Rotary Die Process Soft Gelatin Capsules: The Ultimate Guide

Currently, there are many techniques of making Softgel capsules, however, rotary die process soft gelatin capsules are still cost-effective and reliable.

But, how can you get the best rotary die Softgel encapsulation machine?

First, you need to understand all the vital aspects, including advantages, disadvantages, parts, the working principle, and technical specifications, amongst others.

Second, approach a reliable Softgel encapsulation machine manufacturer, make the user requirement specification (URS) and conduct factory acceptance test (FAT), alongside other processes.

It is a systematic and detailed procedure, a reason you should read the entire guide.

Let us begin with the basics.

Softgel Encapsulation with Rotary Die Press Basics

Softgel encapsulation machine

Softgel encapsulation machine

Contents hide

What is Softgel Capsules?

Softgel capsule is a type of oral dose medicine that closely resembles a capsule with very soft shell covers.

Softgel capsules

Softgel capsules

Advantages of Softgel Capsules

Here are some of the benefits of using Softgel capsules

i. Softgel capsules enhance a quicker rate of drug release and absorption in the human system.

ii. It has a liquid batch that enhances the solubility of drugs that are poorly soluble.

iii. It also improves drug bioavailability.

iv. It assists in the delivery of low component dosages of medical compounds including potent drugs.

v. It enhances the oral intake of drugs as it masks the nasty taste and odors of the active ingredients.

vi. Swallowing a Softgel capsule is very easy and comfortable due to the flexible shape and soft texture.

vii. The outer shell of the Softgel capsule protects the active ingredients from oxidation by the ultraviolet rays.

viii. It also possesses a unique outer shell that provides a safe, airtight enclosure for the inner fill materials.

ix. Softgel have pleasant and unusual appearance that appeals to the consumer especially kids.

x. It also has accurate and precise content that delivers the right medicinal dosage.

xi. It is a tamper proof system since it ensures complete encapsulation of all the ingredients.

xii. Most of them have custom release time thus allowing them to release the content at certain locations.

xiii. It also gives you the chance to customize shapes, color, size, and laser etching to fit your needs.

It is evident that the benefits overshadow the demerits.

That does not mean that they do not have cons.

Disadvantages of Softgel Capsules

Some of the demerits of using the Softgel capsules include:

Soft gelatin capsules

 Soft gelatin capsules

i. There are very few genuine Softgel manufacturers all over the world due to too many constraints.

ii. It involves the use of high tech equipment thus limiting the production to high scale which is very expensive.

iii. It is also moisture and thermal sensitive prompting you to store them well especially in a humid and hot climate.

iv. It poses a lot of dietary restrictions thus cutting out some of the people who follow strict dietary rules.

With that in mind, let us proceed to the ingredients that make up the soft gelatin capsules.

Soft Gelatin Capsules Ingredients

Soft gelatin capsules have a huge reliance on gelatin materials.

Apart from the gelatin, Softgel capsules have other ingredients leading to its full composition.

So, what are the ingredients that make up a soft gelatin capsule?

You will notice that a Softgel capsule consists of two main parts which are the fill materials and outer shell.

Every part of the soft gelatin capsule has a different ingredient composition.

Let’s analyze the two parts of the soft gelatin capsule ingredients individually.

Anatomy of soft gelatin capsule

Anatomy of soft gelatin capsule

I.  Outer Shell of the Soft Gelatin Capsule

It has the basic composition of Softgel capsule formulation.

Some of the components of the shell include:

  • Plasticizers
  • Gelatin
  • Mixture of water (solvent) and plasticizers
  • Coloring agents
  • Preservatives
  • Flavor
  • Sweeteners
  • Gastro-resistant products
  • Opacifying agents

The list of ingredients is long thus limiting our ability to discuss every ingredient.

That should not worry you as we will take you through the details of the most important ingredients.

Let us begin.

· Gelatin for the formulation of soft gelatin capsules

Gelatin is an organic food material that has no taste comprising majorly of collagen.

The main source of gelatin are animal products such as animal skin and bones.

Many of the gelatin products come from cows and pigs.

