Production of smart dies and molds using direct metal deposition

• US 6,937,921 B1
• Filed: 03/16/2000
• Issued: 08/30/2005
• Est. Priority Date: 06/30/1998
• Status: Expired due to Term

• Current Assignee: DM3D Technology, LLC
• Original Assignee: Precision Optical Manufacturing
• Inventors: Mazumder, Jyoti
• Primary Examiner(s): Picard, Leo
• Assistant Examiner(s): Rapp, Chad
• Application Number:
  US09/526,631
• Time in Patent Office: 1,993 Days
• Field of Search: 700/166, 700/123, 700/109, 700/119, 700/182, 700/219, 700197-205
• US Class Current: 700/166
• CPC Class Codes: B23K 26/032 using optical means
• CPC Class Codes: B23K 26/034 Observing the temperature of the workpiece
• CPC Class Codes: B23K 26/34 Laser welding for purposes other than joining

Abstract

A laser-aided, direct metal deposition (DMD) fabrication process is used for dies and molds having integrated sensors for monitoring and controlling characteristics that determine the quality of an article being processed. A method of fabricating such devices, as well as the “smart” devices themselves are disclosed. A system of manufacturing articles uses smart dies or smart molds so that various characteristics that affect the quality of the finished article are monitored during the die-forming or injection-molding process. The sensors, which are an integral part of the product-shaping devices, include simple thermocouples for measuring the temperature in various locations, as well as piezoelectric sensors and strain gages to monitor the build-up of stress and strain history caused by fluctuations in temperature during the fabrication process. This information is transmitted to a computer, where it is analyzed or compared with standardized histories obtained either through calibration experiments or through theoretical calculations.

Claims

1. Product-fabrication apparatus, comprising:

a body constructed using a direct metal deposition process of a type wherein material layers are added in controlled succession, the body including a product shaping or forming portion, and a surrounding portion, the surrounding portion including;

a) a plurality of integrated sensors, each outputting an electrical signal which is a function of temperature, and

b) integral cooling channels having at least one inlet and one outlet for a flow of a coolant,

a plurality of integrated sensors, each outputting an electrical signal which is a function of strain.

2. The apparatus of claim 1, wherein at least one of the strain sensors is embedded within the surrounding portion.

3. The apparatus of claim 1, wherein at least one of the strain sensors is fabricated during the fabrication of the body using the direct metal deposition process.

4. An automated system for real-time monitoring and controlling the temperature of an article during its fabrication, the system comprising:

product-shaping apparatus, including;

a body constructed using a direct metal deposition process of a type wherein material layers are added in controlled succession, the body including a product shaping or forming portion, and a surrounding portion, the surrounding portion including;

a) a plurality of integrated sensors, each outputting an electrical signal which is a function of temperature, and

b) integral cooling channels having at least one inlet and one outlet for a flow of a coolant;

an electronic flow meter operative to adjust the inlet coolant flow by receiving a signal input from a feedback controller; and

a computer receiving the outputs from the temperature sensors and interfacing with the feedback controller, the controller operating to adjust the temperature of the coolant by sending signal input to the flow meter.

5. An automated system for real-time monitoring and controlling the temperature, distortion and stress accumulation of an article during its fabrication, the system comprising:

product-shaping apparatus, including;

a body constructed using a direct metal deposition process of a type wherein material layers are added in controlled succession, the body including a product shaping or forming portion, and a surrounding portion, the surrounding portion including;

a) a plurality of integrated sensors, each outputting an electrical signal which is a function of temperature;

b) a plurality of integrated sensors, each outputting an electrical signal which is a function of strain;

c) a plurality of integrated sensors, each outputting an electrical signal which is a function of stress, and

d) integral cooling channels having at least one inlet and one outlet for a coolant, and

an electronic flow meter operating to adjust the inlet coolant flow by receiving a signal input from a feedback controller; and

a computer receiving the outputs from the temperature sensors, the stress sensors and the strain sensors, the computer interfacing with the feedback controller, the controller operating to adjust the temperature of the coolant by sending signal input to the flow meter, and operating to control the product-shaping process.

6. A method of fabricating a product, comprising the steps of:

providing a computer database describing a product including one or more integrated sensors, each outputting an electrical signal indicative of a fabrication parameter; and

fabricating the product using a laser-aided, computer-controlled direct metal deposition process in accordance with the computer database description.

7. The method of claim 6, wherein at least one of the sensors is a thermocouple.

8. The method of claim 6, including one or more sensors for monitoring temperature, stress and strain.