Hardness Testers

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Hardness of any material is one of the most important parameter in the quality control. Here I attempt to compare certain hardness testers which are generally used.

Table 1: Comparative study of hardness tester for different materials

Hardness tester1-3



Working principle


Types of materials used for testing



Fig 1

Carbide ball

Brinell hardness number is a function of test force divided by curved surface area of indent

Used on almost any metallic material

All kinds of metals like iron, steel, aluminium and soft alloys.

500 to 3000 kg with 5 or 10mm carbide balls


Fig 2

Intender used is a diamond cone or steel ball

Indenter moves into position onpart surface.minor load applied & '0' reference taken,then major load is applied

Used on metal samples and hard plastics

Steel, brass, bearing races, plastics



Fig 3

It uses a 136 degrees pyramidal diamond indenter that forms a square indent

Indenter is pressed into sample by an accurately controlled test force for 10-15sec.then indenter is removed leaving square shaped indent on surface

Any metallic material


Micro-10g to 1000g

Macro-1kg to 100kg


Fig 4

Pyramidal diamond point is used as indenter

Testing very thin materials like foils or measuring the surface of a part, small parts or small areas etc

Brittle materials or thin sheets


Table 2: Comparative Study of different hardness testers used to measure tablet hardness

Tablet hardness testers 8-11


Components/ parts

Working principle

Range/ capacity

Oldest (1930)8,9


Screw thread, spring and sliding scale

Force was applied with a screw thread and spring until the tablet is fractured. Hardness was read from a graduated sliding scale in 1/2kg increments.

Spherical tablets.

Scale: o to 20kgs/cm

Strong-Cobb tester(195012

Fig 5

Manually operated air pump is used to generate force

Testing force generated by a manually operated air pump & tablet breaking force was measured on a dial graduated in 30 arbitrary units.


Electro mechanical tester-C5313

Fig 6

Motor driving system, automated fracture detecting and display

A motor driving system is used to generate force and electronics to automate the test procedure, automatically detecting tablet fracture and displaying force in a variety of units.


Pfizer type14

Fig 7

Pair of plairs, handy, direct dial reading

A handy, tough & direct dial reading type tablet hardness tester working as pair of plairs, generates breaking force in single grip.

Max tablet diameter:25mm

Capacity:0 to 20kg


Fig 8

Brass duly, chromium plated

The tablet is placed between the jaws and screw rotated to find the force required to fracture the tablet

Tablet diameter

1st range:0-15mm




1. Hardness testing. http://www.gordonengland.co.uk/hardness/ (accessed on 10 July' 2010)

2. Hardness Test. http://www.instron.us/wa/applications/test_types/hardness/default.aspx?ref=http://www.google.co.in/search (accessed on 10 July' 2010)

3. Cooper D, Carter S. Some information on hardness testing. Engineering systems, 2009.

4. http://www.farasia.com.cn/products/images/ (accessed on 24 July' 2010)

5. http://static.tecquipment.com/Products/MAT10-RAB_ROCKWELL-BRINELL-HARDNESS-TESTER.jpg (accessed on 24 July' 2010)

6. http://www.farasia.com.cn/products/images/ (accessed on 24 July' 2010)

7. http://www.mitsg.com/English/Products/Matsuzawa/Images/MicroHardnessTester/Hardness%20tester%20MMT.jpg (accessed on 24 July' 2010)

8. Remington- The science and practice of pharmacy. Twenty-first Ed, Lipincott Williams and Wilkins, Philadelphia. USA.

9. K. Ridgway. Aspects of pharmaceutical engineering. The Pharmaceutical Journal, Dec 26, 1970.

10. http://catalogs.indiamart.com/products/tablet-hardness-tester.html (accessed on 28 July' 2010)

11. http://catalogs.indiamart.com/products/tablet-hardness-tester.html-monsanto (accessed on 28 July' 2010)

12. www.scilution.com/product_39280_th?lang=en (accessed on 28 July' 2010)

13. http://www.engsys.co.uk/pages/testing.php - C53 (accessed on 28 July' 2010)

14. www.kshitijinnovation.com/pharmacy-equipment.html (accessed on 28 July' 2010)


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About the Author

P.V.ABHIGNA's picture


Santosh kumar. JH's picture

Good comparison and excellent write up... But one thing the use of Images... since according to the instructions regarding book page topic it was said that "Must use your own image/diagrams. Images from other internet sources NOT acceptable though you give reference" [1]... I think it is against the instructions in the mail which we received what would you say?? Can we use images from net for the book pages?? 1. Organizers mail: Pharmainfo NET On Thu, Jun 17, 2010 at 10:29 PM.
P.V.ABHIGNA's picture

Santosh, Thanks for your support and secondly the use of images is allowed with proper reference Regards,


kranthi kumar's picture

Dear Abhigna, This is awesome, the tables and the pictures are good and understandable. Keep it up.
P.V.ABHIGNA's picture

Thank you very much.I jus wanted to make the matter simple to understand. Regards


Ravi Teja Mallela's picture

Its very informative and may i know the procedure how i can submit a presentation


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