Blister packaging is pretty popular and comes in different shapes and sizes, depending on what you’re packing. The materials and heat-sealing methods also vary. If you want to dive deeper, you might enjoy reading “What Is Blister Packaging – Different Types of Blister Packaging.” It covers a lot of interesting stuff.

You can find more information in “What Is Blister Packaging – Different Types Of Blister Packaging”, if you are interested in the blister packaging. The following will discuss the Working Principle of blister packaging. Although there are some differences in details, it shows a general process of the blister packaging:

• Unwinding
• Film forming (drum type / flat type)
• Filling products
• Heat-sealing (drum type / flat type)
• Trimming, printing, and rejecting scrap

Here’s how it works, my friend: the plastic film, usually PVC, gets uncoiled and moved forward, then heated just right to make it soft and form smooth blisters. Once the PVC blister is ready, it’s filled with materials and pressed into a mold to check everything’s in order. Then, the aluminum foil and PVC are heat-sealed together, and we can print details like the batch number and date on the back of the foil if needed. Finally, the blister is cut to the specified size, and any waste products are removed based on saved signals.

When it comes to machines, the main difference lies in the blister forming and heat-sealing devices. Blister forming can be either drum type or flat-plate type, with flat-plate generally giving better results. Similarly, heat-sealing devices are classified as drum type or flat-plate type. While flat-plate heat-sealing performs better, drum type stands out in terms of speed and reliability.

You can choose to complete this process manually, semi-automatically, or automatically. For large-scale blister packaging with a consistent variety and a focus on safety and cleanliness, using an automatic packaging line is recommended. Also, an automatic blister packaging machine can be linked with other machines, like automatic printers, manual inserters, and boxing machines, creating a fully automated blister packaging line that saves both labor and time.

Case Study

Suppose we want to calculate the printed aluminium foil & PVC base foil for for  given batch size,

Number of tablets = 500,000 Tablets

Tabs/Blister =10 Tabs

Number of blisters = 50,000

Now we will calculate the quantity of printed & base or forming foil for the above batch size, mean for 50,000 blisters first by using the theoretical method and then the practical method.

 

 

1. 1. Theoretical Method

I am used to calling this method theoretical as we can use this method to calculate foils for any new product for which currently we have no tooling available. We can calculate the blister foil from the drawing of the blister using its dimensions.

 

Example

Suppose we have a blister drawing indicating the length & width of the blister as given below,

Length of Blister = 6cm

Width of Blister = 4 cm

The printed foil & base foil length for each full blister will be

6×4 =24 cm²

Calculation of Printed Foil

The concept is to cut the piece of printed foil according to the blister length & weight. In the above case, it is a 24cm² piece of printed or Lidding foil.

For more precise calculation we will take the length of printed foil for the theoretical dimensions of 6 blisters as below & weigh it

24×6 = 144 cm²

Suppose the weight of the printed foil piece for 6 blisters is 1.2 GM & weight of the foil piece for one blister is

1.2/6 = 0.2 GM

Foil Quantity For 50,000 Blisters

As we have calculated that the weight of printed foil for one blister is 0.2gm so for 50,000 blisters we will simply use the unit rule

Weight of printed foil for one blister = 0.2 GM

The weight of printed foil for 50,000 blisters is

50’0000×0.2 GM = 10,000 GM

Convert grams into kilograms

10,000/1000 = 10 kg.

Note

10.0 kg foil is required to blister 50,000 blisters. One most important point to remember is that these 10 kilograms of printed foil is Only required for perfectly cut blisters but we know that some scrape is also removed from the sides of the blister during its cutting.

Scrap Factor: –

The waste which is collected in the form of a web along with the empty rejected Blisters which are removed during machine adjustments is known as the scrap factor.

So, we will add 1 or 2 % scrap factor depending on the efficiency of the blister machine.

Here we will add a 1% scrap factor so the total quantity of printed foil for blistering 50,000 blisters will be 10.1 kilograms.

Important Point

The base foil can also be calculated by using the above method.

This theoretical method calculation may have some variations which are discussed at the end of this article in the summary portion.

2. Practical Method

I named this method a practical method because you can perform calculations practically by taking the original samples.

How To Perform :-

These calculations are performed by taking the original pieces of the printed & base foil which are collected from the blister machine.

To take these samples first of all we install the required tooling & rolls of printed & base foils on the blister machine.

The dummy empty blister is formed on the blister machine in such a way that the blister is not sealed, meaning heat or pressure at the sealing station is not applied.

We get two separate pieces of printed & base foils when the blister is collected after cutting.

Separate the printed foil piece & weigh it & in the same manner, separate the base foil piece & weigh it.

Just like the previous calculation, we will take 6 pieces of each foil for precise weight calculation.

Calculation

Suppose the weight of 6 pieces of printed foil is 1.5 GM & and the weight of 6 pieces of PVC foil is 2.5 GM.

Take the average weight of each piece for one blister as below

For printing foil

1.5/6 = 0.25 GM

For forming foil

2.5/6= 0.41 GM

Printed Foil Calculation For 50,000 Blisters

Weight of printed foil for one blister = 0.25 GM

The weight of printed foil for 50,000 blisters is

50’0000×0.25 GM = 12500 GM

Convert grams into kilograms

12500/1000 = 12.5 kg.

Base Foil Calculation For 50,000 Blisters

Weight of base foil for one blister = 0.41 GM

The weight of printed foil for 50,000 blisters is

50’0000×0.41 GM = 20500 GM

Convert grams into kilograms

10,000/1000 = 20.5 kg

Scrap Factor

In a practical method, we will weigh the actual quantity of scrap (web formed & empty blister during machine adjustments) & add it into the above foil quantities to get more precise results.

Summary

There may be minor variation in the weight calculations by the first method as foil shrinks after pocket formation & we are taking only length & width.

In the 2nd method, we are taking the actual weight of both pieces to give more accurate results.

Both methods have their own importance as the first method may be helpful for cost estimation in the case of a new product where we don’t have product tooling.

🎓 Discover one of the best Quality assurance courses available — click below to explore the course that’s shaping future QA skills.http://🎓 Discover one of the best Quality assurance courses available — click below to explore the course that’s shaping future QA skills.