A coating shop cannot always keep processing large quantities of the same product in the same color under the same conditions.

Actual factories frequently experience the following situations.

Many small lots.
Many colors.
Product shapes that change each time.
Different coating types.
Different film thickness requirements.
Different drying conditions.
Different masking requirements.
Urgent or repair items inserted into the schedule.
Prototypes entering the regular line.
Different inspection standards for each customer.

High-mix, low-volume coating shops face difficulties unlike those of straightforward continuous production.

Equipment capacity alone may appear sufficient for production.
In practice, however, color changes, cleaning, jig changes, coating material preparation, workpiece storage, inspection, and rework stop the line.

In high-mix, low-volume coating production, a poor layout quickly creates shop-floor confusion.

1. Standard flow is easily disrupted in high-mix, low-volume production

On mass production lines, the same product moves in the same sequence, making work relatively easy to stabilize.

In high-mix, low-volume production, however, conditions change each time.

The product changes.
The color changes.
The coating material changes.
The jig changes.
Masking changes.
Drying conditions change.
Inspection items change.

These changing conditions increase the number of shop-floor decisions.

Which coating material should be used?
Which thinner should be used for dilution?
Which jig should hold the workpiece?
In what order should products be coated?
Where should they dry?
Where should they be inspected?
Where should defective products be returned?

If these matters are unclear, operators must decide each time.

The more decisions are made on the spot, the more readily quality variation, work delays, incorrect use, and disorganized storage occur.

In high-mix, low-volume production, flows and rules that accommodate changing conditions are more important than equipment capacity alone.

2. Frequent color changes increase cleaning time

Color changes impose a major burden in high-mix, low-volume production.

A color change requires cleaning guns, cups, hoses, piping, coating supply equipment, and sometimes the area around the booth.

Insufficient cleaning causes the following defects.

• Color contamination
• Dirt inclusions
• Cratering
• Uneven color
• Gloss defects
• Foreign matter contamination
• Coating film appearance defects

Thorough cleaning, on the other hand, takes time.
It also consumes cleaning thinner.
Waste thinner is generated.
The burden on operators increases.

Where color changes are frequent, cleaning time greatly affects productivity.

Problems are particularly severe when cleaning areas or cleaning tool storage are poorly positioned.

The cleaning area is far away.
Cleaning thinner is far away.
Waste thinner storage is far away.
There is no location to check the result after cleaning.
Cleaning tools are disorganized.
Cleaning completion criteria differ between operators.

Under these conditions, each color change disrupts the shop floor.

In high-mix, low-volume production, it is important to design the cleaning area as well as the coating area.

3. More colors increase coating material inventory and leftovers

Coating material inventory is also difficult to manage where many colors are used.

In addition to basic colors such as white, black, gray, silver, red, and blue, customer-specified colors, similar shades, prototype colors, and repair colors may keep increasing.

This causes the following problems.

• More rarely used coating materials
• More small-capacity cans
• More leftover coating material
• Expired materials
• Confusion between similar colors
• Pressure on coating material storage space
• More hazardous materials in storage
• More waste coating material

Coating material is a material when purchased.
However, if it expires before it can be used up, it becomes waste.

In high-mix, low-volume production, coating material inventory itself becomes a source of problems.

Coating material storage is disorganized.
Materials in use, unused materials, leftovers, and materials awaiting disposal are mixed together.
Color code labels are hard to understand.
Materials for different customers are not separated.
There is no rule for using older materials first.

These conditions increase incorrect use and disposal losses.

In high-mix, low-volume production, the layout of coating material storage and mixing areas is also part of quality control.

4. Insufficient jigs and storage areas create shop-floor bottlenecks

Many product shapes require many jigs.

Hanging jigs.
Support jigs.
Masking jigs.
Rotating jigs.
Drying jigs.
Inspection jigs.
Dedicated jigs.
General-purpose jigs.

Disorganized jigs make preparation before coating time-consuming.

