Starting and stopping continuous-feed thermomolding machine

A method of starting a continuous-feed thermomolding machine where during normal operation a foil is advanced in a transport direction at a substantially constant travel speed through a heat station where it is exposed to a heat source such that each piece of the foil is exposed in the station for a predetermined residence time that is a direct function of the parameters of travel speed, heat output of the source, and length in the direction of the station, the starting method comprising the steps of:

• while the foil is stopped, positioning a shield so that it is stationary and extends the length of the station between the foil and the source, whereby substantially no heat is imparted to the foil from the source;
• and thereafter accelerating the foil to the travel speed while simultaneously and synchronously accelerating the shield opposite to the travel direction such that, as the shield fully retracts from the station, the foil reaches the travel speed and, before the shield has fully retracted from the station, every piece of the foil in the station exposed by the retracting shield is exposed to the source for the residence time.