You can extract gelatin from the skin and bones of animals with the help of special machines in a laboratory.

The extraction process also differs thus giving you two main types of gelatin.

The first process involves the hydrolization of animal skin using acidic solutions.

The second one involves the basic hydrolysis of bovine bones.

Vegans also have the opportunity of consuming capsules from vegetable products.

· Plasticizers in the formulation of Soft gelatin capsules

Plasticizers offer the soft gelatin capsule the pliable, elastic and smooth outer cover.

Plasticizers account for about 20 to 30% of the soft gelatin capsule.

You can use glycerol as the most common plasticizer available in the industry.

You can also use propylene glycol- 400 and sorbitol but after using glycerol.

You have to get the composition and combination of the plasticizers right.

Why is it so?

The dissolution, texture, and disintegration of the soft gelatin will vary depending on the plasticizer.

Plasticizers can alter the chemical and physical attributes of the soft gelatin capsule.

· Water formulation

Water occupies about 30 – 40% of the total formulation of the soft gelatin capsule.

It is the major processing solvent for the Softgel preparation and encapsulation process.

Water provides the capsules with enough turgidity and stability even when in the stores.

· Opacifiers formulation in a softgel capsule

You can use opacifiers such as titanium dioxide in the preparation of soft gelatin capsules.

It is an important ingredient in the preparation of light or suspension sensitive fill formulations.

It also disrupts the photodegradation of ingredients that are susceptible to light.

The opacifiers will form an opaque shell that will block light from destroying the sensitive fill materials.

· Coloring agents formulation

You can give the soft gelatin capsule the right color by using a coloring agent.

Colors often assist in the identification of capsules.

You can either decide to use natural or synthetic coloring agents depending on the customer’s preferences.

· Preservatives formulations

You will use very small quantities approximately 0.2% of preservatives even though they perform vital functions.

The most common preservatives are propylparaben and methylparaben.

The preservatives assist in keeping the medical value of the drug in check away from microbe interference.

· Flavoring Agents Formulation

These are the products that assist in masking the unpleasant taste and odor of the active ingredients.

They are available in different variants for you to choose from.

II. Fill Material of the Soft Gelatin Capsule Formulation

You will formulate the components of the fill materials according to your needs.

Implying, every fill material is different and will only achieve the therapeutic value you need it for.

You have to seriously reconsider the chemical stability of the active ingredients during the formulation process.

It will improve the bioavailability of the drugs you are formulating.

There are three main conventional types of fill materials which include:

  • Neat components including oily liquids
  • Solution
  • Suspension

You need to use efficient filling techniques for accurate measurements for a stable capsule.

Structure of soft gelatin capsule

Structure of soft gelatin capsule

III. Soft Gelatin Capsules Formulation

The formulation process is a technical and challenging procedure and you have to be extremely careful.

You have to ensure that the migration or the interaction between the fill materials and the outer shell is negligible.

A good plasticizer will assist you in ensuring that the interaction is at minimal.

Having knowledge on the Softgel capsule formulation will assist you in making a stable final product.

There are two main type of interactions in the formulation of soft gelatin capsules including:

· Chemical Reactions

Chemical reactions involve the different reactions that occur between the fill matrix, against plasticizers and gelatin.

For example, gelatin undergoes crosslinking in case the active ingredient consists of aldehyde.

You can mitigate the problem by adding succinylated gelatin.

· Physical Interactions

Physical interactions occur when the fill elements move as a whole in the gelatin shell.

It could also occur through the outer covers, in the fill matrix, or via the shell.

The degree of physical interactions will depend on:

  • Suitability and type of chemical composition of the fill and outer cover
  • Quantity of the specific components

For example, you have to maintain the water content at critical value and never exceed 5%.

Let us proceed to the next section where you will learn about the Softgel encapsulation process.

Softgel Encapsulation Process with Rotary Die Machine

There are different encapsulation methods that you can use to make a Softgel capsule.

The processes include:

i. Rotary Die Process

ii. The Plating Process

iii. Reciprocating Die Process

iv. Alcogel Process

v. Seamless gelatin capsules Process

In this guide, we shall stick to the rotary die process of soft gelatin encapsulation.

