Bank quantity monitoring method and apparatus, sheet forming method and apparatus, and sheet temperature measuring method and apparatus

An apparatus for monitoring a quantity of bank in a sheet forming machine which comprises an extruding machine for feeding a plastic material controlled at a predetermined temperature, a flat die connected to the extruding machine and having a slit outflow portion through which the plastic material is fed in sheet shape, a pair of forming rolls arrayed substantially in parallel with each other with a predetermined gap therebetween for pressing and forming the plastic material sheet and a control unit for controlling the operation of the extruding machine, the flat die and the forming rolls, and in which a plastic material with a controlled predetermined temperature is fed through the flat die, the plastic material being formed on an upstream side of the gap between the forming rolls and the plastic material being then fed to a downstream side of the gap, the apparatus comprising:

• means for measuring a temperature of the plastic material sheet passing through the gap between the forming rolls;
• means for calculating the quantity of the bank in response to information of the measured temperature from the temperature measuring means and a relationship between the measured temperature information and the quantity of the bank which is stored in a control unit;
• and
• means for displaying information of the quantity of the bank inputted from the calculating means.

A method of forming a sheet by utilization of a sheet forming machine including an extruder, a flat die and a pair of forming rolls, comprising the steps of:

• setting a thickness working as a forming target of a sheet to be formed;
• initiating a supply of a plastic material from the extruding machine and a gap of the pair of forming rolls for forming an initial sheet according to the set thickness;
• feeding the plastic material to the gap between forming rolls from the flat die connected to the extruding machine and having a slit outflow portion, pressing and forming the plastic material on the forming rolls therebetween as forming a bank of the plastic material on an upstream side of the gap between the forming rolls and feeding the plastic material to a downstream side of the gap as a sheet;
• initiating a rotational speed of the forming rolls according to a mean thickness of the initial sheet;
• measuring a temperature of the sheet fed through the gap of the forming rolls;
• and
• adjusting a mechanism for adjusting a distribution of flow running breadthwise which is provided at least near an outflow portion of the flat die so as to adjust the measured temperature information to a predetermined value corresponding to a desired quantity of the bank, thereby adjusting the quantity of the bank.

A method of measuring a temperature of a sheet carried out in a sheet forming machine which comprises an extruding machine for feeding a plastic material controlled at a predetermined temperature, a flat die connected to the extruding machine and having a slit outflow portion through which the plastic material is fed in sheet shape, a pair of forming rolls arrayed substantially in parallel with each other with a predetermined gap therebetween for pressing and forming the plastic material sheet and a control unit for controlling the operation of the extruding machine, the flat die and the forming rolls, and in which a plastic material with a controlled predetermined temperature is fed through the flat die, the plastic material is formed in a sheet by forming a bank of the plastic material on an upstream side of the gap between the forming rolls and the plastic material being then fed to a downstream side of the gap, the method comprising the steps of:

• providing a non-contact type temperature measuring means;
• directing the non-contact type temperature measuring means against an inner portion of a wedge-shaped space formed by a surface of the sheet fed through the gap between the forming rolls and surfaces of the forming rolls facing on the surface of the sheet with a gap therebetween;
• and
• measuring a temperature of the sheet fed through the gap between the forming rolls.

An apparatus for measuring a temperature of a sheet in a sheet forming machine which comprises an extruding machine for feeding a plastic material controlled at a predetermined temperature, a flat die connected to the extruding machine and having a slit outflow portion through which the plastic material is fed in sheet shape, a pair of forming rolls arrayed substantially in parallel with each other with a predetermined gap therebetween for pressing and forming the plastic material sheet and a control unit for controlling the operation of the extruding machine, the flat die and the forming rolls, and in which a plastic material with a controlled predetermined temperature is fed through the flat die, the plastic material is formed in a sheet as forming a bank of the plastic material on an upstream side of the gap between the forming rolls and the plastic material is then fed to a downstream side of the gap, the apparatus comprising:

• a non-contact type temperature measuring means disposed on a downstream side of the forming rolls;
• and
• means for supporting the non-contact type temperature measuring means to face on an inner portion of a wedge-shaped space formed by a surface of the sheet fed through the gap between the forming rolls opposite to the surface of the sheet with a gap therebetween and for scanning the non-contact type temperature measuring means on portions to be measured along the gap.