Apple is adding a new American titanium supplier for its new iPhone Duo models, and is also expanding the local production of 18 Pro related components, as part of the company's efforts to increase manufacturing within its home country.

Apple stated on Tuesday that it will invest up to $100 million over the next three years in Perryman Company located in Houston, Pennsylvania, for the production of titanium materials used in Apple products, including the $1,999 folding model Duo.

Since the beginning of U.S. President Donald Trump's second term, Apple has publicly stated that it will increase its investments in the United States, although the final assembly of most of its iPhone products is still carried out overseas. Last August, Apple launched the "Made in America" program ( AMP ), increasing its domestic spending plan by another $100 billion to a total of $60 billion. Tim Cook, Apple's then CEO, attended the relevant announcement event at the White House, where Trump was urging this iPhone manufacturer and other tech giants to expand production in the United States.

As the latest announcement is released, Apple is facing severe supply constraints with its first foldable phone, which will go on sale in stores on Friday.

Morgan Stanley stated that on the first day of pre-orders, the delivery time for some Duo models online had been extended to about 14 weeks, which is the longest waiting time recorded by the institution in over a decade for this particular model. Apple said on Friday that the demand for pre-orders "far exceeded expectations," but has not yet indicated whether they plan to increase production.

JPMorgan analysts estimate that due to supply constraints, Apple will ship around 8 million to 9 million Duo this year, which is lower than the previous forecast of about 10 million units. Apple has not stated whether the agreement with Perryman will increase short-term production capacity.

Perryman will smelt, forge, and roll grade 5 titanium, with Apple stating that at least 80% of it will be made from recycled materials. Apple claims that the titanium is used for the casing of Duo to provide durability.

In addition to the announcement regarding Perryman, Apple also stated on Tuesday that it is expanding its collaboration with Qnity Electronics, which is headquartered in Delaware. The latter will produce advanced films for iPhone's 18 Pro variable aperture camera system. This feature allows the phone's main camera to adjust the amount of light entering the lens according to environmental conditions, thereby giving users better control over the amount of light and depth of field.

Apple stated that nearly 100 components used in iPhone, Duo, iPhone, and Pro are produced by American companies and are distributed across more than a dozen states.

Apple's Chief Operating Officer, Sabih Khan, stated in a statement: "We are delighted to continue working with companies that produce advanced materials and components in the United States to support our latest iPhone product line."

Apple also emphasized investments in collaboration with other AMP partners, including Broadcom, which manufactures chips for the United States; Corning, which provides specialty glass for iPhone and Apple Watch; and Amkor, which is building a semiconductor packaging and testing factory in Pioria, Arizona.

For Duo, the outside world is still concerned about whether Apple will be able to produce enough phones to meet demand, as this phone faced an exceptionally long waiting time before it was released to the market.

—— CNBC's Kif Leswing contributed to this report