When coating equipment is introduced, the equipment supplier submits approval drawings.

Approval drawings are used to check equipment dimensions, layout, specifications, connections, and construction scope.
Equipment fabrication or construction proceeds after the purchaser reviews and approves them.

Do not treat these drawings as merely formal paperwork.

Approval drawings are the last opportunity to prevent equipment problems.

Problems overlooked on drawings appear on the shop floor after the equipment is completed.

The booth entrance is too narrow.
The route for bringing in the drying oven is inadequate.
The exhaust-duct route is poor.
The conveyor height does not suit operators.
Inspection openings cannot be reached.
There is no space to replace filters.
Robot safety fencing obstructs work routes.
Air, water, and electrical connection positions do not match the site.

Correcting such problems after completion takes substantial time and money.

Identify as many risks as possible at the approval-drawing stage.

1. Approval Drawings Are Not Just for the Equipment Supplier

The equipment supplier prepares approval drawings.
However, the supplier is not the only party that should review them.

The purchaser also needs to review them from the shop-floor perspective.

The following members should be involved in particular.

• Factory manager
• Production engineering
• Quality assurance
• Maintenance
• Coating shop supervisor
• Occupational health and safety
• Purchasing where needed
• Management responsible for investment decisions

Equipment drawings contain different points to examine from each perspective.

Production engineering examines capacity and layout.
Quality assurance examines conditions needed for stable quality.
Maintenance examines ease of inspection, cleaning, and part replacement.
Shop-floor supervisors examine operator usability.
Safety personnel examine hazards, explosion protection, and emergency stops.
Management examines investment objectives and operating costs.

Approval drawings are more than documents received from an equipment supplier.
They allow the purchaser to check whether the equipment truly suits its own shop floor.

2. Equipment That Fits on a Drawing May Not Be Usable on Site

Equipment drawings may show that equipment fits within the allocated space.

However, fitting into a space and being easy to use on the shop floor are different matters.

For example, the following problems occur.

• Operators find it difficult to hang workpieces
• The paint-mixing area is far from the booth
• Filter replacement space is inadequate
• The booth interior is difficult to clean
• Other equipment obstructs inspection openings
• No maintenance space is available beside the drying oven
• Conveyor height does not suit operators
• There is no fixture storage area
• There is no defective-product area
• Routes for finished and uncoated products cross

Problems that are difficult to see on drawings can create major burdens during actual work.

When reviewing approval drawings, imagine staff movement, material flow, cleaning, inspection, and responses to abnormal conditions, as well as equipment dimensions.

3. What to Check in Booth Drawings

Check the following items in coating-booth approval drawings.

First, examine the booth opening dimensions.
Check whether workpieces enter safely and operators can coat them without strain.

Next, examine the working position.
Can operators see the coating surfaces from where they stand?
Can the required gun distance be maintained?
Will the operator’s body obstruct airflow?

Also check exhaust and supply-air positions.
The structure should carry mist toward extraction without returning it toward the operator.

Check the following items.

• Internal booth dimensions
• Opening dimensions
• Operator standing position
• Distance from the workpiece
• Lighting positions
• Filter positions
• Filter replacement space
• Exhaust direction
• Supply-air positions
• Duct connection positions
• Cleaning openings
• Inspection openings
• Locations for managing booth water and sludge
• Safety devices

A coating booth is more than a place to apply paint.
Consider quality, working conditions, exhaust, cleaning, and maintenance together.

4. What to Check in Drying-Oven Drawings

In drying-oven approval drawings, check whether workpieces can dry and cure under the required conditions, as well as dimensions.

Workpiece residence time in the oven is particularly important.
Oven length, conveyor speed, and temperature conditions determine drying time.

Also check entrance and exit dimensions.
Assess whether the maximum overall envelope, including fixtures and hangers rather than the workpiece alone, can pass through.

Check the following items.

• Internal oven dimensions
• Oven length
• Entrance and exit dimensions
• Conveyor speed
• Residence time
• Set temperature
• Method for checking the temperature reached by the workpiece
• Circulation-fan positions
• Exhaust positions
• Exhaust-duct connections
• Inspection openings
• Cleaning openings
• Maintenance space
• Temperature-sensor positions
• Emergency stops
• Fire-prevention measures

A drying oven develops coating-film performance.
Drawing reviews must check whether proper curing conditions can be achieved, as well as whether the equipment fits.

5. What to Check in Conveyor Drawings

A conveyor does more than move workpieces.
It determines application time, drying time, work routes, and production capacity.

Check the following items in approval drawings.

