One and a half month ago I purchased a 3500mW laser from Eleksmaker store in banggood.com
A week ago I finally found the time to test it. The laser module is deficient.
The laser's beam shape is not dot as mentioned in the description but it produces a noticeable thick line around the dot. When I tested the laser on black paper the hole that was created was not round. It was rather oval shaped. Check the pictures below.
Altering the focus lens did not fix the problem. After checking the laser with a microscope I noticed that a very small metal surface under the inner lens is interrupting the laser's beam at its output. Apart from that, the laser entirely stopped functioning after five minutes at the ON state. The onboard led was ON (not blinking) , the fan was active but the laser suddenly turned OFF.
I payed 70 Euros for this laser and nobody replies to my review! I hope I find better attitude here
I must find a solution fast