Let us find out more.

Softgel encapsulation machine

Softgel encapsulation machine

What is Rotary Die Process Soft Gelatin Capsules?

Rotary die process is the process of making a soft gelatin capsule using a Rotary Die machine.

A rotary die machine is an equipment that you will use in filling gelatin shells with liquids, suspensions or semisolids.

You should note that there is a difference between the Softgel and hard gelatin encapsulation machine.

Rotary softgel encapsulation process

Rotary Softgel encapsulation process

hard gelatin encapsulation machine is available in three main variants including:

  • Manual hard gelatin encapsulation machine
  • Semi-automatic hard gelatin encapsulation machine
  • Automatic hard gelatin encapsulation machine.

Softgel encapsulation machines, on the other hand, is only available in the automatic encapsulation form.

Apart from that, the hard gelatin encapsulation machine has additional parts such as dust extractors.

Softgel encapsulation machines will not need dust extractors since it deals with solutions and not powders.

The working principles of the soft gelatin encapsulation machine are different from that of the hard gelatin encapsulation machine.

Softgel encapsulation process may take the form of a rotary or plate die process.

Hard gelatin encapsulation process usually takes the form of dosatorcapsule filling machine or tamping pin capsule filling.

Let us have a look at the benefits of using the rotary die technology in the process of Softgel encapsulation.

Advantages of Rotary Die Process Soft Gelatin Capsules Technology

The main advantages include:

Rotary die softgel encapsulation machine

Rotary die Softgel encapsulation machine

i. The machine produces easy to swallow capsules.

This is more important in situations where you may not be in a position to use tablets or ordinary capsules.

ii. It also ensures the stability of the active ingredients.

A stable active ingredient can last longer as it has a longer shelf life.

iii. The machine will guarantee accurate doses of the active ingredient of the soft gelatin capsules. It fills the capsules with the suspension or liquid of the right doses.

iv. It also makes soft gelatin capsules that are resistant to heat and temperature fluctuations.

v. The technology also gives you the chance to customize your soft gelatin capsules. You have the freedom of making soft gelatin capsules of any shape depending in design of die activity.

vi. It also makes hermetical seals of the soft gelatin capsules. This makes the soft gelatin capsules airtight and tamper proof.

Despite the benefits, it has fallen short of impressing in some other areas.

Disadvantages of Rotary Die Process Soft Gelatin Capsules Technology

Some of the demerits of rotary die process of soft gelatin capsule technology are:

Rotary Die Process Soft Gelatin Capsules

 Rotary die process of soft gelatin capsule

i. The technology is expensive and will require you to spend a lot of capital to set up. Apart from that, it will limit you to large scale production which is costly.

ii. The technology also requires you to have knowledge of the operation. You need to undergo special training or hire a specialist to assist you.

iii. Softgel encapsulation is very sensitive and has a lot of restrictions. Due to the sensitivity of the process, you might not get the chance of using the machine because of numerous restrictions.

Let us shift our attention to the parts of the machine.

In the next section, you will learn more about the parts of the rotary die encapsulation machine.

Parts of Rotary Die Encapsulating Machine for Softgel Capsules

Rotary die encapsulation machines are available in different sizes and shapes.

You should not wonder in case you get a machine with more parts.

In this guide, you will learn about the main parts of the rotary die encapsulation machine.

These parts are common in every machine that you will find in the market.

You should also have a proper review of the catalogue and note any unique parts of the machine.

Let us go straight to the parts.

Parts of rotary die softgel encapsulation machine

Parts of rotary die softgel encapsulation machine

· Product Material Tank

You can also identify it as the medicine hopper

It is a stainless steel container in the upper section for holding all the materials that you want to encapsulate.

It has a special design such as conical shape that will allow the materials to flow seamlessly to the pump.

· Leads

It also has a lead and a handle that will cover the content from contamination.

Besides, you have to ensure that it has no leakages on the joint.

· Product pump

It is below the hopper but above the whole frame of the machine.