• Conveyor route
• Hanger pitch
• Conveying height
• Conveyor speed
• Bend radius
• Angles of ascending and descending sections
• Risk of contact between workpieces
• Operator loading and unloading positions
• Fixture storage areas
• Inspection positions
• Defective-product removal positions
• Maintenance positions
• Emergency-stop positions

Workpiece contact requires particular attention.

Even if straight sections pose no problem, workpieces may sway or move closer together at bends or ascending and descending sections.
Unless checked using the overall envelope including fixtures, contact problems may arise after start-up.

In conveyor drawings, imagine actual workpiece movement as well as the line route.

6. What to Check in Robot and Automatic-Machine Drawings

Drawing reviews become even more important when introducing coating robots or automatic coating machines.

Robots have a wide operating range.
Check safety fencing, operator access areas, teaching space, and maintenance space.

Check the following items.

• Robot operating envelope
• Area to be coated
• Gun distance
• Workpiece position
• Fixture position
• Safety fencing
• Interlocks
• Emergency stops
• Teaching space
• Control-panel position
• Cable routes
• Explosion-protection specifications
• Maintenance space
• Interference with operator routes

A robot does not automatically coat successfully simply because it is installed.
It functions properly only when fixtures, workpiece positions, coating paths, and safety areas are appropriate.

Approval drawings must include checks on surrounding conditions as well as the robot itself.

7. What to Check in Exhaust-Duct Drawings

Exhaust ducts substantially affect booth and drying-oven performance.

Review duct routes, lengths, bends, and exhaust-outlet positions.

Check the following items.

• Duct diameter
• Duct length
• Number of bends
• Presence of sharp bends
• Inspection and cleaning openings
• Exhaust-fan position
• Exhaust-outlet height
• Exhaust direction
• Position relative to neighboring factories
• Rainwater protection
• Particle and odor controls
• Space to add future exhaust-treatment equipment

Excessively long ducts or too many bends reduce airflow.
Poor outlet positions can cause external odor or particle complaints.

Exhaust ducts are more than passages for discharging air outside.
They are important equipment affecting quality, working conditions, and environmental management.

8. Check Electrical, Air, Water, and Gas Connection Positions

Approval drawings require checking utility connection positions, as well as the equipment itself.

Utilities are the electricity, compressed air, water, gas, and other supplies needed to operate equipment.

Check the following items.

• Power connection position
• Control-panel position
• Compressed-air piping connection position
• Required air volume
• Required pressure
• Water-supply position
• Drain position
• Gas connection position
• Piping routes
• Meter and valve positions
• Accessibility for maintenance

Connection positions that do not match the site require additional piping or wiring work.

They may also obstruct work routes.

Utilities may seem to sit behind the equipment.
However, they are important conditions supporting operation.

9. Check Space for Inspection, Cleaning, and Part Replacement

Maintenance space is easily overlooked in approval drawings.

Even with space to install equipment, inability to inspect or clean it causes problems after start-up.

Check the following items.

• Filter replacement space
• Fan inspection space
• Pump inspection space
• Motor replacement space
• Duct cleaning openings
• Drying-oven inspection openings
• Booth cleaning space
• Robot maintenance space
• Working space in front of control panels
• Platforms and passages for safe work

Equipment will inevitably need inspection, cleaning, and part replacement after installation.

If this space is not provided on the drawings, maintenance becomes difficult and equipment condition is more likely to deteriorate.

Equipment that is difficult to maintain destabilizes quality over the long term.

10. Check Safety Devices and Operator Routes

Safety checks are also important for coating equipment.

Check the following items in approval drawings.

• Emergency-stop button positions
• Safety-fence positions
• Operator passages
• Access areas for inspection
• Robot operating envelope
• Explosion-protection areas
• Grounding connections
• Fire-extinguishing equipment
• Ventilation equipment
• Safe clearance around heat sources
• Pressure-vessel safety valves
• Protection against contact with hot areas

Safety devices need more than simply being installed.

Can operators reach them immediately?
Are escape routes available in an emergency?
Does routine work require dangerous postures?
Is safe inspection access available?

Check these points on the drawings.

Safety should not be added only after completion.
It should be incorporated during design.

11. Compare the Drawings with the Site

Do not review approval drawings only at a desk.

Always compare them with the actual site.

Space that appears empty on drawings may contain existing equipment, piping, shelves, columns, beams, passages, or temporarily stored items.
In older factories, drawings may not match actual conditions.

Check the following items on site.

• Planned equipment location
• Nearby equipment
• Columns and beams
• Ceiling height
• Floor condition
• Delivery and installation route
• Piping and wiring
• Exhaust route
• Operator routes
• Maintenance space
• Forklift routes
• Evacuation routes

Walk the site with the approval drawings when reviewing them.

