joints or assembly areas coated?
• Is masking required?
• Which areas must not be coated?

Installing a robot with poorly defined coating coverage may create a mismatch between customer requirements and actual results.

Before installation, clearly show coating coverage in drawings or photographs.

4. Define film thickness requirements

Defining film thickness requirements is essential when introducing a coating robot.

Film thickness is the thickness of the coating film.
It affects corrosion protection, appearance, durability, and functionality.

Without a target thickness, material output, gun speed, gun distance, and overlap cannot be set for robotic coating.

Check the following items.

• Target film thickness
• Minimum film thickness
• Maximum film thickness
• Measurement locations
• Acceptance range
• Film thickness at edges
• Film thickness in recesses
• Differences between visible and non-visible surfaces
• Thickness allocation between primer and topcoat

Unclear thickness requirements lead to repeated adjustments after teaching because the film is “too thin,” “too thick,” “sagging,” or “missing in places.”

Stable robot conditions can be established only with a clear thickness target.

5. Define the level of appearance requirements

Coating quality includes appearance as well as film thickness.

Gloss.
Color.
Surface texture.
Particle defects.
Sagging.
Unevenness.
Grittiness.
Metallic appearance.
Decorative appearance.

Define the required appearance level for robotic coating.

Does the product require a high-quality appearance?
Is corrosion protection the main purpose, with a moderate appearance level acceptable?
Do visible and hidden surfaces have different requirements?
Which defects does the customer assess strictly?

These factors change robot paths and application conditions.

Demanding appearance requirements require strict control of gun distance, overlap, application speed, flash-off, and drying conditions.

Where corrosion protection is the main purpose, achieving film thickness and edge coverage becomes important.

Define the product’s required quality level before introducing a robot.

6. Check production volume and the number of part numbers

Production volume and the number of part numbers are also important.

Coating large quantities of the same part provides greater benefits from carefully developing robot conditions.
High-mix, low-volume production requires more teaching, condition changes, and fixture changes for each part number.

Check the following items.

• Daily production quantity
• Monthly production quantity
• Number of part numbers
• Quantity for each part number
• Setup change frequency
• Color change frequency
• Fixture change frequency
• Number of robot programs
• Frequency of new-product additions

Robots excel at repetitive work.
However, frequent part changes increase setup and program management workload.

Consider the mix of part numbers as well as production volume.

7. Fixture conditions determine robotic coating results

Fixtures are extremely important in robotic coating.

A fixture is a tool or structure that holds the workpiece.

An unstable fixture allows workpiece position to shift even when the robot repeats the same motion.
Position shifts change gun distance and application angle, causing variation in thickness and appearance.

Check the following items.

• Can the workpiece be fixed in the same position every time?
• Does the workpiece sway?
• Does the fixture obscure coated surfaces?
• Does it interfere with the gun or robot arm?
• Can grounding be established?
• Is loading and unloading easy?
• Is cleaning easy?
• Can film buildup change the position?
• Is fixture replacement simple?

Fixture design may affect quality more than the robot itself.

Installing a robot while fixtures remain unsuitable will not stabilize quality.

8. Workpiece positioning accuracy is important

A robot moves on the assumption that the workpiece is in a defined position.

If the position differs each time, the programmed coating path no longer matches the actual workpiece position.

This misalignment causes the following defects or problems.

• Missed areas
• Uneven film thickness
• Excessive buildup at edges
• Changes in gun distance
• Collision risk with the workpiece
• Appearance variation

A manual spray operator can observe the workpiece position and adjust.
A robot may be less tolerant of positional shifts.

Standardizing workpiece positioning is therefore important when introducing a robot.

Check fixtures, stops, sensors, conveying orientation, and hanging methods to create a system that delivers the same position every time.

9. Consider gun and material conditions together

Check coating guns and material conditions as well as the robot arm.

Which gun will be used?
An air spray gun or an electrostatic gun?
What output is required?
Is the nozzle diameter appropriate?
Is viscosity stable?
Is the thinner appropriate?
For a two-component material, can pot life be managed?
Is automatic supply equipment required?
How will color changes be handled?

Accurate robot motion cannot stabilize quality if material supply is unstable.

Consider the robot, gun, material, and supply equipment as one system.

10. Check booth capacity too

Robotic coating continuously sprays material under set conditions.

Insufficient booth capacity therefore causes mist accumulation or a poorer working environment.

Check the following items.

• Booth opening dimensions
• Robot working envelope
• Exhaust airflow volume
• Airflow at the working position
• Mist redeposition
• Filter capacity
• Ease of cleaning
• Explosion protection
• Relationship to safety fencing
• Maintenance space

If robot installation increases coating throughput, it also increases booth load.

Placing a robot in an existing booth causes quality, safety, or environmental problems if the booth cannot accommodate it.

Proceed with robot introduction together with booth capacity checks.

11. Check drying oven conditions too

Even if a robot can apply the coating, film performance will not be completed if the oven cannot accommodate the process.

Increased production after robot installation also changes oven load.

Conveyor speed increases.
Loading increases.
Film thickness changes.
The coating material changes.
Workpiece hanging methods change.

These changes may alter the temperature reached by the workpiece or its holding time.

Check the following items.

• Drying oven temperature conditions
• Temperature reached by the workpiece
• Residence time in the oven
• Conveyor speed
• Oven temperature distribution
• Workpiece hanging method
• Effects of increased film thickness on drying
• Capacity at higher production volume

Automation does not end with the application process.
Check the drying and curing processes as well.

