Die condition detection

A method for detecting the condition of a die for deforming material, the die forming part of a die assembly which comprises:

• a die having a stem which defines at least one gas bleed passage, a separable collar, and a first surface defining a die cavity in which material is to be deformed, the die cavity being defined between the stem and collar;
• and
• a die holder in which the die is supported such that the die is operational with the die cavity being exposed for receipt of the material;
• wherein
• a gas passage extends from the die holder into the at least one gas bleed passage, the at least one gas bleed passage being closed by engagement of the collar with the stem;
• wherein
• the stem has a flange on which the collar is supported and the at least one gas bleed passage is defined in the flange;
• the method comprising:
• applying a gas at a pressure and flow rate to the gas passage, detecting a change in at least one of the pressure or flow rate of the gas in the gas passage and determining from the detected change a condition of the die.

A die assembly comprising:

• a die with a head having a first surface defining a die cavity in which material is to be deformed, and a stem extending from the head in a direction away from the die cavity;
• a die holder in which the die is supported such that the die is operational with the die cavity being exposed for receipt of the material, the stem of the die being received in a bore in the die holder;
• and
• a washer disposed between the die head and the die holder, with the stem of the die passing through the washer;
• wherein
• the die assembly includes a gas passage which extends from the die holder, between the stem and the washer and into channels formed between the washer and the die head.

A method for detecting the condition of a die for deforming material, the die forming part of a die assembly which comprises:

• a die with a head having a first surface defining a die cavity in which the material is to be deformed, and a stem extending from the head in a direction away from the die cavity;
• a die holder in which the die is supported such that the die is operational with the die cavity being exposed for receipt of the material, the stem of the die being received in a bore in the die holder;
• and
• a washer disposed between the die head and the die holder, with the stem of the die passing through the washer;
• wherein
• the die assembly includes a gas passage which extends from the die holder, between the stem and the washer and into channels formed between the washer and the die head;
• and wherein
• the method comprises applying a gas at a pressure and flow rate to the gas passage, detecting a change in at least one of the pressure or flow rate of the gas in the gas passage and determining from the detected change a condition of the die.