Approving without a site walk may result in equipment that is correct on paper but difficult to use in practice.

12. Assign Responsibility for Drawing Reviews

A common problem with approval drawings is uncertainty over who performed the final review.

Drawings arrive from the equipment supplier.
Purchasing receives them.
Production engineering takes a brief look.
They are shared with the shop floor.
Someone stamps them approved.

This workflow can omit important checks.

Assign a person responsible for reviewing approval drawings.

It is also preferable to allocate review items among stakeholders rather than leaving everything to one person.

• Production engineering: Capacity, layout, utilities
• Shop-floor supervisors: Workability, routes, loading and unloading, cleaning
• Maintenance: Inspection, part replacement, maintenance space
• Quality assurance: Quality conditions, inspection, temperature, airflow
• Safety: Safety devices, explosion protection, emergency stops
• Management and factory manager: Investment objectives, future needs, risks

Drawing reviews should be an organizational effort rather than relying on one person’s experience.

13. Common Approval-Drawing Review Issues in Factories in Vietnam

The following review issues commonly arise in factories in Vietnam.

Reviews are left to the equipment supplier.
The Japanese headquarters reviews drawings, but the Vietnamese shop floor does not check them sufficiently.
Shop-floor staff review them but do not understand the technical checkpoints.
Old building drawings differ from actual site conditions.
Understanding differs between English, Japanese, and Vietnamese drawings.
Operators’ opinions are not reflected.
Maintenance space is overlooked.
Safety-device positions do not suit actual work.
Change history after approval is not managed.

These conditions make problems more likely after equipment introduction.

Approval drawings should not be left to the equipment supplier.
They are important documents through which the purchaser checks suitability for its own shop floor.

14. Basic Approval-Drawing Checklist

The following checks provide a practical approach to coating-equipment approval drawings.

1. Equipment Dimensions

Check overall dimensions, opening dimensions, height, and working space.

2. Layout

Check preceding and following processes, work routes, material flow, and inspection areas.

3. Workpiece Conditions

Check maximum dimensions, the overall envelope including fixtures, weight, and sway during conveying.

4. Utilities

Check connection positions and capacities for electricity, air, water, gas, exhaust, and drainage.

5. Exhaust and Supply Air

Check duct routes, exhaust outlets, supply-air balance, and odor or particle risks.

6. Maintainability

Check inspection and cleaning openings, part replacement space, and control-panel access.

7. Safety

Check emergency stops, safety fencing, explosion protection, grounding, fire extinguishing, and evacuation routes.

8. Quality Conditions

Check booth airflow, oven temperature, temperature reached by workpieces, and film-thickness measurement positions.

9. Future Needs

Check whether equipment can accommodate increased production, additional part numbers, paint changes, or expanded automation.

10. Responsibilities

Confirm the respective scopes of the equipment supplier, purchaser, and local contractors.

15. The Value CoatureVietnam Sees in Approval-Drawing Reviews

CoatureVietnam considers approval-drawing review an extremely important process.

Many equipment problems do not suddenly begin when operation starts; they originate in design-stage oversights.

An issue found during drawing review may require only a small correction.
Found after fabrication, it may require major modification.
Found after mass production starts, it leads to quality defects, work burdens, construction delays, or additional costs.

CoatureVietnam’s Coat Systemizer reviews approval drawings from the following perspectives.

• Does the equipment suit the actual workpieces?
• Can it stabilize coating quality?
• Can operators use it without strain?
• Is it easy to maintain?
• Can it be operated safely?
• Are environmental-management risks addressed?
• Can it accommodate future changes?

This puts CoatureVietnam’s guiding principle,
“Coating the Future with Science and Care”,
into practice.

Science means checking drawings, dimensions, capacity, and connection conditions to make equipment risks visible in advance.
Care means providing equipment that the shop floor can use safely and consistently without difficulties after start-up.

Conclusion

Approval drawings are more than paperwork to approve formally.
They are the last opportunity to prevent equipment problems.

Coating booths.
Drying ovens.
Conveyors.
Robots.
Exhaust ducts.
Electricity.
Air.
Water.
Drainage.
Work routes.
Maintenance space.
Safety devices.

Checking these during drawing review reduces problems after start-up.

Equipment fitting in a space differs from being usable on the shop floor.
A design that works on paper also differs from stable mass-production operation.

The purchaser therefore needs to review approval drawings from its own shop-floor perspective, as well as relying on the equipment supplier.

CoatureVietnam treats approval-drawing review as an important process determining the success of equipment introduction and supports equipment introduction suited to factories in Vietnam.