Expressing purpose with to and for

Use to to explain why

We don’t use for -ing to explain the reason or cause behind something.

Example

• I work hard for improving my English. ❌
• I work hard to improve my English. ✅
• Turn the TV on for watching the news. ❌
• Turn the TV on to watch the news. ✅

Use to and for to show purpose or function

Both to + infinitive and for -ing describe an object’s function (the purpose or intended use of an object).

Example

• This machine is used for cleaning cars.
• This machine is used to clean cars.
• This is a special camera for photographing small objects.
• This is a special camera to photograph small objects.

References

• https://test-english.com/grammar-points/a2/purpose-to-for/