The required jig cannot be found.
Jigs in use and stored jigs are mixed together.
Dirty jigs are used without cleaning.
Heavy coating buildup has made jigs heavy.
Jig storage is far away.
Jigs are temporarily placed in aisles.

These conditions lengthen changeovers.
Operators walk more.
The wrong jig is also more likely to be used.

Dirty jigs also affect coating quality.
They may cause contamination, dirt inclusions, contact marks, uneven film thickness, and hanging marks.

In high-mix, low-volume production, jig storage must not simply occupy leftover space.
It must be positioned with consideration for usage frequency, product grouping, cleanliness, and handling routes.

5. Unscheduled production disrupts shop-floor flow

Unscheduled work is readily inserted into high-mix, low-volume production.

Urgent items.
Repair items.
Prototypes.
Items addressing customer complaints.
Items with changed delivery dates.
Small additional orders.

When these enter the regular line, they disrupt shop-floor flow.

The sequence of regular products changes.
Prepared coating materials can no longer be used as planned.
A change to another color becomes necessary.
Cleaning frequency increases.
The drying oven loading sequence is disrupted.
Inspection becomes congested.
The shipping sequence for finished products changes.

Completely eliminating unscheduled production is difficult.
Customer service, in particular, sometimes requires handling urgent items.

However, without rules for inserting work, the shop floor becomes confused each time.

Dedicated locations, identification, approval rules, loading decisions, and rescheduling methods are needed for these items.

Who authorizes insertion into the schedule?
Where are the items placed?
How is their priority relative to regular products decided?
When are they coated?
Who assesses the effect on color changes?
How are they sent to inspection and shipment?

Establishing these matters in advance reduces disruption from inserted work.

6. Even automatic coating machines stop for condition changes

Introducing automatic coating machines is often assumed to improve productivity.

They are, of course, highly effective when conditions are stable.
They may stabilize film thickness, reduce operator burden, and improve transfer efficiency.

However, they also present difficulties in high-mix, low-volume production.

Product shapes change.
Coating areas change.
Colors change.
Film thickness requirements change.
Jigs change.
Programs change.
Gun conditions change.

If changing conditions takes time, the line stops even with automatic equipment.

If automatic coating condition changes depend on a particular person, they cannot be handled when that person is absent.
If condition sheets are not maintained, past conditions cannot be reproduced.
Unclear management of program and product names also creates a risk of coating under the wrong conditions.

Automation is not universal.
Using it effectively in high-mix, low-volume production requires standardized condition changes, common jigs, and clear work instructions.

7. Mixing uncoated, coated, and defective products increases quality risks

The variety of workpieces in high-mix, low-volume production readily causes storage areas to become disorganized.

Uncoated products.
Coated products.
Products awaiting drying.
Products awaiting inspection.
Finished products.
Defective products.
Rework items.
Repair items.

If their locations are unclear, they become mixed on the shop floor.

This creates the following risks.

• Good and defective products are confused.
• Coated products contact uncoated products.
• Undried films are scratched.
• Rework items mix with regular products.
• Inspection is missed.
• Shipping mistakes occur.
• First-in, first-out control breaks down.

Insufficient storage space is more than a space issue.
It is a quality risk.

In high-mix, low-volume production, storage areas must be separated by status as well as divided by color or product.

Untreated.
Before coating.
After coating.
Awaiting inspection.
Finished.
Defective.
Rework.

Clear status categories reduce on-the-spot decisions.
Operators also face less uncertainty.

8. Information flow is important in high-mix, low-volume production

High-mix, low-volume production increases the amount of information.

Product name.
Color code.
Coating material product code.
Thinning ratio.
Film thickness.
Drying conditions.
Masking conditions.
Inspection standards.
Delivery date.
Priority.
Rework instructions.

Problems occur if this information does not reach the shop floor correctly.

For example, the following problems may occur.

