How to Use UNI-T UT343E Upper and Lower Limits for Coating Inspection Malaysia
How to Use UNI-T UT343E Upper and Lower Limits for Coating Inspection Malaysia
Content
Published: 1 October 2026
The UNI-T UT343E Coating Thickness Gauge allows users to set upper and lower measurement limits from 0–2000μm.
When a reading falls outside the selected range, the LED and audio alarm help the operator identify it quickly. This is useful for repeated production checks, incoming inspection and coating quality control.
What Are Upper and Lower Limits?
The lower limit is the minimum acceptable coating thickness.
The upper limit is the maximum acceptable coating thickness.
For example, if an approved specification requires a coating to remain between two defined values:
- Reading below the lower limit: Requires attention
- Reading within the limits: Within the selected range
- Reading above the upper limit: Requires attention
The actual limit values must come from an approved technical requirement.
Where Should the Limits Come From?
Set the UT343E limits according to:
- Customer specifications
- Engineering drawings
- Purchase orders
- Internal quality procedures
- Coating manufacturer recommendations
- Project requirements
- Approved reference samples
- Applicable technical standards
Do not enter arbitrary values simply to create a pass result.
Different products, substrates and coating systems may require different limits.
Why Both Minimum and Maximum Matter
A coating below the minimum may not provide the required coverage, appearance or protection.
A coating above the maximum may cause:
- Excessive material consumption
- Dimensional or assembly problems
- Longer curing requirements
- Surface defects
- Unnecessary production cost
- Difficulty meeting the approved specification
The correct range helps balance performance, appearance and process control.
Check the Gauge Before Setting Limits
Before using the alarm for acceptance decisions:
- Clean the probe.
- Select the correct ferrous or non-ferrous reference plate.
- Check the instrument with a standard coating film.
- Confirm that repeated readings are stable.
- Identify the product’s substrate.
- Verify the approved coating range.
- Enter the upper and lower limits.
An incorrect substrate mode or unstable reference check can make the alarm result unreliable.
Use FE or NFE Mode Correctly
Select:
- FE mode for suitable coatings over steel or iron
- NFE mode for suitable coatings over aluminium or another compatible non-magnetic metal
The UT343E can identify the substrate automatically or allow manual selection.
For repeated inspection of the same product, manual mode may help prevent unexpected substrate changes.
Example: Powder-Coating Production Check
A powder-coating factory can set limits according to its approved production specification.
The operator can then inspect:
- Flat centre areas
- Edges
- Corners
- Welded sections
- Recessed locations
- Multiple components from the batch
The alarm helps identify out-of-range readings, while the actual values should still be recorded for quality analysis.
Example: Incoming Supplier Inspection
An incoming quality-control team may receive painted or powder-coated metal components from several suppliers.
The UT343E limit function can support faster checking by identifying samples that require further investigation.
When an out-of-range reading appears:
- Repeat the measurement.
- Check the same point again.
- Measure nearby locations.
- Inspect additional components.
- Record the supplier and batch.
- Follow the company’s non-conformance procedure.
Do not reject the complete delivery based on one unconfirmed result.
Example: Automotive Paint Comparison
The limit alarm can be used for vehicle inspection only when the operator has a justified comparison range.
Car paint thickness varies between:
- Manufacturers
- Models
- Production years
- Steel and aluminium panels
- Factory painting processes
- Different body locations
A limit suitable for one vehicle should not automatically be applied to every vehicle.
For used-car inspection, comparing patterns across similar panels is often more useful than applying a universal pass-or-fail limit.
Record the Actual Reading
The LED and audio indication improve inspection speed, but the alarm alone does not provide a complete quality record.
Record:
- Actual thickness
- Component identification
- Measurement location
- Substrate mode
- Upper and lower limits
- Inspection date
- Inspector’s name
- Batch or serial number
The UT343E stores up to 3300 readings and supports Bluetooth App and PC data analysis.
Review Minimum Maximum and Average Values
For each component or batch, review:
- Minimum reading
- Maximum reading
- Average reading
- Number of out-of-range points
- Location of low or high results
An acceptable average should not hide a critically low measurement.
Similarly, one isolated high reading should be confirmed before the entire batch is classified as non-compliant.
Common Limit-Setting Mistakes
Avoid these errors:
- Using the same limits for every product
- Entering limits without checking the drawing
- Reversing the upper and lower values
- Using the wrong measurement unit
- Ignoring FE and NFE substrate differences
- Changing limits without recording the revision
- Accepting products based only on the alarm colour
- Measuring only one point
- Failing to perform a reference check
- Using old limits after the product specification changes
Limit control should form part of a documented inspection procedure.
Pass or Fail Requires a Quality Decision
The UT343E indicates whether a measurement is inside or outside the entered range.
It does not determine:
- Whether the entered limits are correct
- Whether the sampling quantity is sufficient
- Whether rework is permitted
- Whether a batch must be rejected
- Whether other coating properties comply
- Whether the inspection method meets a required standard
The final acceptance decision remains with the responsible quality-control personnel.
Coating Thickness Is Not the Only Requirement
Even when the measured thickness falls within the limits, the product may still require checks for:
- Adhesion
- Gloss
- Colour
- Surface appearance
- Curing
- Hardness
- Corrosion resistance
- Impact resistance
- Coverage at edges and recesses
The UT343E measures coating thickness. It does not replace other required quality tests.
Who Benefits from Limit Alarm Inspection?
The UT343E limit function is useful for:
- Powder-coating factories
- Metal fabrication companies
- Incoming inspection teams
- Automotive component manufacturers
- Electrical enclosure factories
- Supplier quality engineers
- Coating contractors
- Production-line inspectors
Factories in Selangor, Kuala Lumpur, Johor and Penang can use the function to improve inspection consistency when approved coating limits are available.
For product availability or assistance selecting a coating thickness gauge for pass-or-fail production checks, contact MTM Precision with your substrate, coating and required range.
MTM Precision Sdn Bhd
Showroom & Service Centre: No. 29-1 & 29-2, Jalan Bandar 18, Pusat Bandar Puchong, 47160 Puchong, Selangor, Malaysia
Tel: 03-8080 7172
WhatsApp: +6016-660 7346
Email: mtmpre@yahoo.com
Website: www.mtmpre.com.my
01 Oct 2026
