Samsung A3. Clock alarm only sounds for 1/2 second when phone is charging

[AC Question]

I charge my phone at night but the swipe screen appears to stop the clock alarm from sounding. It sounds for about 1/2 second if I hear it and swipe the screen then the alarm will continue to ring. Trouble is I don't always hear it. Can I get rid of the swipe screen. I already have security set at none