Its position makes it efficient for the sucking of materials from the material tank or medicine hopper.

It directs the materials from the hopper to the next stage through the feed tubes.

The materials will flow to the injection wedge while excess materials follow the return tube to the hopper.

· Injection wedge

You will realize that the injection wedge is right above the Softgel machine tooling system.

It assumes a geometrical wedge shape and heats the web to the right temperature.

You can either use an electric or water heating system.

As it heats, it injects materials to the web through pressure as they proceed to the die cavity.

You may also decide to use a rotary die machine with a more sophisticated injection wedge.

For example, the injection wedge may have:

i. Sensors that will coordinate motion

ii. Shut off valve systems

iii. The ability to move up and down

You should note that the injection wedge will determine the accuracy of the encapsulation process.

Parts of softgel encapsulation machine

Parts of softgel encapsulation machine

· Gelatin Tank

A gelatin tank is a stainless steel container where you will prepare the main ingredient which is gelatin.

It is stainless steel and you can find it in different capacities depending on the production scale.

It consists of steel valves, a triple wall jacket with a breather and clamps.

You should always consider the following specifications whenever you are looking for a gelatin tank:

i. Power rating

ii. Capacity or volume of the tank

iii. Working temperature of the tank

iv. Type of materials where stainless steel is the best material

v. Size in terms of dimensions and weight

· Spreader Box

This the part right above the cooling drums that will receive the gelatin from the gelatin tank.

It will hold and then spread the gelatin into a very thin film.

A good soft gelatin encapsulation machine will have a spreader box to the right and another on the left.

In many cases, it is the point where there is the main action of forming ribbon shells.

It can form ribbons of about 800 micrometers thick with a width of 150 mm.

You should note that the size can vary depending on the type of soft gelatin capsule.

· Ribbon

The ribbon is the main product that comes from the spreader box.

It forms a constituent ingredient that you will use in making a soft gelatin capsule.

· Cooling Drum

In any Softgel encapsulation machine, you will find the right and the left cooling drums.

The cooling drum will solidify and cool the gelatin web.

It is always in a rotary motion towards the direction where the gelatin web should flow.

You may choose a machine with different cooling drum mechanisms such as:

i. A cooling fan that assists in curing gelatin web for encapsulation.

ii. Circulation of clean water around the system to cool down the gelatin web.

Apart from the two, you may opt for a machine with refrigeration or chilling system.

It will assist in maintaining the skin wheel temperature at specific points.

Here are some of the factors that you need to consider for a chilling system:

i. Power consumption

ii. Weight and Dimension

iii. Capacity of refrigeration

· Oil Rolls

In a modern Softgel encapsulation machine, you will find at least three lubrication rollers.

It ensures that the gelatin ribbon reaches the tooling system while it is still tight.

Apart from that, it also applies lubrication oils on the two sides of the web.

The lubricant will protect the gelatin skin from potential damage.

You have to ensure that the lubricant does not react with the capsules or the gelatin materials.

· Die Rollers

A Softgel encapsulation machine consists of two die rollers with die pockets as part of the tooling system.

It will form the Softgel capsules, one at a time, and then seal them after filling.

It allows material to move into the space between the die rolls.

During the encapsulation process, here are some of the activities that occur in the die rollers:

i. Feeding and filling of gelatin ribbons

ii. Shaping of all the capsules

iii. Hermetical sealing of the capsules

iv. Cutting of the capsules from the ribbon

· Stripper Roller

As part of the tooling system, a stripper roller will remove any capsules that stick on the die rolls.

· Die roll bush

It will also assist you in removing any capsules that will stick on the die rolls.

The die roll brushes are always in constant motion in the opposite direction to the die rolls.

· Mangle Rollers

These rollers will pull the soft gelatin web from the main die rolls.

It assists in adjusting the tension on the soft gelatin web and discharges the rest for further recycling.

· Chute

This is the part that discharges all the capsules from the system on to a conveyor belt.

· Conveyor belt

It assists in the transportation of the soft gelatin capsules for further processing.

Further processing will include drying, sorting and inspection.

