application

MATERIAL TEST i30

Flexural Strength Test on Automatic Pencil Leads
with Shimadzu Autograph

Consumer goods should, fundamentally, have a certain minimum level of quality and performance appropriate to their respective uses. If consumers buy goods and find them inadequate to their needs in quality and performance, consumer assessment of the products suffers accordingly. Standards of qualities are determined by the Japan Industrial Standards (JIS), which specify the details of respective quality specifications for cooking utensils, furniture, interior goods, footwear, stationery, office supplies and other daily necessities.
The following presents the results of a quality evaluation test performed on stationary using the Shimadzu High Performance Universal Testing Machine, Model Autograph.

Flexural strength test of automatic pencil leads (in accordance with JIS-S-6019)

Ten random samples of each hardness of lead were taken from automatic pencils packaged for retail sale, then tested on a holder with a load applied to the center of the two supports at a loading rate of 1mm/min using the Shimadzu Autograph as shown in Fig.1. The load was measured when the specimens were broken.




Fig.3 shows the results of data processing of flexural strengths calculated from the average of the measured values, excluding the max. and the min. values.

Fig.4 shows the relationship between the hardness and fatigue strengths of leads. Lead strength increases proportionally with hardness from the softest class B to the hardest class H. Hardness class 2H is an exception, where strength falls, supposedly due to the fragility of leads.