High-speed polymer-to-metal direct joining system and method

Patent metadata

Field	Value
Publication number	US-11396139-B2
Application number	US-202016856534-A
Country	US
Kind code	B2
Filing date	Apr 23, 2020
Priority date	May 22, 2019
Publication date	Jul 26, 2022
Grant date	Jul 26, 2022

Abstract

A method of directly joining a polymer to a metal along a joint interface through the formation of C—O-M chemical bonds, where M represents an element in the metal to be joined. The method includes heating the metal to a predetermined temperature above a glass transition temperature of the polymer and less than a flash ignition temperature of the polymer and less than a metal melting temperature of the metal; physically contacting at least one of the metal and the polymer; and applying compression pressure to the joint interface of the metal and the polymer when the metal is above the glass transition temperature of the polymer and less than the flash ignition temperature of the polymer and less than the metal melting temperature of the metal to generate intimate atomic contact between the metal and the polymer to create C—O-M chemical bonds between the metal and the polymer.

First claim

What is claimed is:

1. A method of directly joining a polymer to a metal along a joint interface through the formation of C—O-M chemical bonds, where M represents an element in the metal to be joined, the method comprising:
heating the metal to a predetermined temperature above a glass transition temperature of the polymer and less than a flash ignition temperature of the polymer and less than a metal melting temperature of the metal;
physically contacting at least a portion of a surface of the metal;
applying compression pressure to the joint interface of the metal and the polymer when a temperature of the metal is above the glass transition temperature of the polymer and less than the flash ignition temperature of the polymer and less than the metal melting temperature of the metal, the step of applying compression pressure to the joint interface of the metal and the polymer generating intimate atomic contact between the metal and the polymer to create the joint interface comprising substantially C—O-M chemical bonds between the metal and the polymer; and
reducing the temperature of the metal below the polymer melting temperature before 5% of the polymer has pyrolyzed.

2. The method according to claim 1 further comprising forming distributed air pockets between the metal and the polymer for forming three-dimensional distributed C—O-M chemical bonds at the joint interface.

3. The method according to claim 2 wherein the step of forming distributed air pockets comprises forming distributed air pockets by forming three-dimensional surface features, grooves, or protrusions on the surface of the metal prior to the step of applying compression pressure.

4. The method according to claim 3 further comprising forming the three-dimensional surface features, grooves, or protrusions using at least one of a mechanical engraving system, an electron beam, a chemical agent, and an electrical discharge system.

5. The method according to claim 2 wherein the step of forming distributed air pockets comprises capturing a porous structure between the metal and the polymer prior to and during the step of applying compression pressure to the joint interface of the metal and the polymer when the temperature of the metal is above the glass transition temperature of the polymer and less than the flash ignition temperature of the polymer and less than the metal melting temperature of the metal.

6. The method according to claim 1 further comprising removing dirt and grease from the surface of the metal prior to the step of applying compression pressure forming the C—O-M chemical bonds at the joint interface.

7. The method according to claim 1 wherein the step of heating and the step of applying compression pressure are achieved using a unitary system.

8. The method according to claim 1 wherein the step of heating and the step of applying compression pressure are achieved using discrete systems.

9. The method according to claim 1 wherein the step of applying compression pressure to the joint interface of the metal and the polymer comprises applying compression pressure perpendicularly to the joint interface of the metal and the polymer.

10. The method according to claim 1 wherein the applying compression pressure to the joint interface of the metal and the polymer comprises applying compression pressure at an inclined angle relative to the joint interface of the metal and the polymer.

11. The method according to claim 1 wherein the step of heating the metal comprises heating the metal by thermal heating, induction heating, frictional heating, a high-rate plastic deformation heating, electric resistance heating, or high-energy beam heating.

12. The method according to claim 1 wherein the step of applying compression pressure is completed in sequence after the step of heating the metal to the predetermined temperature.

13. A method of directly joining a polymer to a metal along a joint interface through the formation of C—O-M chemical bonds, where M represents an element in the metal to be joined, the method comprising:
heating the metal to a predetermined temperature above a glass transition temperature of the polymer and less than a flash ignition temperature of the polymer and less than a metal melting temperature of the metal;
physically contacting at least one of the metal and the polymer;
applying compression pressure to the joint interface of the metal and the polymer when the metal is above the glass transition temperature of the polymer and less than the flash ignition temperature of the polymer and less than the metal melting temperature of the metal, the step of applying compression pressure to the joint interface of the metal and the polymer to generate intimate atomic contact between the metal and the polymer to create substantially C—O-M chemical bonds along the joint interface, the C—O-M chemical bond being formed from a carbonyl group (C═O) within the polymer; and
reducing the temperature of the metal below the polymer melting temperature before 5% of the polymer has pyrolyzed.

14. The method according to claim 13 wherein the step of heating and the step of applying compression pressure are achieved using a unitary system.

15. The method according to claim 13 wherein the step of heating and the step of applying compression pressure are achieved using discrete systems.

16. The method according to claim 13 wherein the step of applying compression pressure to the joint interface of the metal and the polymer comprises applying compression pressure perpendicularly to the joint interface of the metal and the polymer.

17. The method according to claim 13 wherein the applying compression pressure to the joint interface of the metal and the polymer comprises applying compression pressure at an inclined angle relative to the joint interface of the metal and the polymer.

18. The method according to claim 13 wherein the step of heating the metal comprises heating the metal by thermal heating, induction heating, frictional heating, a high-rate plastic deformation heating, electric resistance heating, or high-energy beam heating.

19. The method according to claim 13 wherein the step of applying compression pressure is completed in sequence after the step of heating the metal to the predetermined temperature.

Assignees

• Univ Michigan Regents

Inventors

• Liu Fengchao
• Dong Pingsha

Classifications

• B29C65/46

  heated by induction · CPC title

• B29C65/0681

  created by a tool · CPC title

• B29C65/1458

  once, i.e. contour welding · CPC title

• B29C65/44

  Joining a heated non plastics element to a plastics element · CPC title

• B29C66/028

  Non-mechanical surface pre-treatments, i.e. by flame treatment, electric discharge treatment, plasma treatment, wave energy or particle radiation (B29C65/14 takes precedence; non-mechanical surface treatment of plastics in general B29C59/08 - B29C59/16) · CPC title