Digital Top Load Tester for PET Bottles and Jars

What is a Digital Top Load Tester?

A Digital Top Load Tester is a laboratory instrument used to measure the maximum vertical load a bottle or jar can withstand before it deforms, buckles or collapses. Plastic containers are exposed to downward pressure at different stages of production and distribution. Bottles may experience force during capping, stacking, warehouse storage and transport. When a container does not have sufficient top-load strength, it may lose its shape, damage the closure or cause an entire stack to become unstable. The tester applies a controlled compression force from the top of the container. A precision load sensor measures the applied force and displays the result digitally. This allows manufacturers to compare bottle designs, monitor production consistency and identify weak containers before they reach the market.

Designed for PET Bottles and 20-Litre Jars
Unlike compact bottle-testing machines, this model is equipped with a large 500 × 500 mm platform and a load capacity of up to 500 kgf. It can accommodate larger containers such as water jars, wide-mouth bottles and heavy-duty rigid plastic packaging. The machine can be used to test containers at different stages of development, including prototype evaluation, incoming-material inspection and finished-product quality control. The load capacity and platform dimensions may also be customised according to the application.

Working Principle
The container is placed centrally between the lower platform and the upper compression plate. When the test begins, the upper plate moves downward at a controlled speed and applies a vertical load to the sample. The load sensor continuously measures the compression force. The test continues until the container reaches the required load, shows visible deformation, buckles or fails. The highest force recorded during the test is retained through the peak-hold function.

This value represents the maximum compression load sustained by the container under the selected test conditions.

What Can Be Measured?
The Digital Top Load Tester can help determine:

• Maximum compression load
• Load at the first point of buckling
• Container strength at a specified load
• Structural failure point
• Batch-to-batch strength variation
• Performance of different bottle designs
• Effect of material reduction on container strength
• Resistance of bottles and jars during stacking

Key Features

• Maximum load capacity of 500 kgf or 5 kN
• Large 500 × 500 mm testing platform
• Precision load sensor for dependable measurement
• Digital display for clear result observation
• Peak-hold function for recording maximum load
• Zero and tare facility
• Adjustable compression speed
• Motorised screw-driven compression mechanism
• Load display in kgf and newtons
• Overload protection for the load sensor
• Upper and lower travel-limit protection
• Emergency stop for operator safety
• Strong fabricated structure for stable testing
• Powder-coated body for corrosion resistance
• Custom load capacity available on request

Test Procedure
Place the machine on a stable surface and check that the compression plates are clean. Prepare the bottle or jar according to the approved test method. The sample may be tested empty or filled, depending on the quality requirement. Position the container centrally on the lower platform. Select the required load unit and test speed, then reset the display to zero. Start the compression cycle and allow the upper plate to apply load vertically. Continue the test until the required load, deformation or failure point is reached. Record the peak compression value displayed by the instrument. Return the compression plate to its original position and repeat the test on other samples from the same production batch.

For meaningful comparison, bottle condition, filling level, orientation, test speed and surrounding conditions should remain consistent.

Applications
The machine is suitable for testing:

• PET beverage bottles
• Packaged drinking-water bottles
• Carbonated-drink bottles
• Edible-oil containers
• Pharmaceutical bottles
• Cosmetic containers
• Household chemical bottles
• Wide-mouth plastic jars
• Five-litre and ten-litre containers
• Twenty-litre water jars
• HDPE containers, where applicable
• Other rigid plastic packaging

Benefits of Top Load Testing
Top-load testing helps manufacturers confirm that a container has enough structural strength for its intended use. It can identify variations caused by uneven wall thickness, poor material distribution, incorrect moulding conditions or unsuitable bottle design.

The results also support lightweighting projects. Manufacturers can reduce plastic consumption while checking that the revised container still meets the required compression strength.

Regular testing reduces the risk of bottle collapse during filling, capping or stacking. It also supports better process control, fewer packaging failures and more consistent product quality.

Standard and Optional Functions

Standard Functions

• Digital load measurement
• Peak-load display
• Zero and tare controls
• Adjustable test speed
• Motorised compression
• Emergency stop
• Load-cell overload protection
• Upper and lower travel limits

Optional Functions

• Computer connectivity
• Test-analysis software
• USB or RS-232 data output
• Result storage
• Load-versus-time graph
• Computer-generated test report
• Custom platform dimensions
• Higher load capacity

Frequently Asked Questions

What does a Top Load Tester measure?
It measures the maximum vertical compression load that a bottle, jar or rigid plastic container can withstand.

Can the machine test 20-litre water jars?
Yes. The large 500 × 500 mm platform and 500 kgf capacity make it suitable for testing large water jars, subject to sample dimensions.

Can both empty and filled bottles be tested?
Yes. Bottles may be tested empty or filled depending on the approved test method and intended application.

What is peak load?
Peak load is the highest compression force recorded before the container deforms, buckles or fails.

Can the load capacity be customised?
Yes. Higher or application-specific load capacities can be provided according to customer requirements.

Why is test speed important?
Compression speed affects container behaviour and results. The same speed should be used when comparing different samples or production batches.

How frequently should the machine be calibrated?
Calibration frequency depends on usage and the quality system followed by the laboratory. Periodic verification using certified master loads is recommended.

Does the standard machine provide computer reports?
The standard model provides digital load measurement. Software, computer connectivity and automated reports may be supplied as optional features.

Why Choose Pacorr?
Pacorr manufactures testing instruments for the quality evaluation of packaging and plastic products. The Digital Top Load Tester is built to provide controlled compression, dependable load measurement and safe operation in production and laboratory environments.

Technical consultation, product demonstrations and customised machine configurations are available according to the container size and testing requirement.