Ford investigates surface defects not seen by the naked eye

(October 13, 2011) COLOGNE, Germany —The surface of an alien planet or a drop of oil? A piece of abstract art or a close-up look at the smallest details on a metal surface? The hugely magnified images produced by Ford’s Scanning Electron Microscope, as the company’s engineers develop new parts, can often make seemingly everyday objects look a world apart from that which the naked human eye can see.

“We need to investigate possible reasons why a development part may not meet our stringent requirements,” said Roger Davis, materials engineering and testing, Ford of Europe.

“In some cases that reason can be the smallest anomalies, something that can be found by using the Scanning Electron Microscope. The machine can magnify a part by up to 200,000 times and make it look quite surreal, but to the trained eye any defects become quickly apparent at these levels of magnification.”

A droplet of water caught on a leaf. Try thinking more than 1,000 times smaller and you can understand how tiny this rogue steel hemisphere is (2µm = two thousandths of a millimeter)

The SEM works by creating magnified images using electrons rather than light waves, which results in highly-detailed, three-dimensional representations. They are achieved by putting samples into the microscope’s vacuum column through an air-tight door (these conditions being crucial as electrons do not travel well through air). The sample part is then subjected to an electron beam that is pulled back and forth across its surface by a series of electromagnetic coils.

That electron beam effectively bounces off the face of the sample resulting in reflected electrons that are directed to something similar to a traditional cathode-ray TV screen. It is on this screen that the often incredible image of the magnified part is created.

While the end results make for impressive viewing to most people, they are a valuable source of information for the engineers who capture them. Only by examining parts at this ultra-microscopic level can Ford’s materials specialists spot the smallest of anomalies and allow the development engineers to take appropriate action.

This attention to detail naturally benefits the customer, who can rest assured that every part of a Ford vehicle will have been examined to levels far beyond the scope of the naked human eye, during the development phase of the vehicle’s design. This happens well before anyone gets behind the wheel.