Work is performed using old instructions.
Similar colors are confused.
Film thickness requirements are mixed up.
Drying conditions are wrong.
The priority of inserted work is not communicated.
Rework instructions are unclear.
Inspection standards differ between operators.

In high-mix, low-volume production, the location of information is also part of the layout.

Where are work instructions displayed?
Where are coating condition sheets checked?
Where are color sample panels placed?
Who issues change instructions?
Where are inspection results sent back?

Poor information flow also disrupts product flow.

9. With a poor layout, the shop floor resorts to temporary placement

Temporary placement is common in high-mix, low-volume production.

Workpieces are placed in aisles.
Coating material cans are placed near the booth.
Jigs are placed along walls.
Defective products are placed in available spaces.
Waste thinner is temporarily kept on the shop floor.
Urgent items are placed beside the inspection table.

The shop floor uses temporary placement to keep work moving.
It may appear necessary at the time.

However, when temporary placement becomes routine, the shop floor becomes disorganized.

Aisles narrow.
Forklifts have difficulty passing.
Dust accumulates.
Coated products are scratched.
Good and defective products mix.
Hazardous material control breaks down.
Operators become uncertain.

Frequent temporary placement is often a layout and operating rule problem rather than an operator problem.

It is important to examine why temporary placement is necessary rather than blame it.

10. Layout improvement points for high-mix, low-volume production

The following improvements can be made in high-mix, low-volume coating shops.

Color change routes

Position coating materials, thinners, cleaning areas, and waste thinner storage nearby, safely, and clearly.

Jig storage

Organize jigs by product, usage frequency, and cleanliness, making them easy to retrieve from the working area.

Storage by status

Clearly separate products before coating, after coating, awaiting inspection, finished, defective, and for rework.

Locations for inserted work

Create dedicated locations so urgent or repair items do not mix with regular products.

Information displays

Make working conditions, color codes, drying conditions, and priorities easy to check on the shop floor.

Cleaning standards

Clarify cleaning procedures, completion criteria, and waste thinner separation.

Operator routes

Keep necessary items nearby so operators do not need to walk around searching for them.

Inspection feedback

Create positions and systems that return inspection results immediately to the coating process.

These improvements may be possible without major equipment investment.

11. How CoatureVietnam examines high-mix, low-volume coating shops

CoatureVietnam does not assess high-mix, low-volume coating shops by equipment capacity alone.

It checks the following items.

• Number of color changes
• Cleaning time
• Cleaning thinner consumption
• Coating material inventory and leftovers
• Jig types and storage locations
• Operator walking distance
• Rules for handling inserted work
• Clarity of storage by status
• Methods for changing automatic coating conditions
• How inspection results are returned
• Return routes for defective products and rework

High-mix, low-volume production requires shop-floor flexibility.
However, flexibility does not mean making every decision on the spot.

It means establishing locations, displays, procedures, and decision criteria in advance so that flexible responses are possible.

Conclusion

In high-mix, low-volume coating production, productivity cannot be judged by equipment capacity alone.

Color changes increase.
Cleaning increases.
Coating material inventory increases.
Jigs increase.
Inserted production increases.
Storage areas become more complex.
Work instructions also become more complex.

If the layout and operating rules are weak, the shop floor comes to rely on temporary placement and operator judgment.
This causes quality defects, work delays, increased waste, and safety risks.

What matters in high-mix, low-volume production is more than adding equipment.

Routes that facilitate color changes.
Locations that facilitate cleaning.
Jig storage that eliminates searching.
Workpiece storage divided by status.
Rules for inserted work.
Clear work instructions.
Prompt inspection feedback.

Establishing these stabilizes productivity and quality.

CoatureVietnam reviews high-mix, low-volume coating shops through setup, movement routes, storage locations, and information flow rather than equipment capacity alone.
It supports coating processes in which the shop floor can respond consistently without uncertainty or undue strain each time.

Coating the Future with Science and Care
Organizing the confusion of high-mix, low-volume production is an important improvement that reduces the burden on people working on the shop floor and increases factory competitiveness.