Author :               Rohit Chawla (rohit@packtest.com)

Date :                    13^th August 2017.

Subject :               Brief explanation of Vibration Tests.

Basically there are 3 types of vibration test.

1. Rotary vibration.

Where the motion of the package is left – up – right – down.

From a center position the package will move left 12.5mm then up 12.5mm then right 12.5 mm and then down 12.5mm. Its like performing an Aarti (Puja).

The product gets an effective 1 inch up-down displacement / throw. But its not a true vertical linear bump.

Its like riding a camel.

This confirms to ASTM D999 for loose load vibrations.

This is to be done on a single package and the package is required to bounce.

Test is very aggressive but the only problem is that we were unable to achieve speeds of more than 3 hz (180 RPM). While the product usually starts to bounce between 210-250 RPM. So it doesnot fully confirm to ASTM D 999.

We used to make this machine until 2015.

2. Linear Vibration / Vertical Bump.

In this machine the product gets a true linear bump of 1 inch.

No side-ways motion.

It may seem not as aggressive as rotary vibration. But is more practical if you imagine vibration in high speed transits.

This one is like riding a horse. Straight shock to the spine.

In this machine we can achieve speeds of even upto 5 Hz or 300 RPM. The package truly bounces off the table as required by ASTM D 999.

We started manufacturing this machine in 2014.

3. Random Vibration Test using Servo Hyradulics.

This is a highly sophisticated machine, which can be programmed to run like the one above (fixed displacement of 1 inch as per ASTM D 999) or you can program it to give different levels of shock and displacement (Random Vibration as per ASTM D 4728).

You can even use PSD data from a shock logger (data logger needs to be sent with your real truck to collect realtime data).

This machine is a very expensive piece of equipment. Not a lot of users due to high cost involvement.

This is the latest technology but pretty complicated to understand and use.

I have seen the Global R&D Center of one of the world’s largest FMCGs, at Shanghai using this machine for the simple Linear Vibration / Vertical Bump Test. Its like buying an Supersonic Aeroplane to go shopping to the neighbouring Walmart.

Majority of the buyers (except for probably research and test labs) are using the machine for the simple test. If you want a car, then buy a car. Why buy a rocket ?

Technology is great. Prospects are huge. Price is the biggest deterrent. And people need more education on this front.

What is the real use of a vibration test ?

A vibration test will tell you whether your product and packaging are fit enough, to withstand the torture of poor transportation, handling and warehousing.

Usually, the vibration test is to be performed on a single carton.

Some people also perform this test on a stack of cartons. Or even an entire pallet.

This will not allow the product to bounce and hence ASTM D 999 will not apply to this method.

People may say that they are doing a dynamic compression-vibration test by stacking.

But the fact remains that for Box quality you have a Box Compression Test (BCT).

Vibration test is not about “box” quality.

Its about the products and cushioning inside the box.

Its about Product Fragility, Fitments, Print Quality, etc.

Will your tablets break during vibration?

Will your bottle caps open up and product will leak ?

Will your unit carton’s printing quality remain intact or will get scuffed offer ?

Will your batch coding survive the transit ?

The vibration test is the final test encompassing the Scuff Test, leakage test, and product fragility tests.

But its surely NOT a Box test.

—X—