MATERIAL ONTO A METAL-POLYMER INTERFACE

DESCRIPTION

OBJECT OF THE INVENTION

It is the object of the present invention, as the title of the invention establishes both a device and a system for injecting a reinforcement filler material onto a metal-polymer interface, particularly using frictional heating and injection of consumable reinforcement materials (polymeric or metallic), reinforcement solutions and/or polymeric matrix composites.

Embodiments of the invention include friction-based fabrication tooling comprising a non-consumable member with a throat and a consumable member disposed in the throat, wherein consumable filler material is capable of being introduced to the throat in a continuous manner during injection or deposition using frictional heating and compressive/shear loading of the reinforcement filler material onto the metal-polymer interface.

The device is operably configured for applying a force or displacement to the reinforcement filler material during deposition. Especially preferred embodiments can include using various polymers and reinforcement powder- type consumable materials or combinations during the injection process to obtain a continuous compositional gradient in the filler material yielding a composite, simple or functionally graded joint at interface of metals and polymers.

BACKGROUND OF THE INVENTION

The recent increase in decreasing energy consumption has caused Metal- polymer structures combined were considered for the production of lightweight frames. The metal-polymer arrangements are in the attention of various engineering companies like automobile, railway, and aero industries. Combining mechanical, chemical, and physical properties of metallic materials and polymeric materials can decrease the weight of various engineering structures. In transport structures, lower weight decreases fuel usage during working time, and this issue helps to environmental problems and the costs that customers pay for their services.

A big challenge in the manufacturing of metal-polymer structures is the joining of them. Nowadays, it is possible to weld metallic materials and polymeric base materials by introducing a new joining process. One of the most considered for joining polymer-metal structures is friction stir welding (FSW). FSW is a solid- state joining process that has various benefits compared to other welding processes for welding polymers and metals hybrid structures. Friction stir welding is a thermo-mechanical process involving a non-consumable rotating tool that locally softens the underlying material through heat produced by frictional and plastic work.

FSW (friction stir welding) demands high performing machines leading to high processing costs (as compared to typical welding processes). As the stirring material is under a “pasty” state (the material melts rarely), FSW offers higher flexibility concerning the orientation of the weld path, as gravitational effects do not affect it. In this process, the frictional heat rarely increased near the melting point of base materials. For this reason, the researchers calls this solid-state process joining. Usually, the tooling system in this method is provided by a mechanical power transfer system (like a gearbox). It is impossible to join the FSW tooling system to pneumatic, hydraulic, or even belt and pulley. In this system, the permanent continue axial force should be applied to the tool during the joining process. The FSW process's standard mechanical power transfer system are computer numerical control (CNC) robot arms and modified milling machine as FSW machine.

One of the benefits of the FSW process is the joining of metallic materials and polymers. Due to the massive difference between mechanical and chemical materials, welding and joining are complicated and sometimes impossible. Adhesive Bonding, Mechanical Fastening, and laser welding are the most common permanent joining processes for joining metal and polymers. But with the emerging FSW process, a new class of welding processes is available with many benefits and was more effective than others. The metal-polymer joints that were welded by the FSW process had more robust mechanical and chemical properties than other welding processes.

Flowever, one of the most worrisome issues in metal-polymers FSW joining is the degradation of polymer side. Generally, the input heat of the welding area in the FSW process is under the melting point of base materials. Flowever, in the production of metal-polymers hybrid structures, the polymeric side melts and re solidifies. This phenomenon is due to high frictional heat in the metallic side that is more than the melting temperature of the polymeric side. This defect is inevitable, and the sensitivity of this defect in other welding processes is severe.

The production of frictional heat more than melting point of polymeric side causes degradation of the polymers after FSW, which reduces polymers' mechanical, chemical and thermal properties. Due to the type of polymer and metallic materials we expected to join, the degradation could be different. For example, after FSW with hard metal like steels, the polymer side is much weaker than FSW with soft metal like aluminium plates.