· Drying Systems

The drying system consists of two main options including tumble dryers and drying trays.

· Tumble Dryers

Depending on the design, you will use the drying system for simple and easy drying mechanisms.

Here are some of the factors that you have to consider:

i. Quantity of the tumble dryers

ii. Dimensions of tumble dryers such as size and weight

iii. Power supply

The Softgel capsule remains in the tumble dryers before you move them to the drying trays

· Drying Trays

You will use these trays to transfer the capsules from the tumble dryers to the drying tunnels.

The drying trays are available in different dimensions.

· Control Panel

Modern, Softgel encapsulation machines have PLC control system.

You will use the control panel in the monitoring and controlling of different encapsulation processes.

In short, these are the main parts of a soft gelatin encapsulation machine you should know about.

Of course, you will notice other parts on the machine. You will learn more about them in the manual of the machine.

Let us proceed to the next section where you will learn about the working principles of the machine.

Working Principle of Rotary Die Process Machine for Softgel

Knowing how the parts of the machine work in detail, gives you the foundation of the working principles.

In this section, you will go through a step by step process of how the machine operates.

Without further ado, let us proceed to the first step.

Step One: preparing Gelatin

You have to collect all the materials you need for the preparation of gelatin.

Apart from that, you need to have the correct formulation for the gelatin.


The gelatin substance forms the main shell of the capsule and you have to get all factors right.

In most scenarios, here are the main ingredients you need to have:

i. Gelatin substance

ii. Plasticizers

iii. Water and opacifiers

You need to pour the gelatin ingredients in the gelatin tank for further preparations.

The preparations include blending, heating and stirring to form a thick syrup.

You will allow the syrup to flow to the spreader box for spreading and the formation of the ribbon.

After that, the ribbon will undergo cooling under the cooling drums before proceeding to the tooling system.

You should remember to program the speed and other parameters at the control panel before you begin.

In other words, these are the main principles in the first phase of the rotary die process.

Step Two: Preparing Fill Material

All the activities of preparing the fill materials take place in the hopper.

In this case, you need to have all the specific contents that you need for the fill materials.

You can process all the ingredients of the fill material to form paste like or oil-based products.

You will need to have fluid bed dryers or granulators, hammer mills, and processing tank.

Your requirements will vary according to the type of Softgel capsule you intend to make.

With an appropriate fill material, allow it to flow to the injection wedge from the hopper.

Step Three: Beginning the Rotary Die Process

This the beginning of the main stage of the encapsulation process using a rotary die machine.

At this stage, the fill materials and the gelatin will meet.

The ribbons move into the die roll system in a rotary motion.

The rotation will create a very unique capsule shape.

As this continues, the machine will be administering the fill materials between the two gelatin ribbons.

The gelatin ribbons will wrap the fill material thus forming a capsule.

The shape of the capsule will depend on the die roll cavity.

The capsules will move from the machine through the discharge chute.

The brush will remove any capsule that will stick on the die rolls.

You will also realize that the stripper rolls will also remove all the capsules that will stick on the web.

The process is always continuous and moves very fast.

Step Four: Further Rotary Die Processing

This is the final stage of the soft gelatin encapsulation process.

As the Soft gelatin leaves the machine through the discharge chute, you have to take it through other processes.

You will take the soft gelatin through drying, sorting, cleaning and packing.

The machine will assist in the movement of the capsules on the conveyor belt to the tumble dryer.

You have to allow the capsules to stay in the tumble dryer for a while.

After that you will load them on to dry trays and transport them to the drying tunnels.

The drying and sorting systems are not main parts of the encapsulation machine.

You can identify them as auxiliary parts of the encapsulation machine.

Step Five: Finishing

In this stage, you will sort out the soft gelatin capsules making sure they are of the right specifications.

You can also polish and print the Softgel capsules for better identification.

You are now free to package the soft gelatin capsules in different types of packages.

In the next section, you will learn about the support equipment for the encapsulation machine.

Support Equipment for Rotary Die Soft Gelatin Encapsulation Machine

Here are some of the support equipment for the soft gelatin encapsulation machine:

i. Softgel Polisher

It consists of blankets and electric parts.

