Tablet Inspection Machine: The Ultimate Guide

Tablet manufacturing line is not complete without a tablet inspection machine.

Why?

Because, after tablet compression process, there are possibilities of having broken or deformed tablets among the products.

You need to sort these tablets with defects before packaging your pharmaceutical products for distribution.

It is an important quality inspection process, you cannot avoid it.

Now, today, you’re going to learn how to choose the best tablet inspection machine.

The guide covers everything, from basics to advanced aspects on tablet inspection machine.

Let’s dive right in…

What is a Tablet Inspection Machine?

This is a machine that helps in the visual examination of tablets, both coated and uncoated kinds, of different sizes.

Tablets

Tablets

The equipment does the inspection conveniently and at a very fast rate, ensuring stringent quality control as well as maintaining a good rate of examination.

Normally, tablet inspection machine has a complex design that ensures total rejection of tablets with flaws.

It does this before the pharmaceutical products leave the production line.

The equipment offers fast and precise inspection for visual flaws on different tablets.

Tablet inspection machine examines nearly the entire surfaces consisting of the front, rear and side surface.

It is also possible to inspect tablets of varying shapes including oval, triangular, round, caplet, among many other shapes.

The tablet inspection machine guarantees top performance and high volume examination.

Types of Tablet Inspection Machine

Broadly, there are two types of tablet inspection machines:

Tablet inspection machine

Tablet inspection machine

· Manual Tablet Inspection Machines

For many years, there have been machines that can aid in the manual inspection of tablets.

Manual tablet inspection machine feeds the pills from a chute onto a conveyor belt that rotates.

Or, vibrates the tablets through 360 degrees to enable the operators identify physical defects.

Stainless steel 304 structure forms the base of the manual tablet inspection machine.

It constitutes of an endless conveyor belt at the center.

An AC motor controlled via AC Variable Frequency Drive controls the belt.

Tablets from the Stainless Steel Hopper drop on a magnetic vibrator, which eliminates dust and chips from the tablets.

In addition, the manual tablet inspection machine has two-foot switches and two inspection lamps for two operators. The foot switches enables the operators to stop the conveyor belt when necessary.

The design of the machine facilitates manual tablet inspection from both sides.

You can inspect approximately 0.7 to 0.8 tablets per shift based on the operator skill and size of the tablet.

Here, the yield normal relies on these two variable (size of tablet and operator skill).

You fill the tablets you want to inspect in the hopper, which in turn automatically position themselves on the conveyor belt by vibration.

 Worker inspecting tablets

Worker inspecting tablets

An operator examines the front side of the tablets from one end while the second operator examines the rear side from the other end.

Moreover, the manual tablet inspection machine can come fitted with dust extractor essential in collecting dust. Rejection tablet tray collects the tablets with defects while 100 percent perfect tablets drop into the collection drum.

Most pharmaceutical producers and packers that inspect their products before packaging today apply manual inspection.

This is due to the fact that it offers a rationale for claiming diligence and involves reduced capital cost.

However, the greatest disadvantage of manual tablet inspection machine is that humans are astonishingly poor at inspection, particularly over time as attentiveness deteriorates.

Another big disadvantage of the manual inspection equipment is the expensive nature of human resource, and this increases the general cost of production.

Production suffers as workers pull good tablets in their attempts to be active.

Finally, adding individuals to the inspection process can in effect enhance the possibility of contamination and tablet safety. This can be due to malicious actions and unintentional mistakes.

Various mechanical systems such as rotary table and in-line conveyors are available to help in manual tablet inspection.

The design of these systems is to enable the inspection process.

However, the advantages and disadvantages of manual tablet inspection stays the same regardless of the technology that aids the operation.

Mechanical Sorting

There exist two kinds of mechanical sorters for tablet pharmaceuticals today:

  • Traditional diverging roller sorters and
  • Newer vibratory size graders.

Both types of machine are efficient in eliminating broken tablets and foreigners of a differing size.

However, they are not capable of removing defects and foreigners with the similar size as the right product.

Numerous additional disadvantages of diverging roller sorters are the outcome of their mechanical sophistication. They consist of several moving parts that need significant maintenance.

Normally, they rely on the expertise of the operator to install and adjust, which lowers the repeatability of performance.

