Rotary Friction Welding for Precision Polymer Joining

Abstract

ABSTRACT Rotary Friction Welding for Precision Polymer Joining A compact, desktop rotary friction welding machine (100) is presented for joining polymer materials, specifically pipes, through controlled rotational motion and axial pressure. The invention provides precise management of welding parameters, including rotational speed, axial pressure, and heat duration, allowing customization based on polymer properties to ensure high-quality, uniform joints. A robust clamping and alignment system is integrated to stabilize workpieces, minimizing deformation and enabling strong, consistent welds. The machine (100) includes essential components such as a primary rotational motor (101), a rotating chuck (102), a linear movable chuck (103) controlled by a servo motor (104), and a PLC control unit (106) mounted on a base platform (108). This configuration offers an efficient, reliable solution for both similar and dissimilar polymer joining without external heating elements, making it suitable for small-scale applications. Figure 3

Specification

Description:FIELD OF THE INVENTION
The present invention generally relates to the domain of polymer welding technologies, specifically to a compact rotary friction welding machine designed for joining polymer materials through controlled mechanical friction and pressure.

BACKGROUND OF THE INVENTION
The background of this invention concerning a portable, desktop rotary friction welding machine specifically for polymers aligns with and builds upon several past innovations in rotary friction welding. Traditional rotary friction welding has been utilized primarily for metals, where frictional heat is generated between rotating workpieces, resulting in material joining. However, with polymers, challenges such as thermal sensitivity and lower melting points necessitate more precise control over welding parameters.

The patent US 20180029158 descripts the challenges of RFW for axisymmetric workpieces, focusing on the need for precise interface management to prevent material defects. This patent focuses on optimizing the geometry and angles of weld interface to enhance the quality of the weld, preventing uneven material distribution and ensuring durability.

The patent US 20160039043 focuses on improvements to friction welding interface, particularly for tubular workpieces. The patent highlights how improper alignment and eccentricities leads to poor weld quality, a challenge the present machine mitigates by integrating a robust clamping and alignment system tailored to the unique characteristics of polymer materials. This ensures that even with polymers, where heat sensitivity and deformation are significant risks, welding process remains stable and produces high-quality joint.

Another key reference, US 20050218192, describes a system that uses controlled rotational speeds and thrust phases to achieve precise inertia friction welding. It highlights the role variable speeds and phases that are critical to the integrity of weld, especially in the transition from acceleration phase to deceleration phase. This invention, with its precision controls for frictional heat and pressure, draws on this by enabling customization of these phases to accommodate the lower melting points of polymers compared to metals.

Thus, there is a need of polymer welding techniques that provides time and cost-effective means of joining thermoplastics polymers that are difficult or impossible to weld with traditional methods.

OBJECTS OF THE INVENTION
It is the primary object of the invention to provide a desktop-sized rotary friction welding machine specifically suited for welding polymer pipes.

It is another object of the invention to enable welding of similar and dissimilar polymer materials by allowing precise control over welding parameters such as rotational speed, axial pressure, and heating duration.

It is another object of the invention to integrate a robust clamping and alignment system for stable, high-quality joints.

It is yet another object of the invention to create an accessible, efficient, and portable solution suitable for laboratories and small-scale production setups.

SUMMARY OF THE INVENTION
To meet the objects of the invention, it is disclosed here a compact rotary friction welding machine for joining polymer materials, comprises: a primary rotational motor; a rotating chuck; a linear movable chuck; a servo motor; a support block; a programmable logic control unit; a grab rail; and a base platform, wherein the primary rotational motor is configured to impart rotational motion to the rotating chuck, the rotating chuck secures a first polymer component during the welding process, a linear movable chuck, axially movable along the support block, configured to hold and press a second polymer component against the first polymer component during welding, the servo motor is configured to control the axial movement of the linear movable chuck, enabling adjustable pressure between the polymer components, the programmable logic control (PLC) unit operatively connected to the primary rotational motor and the servo motor, configured to regulate rotational speed, axial force, and operation duration, the grab rail is attached to the machine for easy handling, and the base platform supports the structural elements of the machine; and wherein the primary rotational motor generates frictional heat at the interface between the polymer components by rotation, and upon achieving the desired softened state of the polymers, the rotation is stopped, and axial pressure is applied to join the components.

Further disclosed here a process for joining polymer materials using a rotary friction welding machine, comprising steps of: securing a first polymer component in a rotating chuck coupled to a primary rotational motor; securing a second polymer component in a linear movable chuck that is axially aligned with the rotating chuck; rotating the first polymer component at a predefined rotational speed while applying axial pressure between the polymer components; generating frictional heat at the interface of the polymer components to achieve a softened state; ceasing the rotational motion upon achieving the softened state; and applying additional axial pressure to bond the polymer components as they cool and solidify.

