Patent ID: 7313944

Claim:
A method for manufacturing unleaky closed containers with at least one flexible wall area, comprising: providing a closed container with at least one flexible wall area; moving a biasing member relatively to, towards and onto said wall area of the closed container; stopping said moving; monitoring a biasing force of said container; sampling said biasing force monitored at a first point in time, resulting in a first force measuring signal; storing said first force measuring signal; sampling said biasing force monitored at at least one second subsequent point in time, resulting in a second force measuring signal; generating a difference signal in dependency of said stored first measuring signal and second measuring signal as leak indicative signal; and wherein said method includes generating a difference signal at said first point in time from said first force measuring signal stored and said first force measuring signal, storing said difference signal as a zero offset signal and compensating zero offset of said generating a difference signal by said stored zero offset signal, and rejecting a container indicated as leaky by said leak indicative signal.