Tablet in inspection machine

Tablets in inspection machine

Moreover, these tablet inspection equipment can be time-consuming to clean during changeovers, normally losing about 2 hours of production time.

In contrast, newer vibratory size graders compose of fewer moving components and lack rotating parts.

This minimizes maintenance and leads to a reduced total cost of operation than diverging roller sorters.

You can clear and clean vibratory size graders in about 5 minutes, and they employ removable decks having definite hole sizes for repeatable replicable grading.

This makes the operation unconnected to the operator’s skill.

Furthermore, vibratory size graders can attain the throughput of diverging roller sorters thrice, managing up to 1 million tablets per hour.

Blister Inspection

Majority of blister packaging lines have incorporated inspection systems that confirm that every blister pocket contains a tablet.

Tablets in blister packing

Tablets in blister packing

However, these systems are not effective at detecting and eliminating blisters with defects or foreign tablets.

To ensure end product quality, extra inspection needs to be in place before the blister packing system.

Single-File Optical Inspection Machine

Introduced 25 years ago, single-file inspection systems find application only when the desire to guarantee the highest tablet standards supersede other commercial considerations.

Majority of these systems are exceptionally efficient in detecting and eliminating defects and foreigners depending on differences in size, shape, and color.

Even so, their adoption has not been that wide. This is because of the machine’s low throughput (usually about 50,000 doses per hour), high capital costs, and many costly change parts.

The changeovers often require more than 8 hours to complete.

Automatic Tablet Inspection Machine

Not long ago, automated inspection of pharmaceutical tablets was either crude or costly, slow and hard to changeover.

For this reason, majority of pharmaceutical producers and contract packers have depended only on sampling or manual inspection. These two mechanisms are far from error-proof.

Automatic tablet inspection machine

Automatic tablet inspection machine

However, with the development of digital image recognition technology and applications, there are machines that can automatically detect and eliminate tablets with defects.

The progressing technology has brought a new generation of bulk optical inspection machines.

Remember, the new systems are effective, cost-effective and provide fast way to attain 100 percent inspection.

The recent technology is prompting pharmaceutical industry leaders to re-examine the industry standards.

They do this with the intent of applying the best practices currently available.

Automatic optical inspection is presently a popular technique in industrial processes.

It applies optical instruments to attain the surface finish of the final product.

It then inspects abnormal patterns, foreign objects, and other flaws through the computer image processing technology.

Tablet inspection machine employs the optical lighting and image measurement technology to examine:

  • Size mismatch
  • Staining, pucker
  • Breakage
  • Surface foreign object
  • Twining of the tablet.

The automatic tablet inspection equipment applies state-of-the-art technologies to check and sort tablets, establishing whether they are good or defective.

You can configure the automated machine for comprehensive high-speed tablet inspection.

The equipment makes use of 2D and 3D cameras to generate high-quality pictures of any tablet passed across them.

Here, the 2D cameras generate images for 360º observation of the tablet, making sure there exist no blind spots for any tablet during inspection.

Automation makes the machine have higher rate of inspection. It can inspect tablets from 5mm to 12mm at rates up to 300,000 every hour, for defects including:

  • Chips
  • Breakages
  • Sticking tablets
  • Spots
  • Coloration
  • Foreign objects (fibers, hair) and other flaws.

The design of the automatic optical tablet inspection machine is ergonomic and simple to use and configure.

Normally, the machine shape and the wide opening doors facilitate for an ease of disassembling for sanitization or job changeover.

You can accomplish this operation in less than an hour, and it requires minimal or no tooling.

Why you need a Tablet Inspection Machine

As stated earlier, quality control is an important aspect in the pharmaceutical industry.

And in this section, you’re going to know the main reasons why a tablet inspection machine is a must-have accessory.

Tablet inspection process

Tablet inspection process

1. State-of-the-art inspection

The automatic tablet inspection machine aims to ensure high quality of the finished product while sustaining high production throughput.

You attain this courtesy of the high-resolution 2D and 3D cameras, which are efficient in inspecting tablets of varying shape, size, and color.

Some automated optical tablet inspection machines are highly effective. They guarantee elimination of 100 percent of:

  • Foreign tablets, while also eliminating foreign objects
  • Broken tablets
  • Stained tablets
  • Tablets having scratched coating when the coating is of contrasting color as the underlying tablet.

