Why most hydraulic failures start with BOM errors, not pressure issues?

Hydraulic systems are usually linked to large loads, high pressures, and harsh operating conditions. When a system fails, the first thought is typically that excessive pressure, shock loads, or system overload are the primary causes. While these causes can cause harm, they are usually secondary causes instead of the root cause.

In reality, a substantial amount of hydraulic system failures begin much earlier--during the procurement and design phase, specifically in the Bill of Materials (BOM). Incorrect entries within the BOM may appear to be minor at first, but they could cause serious safety, reliability, and performance issues as time passes.

This article explains the reasons BOM problems are often the unintentional source of hydraulic problems, how they show up in real-world systems, and the best way to avoid them.

Understanding the role of the BOM in hydraulic systems

A Bill of Materials is more than a simple list of parts. It's the basis of hydraulic system design that lists every piece needed, from valves and pumps to seals, fittings, and fasteners.

A properly-prepared BOM will ensure:

• Compatibility between components

• Proper flow and pressure ratings

• Material selection that is suitable for the operating conditions

• Correct assembly and maintenance procedures

An inadequate BOM creates inconsistencies that could affect the whole system.

Why is pressure often blamed?

Pressure is simple to measure and track. If a hose ruptures or the fitting breaks, technicians will often notice pressure spikes or operating conditions that exceed the design limit. This can lead to the conclusion that the pressure was responsible for the failure.

However, failures caused by pressure tend to be more of a symptom than a cause. For instance:

• A fitting that is rated for less pressure than what is required could fail in normal conditions.

• A damaged seal could be damaged and leak when under normal pressure

• A valve that is not designed correctly could result in pressure surges

In these instances, the issue is not pressure, but an incorrect selection of components of the BOM.

Common BOM errors that lead to hydraulic failures

1. Incorrect pressure ratings

One of the most serious errors is to specify components that are not able to manage the pressure of the system.

This is often because of:

• The misinterpretation of the pressure demands

• Confusion between working pressure and burst pressure

• Inspecting the transient pressure spikes

A hose that is rated for 200 bars in equipment that occasionally can spike to 250 bars might start working, but end up failing early.

2. Material incompatibility

Hydraulic systems are used in a variety of environments, including high temperature, corrosive conditions, or exposure to chemicals. The wrong choice of material in the BOM could result in:

• Metal components are corroded by corrosion

• Seals that are prone to swelling or degrading.

• Cramping, or possibly embrittlement, of the hoses

For example, using conventional rubber seals with corrosive fluids can cause rapid degradation, which can lead to the formation of leaks as well as contamination.

3. Mismatched thread types and fittings

Hydraulic fittings can be found in many thread specifications: BSP, NPT, JIC, metric, and more. A BOM that combines incompatible thread types may result in:

• Unsealed and improperly sealed

• Micro-leaks

• Progressive loosening under vibration

These issues might not be apparent immediately, but they can cause significant problems over time.

4. Inadequate filtration components

Contamination is one of the main causes of failures in hydraulic systems. A BOM that contains:

• Filters with inaccurate micron ratings

• A low dirt-holding capacity

• Insufficient placement in the system

could allow contamination to circulate and damage pumps, valves, and actuators.

Even if pressure stays within acceptable limits, contamination may result in wear and eventually failure.

5. Overlooking dynamic loads and cyclic stress

Hydraulic systems are not static. Components experience:

• Pressure fluctuation

• Vibration

• Thermal expansion

If the BOM doesn't take into account these dynamic conditions, parts might be damaged due to wear and tear, rather than pressure overload.

For instance:

• Tubing that is rigid and not supported properly can crack when impacted by vibrations.

• Fittings that are not designed for cyclic loads can cause fatigue cracks to develop.

6. Incorrect seal selection

Seals are tiny components; they are crucial to the system's integrity. BOM mistakes related to seals can be:

• Material that is not suitable (e.g., not compatible with temperature or fluid)

• The wrong size, or the tolerance

• The seal type is not appropriate for static or dynamic applications

Seal failures are often the cause of contamination, leaks, and pressure loss, luring technicians into believing that pressure is the cause.

