How to Check Powder Coating Thickness During Factory QA/QC Malaysia
How to Check Powder Coating Thickness During Factory QA/QC Malaysia
Content
A powder-coated metal component may look smooth and uniform, but visual appearance alone cannot confirm whether the coating thickness is consistent.
For factory QA/QC inspection, coating thickness should be measured and compared against the required product, customer or coating specification.
A portable Fe/NFe coating thickness gauge, such as the UNI-T UT343A, can be used for suitable powder coatings over compatible metal substrates.
The UT343A offers a measuring range of up to 1750 μm, making it suitable for a variety of coating inspection applications.
Why Check Powder Coating Thickness?
Powder coating thickness can affect:
Product finish
Corrosion protection
Coating performance
Material consumption
Production consistency
Customer acceptance
A coating that looks acceptable may still have areas that are significantly thinner or thicker than required.
This is why measurement should form part of a controlled QA/QC process.
Step 1: Know the Required Specification
Before measuring anything, determine the required coating thickness.
Do not create a pass/fail value based simply on what another factory or another product uses.
The requirement may come from:
Customer specification
Product drawing
Internal QA procedure
Coating supplier recommendation
Relevant inspection standard
Project specification
The coating thickness gauge tells you the measured value.
The specification tells you whether that value is acceptable.
Step 2: Identify the Metal Substrate
Determine what is underneath the powder coating.
Common substrates include:
Steel → Fe
Aluminium → NFe
The UNI-T UT343A supports both Fe and NFe measurement, making it useful for factories producing different types of coated metal products.
Step 3: Select Measurement Locations
Do not take only one reading from the easiest part of the component.
For a powder-coated cabinet, for example, measurement locations might include:
Front panel
Left panel
Right panel
Top
Bottom
Rear panel
For a large component, several readings may be required within each area.
The objective is to obtain a representative picture of coating consistency.
Step 4: Take Multiple Measurements
Suppose a specification requires the coating to fall within a defined acceptable range.
The inspector measures:
Point 1: 91 μm
Point 2: 94 μm
Point 3: 93 μm
Point 4: 92 μm
Point 5: 95 μm
These readings show relatively consistent application.
Now compare:
Point 1: 91 μm
Point 2: 94 μm
Point 3: 172 μm
Point 4: 92 μm
Point 5: 95 μm
Point 3 should be rechecked and investigated.
Step 5: Do Not Rely Only on the Average
Consider these five measurements:
80 | 82 | 81 | 79 | 178 μm
Looking only at an average can hide an unusual individual measurement.
A better QA/QC review considers:
Minimum + Maximum + Average + Individual readings + Measurement location
The UNI-T UT343A provides MAX, MIN and AVG functions, which are useful when reviewing a series of measurements.
Step 6: Recheck Abnormal Readings
An abnormal reading does not automatically mean the powder coating process has failed.
First:
Clean the measurement area
Check the probe
Repeat the measurement
Measure nearby points
Confirm the substrate
Verify the instrument if necessary
If repeated measurements around the same area remain significantly different, investigate the coating process further.
Common Reasons for Different Powder Coating Readings
Variation can be caused by factors such as:
Coating application
Component geometry
Corners and edges
Surface preparation
Recoating
Operator technique
Probe positioning
Actual process variation
The purpose of measurement is to identify these patterns objectively.
Example: Electrical Enclosure QA/QC
A manufacturer produces powder-coated electrical enclosures.
Instead of checking only one point, QA/QC establishes measurement positions for every unit or production sample:
Door → Left Side → Right Side → Top → Rear
This creates a repeatable inspection process.
Over time, the factory can identify whether coating variation is random or repeatedly occurs in a particular location.
This is much more useful than measuring different locations every time without a defined inspection procedure.
Example: Incoming Inspection
Coating thickness gauges are not limited to production lines.
A factory receiving coated parts from an external supplier can also perform incoming inspection.
For example:
Supplier delivers 100 powder-coated brackets.
QA/QC selects samples according to its inspection procedure and measures defined locations.
The readings are then compared against the purchase or product specification.
This gives the purchasing and QA teams objective measurement data when discussing coating quality with the supplier.
Set Upper and Lower Limits
When an inspection specification defines acceptable upper and lower values, limit functions can make routine checking more convenient.
The UNI-T UT343A supports upper and lower limit settings.
This can help operators quickly identify measurements that require attention.
However, the instrument should not decide the specification.
The limits should come from the relevant engineering, customer, coating or QA requirement.
UT343A for Factory Coating Inspection
Key UT343A functions include:
0–1750 μm measuring range
Fe/NFe substrate recognition
Single measurement
Continuous measurement
MAX/MIN/AVG
199 data storage
μm/mil units
Upper and lower limit settings
Potential users include:
Powder coating factories | Metal fabricators | Electrical enclosure manufacturers | Metal furniture manufacturers | Automotive component manufacturers | General manufacturing QA/QC
Build a Repeatable QA/QC Procedure
For better coating inspection, define:
What to measure
Where to measure
How many points to measure
Acceptable range
What happens when a reading fails
How results are recorded
The coating thickness gauge is only one part of the QA/QC system.
A consistent inspection procedure makes the measurement data much more useful.
Powder Coating Thickness Gauge Malaysia
If your factory needs to check powder coating or paint thickness on steel or aluminium, provide MTM Precision with:
Product: What are you manufacturing?
Coating: Powder coating / paint / other
Substrate: Steel / aluminium
Expected Thickness: Approximate μm range
Application: Incoming / production / final QA
We can help determine whether the UNI-T UT343A is suitable for the application.
MTM Precision Sdn Bhd
Showroom & Service Centre: Puchong, Selangor, Malaysia
Tel: 03-8080 7172
WhatsApp: +6016-660 7346
Email: mtmpre@yahoo.com
Website: www.mtmpre.com.my
Serving industrial customers across Selangor, Kuala Lumpur, Johor, Penang, Melaka, Negeri Sembilan, Perak, Pahang, Kedah, Kelantan, Terengganu, Perlis, Sabah and Sarawak.
22 Sep 2026
