Is there a standard for the number of people needed to feed an RDC?

August 3, 2022

Brad asks:

A recent safety question has come up.  Is there an industry standard for 1 vs. 2 employees required to manually fed rotatory converters?  We have a non-documented rule of thumb based of sheet size, single wall and double wall.  But I am looking for additional information to determine if what we are currently using fits within the standards of the industry.

I’ve asked Les Pickering for his input on this question. According to Les,

“There is no hard and fast rule, but I will outline the custom and practice.

Assuming it’s a machine like a 618 or an Emba…

  • A sheet width of 36” x 24” is a single person feeding operation.
  • If the sheet increases width to 40” x 24” it’s still a single person feeding operation.
  • If the sheet width is 36”, but the body increases to 30 or more inches, then it becomes a two-person operation as the sheet is more difficult to handle and its weight is heavier.
  • Usually anything over 40” becomes a two-person operation. This makes getting the weight of the bundle into the feeder manageable, maintains the speed up of the machine and creates a more ergonomic operation.”

We might also note that OSHA does not have a published standard on the amount of weight a person may lift. According to the U.S. department of Labor…

“OSHA does not have a standard which sets limits on how much a person may lift or carry. However, the National Institute for Occupational Safety and Health (NIOSH) has developed a mathematical model that helps predict the risk of injury based on the weight being lifted and other criteria. The NIOSH model is based on previous medical research into the compressive forces needed to cause damage to bones and ligaments of the back. The mathematical model is incorporated in the Applications Manual for the Revised NIOSH Lifting Equation, which can be found on the NIOSH website ( It should be noted, however, that this NIOSH document provides only voluntary guidelines”

— Ralph

Trouble Stacking RSCs

July 14, 2022

Armando asks:

You know most RSC box styles when glue and strapped are not totally flat, due to the extra thickness of the glue flap. This adds some instability to the finished pallets and may prevent stacking.

To solve it we´ve tried to crush the glue flap, but if we do this, the scoring between the flap and the first panel, kind of disappears and it causes the box to fold in a weird way.

We´ve also tried alternating the directions of the bundles, and it helps in some styles, but some others, have the flap right in the middle and it’s difficult to avoid.

Do you have an idea how can we solve the problem without affecting the score?

Yeah, that’s a tough one and one that most plants encounter at one time or another. Unfortunately, there is no one-size-fits-all answer. Crushing the glue tab helps, but, as you mentioned, you sometimes get a soft crease at the glue tab fold. That typically may not be a big deal for manually set up boxes but can be a huge issue for case erectors. It helps with the center thickness issue, but it will never completely alleviate the problem. You still have the thickness buildup of the liners and the medium. The two folded scores on the on flat RSC also contribute to this issue. When it’s folded flat there is tension caused by the two panels at the score pressing against each other. This makes the folded box want to spring open. So, you are not only fighting thickness, but you are also fighting tension.

Try to keep the bundle or batch count as small as possible. The fewer in the bundle or batch the less deviation you’ll get, or at least the more opportunity you will have to compensate for it. And always try to interlock your layers.

When you have a center glue flap, whether running bundles or batches, interlock the bundles or batches of RSCs as much as possible. If you can overlap three lengths across your pallet you can build a pretty stable load. You just need to make sure your top layer is the center bundle that locks the two outer bundles in place as shown below.Offsetting layer stack


A chimney stack configuration (similar to the illustration below) may help as well. Again, keeping your bundles or batches as small as possible and interlocking the layers.chimney stack


Of course, shrink wrapping or cross-strapping will help keep them together during shipping. Most of the time the end user wants to rip all the shrink wrap off first thing. If they can cut the wrap and open on only one side, the rest of the wrap may hold the stack in place until it gets used down. That will probably require changing the customers procedures or habits. Sometimes it’s not practical… and sometime not possible.

— Ralph

Searching for Glossary of Industry Terms for US and UK

July 14, 2022

Ted asks:

I’m looking for a glossary of corrugated terms that we use in the United States. Everything to do with corrugated, containerboard, tooling, equipment and testing as much of a comprehensive list as we can compile. We’re working with a company in the UK and their design team is using terms that we’re unfamiliar with or can’t easily translate off the top of our heads. I want to compile a glossary of industry terms with brief definitions, much like a translation lexicon, so they can then add their term next to the relative definition. The goal is to streamline communications and make life easier for both groups.

I have an old Fiber Box Handbook that is the starting point but very incomplete. If you have something that you can send me or guide me to, it would be most appreciated.

Even here in the US we can have different terms for the same thing. Anilox roll and ink roll for example. So, communicating with someone in another country where, for example, ‘printing plates’ may be called ‘stereos’, can certainly be a bit of a task until you learn the lingo.

Below are a few links to some publicly accessible collections of industry terms that are a good source of information and hopefully will contribute to your project.

When you complete your glossary, I hope you will share it with us and our readers.

Glossary of Corrugated Material Terms (Pro Pac)

Packaging Terminology: A glossary of terms and definitions (GWP Group)

The Packaging School Glossary

— Ralph

How Does Pea Starch Compare to Corn Starch

July 6, 2022

Nat asks:

We received an inquiry today from one of our plants about using pea starch as an alternative to corn starch. The question I have is what are the critical properties of unmodified Pea Starch used in corrugating adhesives? Also, is there a Caustic Sensitivity Test Procedure for pea starch.

What a coincidence, just last week we had a presentation by Roman Skuratowskicz from Ingredion regarding this very subject. He has again been so gracious to share his knowledge.

Most of the critical properties are the same that apply to corn starch used in corrugating.

Primarily, the alkali sensitivity must be controlled to prevent the adhesive from having an unstable viscosity and prevent possibility of gelling in storage.

The base starch needs to have consistent viscosity as well. Because of the high variability of base pea material, and the lack of expertise with manufacturing product for corrugating applications, it is difficult to find a consistent source of pea starch for corrugating.

Also, many providers will actually have lower purity (closer to pea flour) since their primary product is the pea protein for food use. This will impact both formulation and stability in storage.

Pea starch is also significantly different than corn starch in formulation. It will require less caustic and borax, is hydrophobic, and has a larger particle size than corn starch which impacts conveyance and cookout. As a result, significant formulation changes will be necessary if you find a consistent source of pea starch. If the starch properties are inconsistent, then each batch will need custom formulation.

We have two internal test methods we use on incoming starch. I’ll provide these as reference only.

    • SMA-A51 – Brookfield UL method – fast test, requires specific instrument.
    • SMA-A52 – settling test method – basic equipment required, takes 24 hours to run and prone to errors, otherwise useful as field test.

Thank you Roman for sharing your knowledge and this useful information.

I’ll research this a bit more as interest in the topic seems to be growing. Some information I have discovered. If, as Roman points out, you can find a supplier with a consistent product, and achieve the proper formulation, tests have shown that pea starch can be stable and have similar performance characteristics to corn starch. The addition of waterproof resins can result in a water resistance exceeding 24 hours.

Tests have shown pea starch has a gel temperature approx. 5 degrees F lower than corn. Therefore, it could lead to lower energy consumption/cost, and faster tack/setup could lead to higher running speeds on the corrugator. However, more research is needed before it’s decided if this is a viable option for NA corrugated operations.

We’ll keep digging, and as usual, if others have knowledge or experience to share, please do.

— Ralph