Flexible Packaging Testing Equipment for a QC Lab
By Lim Xu, Export Manager
Flexible packaging testing equipment for a QC lab is a small set of instruments that answer the questions production asks every day. Most film and pouch labs need seal integrity, heat-seal specimen preparation, seal strength, coefficient of friction, dart impact and thickness. The mix depends on your package, but those six cover the usual flexible-line risks.
Which tests does a flexible packaging QC lab run?
Start from the failure modes you actually see, then map each one to a standard method.
| Need | What it answers | Common method |
|---|---|---|
| Seal integrity / leak | Does the pouch or sachet hold gas at a gross leak level? | ASTM D3078 bubble emission |
| Heat seal preparation | Which time, temperature and pressure window makes a usable seal? | ASTM F2029 laboratory heat seals |
| Seal strength | How much force opens or peels the seal? | ASTM F88 / F88M |
| Coefficient of friction | Will the film feed, open and stack on the line? | ASTM D1894 (or ISO 8295) |
| Dart impact | How does the film resist a free-falling blunt impact? | ASTM D1709 |
| Thickness | Is the web or bottle wall in the range your process needs? | Contact or Hall-effect gauges |
You do not need every instrument on day one. Add a station when a complaint, a customer audit or a new structure makes that method unavoidable.
Seal integrity and leak testing
ASTM D3078 covers gross leaks in flexible packaging that contains a headspace gas. The package sits in a transparent vacuum chamber under immersion fluid, and the operator watches for bubbles as the vacuum is drawn.
D3078 also warns that small leaks may be missed, because product or trapped air can plug them. Use it for obvious channel or seal failures, not as your only check when you need very small-leak detection.
Our MFY-01 vacuum leak tester runs this bubble emission method, with a vacuum range of 0 to -90 kPa and Class 0.5 vacuum accuracy. For a non-destructive method used on many pharmaceutical packages, see our article on the vacuum decay leak test.
Heat seal preparation and seal strength
A laboratory heat sealer prepares seals under controlled time, temperature and pressure. ASTM F2029 covers that specimen preparation. Seal strength itself is measured separately under ASTM F88 / F88M, which reports the force to separate a strip that contains the seal and the failure mode.
F2029 notes that a lab sealer can differ from manufacturing equipment in scale, sealing area and speed. Treat the lab heat-seal curve as a starting point for production settings, not as a finished validation.
Our STH-5 gradient heat seal tester has five 40 × 10 mm jaws, each set to its own temperature up to 250 °C, so one run can map a seal curve. Strength is then measured on a tensile tester per ASTM F88.
Want to see a seal or film test on material like yours? Tell us your test requirements. We source similar samples, run the test and send you the video. No need to ship samples.
Coefficient of friction for film handling
ASTM D1894 measures the starting and sliding friction of plastic film and sheeting when it slides over itself or over another surface. Packaging lines care about those slip properties because they affect bag opening, magazine feeding and stack stability.
D1894 also notes that slip additives can bloom over time, so results depend on film age and surface condition. A COF number without that context is hard to use in a disposition.
Our MXD-02A coefficient of friction tester runs ASTM D1894 and ISO 8295 sled tests, with a 5 N force range and force accuracy of 0.5 % FS.
Dart impact and thickness checks
ASTM D1709 determines the energy that causes plastic film to fail under a free-falling dart, reported as the missile mass that produces failure of half the specimens under the chosen method. Method A and Method B use different dart heads and drop heights, and their results are not directly comparable.
A falling dart station belongs in the lab when bags or pouches see blunt impact in packing or transport. Match the method (A or B) to the specification you ship against.
Thickness closes the set. Film labs often use a contact thickness gauge on webs; bottle and container labs often use a Hall-effect gauge so the part is not cut. Our MTG-100 Hall-effect thickness gauge measures wall and base thickness on non-magnetic bottles and containers.
How to choose the first instruments
Buy for the questions you already answer by hand or by customer complaint.
- If seals leak in transit, start with bubble emission and a clear vacuum range you can hold
- If you tune seal recipes, pair a lab heat sealer with a tensile tester for F88
- If the filler jams or bags will not open, add a COF sled tester and record film age
- If bags split under blunt drops, add dart impact under the method your customer names
- If blow-moulded bottles fail from thin walls, add a non-destructive thickness gauge and a point-by-point record
Keep methods on separate stations when sample prep would contaminate the next test. A wet bubble chamber and a clean COF sled do not share a bench well.
Frequently asked questions
Does a heat sealer replace a tensile tester for seal strength?
No. ASTM F2029 prepares the seal; ASTM F88 measures the force to separate it. Your lab needs both steps, even if one supplier provides both instruments.
Is ASTM D3078 enough for every flexible pouch?
No. D3078 targets gross leaks in packages with headspace gas and can miss small or plugged leaks. Choose a second method when your risk or customer requires a smaller detection level.
Do ASTM D1894 and ISO 8295 give the same COF value?
No. ASTM D1894 states that it is not equivalent to ISO 8295, and results cannot be directly compared. Pick one method for a given control plan and stay with it.
Get a test video for your packaging
Tell us your test requirements, such as the material, the size and the test you need. We source similar samples here, run the test on the instrument you are looking at and send you the video. No need to ship samples.
Questions about a model or a test? Email Amy Zhao, Export Manager, at [email protected].