2. Reduced Costs

These systems offer additional advantages beyond superior final product quality.

In comparison to manual inspection equipment, automatic tablet inspection machines significantly reduce the cost of labor.

Typically, the substitute 10 to 15 manual inspectors, and boost output.

Generally, the simple operation of automatic tablet inspection machines minimize the overall cost of tablet production; thus, higher profit margins.

3. Increased Tableting process control

In addition to ensuring high pharmaceutical product quality and minimizing labor costs, automatic tablet inspection machines can as well help in process control.

The automated system allows manufacturers to enhance upstream processes and organize downstream operations in real-time.

This is possible due to the machine’s ability to capture a continuous stream of data concerning tablets on the production line in real-time.

In future, making use of this data may help incorporate into Process Analytical Technology (PAT) measures.

4. Quick and simple cleaning and change over

Compared to single-file optical tablet inspection systems and diverging roller sorters, automatic optical tablet inspection machines fasten changeovers.

There exist reduced number of components that you need to remove for product change over or cleaning.

Once you have removed the parts, you can easily and quickly clean the remaining compartments.

5. Integrated process control and processing

Nonetheless, there exist less evident advantages that you can obtain with automated tablet inspection machines.

The benefits related to substituting batch processes with continual, consolidated process control and processing.

Presently, at each stage between two batch operations, tablet producers and packagers involve human labor to transfer product and take up space to keep work-in-progress inventory.

But more essentially, at each stage, the danger that a foreign object or tablet finds its way into the product stream increases.

Being aware of all this, it is important to automate your manufacturing line by substituting batch processes with continuous processes.

Automatic tablet inspection machines assist in facilitating this paradigm shift.

Parts and Components of a Tablet Inspection Machine

Like other machine, a tablet inspection machine is an assembly of various parts and components.

Each parts ensures only quality tablets move to the packaging section.

And, before introducing you to the working principle of tablet inspection machine, let’s quickly look at the basic parts and components.

Technical drawing of tablet inspection machine

Technical drawing of tablet inspection machine

· Hopper

A hopper is the material feeding part of the tablet inspection machine.

This is the section that you will place all the tablets that you want to inspect and the material used to make it is stainless steel.

You can vertically adjust the height of the hopper with a knob, and based on the design of the inspection machine, the process of feeding can either be manual or automatic.

From the hopper, the tablets drop on a magnetic vibrator.

· Magnetic Vibrator

This is a perforated vibratory plate that is useful in extraction of dust.

The component eliminates dust and chips from the tablets before feeding them onto the conveyor belt.

It is possible to vary the vibration intensity of the vibrator to make sure there is smooth falling of tablets onto the conveyor.

Electronic regulator helps in controlling the speed of feeding the tablets.

· Conveyor Belt

Stainless steel grade 304 fitted with Food Grade PVC endless belt make up the inspection belt unit.

You can wash and easily replace the conveyor belt.

For manual inspection, the belt makes the tablets to flow smoothly as the operators pick out defective ones.

On the other hand, as the tablets flow on the conveyor belt in automatic inspection machine, a camera captures their image.

The machine analyzes these images and decides to reject or accept the tablets based on the outcome of the analysis.

You can adjust the speed of the belt so as to increase or decrease the rate of inspection based on the percentage of rejection.

· Motor

This is a fixed motor with variable speed drive that rotates the conveyor belt. You can adjust independently adjust the speed of the motor as you desire.

· Two-foot Switches

The foot switch arrangement helps the operators stop the conveyor belt immediately they identify defective tablets. The switches are on both sides of the belt.

· Two Inspection Lamps

The tablet inspection machine comes with two fluorescent inspection lights for illumination of the tablets.

It is also possible to adjust the height of the lamps depending on your requirements.

· Discharge Chute

This part ensure smooth and safe ejection of the inspected tablets. It has a design that makes sure there is no damage caused on the products.

· Collector Drum

This is the part where 100% perfect tablets fall into from the discharge chute.

· Rejection Tray

As the name suggest, the rejection tray collects the tablets with defects.

· Control System

Microprocessor electronic control panel facilitates easy operation of the tablet inspection machine.

Most equipment have touchscreen control panels.

It is essential you recognize that stainless steel makes the top cover, hopper and entire body of the inspection machine.