BRIEF DESCRIPTION OF THE FIGURES
Figures 1, 2 and 3 are the front view, top view and isometric view of the present invention respectively.

DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to the field of polymer welding technologies, specifically to rotary friction welding machines adapted for welding polymer materials. Rotary friction welding (RFW) is a solid-state joining process in which frictional heat is generated from high-speed rotation and axial pressure to bond materials. This technology is conventional in welding metal, but recent advancements and research allow for its adaptation to thermoplastics and dissimilar polymer materials. The invention aims to develop a compact, desktop-sized RFW machine tailored for welding polymer pipes. This enables welding of similar and dissimilar polymers through controlled friction, making it ideal for laboratory work, small scale application, and prototyping. Important developments concerning the machine include precise control over the welding parameters such as rotational speed, axial pressure and heating time. These controls allow for accurate adjustment according to the polymer being welded, enabling high quality joints with minimal heat affected zones. Another advantage concerning the use of friction welding for joining different types of polymers is obviation of need for filler materials or external heat sources, streamlining the process for welding polymers with different melting points.

The objective of the invention is to introduce a compact, desktop rotary friction welding machine (Figures 1 to 3) particularly designed for polymer materials, which addresses the limitations of current welding technologies. Traditional methods for welding polymers often struggle with maintaining uniform heat distribution and pressure, leading to subpar weld quality. This invention provides a portable, laboratory-scale solution capable of welding both similar and dissimilar polymer pipes through controlled rotary friction welding. The key objective is to ensure precision in welding process by integrating advanced control mechanisms for regulating frictional heat and pressure, which are critical in achieving high-quality, consistent welds across varying polymer types and dimensions. This machine is designed to handle unique challenges of polymer materials, which are often sensitive to temperature variations, while providing a reliable solution for small-scale or experimental production environments. Furthermore, the machine aims to optimize resource efficiency, reducing both time and material wastage through precise, programmable control systems. This aligns with growing demand for lightweight, high-performance polymers in various industries, particularly in automotive, aerospace, and consumer goods sectors where dissimilar materials often need to be joined seamlessly. The system also offers a robust clamping and alignment mechanism to prevent deformation during the welding process, ensuring that weld integrity is maintained even for complex or delicate parts. By offering a compact, desktop solution, the machine supports research purposes and small-scale industrial application, enabling rapid prototyping, material testing, and specialized production runs.

This invention relates to a desktop rotary friction welding machine engineered to overcome the limitations of traditional polymer welding methods. These methods, such as hot plate welding, ultrasonic welding, and laser welding, struggle with maintaining consistent heat distribution, proper material fusion, and high joint strength without compromising material integrity. This invention addresses these limitations by leveraging rotary friction as a heat generation mechanism, ensuring strong and uniform welded joints while minimizing thermal damage to polymer materials. It also allows for welding of both similar and dissimilar polymers, a significant challenge in the past. It integrates automated control mechanisms for precise management of critical parameters, allowing users to customize settings based on specific material properties of polymers being welded. This precision ensures a uniform and high-strength bond, regardless of differing thermal and mechanical properties. A robust clamping and alignment system is introduced to ensure proper pipe positioning during welding, addressing issues of misalignment and poor fit that often plague other welding technologies. This compact, desktop-sized machine is an accessible alternative to large industrial polymer welding machines, lowering the entry barrier for industries.

The invention represents a significant advancement in polymer welding technology, offering a compact, energy-efficient, and adaptable solution for welding similar and dissimilar polymer pipes. By addressing the limitations of traditional methods, this machine paves the way for more reliable, cost-effective, and high-quality polymer welding applications in various industrial sectors.

As shown in Figure 3 the compact desktop rotary friction welding machine includes:
Primary Rotational Motor: Provides rotational motion for friction generation.
Rotating Chuck: Holds the rotating component during the welding process.
Linear Movable Chuck: Moves axially to apply pressure during the welding process.
Support Block: Provides stability and support for the linear movable chuck.
Servo Motor: Controls the axial movement of the linear movable chuck.
Bed: The base platform of the machine.
PLC Control Unit: Regulates the machine's operation.
Grab Rail: Provides a handle for easy movement of the machine.

Desktop rotary friction welding machine for polymer materials represents a significant breakthrough in the field of polymer welding by addressing the limitations encountered by traditional welding methods. One of the key challenges in welding polymers is the inconsistency of heat distribution and difficulty in achieving strong, reliable joints. Traditional welding techniques such as hot plate welding often apply external heat unevenly, which leads to poor-quality welds, material degradation, or a prolonged failure. This rotary friction welding machine overcomes these drawbacks by employing mechanical friction as a heat generation source, providing a more controlled, energy-efficient, and sustainable welding process. The machine design enables it to generate heat through friction, eliminating the need for external heating elements. Rotational motion of the two components being welded induces interfacial friction under axial pressure, resulting in localized heat generation at contact point. Once the polymer softens, the rotation is stopped, and pressure is applied to bond the materials as they cool and solidify. This method ensures that heat is concentrated only at the weld joint, preventing the risk of thermal distortion or warping of material, which are common issues with traditional welding techniques.

