Why Temperature Transmitters Drift—and How Our Production Process Prevents It

From: Issued date 2026.07.22 Back

Introduction

A temperature transmitter can pass calibration today and still develop measurement drift months later. When that happens, many people assume the sensing element is responsible. In our manufacturing experience, however, long-term accuracy depends on far more than the RTD element itself.

We have found that measurement instability often originates from seemingly small production details: a poorly secured platinum resistor, inconsistent welding quality, insufficient insulation powder filling, assembly deviations, or calibration data collected before the signal has stabilized.

This is why our production team focuses on controlling every stage of the manufacturing process rather than relying solely on final calibration.

For a temperature transmitter, accuracy is not created at the calibration station. It is built gradually through a sequence of manufacturing controls that begin with resistor assembly and continue through welding, insulation, calibration, assembly, and final testing.

In this article, we will walk through the seven manufacturing controls we use to improve stability, consistency, and long-term reliability in temperature transmitter production.

Why Temperature Transmitters Drift—and How Our Production Process Prevents It

Accuracy Begins Long Before Calibration

When OEM customers evaluate a temperature transmitter supplier, they often focus on calibration certificates and accuracy specifications.

Calibration is important, but calibration alone cannot compensate for manufacturing defects introduced earlier in the process.

Consider the following examples:

A platinum resistor that is not securely fixed may fail during installation or vibration.
Poor welding quality can affect mechanical strength and sealing performance.
Incomplete insulation powder filling can influence heat transfer characteristics.
Improper assembly may introduce electrical instability.
Premature data collection during calibration can lead to inaccurate compensation values.

For this reason, our manufacturing workflow is designed around prevention rather than correction.

Every process serves a specific quality-control purpose before the transmitter moves to the next stage.

Why Temperature Transmitters Drift—and How Our Production Process Prevents It

Seven Manufacturing Controls That Reduce Temperature Drift

STEP 1: Crimping the Platinum Resistor

Why This Step Matters

The manufacturing process begins by securing the platinum resistor to the lead wire.

According to our production requirements:

The platinum resistor is welded onto the lead wire.
The connection is used for pull-strength protection.
The welded connection must not break.

At first glance, this appears to be a simple operation. In reality, it directly affects the mechanical reliability of the sensing assembly.

If the connection between the platinum resistor and the lead wire lacks sufficient strength, transportation vibration, installation stress, or long-term thermal cycling may eventually damage the connection.

Quality-Control Checkpoint

During this stage, operators verify:

Correct resistor positioning.
Welding quality.
Mechanical connection strength.
Pull-resistance capability.

Engineering Insight

A temperature transmitter cannot maintain measurement stability if the electrical signal path is unreliable. The purpose of this process is not only electrical connection but also mechanical reinforcement.

A secure connection creates the foundation for every subsequent manufacturing step.

Why Temperature Transmitters Drift—and How Our Production Process Prevents It

STEP 2: Argon Arc Welding

Joining the Temperature Probe and Pressure Head

Once the sensing element assembly is complete, the temperature rod is joined to the pressure head using an argon arc welding process.

This operation creates the primary structural connection within the transmitter assembly.

The welding process must be performed according to the established welding parameters.

Our production personnel strictly follow the Process Parameter Record Sheet during welding operations.

Why Temperature Transmitters Drift—and How Our Production Process Prevents It

What We Verify

At this stage, we verify:

Correct alignment between the temperature rod and pressure head.
Welding continuity.
Welding appearance.
Compliance with the Process Parameter Record Sheet.

Why Process Parameters Matter

Many welding defects are not visible immediately after production.

A weld may appear acceptable while hidden variations in welding parameters can affect long-term reliability.

Following the Process Parameter Record Sheet helps maintain consistency across production batches and reduces variation between operators.

Internal Resource

For more information about our welding and sensor production capabilities, see our Pressure Sensor Manufacturing Guide.

Why Temperature Transmitters Drift—and How Our Production Process Prevents It

STEP 3: Filling Insulation Powder

One of the Most Overlooked Manufacturing Processes

Among all temperature transmitter manufacturing steps, insulation powder filling is often underestimated.

Yet this process plays an important role in protecting the internal sensing structure.

According to our production procedure:

Aluminum oxide powder is filled into the interior of the temperature rod.
The assembly is placed on a vibration platform.
The vibration platform is operated twice.
Operators visually confirm that the powder filling is complete.

Every one of these actions is required.

Why Vibration Is Performed Twice

This detail is easy to overlook.

The purpose of vibration is to allow the aluminum oxide powder to settle uniformly throughout the internal cavity.

Simply pouring powder into the probe does not guarantee complete filling.

After vibration, voids can become visible and additional powder may be required.

For this reason, the assembly is placed on the vibration platform and vibrated twice before visual verification.