The structure of the pendulum impact tester and hammer is an important consideration. Instron’s pendulums come with dedicated energy hammers. Others require you to add/remove weights to reach the desired capacity. The latter tend to be less safe and efficient due to various reasons:
Handling weights can lead to musculoskeletal disorders as well as hand injuries.
Weights may fall and damage the pendulum, which can affect test repeatability.
Having to add/remove weights typically leads to downtime.
When choosing dedicated energy hammers, design is paramount. Bolted models may become loose after repeated testing, which can affect repeatability.
The pendulum frame is another important consideration. Some pendulum models have dedicated frames for different hammer capacities. Every time you switch hammer, you must change the frame too, which can contribute to downtime.
All Instron pendulum testers feature a solid monolithic hammer structure and monolithic cast iron frame. This design can go a long way towards minimizing vibrations, helping maximize test repeatability. Not only that. The test setup process is faster as the frame is compatible with multiple hammers.