LONDON-A new ultrasonic tire testing system, called Tyrescan, has received the support of the United Kingdom's Retread Manufacturers' Association. The association helped develop the Tyrescan system-produced by Technic Systems Ltd., a small U.K. firm-and is recommending the unit's use to its members.
Ultrasonic tire testing is not new, of course. Existing ultrasonic tire testers include Bandag Inc.'s NDI system and Oliver Rubber Co.'s Tuff Scan system. But their results sometimes are hard to interpret, Technic Systems said.
The manufacturer added that Tyrescan's novelty is that it offers a practical, easy-to-use imaging system at moderate cost. The unit turns ultrasonic data into a clear image of the tread. Each successive scan shows on screen as a section of tread in a grey pattern. Defects appear in red.
Tyrescan can be used for checking both retreadable casings and finished retreads.
The system works by locating air gaps resulting from defects-such as improper curing, casing separations or improperly bonded tread. It also identifies rusty cords, the manufacturer said.
The ``main problem with remolds is separation in the belt package at the top of the tire,'' said John O'Connell, managing director of the British retreading firm, Bandvulc Ltd. Ultrasonic testing, ``tells us what we need to know,'' he said.
Other tests-holography and shearography-are expensive, ``relatively slow and not easy to interpret,'' according to Mr. O'Connell. They're not appropriate for quality control of casings in a retread shop, he said.
X-ray analysis is not useful in finding the type of casing defects that cause retreading problems, according to David Brooks, technical executive for the British retreaders association. It will identify fractures and kinks in the wire but not any trapped air.
Mr. O'Connell expressed surprise that the system isn't more widely used by retreaders.
Technic Systems has retained McNeil & NRM Inc. of Akron to act as its sales agent in North and South America.