7. Missing or incomplete components

Sometimes, the issue isn't the incorrect part; the parts are missing. Omissions in BOM can be:

• O-rings and backup rings

• Hardware to mount

• Guards or covers that protect you

This can result in an improper installation, contact with toxins, or mechanical damage.

What happens when BOM errors translate into real failures?

To better understand the effects of BOM mistakes, it's useful to track how they progress into system malfunctions.

First step: install using the incorrect components

The system is constructed using BOM as a reference. BOM as a reference. Any mistakes are built into the system right from the beginning.

Step 2: Initial operation appears normal

The majority of systems function properly at first, even with the wrong components.

Step 3: progressive degradation

As time passes, problems start to surface:

• Small leaks

• More wear

• Inefficiency reduced

Step 4: secondary effects

Small issues can lead to more serious issues:

• Contamination spreads

• Pressure fluctuations are increasing

• Components are subjected to added stress

Step 5: Failure event

In the end, a clear malfunction occurs:

• Hose blast

• Pump failure

• Valve malfunction

In this phase, pressure is usually blamed; the real reason lies within the BOM.

Case examples

Case 1: hose failure in mobile equipment

A hydraulic hose breaks repeatedly at normal pressure. An investigation reveals that the hose was tested at or below the system's maximum pressure. The BOM listed the incorrect pressure class.

Case 2: valve malfunction in industrial machinery

A valve for control begins to stick in a sporadic manner. The cause is the contaminant caused by an insufficient filter as specified within the BOM.

Case 3: persistent leaks in assembly line equipment

Multiple fittings leak as time passes. The cause is a mixture of thread standards defined in the BOM that can cause leaks due to inadequate sealing.

Why BOM errors are so common

1. Complexity of hydraulic systems

Modern hydraulic systems comprise a myriad of parts with interdependent specifications. Even the smallest of errors can lead to serious effects.

2. Lack of standardization

Different regions and industries employ different standards, which increases the chance of a mismatch.

3. Communication gaps

The design engineers and procurement groups, and assembly technicians, might not always be in sync, which can lead to incorrect parts selection.

4. Cost pressures

Substituting components in order to lower costs may result in compatibility issues if not evaluated carefully.

5. Version control issues

Older BOMs or inaccurate revisions could cause the use of outdated or incompatible components.

Preventing BOM-related hydraulic failures

1. Rigorous design validation

Make sure that all components are checked against the system requirements, for example:

• The pressure ratings (with safe margins)

• Temperature limits

• Compatible with fluids

2. Standardization of components

Standardizing components decreases the chance of mismatches and makes maintenance easier.

3. Cross-functional review

Include diverse parties throughout the BOM review:

• Design engineers

• Maintenance personnel

• Procurement experts

This allows you to identify any potential problems early.

4. Detailed documentation

Include the complete specification in the BOM

• Materials of all kinds

• Thread standards

• Ratings for performance

Avoid confusion that could result in mistakes in substitutions.

5. Supplier qualification

Choose reliable suppliers who offer consistent quality and precise specifications.

6. Change management

Establish strict controls for BOM revisions to assure:

• Updates are recorded

• Changes are made public

• Old versions aren't used.

7. Testing and prototyping

Before deployment on a full scale, try the system out under real-world conditions to determine any potential BOM-related problems.

Shifting the mindset: from pressure to root cause

To prevent hydraulic failures, businesses must shift their focus away from troubleshooting reactively to proactive development and planning.

Do not ask:

• "Was the pressure excessive?"

Ask:

• "Were all components specified correctly?"

• "Did the BOM reflect real operational conditions?"

• "Were durability and compatibility completely taken into account?"

This change in attitude will significantly increase the reliability of your system and decrease the amount of downtime.

The causes of failures in hydraulics are not always as straightforward as they seem. Although pressure is usually an obvious reason, the causes are often deeper in the Bill of Materials.

BOM errors can introduce weaknesses into the system right from the beginning. These flaws may be in the beginning, but eventually they lead to degradation and failure.

By understanding the importance of the BOM and using solid design, validation, and review procedures, organizations can avoid a variety of common hydraulic failures prior to them even occurring.

In the final analysis, the reliability of a hydraulic system isn't only determined by the way it works, but by how well it is designed from the beginning.