Working Principle of Tablet Inspection Machine

Now, let’s have a quick look at how tablet inspection machine works:

Tablet inspection process

Tablet inspection process

How Manual Tablet Inspection Machines Work

After feeding the tablets into the hopper, they flow into a vibratory chute, in which a perforated screen removes chips and coarse dust that collects in a container.

The tablets move into the inspection phase in a single layer.

Here, the vibratory chute directs the tablets onto rotating rollers.

They continually spin and move in front of the operator, who guarantees a dependable all-sided visual inspection.

A variable mirror allows the operator to examine the opposite side of the tablet.

With manual tablet inspection machine, it is possible to adjust the speed of rotation of the inspection rollers solely, independent of the speed of inspection.

The speed of rotation and inspection of tablet is infinitely adjustable.

No blind areas and hidden corners in inspection stage.

The material used to make the inspecting roller or conveyor belt is approved transparent high-density polymers.

Remember, the lighting fixture fixed below the roller conveyor belt illuminates the tablets from below.

The operator can remove the defective tablets using a flexible handheld vacuum nozzle.

To halt the conveyor belt at given time, you use the foot pedal.

When you press the foot pedal, the tablets keep spinning before the operator at a different variable speed.

Lighting installed below the roller conveyor belt for illumination purpose is non-flashed fluorescent lamp, and this reduces fatigue of vision.

Additionally, you can easily dismantle the machine minus any tools in a few minutes.

This facilitates easy cleaning and reduced risks of cross-contamination.

How Automatic Tablet Inspection Machines Work

This machine as well inspects the tablets from all dimensions employing advanced optic techniques.

It can even examine the edges by taking images from front, back and sides.

Tablet inspection process

Tablet inspection process

This tablet inspection equipment carries out inspection on tablets for several types of defects like cracks, dirt, imprints, and many others.

To commence the inspection process, a powerful camera captures the image of the tablets.

The captured pictures act as input to the system software for post-processing to derive helpful information.

Automatic tablet inspection machine uses the final results to verify if the tablets conform to the original dimensions.

The Tablet inspection machine has a conveyor belt with a fastened DC motor, a camera to capture images of the tablets and two containers for rejected and accepted tablets.

To ensure a straight movement of tablets, you need to control the alignment sensor of the conveyor belt and the speed of the conveyor.

Also, the camera gadget captures the pictures and transmits to the computer for more processing.

The outcome of that post-processing inspects for the quantity of tablets, rate of production and rejection and establishes whether the system should accept or reject any specific tablet.

There is also the option of transferring the data remotely to the data logging department for record keeping.

The figure below shows the block diagram of the entire system.

emage section

 

The Image Section takes all the images in the course of the inspection process and employs various mechanisms to process the image.

And, the conveyor section is useful in moving the belt that transfers the tablets within the system.

Finally, the Control Section decides on whether the automatic tablet inspection should accept or reject the tablets.

LabVIEW Working

Lab work view

 

LabVIEW

LabVIEW display has three parts as depicted in the diagram above. Let’s have a look at the part.

  • Image Out which is the real-time feed from the camera gadget
  • Snap Image which snaps any specific image frame for identification
  • Template image is useful for comparison with the captured image.

The camera continuously captures images and the system creates a pattern by cropping any distinct area in the image. It then matches the pattern with the template.

The LabVIEW has two loops as displayed in the diagram:

1. Image Acquisition and Operation Loop

This loop is critical for getting the images from the camera instrument.

After getting the pictures, it awaits the second loop to cause a trigger and carry out the process of recognition employing image processing functions.

The automatic tablet inspection machine first converts the captured images into grayscale then it transmits them to the second loop to get the template.

It crops the image in any specific region and then transfers it to this loop for comparison.

2. User interface loop

This loop has the role of checking the input from the front panel interface and developing the needed trigger operation for the first loop to carry out matching and taking action.

Automated optical inspection of tablets examines the products based on features such as shape, size, color, and some chemical and structural constituents, with the aid of cameras.

The technique finds wide application in pharmaceuticals and food processing industries.

This is due to its accuracy and capability to optimize the output while managing all likely errors during operation.

Maintenance and Troubleshooting of Tablet Inspection Machine

For both manual and automatic tablet inspection equipment, it is crucial that you thoroughly clean the machine before commencing the examination of any new batch of pharmaceuticals.

