Factory Acceptance Test (FAT) in China: Six Critical Readiness Risks That Cause FAT Failure

For manufacturers, system integrators, and overseas buyers, a Factory Acceptance Test (FAT) is far more than a routine inspection before shipment. It is the final opportunity to verify that an automation system is ready for production before it leaves the supplier’s factory.

Yet many FATs fail to achieve their real purpose.

Machines are powered on. Products are successfully produced. Documents are signed. The equipment is shipped.

Weeks later, the same production line arrives at the customer’s site, where unexpected failures begin to appear—unstable production, quality defects, software modifications, endless commissioning, project delays, and costly disputes over responsibility.

In many industrial automation projects, these problems do not originate during Site Acceptance Testing (SAT). They already existed during the Factory Acceptance Test but were never properly identified.

From an independent industrial risk management perspective, a successful FAT is not about demonstrating that a machine can run. It is about proving that the entire delivery system—including people, equipment, materials, processes, and operating conditions—is ready for real production.

This article examines six of the most common risks that turn FATs into chaotic events rather than effective risk control activities.

1. The Right People Are Missing From the FAT

One of the most common misconceptions is that a Factory Acceptance Test belongs solely to the equipment supplier.

In reality, FAT is a joint verification process between the supplier and the customer.

Many projects follow a familiar pattern.

The supplier assigns commissioning engineers to operate the machine.

The customer sends a purchasing representative.

Everyone gathers around the equipment, observes several production cycles, and concludes that the FAT has been completed.

However, the key decision-makers are often absent.

Questions that determine whether the equipment is truly production-ready remain unanswered.

• Who verifies that product quality meets production standards?

• Who confirms that process parameters are acceptable?

• Who evaluates long-term production stability?

• Who will actually operate the equipment after installation?

• Who is responsible for future maintenance?

Purchasing personnel can confirm contractual delivery requirements, but they rarely have the authority to approve manufacturing processes or production capability.

Likewise, if quality engineers, production managers, process engineers, maintenance specialists, and project managers do not participate, critical operational risks remain invisible until the equipment reaches the customer’s factory.

An effective Factory Acceptance Test should evaluate the complete production system rather than simply demonstrating machine functionality.

2. The Equipment Is Not Actually Ready for FAT

Another frequent issue is scheduling the FAT before the machine is technically ready.

This situation usually develops because delivery dates have already been committed.

Customer flights are booked.

Shipping schedules are fixed.

As a result, suppliers feel pressured to proceed with FAT despite knowing that the equipment is still under development.

Typical warning signs include:

• PLC software is still being modified.

• Machine logic remains unstable.

• Safety interlocks have not been fully verified.

• Mechanical corrections are still underway.

• Major engineering issues remain unresolved.

Under these circumstances, the FAT becomes an extension of commissioning rather than a formal acceptance activity.

Many experienced automation companies therefore conduct a FAT Readiness Review before inviting customers to the factory.

This internal review confirms that:

• Hardware installation is complete.

• Electrical systems are stable.

• Software versions have been frozen.

• Safety functions have passed verification.

• Critical corrective actions have been closed.

• Test procedures are fully prepared.

Only after these conditions are satisfied should the formal FAT begin.

A Factory Acceptance Test should validate a finished system—not serve as a live debugging session.

3. Incorrect Production Materials Can Invalidate the Entire FAT

Material consistency is one of the most overlooked aspects of Factory Acceptance Testing.

Unfortunately, it is also one of the most significant causes of unsuccessful project handovers.

Several scenarios are commonly encountered.

During commissioning, the supplier uses temporary samples because production materials are not yet available.

When FAT begins, the same temporary samples continue to be used.

Alternatively, commissioning may have been completed using prototype parts, while FAT is conducted using different verification samples that do not represent actual production.

In some projects, customers can provide only a very limited quantity of material, allowing the equipment to complete just a few production cycles.

Although the machine appears to operate normally, no meaningful assessment of process stability can be performed.

The consequences often emerge after installation.

Machine parameters require extensive adjustment.

Cycle times change.

Product quality becomes inconsistent.

Previously accepted process settings no longer perform as expected.

The root cause is simple.

The FAT never validated the machine under real manufacturing conditions.

Whenever possible, FAT should be conducted using actual production materials with the same specifications, dimensions, tolerances, packaging conditions, and process characteristics that will be used during mass production.

Short demonstration runs cannot replace continuous production verification.

A machine capable of producing ten acceptable parts is not necessarily capable of producing ten thousand.

That distinction often determines whether a project succeeds or fails.

4. A Machine May Perform Perfectly, but Poor Operating Practices Can Still Cause FAT Failure

A Factory Acceptance Test evaluates more than equipment performance. It also verifies whether the operating procedures are standardized, repeatable, and understood by everyone involved.

In many projects, inconsistent operating methods become a hidden source of risk.

Common examples include:

• Different engineers using different startup and shutdown procedures.

• Customer representatives operating the equipment for the first time during FAT.

• Machine parameters being adjusted without documented authorization.

• Operators lacking a clear understanding of alarm recovery and fault-handling procedures.

• No standardized Standard Operating Procedures (SOPs) available during testing.

Under these conditions, identical equipment can produce completely different results depending on who is operating it.

The consequences are often misunderstood. A customer may conclude that the machine is unreliable when, in reality, the inconsistency originates from human operation rather than equipment design.

In more serious cases, incorrect operating methods can damage mechanical components, create safety hazards, or invalidate the test results altogether.