Therefore, it is the object of the present invention to create a new joining device or tool integrated within a system which overcomes the drawbacks we have just exposed, namely, degradation of polymer side, high frictional heat in the metallic side that is greater than the melting temperature of the polymeric side, developing the device we proceed to expose and which it is stated in its essentiality in claim one. to increase metal-polymer joint is necessary and exciting for various industries to improve their structures' properties. For this aim, this invention introduced a new solid-state joining process with an advanced and modern mechanism. This process, DESCRIPTION OF THE INVENTION

A device and a system for injecting reinforcement filler material onto a metal- polymer joints is the object of the present invention.

The device allows to develop a new joining process called Fed Friction Stir Processing (FFSP), which is developed on the FSW process and can in-situ injection nano-size materials during the joining of metals and polymers. With FFSW, the wide various metals and polymers can be welded, and different types of nanomaterials can be injected into the interface of base materials.

This invention is highly scalable for nanocomposite joining, coating, and additive manufacturing based on friction stir welding (FSW) processes. With this technique, it is possible to produce high-strength metal-polymer welds and structures (strengths comparable to the raw material's ultimate tensile strength (UTS)). In addition, the inventive nanocomposite structures exhibit superior qualities compared to traditional structures produced by regular FSW. Benefits of the invention include creating substrates and interfaces with little to no porosity, a typical undesirable result of parts prepared using regular FSW in producing metal-polymer hybrid structures. With this system, all joint configurations could be produced, and it does not matter the placements of polymer and metal into the welding fixture.

The method which uses the device for injecting, includes injecting a reinforcing material on an interface by way of frictional heating and compressive loading of a reinforced material against the interface; continuously delivering the reinforcing material through a stirring tool during frictional heating and compressive loading, and forming and shearing a composite at the interface of metals and polymers. The feed material can be fed through the spindle no- continuously, semi-continuously, or preferably continuously.

The inject reinforcing material is consumable, meaning as frictional heating and compressive loading are applied during the process, the reinforcing material is consumed from its original form and fed or injected to the metal-polymer interface. For continuous-feed applications, it is preferred that the feed material is in the form of a powder, chemical solution, lotion, or mixture by polymers that can be injectable by the pressure of screw mandrel. More particularly, as the applied pressure of fed material increases, the excess reinforcing material is ejected from the system by the exit channel.

The fundamentals of the Fed Frictional Stirring technology achieved with this new device, is based on introducing the reinforcing material in the device. Injecting or feeding of reinforcement materials during the process through the holes inside the rotating tool (shoulder and pin) under the hydrostatic pressure during thermo-mechanical treatment. This technique can be implemented for the simultaneous accomplishment of materials joining and nanocomposite production, as we call it ‘nanocomposite joining’ in this research.

The reinforcing materials could be Nano, micro, or macro-size elements (metallic, glass, polymers, or composite structures) in this system. There is not any limitation about the shape and composition of reinforcing elements. The reinforcing complex could be a solution, lotion, paste, solid, or even mixing of them. The reinforcing elements prepared in advance import into the tooling system by a gate (number 1). The reinforcing materials pour in container and guide to the inlet gate by any electric, pneumatic of hydraulic equipment like parasitic pump.

Unless otherwise indicated, all technical and scientific elements used herein have the meaning commonly understood by one of ordinary skill in the art to which this invention pertains. Methods and materials similar or equivalent to those described herein can be used in the practice of the present invention.

Throughout the description and the claims, the word "comprises" and its variants are not intended to exclude other technical characteristics, additives, components or steps. For those skilled in the art, other objects, advantages and characteristics of the invention will emerge in part from the description and in part from the practice of the invention. EXPLANATION OF THE FIGURES

To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, according to a preferred example of a practical embodiment thereof, a set of drawings is attached as an integral part of said description where by way of illustration and not limitation, the following has been represented.

In figure 1 , we can see a representation a sectional view of the device object of the invention

In figure 2, we can see a representation of how the reinforcing materials flow through the device and the joining.

In figure 3, we can see a perspective representation of the device.

In figure 4 is shown a detail of the rotating head mounted at the end of the screw.