 SaintyCo tablet inspection machine

SaintyCo tablet inspection machine

The following is a short guide that you can apply to the maintenance of the tablet inspection machine.

Pre Start-Up Tablet Inspection Machine

  1. Check the area of location of the inspection machine and make sure the equipment is clean and there exist no debris of previous products in the equipment or area.
  2. Confirm the relative temperature and humidity of the operation area and record it in the logbook.
  3. In case the temperature is beyond the recommended limits, alert the maintenance department and do not commence the operation.
  4. If temperature is within permitted limits, begin the tablet inspection process.
  5. Make sure the labeling of the machine is correct for the specific batch of tablets.
  6. Seek line consent from the Quality Assurance (QA) department to begin the process.

Operation of Tablet Inspection Machine

  1. Turn the mains electricity ON.
  2. Inspect for any abnormal noise by pressing the start button.
  3. To gather the inspected tablets, put an appropriately marked high-density polyethylene bin under the discharge chute of the machine.
  4. Place the needed batch of tablets into a trolley and position the trolley close to the inspection machine.
  5. Manually feed the products into the hopper of the tablet inspection machine.
  6. Set the rotation or vibration of the conveyor as wanted.
  7. Turn on the conveyor belt.
  8. In the scenario of manual inspection, observe for any flaws on the tablets as they flow along the conveyor belt.
  9. Gather the redeemable rejected tablets out of the rejection box and place them in a plastic container.
  10. When the container below the discharge chute gets full, substitute it with a similar one.
  11. Remove the container and fasten the bag using a tie band. Place it in a separate trolley to the products.

Shut Down Tablet Inspection Machine

  1. Switch the machine off after you are through with the tablet inspection.
  2. Insulate the main electricity supply.
  3. Transfer the product tablets to the rightful placement location.
  4. Detach the machine status logo and throw it away.
  5. Fix a “to be cleaned” mark on the tablet inspection machine.

Cleaning Tablet Inspection Machine

  1. Detach the “to be cleaned” mark and tear it after reading the information on it.
  2. Clean the hopper and the conveyor belt of the machine with a lint-free cloth soaked in purified water.
  3. Send a wash sample to the in-process Quality Assurance department.
  4. Clean the tablet inspection machine using lint-free cloth soaked in purified water and also use lint-free cloth to dry it.
  5. Clean the body of the machine using dry lint-free cloth.

Troubleshooting Tablet Inspection Machine

Whenever you’ll be using tablet inspection equipment, you may encounter some challenges.

This section focuses on some of the most common challenges and how to solve them.

 Flow of tablet inspection process

Flow of tablet inspection process

 I. Abnormal noise or vibration

A tablet inspection machine has moving parts joined together with bolts or any other fastening method.

To correct this, you should grease all moving parts and confirm in case there are any detached bolts.

Use the appropriate device to tighten the bolts.

Furthermore, you should confirm if the driving systems are in the right positions.

Check if there is proper meshing of the gears and ensure you accurately fix the conveyor belts.

II. Machine fails to vibrate even after powering it on

This issue could be because of poor connection between the plug and the electric outlet.

Additionally, any disconnected cables or loose connections could be the origin.

You need to use an appropriate electric instrument to tests continuity.

To correct this problem, connect any unlinked cables.

Nevertheless, if all these fail to work, you ought to contact your tablet inspection machine supplier.

III. Tablets dropping into the vibratory dust-collecting plate

This occurs if either the feeding system or the discharge chute is loose. Moreover, it may be because of a dislodged part.

You solve this problem by fastening loose parts or checking and adjusting the dislodged components.

IV. Motor Vibrates

  • Motor misaligned to load – You correct this by realigning the load.
  • Load out of balance – Detach the motor from the load and examine the motor.

Confirm that the shaft of the motor is not bent.

  • Defective motor bearings – Assess the motor by itself. If it has faulty bearings, you will feel roughness or hear noises.
  • Load too light (single phase motors only) – The motor vibrating at a light load is normal.

Consider changing to a smaller load when the vibration is excess.

  • Defective winding – Check the winding for open or shorted circuits.

The amps may as well be high. For faulty winding, change the motor.

  • High voltage – Examine the power supply to make sure there is correct voltage.