Another major advantage of this machine is its ability to join dissimilar polymers. Dissimilar materials due to their different melting points and thermal behaviours, present a challenge for many welding processes. With this rotary friction welding machine, parameters such as rotational speed, axial force, and time is adjusted according to the specific materials being joined. This customization enables welding of polymers with significantly different properties, enhancing machine's flexibility in multi-material manufacturing application. This feature is particularly useful for industries like automotive, aerospace, and consumer electronics, where components often involve complex material combinations requiring precise and durable joining.

Compact desktop design of machine addresses growing demand for portable and space-efficient equipment in laboratories and small production facilities. Unlike bulky industrial machines, which are often impractical for smaller operations, this desktop machine provides a versatile and user-friendly solution. Researchers and developers can now prototype or test new polymer combinations and welding techniques without requiring extensive industrial-scale setups. This compact machine is ideal for R&D departments focused on material science, where frequent experimentation with different polymers is common.

The clamping and alignment system incorporated into the machine ensures both polymer components are perfectly aligned during welding process. This level of precision is critical in achieving high-quality welds, especially in application where leak-proof joints or structural integrity are essential. Misalignment during welding can lead to defects, weakening the joint or causing leaks in application such as fluid transport systems. By preventing such issues, this machine ensures repeatable, high-strength welds that meet the stringent quality standards demanded by industries like medical device manufacturing and aerospace.

List of Reference Numerals
100 - Rotary friction welding machine
101 - Primary rotational motor
102 - Rotating chuck
103 - Linear movable chuck
104 - Servo motor
105 - Support block
106 - PLC control unit
107 - Grab rail
108 - Base platform
 
, Claims:We Claim:

1. A compact rotary friction welding machine (100) for joining polymer materials, comprises:
a primary rotational motor (101);
a rotating chuck (102);
a linear movable chuck (103);
a servo motor (104);
a support block (105);
a programmable logic control (PLC) unit (106);
a grab rail (107); and
a base platform (108),
wherein the primary rotational motor (101) is configured to impart rotational motion to the rotating chuck (102), the rotating chuck (102) secures a first polymer component during the welding process, a linear movable chuck (103), axially movable along the support block (105), configured to hold and press a second polymer component against the first polymer component during welding, the servo motor (104) is configured to control the axial movement of the linear movable chuck (103), enabling adjustable pressure between the polymer components, the programmable logic control (PLC) unit (106) operatively connected to the primary rotational motor (101) and the servo motor (104), configured to regulate rotational speed, axial force, and operation duration, the grab rail (107) is attached to the machine for easy handling, and the base platform (108) supports the structural elements of the machine; and wherein the primary rotational motor (101) generates frictional heat at the interface between the polymer components by rotation, and upon achieving the desired softened state of the polymers, the rotation is stopped, and axial pressure is applied to join the components.

2. The rotary friction welding machine (100) as claimed in Claim 1, wherein the PLC unit (106) is configured to allow user-defined control over rotational speed, axial force, and timing parameters to accommodate polymers with different melting points and thermal behaviors.

3. The rotary friction welding machine (100) as claimed in Claim 1, wherein the machine comprises a clamping and alignment system integrated with the chucks (102, 103) to prevent misalignment or deformation of the polymer components during the welding process.

4. The rotary friction welding machine (100) as claimed in Claim 1, wherein the support block (105) provides structural stability to the linear movable chuck (103), enhancing the consistency of axial pressure application throughout the welding process.

5. The rotary friction welding machine (100) as claimed in Claim 1, wherein the PLC unit (106) includes a touch-screen interface for setting and monitoring the welding parameters in real-time.

6. A process for joining polymer materials using a rotary friction welding machine (100), comprising steps of:
securing a first polymer component in a rotating chuck (102) coupled to a primary rotational motor (101);
securing a second polymer component in a linear movable chuck (103) that is axially aligned with the rotating chuck (102);
rotating the first polymer component at a predefined rotational speed while applying axial pressure between the polymer components;
generating frictional heat at the interface of the polymer components to achieve a softened state;
ceasing the rotational motion upon achieving the softened state; and
applying additional axial pressure to bond the polymer components as they cool and solidify.

7. The process as claimed in Claim 6, wherein the predefined rotational speed and axial pressure are controlled through a programmable logic control unit (PLC) (106) to achieve a uniform joint quality suitable for polymers with varying thermal characteristics.

8. The process as claimed in Claim 6, wherein the method comprising step of aligning the polymer components with a clamping and alignment system before initiating the rotation to prevent misalignment during welding.

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