A molding device, comprisi ng: a mold, having a mold cavity, a feeding port in communication with the mold cavity; and a pressure regulating system, including: a first gas conduit, in communication with the mold cavity; a first valve, disposed at the first gas conduit and configured to control gas injection from a gas source through the first gas conduit to the mold cavity; a pressure sensing unit, configured to sense the pressure within the mold cavity; a second gas conduit, in communication with the mold cavity; and a second valve, disposed at the second gas conduit, configured to control the discharging of gas out of the mold cavity, wherein the mold further includes an inner sidewall, an inner top wall, and an inner bottom wall opposite to the inner top wall defining the mold cavity, said feeding port is disposed at the inner top wall, said second gas conduit is configured to discharge gas from the mold cavity, and said inner sidewall of the mold cavity has a junction point, wherein the first gas conduit is in communication with the mold cavity via the junction point, characterized in that said first gas conduit is in communication with the mold cavity through a plurality of first pores disposed at the mold; said second gas conduit is in communication with the mold cavity through a plurality of second pores disposed at the mold; a number of the plurality of second pores is substantially greater than number of the plurality of first pores. a mold, having a mold cavity, a feeding port in communication with the mold cavity; and a pressure regulating system, including: a first gas conduit, in communication with the mold cavity; a first valve, disposed at the first gas conduit and configured to control gas injection from a gas source through the first gas conduit to the mold cavity; a pressure sensing unit, configured to sense the pressure within the mold cavity; a second gas conduit, in communication with the mold cavity; and a second valve, disposed at the second gas conduit, configured to control the discharging of gas out of the mold cavity, a first gas conduit, in communication with the mold cavity; a first valve, disposed at the first gas conduit and configured to control gas injection from a gas source through the first gas conduit to the mold cavity; a pressure sensing unit, configured to sense the pressure within the mold cavity; a second gas conduit, in communication with the mold cavity; and a second valve, disposed at the second gas conduit, configured to control the discharging of gas out of the mold cavity, wherein the mold further includes an inner sidewall, an inner top wall, and an inner bottom wall opposite to the inner top wall defining the mold cavity, said feeding port is disposed at the inner top wall, the mold further includes an inner sidewall, an inner top wall, and an inner bottom wall opposite to the inner top wall defining the mold cavity, said feeding port is disposed at the inner top wall, said second gas conduit is configured to discharge gas from the mold cavity, and said inner sidewall of the mold cavity has a junction point, wherein the first gas conduit is in communication with the mold cavity via the junction point, said first gas conduit is in communication with the mold cavity through a plurality of first pores disposed at the mold; said second gas conduit is in communication with the mold cavity through a plurality of second pores disposed at the mold; a number of the plurality of second pores is substantially greater than number of the plurality of first pores.