V. Incorrect tracking of the conveyor belt

This may be due to off-center or incorrect loading of the conveyor belt.

Make sure that the tablets flowing down the vibrator plate are facing the direction to which the conveyor belt is moving.

It can also be because of differences in the nature and arrangement of the load at the point of load.

Utilize a notched/deflector chute to cause the load peak as near to the center of the belt as possible.

Features and Technical Specifications of Tablet Inspection Machine

Are you planning to buy a tablet inspection machine?

Well, here are some important aspects you should consider:

Characteristic Features of Tablet Inspection Equipment

  • The tablet inspection machine ensure customer fulfillment with 100% quality assurance
  • Elimination of production problems with defective batch inspection
  • The tablet inspection machine has speed of up to 300, 000 tablets per hour
  • Complete and excellent surface inspection for all sort of defects
  • Suitable for all shapes consisting of round, triangular, oval, among others.
  • Designed with open architecture for trouble-free handling, cleaning, and line clearance
  • Superior quality inspection for all types of defects
  • A compact-sized tablet inspection machine that complies to international electrical safety standards
  • A cGMP based machine manufactured using stainless steel material
  • No change parts needed for any tablet size or shape
  • Easy installation using specially designed tools for a variety of tablets
  • Fast and effective cleaning using some of the top quality cleaning agents available
  • Suitable for tablets of all kind
  • Good quality food grade substances utilized for rubber and plastic parts
  • Maintenance-free components utilized for the reduction of downtime and optimization of output
  • Wholly illuminated inspection area for stain-free operation
  • Top face inspection for cracked or excess defects.
  • Rejection of all undesirable materials that needs to be removed
  • Complete and easy remedy for all types of tablet inspection

Technical Specifications of Tablet Inspection Equipment

 

 

ApplicationInspection of small and medium-sized tablets.
Production SpeedInfinitely adjustable.
OutputUp to 50 kg tablets, based on product and product size
Feed hopper30 L,
Electrical Connection220V/50Hz, single phase
110V/60Hz. single phase
Power Output0.6 kw
Compressed Air0.6 MPa
Dimensions1850 x 850 x 1315 mm
Weight150kg

How to Select Tablet Inspection Machine

You should choose a machine that meets international regulations standards and complies with Good Manufacturing Practices Guidelines.

Nonetheless, you should carefully consider additional selection criteria if you are to achieve all of the operational benefits highlighted in the proceeding section of this article.

The finest tablet inspection equipment recognizes the tiniest differences in color, size, and shape to make sure each tablet adheres to product specifications.

Furthermore, the system should provide ultra-high resolution (0.17 mm square pixels).

With such resolution, it is possible to detect and eliminate foreign products as well as the slightest defects in color and shape.

Tablet inspection machine

Tablet inspection machine

Tablet inspection machines with four cameras positioned both above and underneath the tablet stream to inspect the products from all sides are best for 100 percent inspection.

Such systems are presently available to examine up to a million tablets per hour.

Moreover, the effectiveness of the tablet inspection machine not only depends on the hardware but also on the software.

These are the algorithms that handle raw data and group information depending on the customer-established accept/reject thresholds.

The art and science of image analysis depends on creating computerized systems.

Of course, those that enhanced the efficiency of the tablet inspection process while offering simple user-interface to the employee.

Thus, you should as well consider the experience and success of the supplier with inspection machines for the pharmaceutical sector and tablets in particular.

This is a crucial indicator of their capability to deliver tablet inspection machine that will attain optimal performance.

The tablet inspection systems manufacturer should be able to help with the development and implementation of the needed qualification protocols.

They should as manufacture inspection machines that comply with most international standards and GMP requirements.

Moreover, it is essential to factor in the level of service a producer can offer in your area – from engineering to verification and after-sales support.

Conclusion

With the automation in tablet inspection, pharmaceutical manufacturers and packers are able to offer tablets with appropriate quality guarantee.

Automatic tablet inspection system may appear costly than the manual inspection type.

However it is a one-off expense and offers more accuracy than the manual tablet inspection machine.

Understanding all the advantages of automation, pharmaceutical manufacturers are now making upgrades and they should complete the automation in the next few years.

I believe the information provided in this article will help in making the right decision while shopping for a tablet inspection machine.

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