For this reason, experienced project teams treat operator readiness as an essential part of FAT.

Before testing begins, all participants should receive appropriate operational guidance, understand the agreed testing sequence, and follow documented procedures throughout the acceptance process.

Only when equipment and operators perform consistently can the FAT produce reliable and repeatable results.

5. Failing to Simulate the Real Production Environment Creates Hidden Risks

Another common weakness in Factory Acceptance Testing is the failure to reproduce the customer’s actual production environment.

Equipment may perform flawlessly inside the supplier’s factory but behave very differently after installation.

The reason is often environmental rather than mechanical.

Typical examples include:

• Equipment designed for dusty production areas being tested inside a clean workshop.

• Systems intended for high-humidity manufacturing environments being validated under dry indoor conditions.

• Temperature-sensitive production processes being tested without environmental control.

• Differences in compressed air quality, electrical supply, utilities, or raw material storage conditions never being evaluated.

Each of these factors can significantly influence machine performance, process capability, and product quality.

International machinery risk management principles, including those described in ISO 12100, emphasize that risk assessment should consider the intended operating environment rather than laboratory conditions alone.

A FAT that ignores real production conditions may confirm equipment functionality while completely overlooking operational reliability.

The closer the testing environment matches the customer’s actual factory, the greater the value of the acceptance process.

6. Most FAT Problems Are Actually Project Management Problems

When a Factory Acceptance Test becomes chaotic, the underlying issue is rarely technical.

More often, it reflects inadequate project planning.

Many FAT events are organized only days before the customer’s arrival.

Responsibilities remain unclear.

Test sequences change without notice.

Acceptance criteria are revised during the meeting.

Engineering issues are discussed without documented action plans.

As a result, valuable time is lost resolving organizational problems instead of validating equipment performance.

A well-managed FAT should begin long before anyone enters the factory.

An effective FAT plan typically defines:

• Acceptance objectives and project scope.

• Detailed test procedures.

• Pass and fail criteria.

• Roles and responsibilities for every participant.

• Equipment readiness confirmation.

• Software and firmware version control.

• Material preparation.

• Tooling and fixture verification.

• Environmental requirements.

• Risk registers and contingency planning.

• Nonconformity management.

• Corrective action tracking.

• Final reporting and formal approval procedures.

When these elements are prepared in advance, the FAT becomes a structured engineering activity rather than a series of improvised discussions.

Successful projects rarely depend on luck.

They depend on preparation.

A Real Project That Was Never Truly Ready for FAT

One automation production line project illustrates how multiple risks can accumulate before Factory Acceptance Testing even begins.

At the scheduled FAT date, the only completed project document was the technical specification.

The customer’s product was still under development.

Final production samples did not yet exist.

Manufacturing processes had not been fully validated.

As a result, commissioning relied entirely on temporary prototype materials.

Those prototype materials differed significantly from the final production product in dimensions, material properties, and manufacturing requirements.

Machine parameters established during commissioning therefore had little relevance to future production.

Material availability created another obstacle.

Only a small number of samples could be supplied for testing, making continuous production verification impossible.

The customer was also developing the product for the first time and had limited experience with Factory Acceptance Testing.

During FAT, new technical requests were introduced repeatedly.

Process requirements changed throughout the acceptance process.

Engineering adjustments continued while testing was already underway.

The project lacked operational stability because neither the product nor the manufacturing process had been finalized.

Another critical issue involved environmental requirements.

The product required production within a controlled range of temperature and humidity.

However, these requirements were not communicated before FAT.

Testing therefore took place under conditions that differed from the intended production environment, leading to product quality problems that could not be properly explained during acceptance.

Personnel participation was equally incomplete.

Only purchasing representatives and process engineers attended the FAT.

Quality engineers were absent.

Future production operators did not participate.

Maintenance personnel were not involved.

Consequently, the equipment completed a functional demonstration, but it never underwent a comprehensive production readiness evaluation.

Although the project technically completed its Factory Acceptance Test, the fundamental delivery risks remained unresolved.

Factory Acceptance Testing Is About Verifying an Entire Delivery System

Many organizations continue to view Factory Acceptance Testing as a simple equipment inspection before shipment.

That perspective significantly underestimates its value.

A professional FAT should answer much broader questions.

Is the equipment technically complete?

Are the right people involved?

Have production materials been fully validated?

Are operating procedures standardized?

Does the testing environment reflect real manufacturing conditions?

Are project responsibilities clearly defined?

These questions extend far beyond machine functionality.

They evaluate whether the complete delivery system is capable of supporting stable production after installation.

A practical way to organize this evaluation is through the well-established manufacturing framework known as the 5M Model:

• Man – People and competencies.

• Machine – Equipment readiness.

• Material – Production materials.

• Method – Operating procedures.

• Environment – Manufacturing conditions.

When all five elements are properly prepared, Factory Acceptance Testing becomes an effective risk management tool rather than a routine customer visit.

For exporters of industrial automation equipment, a well-executed FAT reduces commissioning time, minimizes engineering changes after shipment, lowers warranty costs, decreases contractual disputes, and significantly improves customer confidence.

Ultimately, the purpose of Factory Acceptance Testing is not to prove that a machine can run for a few minutes inside a factory.

Its purpose is to demonstrate that the entire manufacturing system is genuinely prepared for reliable, repeatable, and sustainable production.

Organizations that treat FAT as a strategic risk control process consistently achieve smoother project delivery, lower lifecycle costs, and stronger long-term customer relationships.