You will use the Softgel polisher to give soft gelatin a smooth and shiny finish that appeals to the eye.

Soft gel polisher

Softgel polisher

ii. Softgel Pulverizer

You will use it to recycle capsules that are not of the right shape or do not qualify for sale.

It assists in saving costs and limiting waste.

Softgel pulverizer

 Softgel pulverizer

iii. Softgel Sorting Machine

You can use it for sorting the Softgel pills and capsules.

It will sort the soft gelatin capsules according to the diameter and other parameters.

Softgel sorting machine

Softgel sorting machine

iv. Inspection Machine

It assists in the inspection and elimination of all the negative aspects of the soft gelatin capsules.

It assists in eliminating coarse chips and dust.

Softgel inspection machine

Softgel inspection machine

v. Medicine Mixing Tank

It consists of three layers including inner layer jacket, insulation jacket, and SUS 304 stainless steel.

You can use it to thoroughly mix the active ingredients of the medicine.

 Medicine mixing tank

Medicine mixing tank

vi. Gelatin Melting Systems

You will use this machine for melting gelatin at a faster rate than that of the encapsulation machine.

Gelatin melting system

Gelatin melting system

vii. Moving Gelatin Melting Tank

It consists of a glue melting technology for melting gelatin.

It can control the melting temperature of the system thus maintaining constant melting rates.

Moving gelatin melting tank

Moving gelatin melting tank

viii. Gelatin Service Tank

You will use the gelatin service tank for providing extra services to gelatin.Gelatin service tankGelatin service tank

ix. Medicine Service Tank

You can use it in the provision of extra services to the medicine you intend to mix.

It will assist in maintaining right pressure and temperature among others.

Medicine service tank

Medicine service tank

x. Vacuum Mixer

It allows you to mix all the necessary ingredients in a vacuum.

This allows very minimal interference from other ingredients in the environment.

Vacuum mixer

Vacuum mixer

xi. Colloid Mill

You can use the colloid mill for emulsification, homogenizing, and mixing of different types of emulsions and semi-liquids.

Colloid mill

Colloid mill

xii.  Drying Trays

With the help of the drying trays, you can move Softgel capsules from the tumble dryer.

It will assist you in transporting capsules to the drying tunnels.

Drying trays

Drying trays

Of course, you will also need a tumble dryer.

It is a critical aspect of rotary die process soft gelatin capsules manufacturing.

Tumble dryerTumble dryer

xiii. Softgel Tooling

The component assists in shaping of the capsules to the shape you desire.

It consists of different shapes that will match the shape of capsule you desire.

Softgel tooling system

Softgel tooling system

With that in mind, we will proceed to the last section of this guide.

Technological Advancement in Rotary Die Process Soft Gelatin Capsules

Technology in the encapsulation process continues to evolve as time goes by.

In this section, we are going to learn about the technological advancements the rotary die process of Softgel capsules.

Rotary softgel encapsulation machine

 Rotary softgel encapsulation machine

Here are the main advancements:

1. High production capacity

You can find modern equipment with a higher production capacity.

Technological improvements create machines that can produce more Softgel capsules per minute.

2. Automation

Apart from the high production rate, you will find machines with SIEMENS PLC and touchscreen HMI.

This will allow you to remotely control the encapsulation machine.

You can also inspect the process of soft gelatin encapsulation from the control panel in an automatic system.

3. Flexibility in Softgel encapsulation

You have the freedom of producing soft gelatin capsules of varying shapes and sizes.

Modern equipment allows you to come up with custom designs, shapes and sizes that you can comfortably produce.

Well, it will be unfair to conclude this guide without recommending a rotary die Softgel encapsulation machine.

Here are just a few machines you can consider – Softgel Capsules Manufacturing Equipment Line.


So far, this has been an exciting and informative journey.

I believe that you are now an expert in the rotary die process of soft gelatin capsules.

You can comfortably handle the machine and the whole process without any hitches.

Don’t you think it is time to proceed with your idea?

Well, I think with this information, you can do wonders in the production of soft gelatin capsules.

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