Why Tear Notches Sometimes Don’t Work

Jul 31, 2026

The Notch Was There. So Why Wouldn’t the Bag Open?

If you have ever pulled at the small V-shaped cut on a pouch and thought, “Why won’t this open?”, the notch itself may not be the real problem.

In this case, the notch sat about 10 mm below the top edge. That is a normal position for many pouches. The problem appeared later, when the customer filled the bag and made the final top seal.

The customer’s machine made a wider sealed strip across the top. That strip reached down to the notch. The notch was now stuck inside a thick, sealed area, so it could no longer give the tear an easy starting point.

A 10 mm notch is not automatically wrong
The right position depends on the finished top seal. A notch that works with a narrow seal may fail with a wider one.

The notch is only the starting point. It is like making the first tiny cut in wrapping paper. If the paper becomes thicker, harder to hold or stuck together, that first cut may no longer help very much.

Four Simple Reasons a Tear Notch May Not Work

You do not need to be a packaging engineer to spot the most common problems. Start with these four questions.

01 DID THE TOP SEAL COVER THE NOTCH?
This is what happened in our example. The sealed area reached the notch and made the starting point too thick and stiff.

02 IS THE BAG MATERIAL HARD TO TEAR?
Pouches are made from several thin layers. Some combinations are tougher than others and may need a different opening design.

03 IS THERE ENOUGH ROOM FOR YOUR FINGERS?
Even a good notch can be frustrating when the strip above it is too small, slippery or close to a zipper.

04 DID FILLING CHANGE THE FINAL BAG?
The filling machine may move the bag, make a wider seal, create wrinkles or leave product near the top.

One easy clue

If the tear will not start, check the notch, top seal and finger grip. If it starts but then stops or turns, the bag material or tear path may be the problem.

A Short Conversation Can Prevent a Long Problem

The Pre-shaped bags supplier knows the bag. The customer knows the filling machine. Good packaging happens when both sides share a few simple details before production.

THE POUCH SUPPLIER SHOULD SHOW

• Where the notch will be placed.

• How much the position may vary.

• Where the bag is meant to tear.

• How much free space is left above any zipper.

THE CUSTOMER SHOULD SHARE

• How wide the real top seal will be.

• Where that seal will sit on the finished bag.

• How the bag will be filled and held by the machine.

• Whether the first filled bags are easy to open.

THE CUSTOMER SHOULD SHARE

• How wide the real top seal will be.

• Where that seal will sit on the finished bag.

• How the bag will be filled and held by the machine.

• Whether the first filled bags are easy to open.

FIVE QUESTIONS TO ASK

01 Where will the finished top seal end?

02 Will the notch stay clearly below that seal?

03 Can a person hold the top of the pouch easily?

04 Have we tested real filled and sealed bags?

05 What changes mean we should test again?

The best sample is a finished sample

An empty pouch can look perfect. Always approve bags after they have been filled and top-sealed on the real machine.

Check the Bags at Three Simple Moments

If you fill and seal your own pouches, you are creating the final opening experience. A quick check at the right time can save a full batch of hard-to-open bags.

BEFORE YOU START

• Make sure you have the correct pouch and machine settings.

• Check that the notch sits below the planned top seal.

• Keep food, powder and wrinkles away from the seal area.

CHECK THE FIRST FEW BAGS

• Fill and seal a small number of bags first.

• Look at where the bottom edge of the seal actually ends.

• Open bags from both sides and ask someone else to try too.

WATCH DURING THE RUN

• Check again after stops, setting changes or a new bag lot.

• Watch for the seal moving down toward the notch.

• Keep a few good bags as your reference samples.

WARNING SIGN	WHAT TO DO
The seal touches or covers the notch	Stop and correct the seal position or bag design before the full run.
People need scissors or a lot of force	Do not treat this as normal. Make new samples and test again.
The tear starts but goes the wrong way	Ask the pouch supplier to check the film and the intended tear path.
The result changes during production	Check bag position, wrinkles, machine settings and the seal area.

Do not trade easy opening for a weak seal
Changing the seal can also affect leaks and shelf life. Any new setting must still make a strong, safe seal.

Start With What You Can See andFeel

When a pouch is hard to open, do not change everything at once. Take one filled bag and check it in this order.

THREE COMMON QUESTIONS

• 01 Is a 10 mm notch position bad?

No. It can work very well. The key question is whether the final top seal stays above it and leaves enough room to grip.

• 02 Can we fix the problem only on the filling machine?

Sometimes. If the seal can be moved safely, the machine setup may solve it. If not, the pouch may need a lower notch, more top space or another opening design.

• 03 Who should test the final bag?

The pouch supplier and the customer should both review filled samples. The supplier controls the pouch, while the customer controls the filling and final seal.

The takeaway

A tear notch does not work alone. The notch, the bag material, the top seal and the filling machine all need to match. Test the finished bag before making the full order or full production run. For more information or to request a bag quotation.

Note: This guide uses the supplied 10 mm example to explain the issue in simple terms. There is no single notch position or seal width that works for every pouch. Always test the real bag on the real filling line.