Japan’s reputation for manufacturing prowess has just taken another hit, as Mitsubishi Materials admitted this week that it falsified data on some products just weeks after a similar scandal engulfed Kobe Steel.

Buyers of Japanese industrial goods from Boeing to Airbus were once again scrambling to confirm whether safety had been compromised after Mitsubishi Materials said three of its units had faked data on products that might have been delivered to more than 250 customers. Its shares plunged as much as 11 percent in Tokyo, the most in 18 months.

Mitsubishi Cable Industries falsified data on rubber seals, while Mitsubishi Shindoh misreported the strength of metal strips for auto parts, according to a statement Thursday. The products might have been shipped to 229 Mitsubishi Cable clients, in industries ranging from aerospace to electric power, and 29 customers of Mitsubishi Shindoh. The two subsidiaries accounted for about 12 percent of total revenues in the year ended in March.

A third unit, Mitsubishi Aluminum, also supplied products that didn’t meet standards, although it has already told customers that the products are safe, the company said, adding that its investigation hasn’t uncovered any cases that raise the possibility of legal violations or safety issues.

The revelation is the latest in a series of scandals to dent the image of Japanese manufacturers and echoes closely the admissions by Kobe Steel that it falsified data on the strength and durability of its products. In the auto sector, Nissan has said it conducted vehicle inspections that didn’t comply with regulations for almost four decades, while Subaru allowed uncertified workers to inspect vehicles before shipment. Takata filed for bankruptcy earlier this year because of faulty airbags.

Mitsubishi Materials president Akira Takeuchi told a briefing in Tokyo Friday that the company didn’t disclose the problem when it reported earnings earlier this month because it wanted to find all of the customers affected. Takeuchi also said he won’t quit because of the misconduct.

‘‘My duty is to instruct and supervise the investigation of the causes, and to take preventive measures swiftly,’’ he said. The company will update on its probe by the end of the year, executive vice president Naoki Ono said.

According to the statement, Mitsubishi Cable uncovered the falsification in February and stopped shipping affected products on Oct. 23; the company told its parent two days later. Mitsubishi Shindoh found out about its problem in October and stopped shipments on Oct. 18, alerting Mitsubishi Materials the following day.