12. Incorporate safety measures from the outset

Safety measures are extremely important when introducing a robot.

Robots are machines that move at high speed.
Coating processes also involve solvents, static electricity, powder, exhaust, explosion protection, and flammable atmospheres.

Check the following safety items.

• Safety fencing
• Interlocks
• Emergency stops
• Robot working envelope
• Safety during teaching
• Explosion-protection specifications
• Grounding
• Exhaust
• Fire risks
• Access procedures during maintenance
• Operator training

Safety measures should not be added after installation.
Incorporate them from the start of equipment planning.

Inadequate safety makes robot installation hazardous to the shop floor.
Adding measures later also tends to require layout changes and extra expenditure.

13. Estimate the teaching workload

Robotic coating requires teaching.

Teaching is the task of defining robot motion.
It sets the positions, angles, and speeds at which the robot moves.

Teaching is relatively simple for a simple workpiece.
Complex shapes or many part numbers, however, substantially increase teaching labor.

Check the following items.

• Number of part numbers
• Complexity of coated surfaces
• Difficulty of film thickness adjustment
• Number of gun angle changes
• Fixture types
• Color change conditions
• Program management method
• Who can perform teaching
• Response when new products are added

Consider revisions after mass production starts and accommodation of new products, as well as initial teaching.

Without personnel who can perform teaching, continued robot use becomes difficult.

14. Robots convert manual spraying skill into defined conditions

Introducing a robot does not eliminate the need for operator skill.

Instead, it analyzes experienced operators’ skills and translates them into process conditions.

Experienced operators make many judgments unconsciously.

Gun distance.
Application speed.
Overlap.
The start and end of spraying.
How to coat edges.
How to reach recesses.
A sequence that prevents sagging.
An intuitive sense of how to achieve thickness.
Fine adjustments while observing appearance.

Robot implementation requires these to be expressed in words, quantified, and programmed.

Automation does not reject human skill.
It converts that skill into repeatable conditions.

15. Common robot implementation challenges in Vietnamese factories

The following challenges commonly arise in Vietnamese factories.

The process starts with robot selection.
Workpiece conditions are undefined.
Coated and uncoated surfaces are unclear.
Fixture accuracy is insufficient.
Workpiece position shifts each time.
Many part numbers create a heavy teaching workload.
Booth capacity is insufficient.
Drying oven conditions are not examined.
Safety fencing or explosion protection is postponed.
No shop-floor personnel can perform teaching.

Under these conditions, installing a robot is unlikely to deliver the expected quality stability or labor savings.

Define conditions before selecting equipment.

16. Basic items to check before introducing a robot

The following checks are practical before introducing an automatic coating machine or robot.

1. Workpiece geometry

Check dimensions, weight, shape, contours, holes, and back surfaces.

2. Coating coverage

Clearly define coated surfaces, uncoated surfaces, and masked areas.

3. Quality requirements

Check film thickness, appearance, color, gloss, corrosion protection, and functionality.

4. Production conditions

Check production volume, part numbers, setup change frequency, and color change frequency.

5. Fixtures

Check positioning, holding, grounding, obscured surfaces, and ease of cleaning.

6. Coating guns

Check gun type, output, nozzles, air conditions, and electrostatic conditions.

7. Material supply

Check viscosity, thinner, pressure feed, two-component material management, and color changes.

8. Booth

Check the robot working envelope, exhaust, airflow, safety, and explosion protection.

9. Drying oven

Check workpiece temperature, drying time, and oven capacity.

10. Personnel

Confirm who will perform teaching, maintenance, and quality checks.

17. The value CoatureVietnam sees in robot implementation support

CoatureVietnam does not regard robot implementation simply as equipment sales.

It is an activity that redesigns the coating process.

Workpiece conditions.
Fixtures.
Coating guns.
Coating materials.
Booths.
Drying ovens.
Safety.
Teaching.
Quality checks.
Shop-floor training.

Consider these together.

Before robot implementation, CoatureVietnam first defines shop-floor conditions.

What will be coated?
What quality will be assured?
Which tasks will be automated?
Which tasks should people perform?
Where are the risks?
Can the shop floor continue using the system after installation?

We assess automation possibilities after checking these points.

This puts into practice the principle CoatureVietnam values:
“Coating the Future with Science and Care”
.

Science means defining workpiece conditions, film thickness, paths, fixtures, and equipment conditions to create repeatable application conditions.
Care means reducing operator workload and hazardous tasks and creating conditions in which the shop floor can use automation confidently.

Conclusion

Automatic coating machines and robots are powerful tools for improving coating processes.

However, purchasing a robot does not itself stabilize quality.

Robot introduction must start with defining workpiece conditions.

Workpiece geometry.
Coated surfaces.
Uncoated surfaces.
Film thickness requirements.
Appearance requirements.
Production volume.
Part numbers.
Fixtures.
Workpiece positioning.
Coating materials.
Coating guns.
Booths.
Drying ovens.
Safety.
Personnel who can perform teaching.

Only after these are defined can a robot deliver value on the shop floor.

Automation does not eliminate the need for human skill.
It converts skill into defined conditions that can be reproduced.

CoatureVietnam views automatic machine and robot introduction as an improvement to the entire coating process, rather than equipment alone, and provides automation support suited to Vietnamese factories.