Hi Jose,
While working at HP, I had an issue with box vibration scuffing as well. The problem only occurred in India even though these products were sold worldwide. By taking a trip there, I discovered a few important details that folks hadn't reported. Before I tell you about employing the Sutherland Rub Test, I want to tell you about root causes. First of all, it was extremely hot and humid, beyond conditions we had ever tested for. Also, virtually no truck loads had stretch wrapped unitized loads. In other words, all boxes were hand stacked, one at a time, in virtually all trucks and bouncing freely. The roads and trucks in India were the worst I've seen anywhere, especially when you consider the distances between cities. There were virtually no freeways in the entire country and large potholes on side streets was common.
Upon further inspection, it turned out that 100% of all the boxes that had issues had come from a single box maker in Thailand. In contrast, even though all of HP's products traveled through similar conditions throughout India, only this particular product, and only from a single manufacturing site that had used boxes from one supplier, experienced the problems. Knowing that most products didn't have vibration-related issues allowed us to develop a test that not only replicated the known, consistent problem, but also allowed us to test "good" boxes until they finally were damaged. Knowing the limits of the bad and good meant that real input conditions lay somewhere in between. To be conservative, you'd want to set the standard at something closer to the level the good boxes could withstand, but with the understanding that you'll be paying for some amount of excess design margin.
In developing a test, we found the Sutherland test did eventually work. We had added more weight than called for in ASTM D-5264 and went many more cycles than others normally tested to. We then decided to increase the intensity of vibration inputs, using 0.73 Grms, along with preconditioning at high temp and humidity, allowing stacked boxes to move freely, without stretch wrap. This test was able to replicate the damage. In both instances, these inputs didn't cause damages to boxes that did not experience damage in India.
In visiting the box maker in Thailand, we discovered they had used a particularly thin outer liner as a way to limit costs. Though the box met compression strength requirements, it did so by increasing the thickness of the corrugated medium. The thin liner, which is the most expensive layer, was the reason for the vertical lines shown in the picture. On top of that, they had used a very thin amount of varnish to protect the pre-print graphics. We then tested a few options and approved a thicker liner with better varnish. As a result of discovering the thin liner, we added a Mullen burst value to the drawings, along with a performance spec of passing the Sutherland test with a certain number of cycles and weight. I returned to India a few months later and saw all issues had disappeared.
If you too can travel in your supply chain and see where damages occur, and ascertain which products have problems and which don't, then you'll have a chance to replicate the known, consistent failures and not create an excessive test.
Hope this helps,
Kevin
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Kevin Howard
Consultant
Packnomics LLC
Portland, OR
cell: 360-606-0235
desk: 360-828-8822
kevin.howard@packnomics.comwww.packnomics.comwww.linkedin.com/in/kevin7howard------------------------------
Original Message:
Sent: 07-25-2022 12:22
From: Matt Gibney
Subject: Sutherland Test
We have experience with this and have done it recently. You can use Sutherland Rub tester with different block weights or a Taber Linear Abraser with different abrasion tips to correlate to shipping. It depends on the shipper packout and distribution vibration experienced as well. Feel free to email me at matt@pt-innovation.com.
thanks,
Matt
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Matt Gibney CPP, CPLP
Principal and Founder
Package Testing + Innovation
Tuxedo NY
(914) 552-4386
Original Message:
Sent: 07-21-2022 10:34
From: Jose Rodriguez
Subject: Sutherland Test
Hello everyone,
Just checking in on this forum to see if anyone has experience with Sutherland testing used as a Rub Test for printed cartons. We have observed scuffing issues on cartons we use during transit, so our intention is to see if we can use the Sutherland test to specify the supplier, the minimum passing strokes the cartons must be subjected w/o getting scuffed. I figure that the challenge here is to determine what would be the correct testing parameters that would translate into an acceptable scuffing resistance (i.e. samples can survive 40 strokes but scuffing issues are still observed during transit).
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Jose Rodriguez CPP
Staff Packaging Engineer
Johnson and Johnson
Bayamon PR
(787) 203-5496
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