HAMMERHEAD
Die Grinder Redesign: Rotary Tool
Applied Ergonomics in User-Centered Design
The scope of this project was to redesign an existing die grinder after a one week trial of use. The key was to identify the areas of improvement after having performed an assessment about its ergonomic properties. For this purpose, the DeWalt DWE4887N 1-1/2" Die Grinder was used.
Safety Lock-On Switch.
This emergency button allows the user to quickly cut the power and bring the motion to a halt.
A side button is necessary for preventing accidents. Color contrast plays an important role for this element to be instantly perceived. Its visual dominance allows the user to locate it easily.
Power slider.
The switch works both as a controller and an indicator. Sliding the button forward will display an orange tab that indicates the power tool is off. When pulled backwards, the die grinder is turned on.
A naturally-occurring movement for powering the tool makes it easy to operate. The button is strategically located so the user can rapidly switch between On and Off modes.
Additional handle for extra grip.
Die grinders and rotary power tools exert a great amount of force. Users require proper handling features for reducing the risks caused by poor grip.
Handle diameter recommendations vary. In general, cylindrical handles at 40mm (1.5 in) offer a better power grip, with a range from 30-50mm (1.25 to 2 in). For precision grips, a diameter of 12mm (0.45 in) is recommended, with a range of 8-16mm (0.3 to 0.6 in). The larger diameter will allow for maximum torque, while the smaller diameter helps with dexterity and speed.
Safety features
An orange caution-line on the front end is a visual warning that prevents the user from placing his hands beyond the border.
Physical affordances are key for communication how the tool should be used. Placing fingers on this line will power off the tool.
Safe Materials.
To ensure a good grip on a handle, sufficient friction must exist between the hand and the handle.
This is non-slip, non-conductive rubber handle provides a good grip and reduces the effort needed to use the tool effectively.
The semi-matte coating has a grainy texture to avoid slippage. The steel and aluminium body ensures a sturdy and long-lasting equipment.
