Injection molding machine and method of operating the same

An injection molding machine comprising:

• a clamp that generates an electromagnetic force and that secures a moving plate or a fixed plate to the clamp using an attractive force that is produced by the electromagnetic force;
• an ejector pin drive mechanism that drives an ejector pin for pushing out a product from the moving plate;
• a pressure sensor that is provided in the clamp, wherein the pressure sensor measures contact pressure that acts between (i) the moving plate or the fixed plate and (ii) the clamp;
• and
• a controller configured to:
• obtain a retaining force of the clamp from the contact pressure that is measured by the pressure sensor, and
• control the ejector pin drive mechanism to control a speed of the ejector pin such that a separation force that acts on the moving plate or the fixed plate is less than the retaining force to prevent detachment of the moving plate or the fixed plate from the clamp, wherein:
• the separation force includes an ejector pin reactive force that is generated in the moving plate when the ejector pin is operated, and
• the controller controls the ejector pin drive mechanism such that the ejector pin reactive force is less than the attractive force.

An injection molding machine comprising:

• a clamp that generates an electromagnetic force and that secures a moving plate or a fixed plate to the clamp using an attractive force that is produced by the electromagnetic force;
• a pressure sensor that is provided in the clamp, wherein the pressure sensor measures contact pressure that acts between (i) the moving plate or the fixed plate and (ii) the clamp, wherein the pressure sensor measures the contact pressure at a specific timing in a molding process;
• and
• a controller configured to:
• obtain a retaining force of the clamp from the contact pressure that is measured by the pressure sensor, and
• output an alarm when the retaining force is less than a reference value for the alarm.

A method of operating an injection molding machine, wherein the injection molding machine comprises a clamp that generates electromagnetic force, a clamping mechanism, and a controller, wherein the clamp secures a moving plate or a fixed plate to the clamp using an attractive force that is produced by the electromagnetic force, wherein the clamping mechanism drives the moving plate, the method comprising the steps of:

• using a pressure sensor to measure contact pressure that acts between (i) the moving plate or the fixed plate and (ii) the clamp;
• using the controller to obtain a retaining force of the clamp from the contact pressure that is measured by the pressure sensor;
• and
• using the controller to control a mold-opening speed of the clamping mechanism such that a separation force that acts on the moving plate or the fixed plate is less than the retaining force to prevent detachment of the moving plate or the fixed plate from the clamp, wherein:
• the separation force includes a mold-opening force that is generated in the moving plate or the fixed plate in a mold-opening step,
• the moving plate has a sliding part that slides relative to the fixed plate and that thereby generates the mold-opening force, and
• the controller is used to control the mold-opening speed of the moving plate such that the mold-opening force is less than the attractive force after a main body of the moving plate is separated from the fixed plate and until the sliding part is separated from the fixed plate.

A method of operating an injection molding machine, wherein the injection molding machine comprises a clamp that generates electromagnetic force, an ejector pin mechanism, and a controller, wherein the clamp secures a moving plate or a fixed plate to the clamp using an attractive force that is produced by the electromagnetic force, wherein the ejector pin mechanism drives an ejector pin for pushing out a product from the moving plate, the method comprising the steps of:

• using a pressure sensor to measure contact pressure that acts between (i) the moving plate or the fixed plate and (ii) the clamp;
• using the controller to obtain a retaining force of the clamp from the contact pressure that is measured by the pressure sensor;
• and
• using the controller to control the ejector pin mechanism to control a speed of the ejector pin such that a separation force that acts on the moving plate or the fixed plate is less than the retaining force to prevent detachment of the moving plate or the fixed plate from the clamp, wherein:
• the separation force includes an ejector pin reactive force that is generated in the moving plate when the ejector pin is operated, and
• the controller controls the ejector pin mechanism such that the ejector pin reactive force is less than the attractive force.

A method of operating an injection molding machine, wherein the injection molding machine comprises a clamp that generates electromagnetic force and a controller, wherein the clamp secures a moving plate or a fixed plate to the clamp using an attractive force that is produced by the electromagnetic force, the method comprising the steps of:

• using a pressure sensor to measure contact pressure that acts between (i) the moving plate or the fixed plate and (ii) the clamp, wherein the pressure sensor measures the contact pressure at a specific timing in a molding process;
• using the controller to obtain a retaining force of the clamp from the contact pressure that is measured by the pressure sensor;
• and
• using the controller to output an alarm when the retaining force is less than a reference value for the alarm.