In figure 5 is shown the system where the spindle is integrated.

PREFERRED EMBODIMENT OF THE INVENTION

In view of the figures, a preferred embodiment of the proposed invention is described below.

In figure 1 we can see the device object of the invention which comprises a hollow sleeve (2) having a cylindrical shape, wherein within the hollow sleeve (2) is located a screw (4), being closed both ends of the hollow sleeve (2) by gaskets (3) placed on the upper end of the hollow sleeve (2) and a head (6) placed on the lower end of the hollow sleeve (2), wherein the lower end of the screw (2) is outwardly connected through a rotating tool (7) provided with different holes for supplying the reinforcing materials. The hollow sleeve (2) is provided with a inlet flow (1) through which the reinforcing material to be applied is supplied, and it is also provided with and exit of the surplus fluid (8) wherein over-injected materials with high pressure that stays at the back of the FSW tool are ejected through the exit (8).

The hollow sleeve (2) is provided with a belt heating element (5) placed surrounding the hollow sleeve (2) and preferable between the space comprise between the inlet flow (1 ) and exit of the surplus fluid (8).

The rotational direction and rotational speed of the screw mandrel can be different. The rotational direction and rotational speed could be varying due to various applications. Due to various types of reinforcing material, the heater can help increase flowability or vaporization of extra elements from reinforcing material. For example, if the reinforcing material is a mixture of polymer granule and nanoparticles, the heating system help to melting and flowability of polymeric base reinforce. On the other hand, pasty or lotion types of reinforcing are a mixture of the liquid phase that can harm the metal-polymer interface. For this aim, using heating assist helps to vaporize of liquid phase before trapping in the interface.

Figure 2 seeks to show how the reinforcing material flows within the device, being supplied through the inlet flow (2) advancing along the hollow sleeve (2) thanks to the rotation of the screw (4) and exiting through the different holes of the rotating (7) and being finally placed on the metal-polymer interface having a rotational disposition (9) as it is shown in the figure.

Figure 3 shows the already explained elements and where is possible to appreciate a ball bearing (10) being placed at the upper end of the screw (4).

In figure 4 can be appreciated the constructive details of the rotational tool (7) mounted on the lower end of the screw (4). The rotational tool (7) has a cylindrical shape which on top of which there is a pin (12) defining a shoulder (11) where there are different connecting holes (13), wherein the pin (12) is provided with different perimeter grooves (15) placed parallel to each other and some pin holes (14) and on top of the pin (12) there are some protruding elements (16).

The size and number of holes (13) and pin holes (14) determine the amount of injected reinforcements into the joint line. The hole size of the tool selects very small for increasing pressure of reinforcing solution, lotion, paste, solid. With increasing pressure, it is guaranteed that the reinforcing will inject into the joint line. The over-injected materials with high pressure that stays at the back of the tool will be ejected from the exit of the surplus fluid (8).

In fact, with this system, in this invention can be sure that the necessary pressure for injection always is available and over materials can be ejected from the tooling system. Both screw mandrel (4) and hollow sleeve (2) join by the mechanical power system. The rotational direction and rotational speed can be changed by electric power that supplies machine energy and gearboxes. In some cases, with using reduce ball bearing, can changes the rotation of sleeve and screw mandrel with same rotational direction.

Finally in figure 5 it is shown the system where the device object of the invention is placed.

The device is connected with a parasitic pump (17) by means of a tube (17.1) connected to the inlet flow (1). This parasitic pump (17) at the same time is connected with an inlet tank (18) into which the reinforcing material is supplied. The system is provided with and outlet tank (19) connected to exit of the surplus fluid (8) through a tube (19.1 ).

In this figure it is exemplified how the device is used for applying a reinforcing material into a interface (22) of metal sheets (20) and a polymer sheet (21).

Having sufficiently described the nature of the present invention, as well as the manner of putting it into practice, it is stated that, within its essentiality, it may be carried out in other embodiments that differ in detail from that indicated by way of example. , and to which the protection sought will also be achieved, provided that it does not alter, change or modify its fundamental principle.