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Welding Automation For Honeycomb Rings

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Sophia Davila, Lucca Frey, Rohan Shah, Parth Jha

27^th February 2024

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Our Sponsors

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2 Parth

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Manufacturing Honeycombs

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3 Parth

Corrugation

Automated

Laser Spot Welder

Roller Machine

Manual Tack Welder

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2

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Brazing process

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Manufacturing Honeycombs

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4 Parth

Corrugation

Automated

Laser Spot Welder

Roller Machine

Manual Tack Welder

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3

2

1

Brazing process

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Resistance Tack Welding

What is it?

5 Rohan

Tack Welding: Temporary weld to hold metal pieces together before the final welding process.
Resistance Tack (or Spot) Welding: Welding method that uses heat generated by the resistance of the material to fuse the pieces together.

Figure. Schematic of Resistance Tack Welding

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Resistance Tack Welding

How is it used in Honeycomb Structures?

6 Rohan

HTH uses this welding technique to manufacture specific shapes such as rings, differential heights and belts using Honeycomb Structures before being sent to brazing furnaces.
At the moment, this process is done manually using the Amada THP Tweezer Handpiece

Figure. Actual and Schematic Diagram of the Amada THP Tweezer Handpiece

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Functional Requirements and Constraints

7 Lucca

What the sponsors wants

Increase welding speed without losing accuracy
Reduce worker fatigue and possible long term health issues
Facilitate the process for workers

Biggest challenges

Maintaining accuracy and quality
Handling different types of honeycomb

Dream scenario

Tack welding table that works for different cell sizes without losing accuracy
Adaptable system that can work for different heights of the product
Automation to minimize manual labor

Figure. 1/32’’ cell size

Figure. 1/16’’ cell size

Figure. ⅛’’ cell size

As Parth said, tack welding is the longest part of the manufacturing process of honeycombs, because of that our main goal for this project is to speed up the tack welding process without losing any accuracy, we also want to reduce worker fatigue and possible long term health issues, as rohan said, this process is very repetitive and our sponsor wants to avoid letting that become a big issue, an example of that is the silicone grip they are implementing during production.�Our biggest challenges so far are maintaining accuracy and quality of the welds with our new design and also handling different types of honeycombs, since hi tech honeycomb works with different cell sizes 1/32, 1/16 and ⅛ and also different heights.

The dream scenario would be designing a tack welding table that would work for all 3 different cell sizes without losing accuracy for any of them, it should have a mechanism to adjust to different heights of the honeycomb strip, and lastly we want to automate as much as possible to minimize the amount of human input.

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Rabbit Hole

Laser Welding

Industry is shifting to laser manufacturing due to its precision and efficiency
Laser welding fit all our FRs, and made the entire process automatable
However, laser welding had its own set of challenges:

Difficult to focus into honeycomb cells
Aluminum is a reflective surface, could scatter the laser beam
Weld quality could be affected by the non-perpendicular laser beam

8 Rohan

Figure. Laser Welding for Aluminum

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Risk Reduction

Electrical Risks:

Power supply

Heat distribution

9 Sophia

Mechanical Risks:

Reaching inside the honeycomb cell

Ensuring proper contact

Figure. Picture of result of a weak weld

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Electrical Risk Reduction

Power Supply for Multi-Tip Design

10 Rohan

There is no power supply available off the shelf to power more than two tips at once.
The current power supplies haven’t been tested for heating multiple tips.
We THOUGHT we’d have to introduce transformers to ensure equal energy transmission to all the tips.

Figure. Circuit Diagram of a Power Supply with Transformer

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Electrical Risk Reduction

Power Supply for Multi-Tip Design

11 Rohan

After extensive research of the power supply, we found that we could actually power ~10 sets of tips with just one power supply
Each set requires 12.5 W/s and the power supply can deliver up to 125 W/s

Figure. 125 DP Resistance Welding Power Supply

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Risk Reduction

Mechanical Risks - Reaching and Ensuring Proper Contact

The Problem:

Testing methods:

Reaching:

Test ease of access, positioning, and maneuverability with our double-tip prototype.

12 Sophia

Problem	Double-tip design	Effect on welding
Reaching inside the honeycomb cell	Adding a second tip makes it harder to align both tips inside the cell	Misalignment can lead to misplaced or weak welds.
Bad contact = bad weld	Misalignments between tips can cause uneven pressure and bad contact	Welding relies on contact resistance, and poor contact can cause weak welds or overheat.

Contact:

Force sensor to check even force distribution between tips.

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Mechanical Risk Reduction

Double-Tip

13 Lucca

Design Choice

Swap single tip design for double tip
Use same hand weld machine and adjust current
Manufacturing Issues
Solution to make manufacturing more simple:�Screw vs 1 component
Material - copper

Figure. Fully assembled tack welding tool with double tip configuration

Figure. CAD design of double tip branching design

As Sophia said, the prototype we are currently working on is this double tip design, we tried to keep it simple so we just came up with a component that would have space for 2 tips instead of just one, with this design we would still be able to use the same hand weld machine and voltage, and we would adjust the current accordingly.�We did run into some manufacturing issues, as you can see, this CAD design had the thread to attach to the talk welding tool, but that added a level of difficulty to the manufacturing and had a lot less precision then we were expecting, so the new idea is to manufacture a simple block with two threaded holes on one side and one on the other, we ran a double sided screw through it and that added some rigidity to the component.

The material we used for our first prototype was aluminum since it is easier to work with than copper, but our next prototype should be made out of copper, as it is a much better electrical conductor than aluminum

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Mechanical Risk Reduction

Force Analysis

We wanted to ensure equal force distribution from the welding tips on our material.

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Mechanical Risk Reduction

Throughout our design process, we were looking the problem from our sponsor’s perspective

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Mechanical Risk Reduction

Welder Feedback

Most welders complained about pain in their hands from welding continuously throughout the day.

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Mechanical Risk Reduction

Welder Feedback

Some welders wanted to adopt our new designs and some didn’t.

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Future Work

Multi-tip Design without tweezers

In the next steps, we have to work towards achieving the “dream” goal of automation
While complete automation is out of our scope, we plan to implement a semi-autonomous system capable of welding more than two sets of honeycomb cells at a time

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Future Work

Welding Table

We aim to integrate the multi-tip system into a “Welding Table”
This table will allow the welders to give shape to the honeycomb sheet
The resistance welding can be activated by the use of foot pedals

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Future Work

Manufacturer Quotes

Waiting on four copper manufacturer quotes for our latest double tip design

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Project Management

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ICA’s

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Clamp Design Rohan

Designing Welding Tips Lucca

Power Supply Design and Analysis Sophia

Contact Force Analysis Parth

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Thank You!

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Questions?

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Appendix

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Appendix: Why are fluctuations important?

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honeycomb seals are a type of seal used to prevent the leakage of fluids (such as air or oil) between rotating and stationary components in aircraft engines.

Appendix: Sealing the turbines

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Appendix: Honeycomb Overview

Material Composition:

Made from thin metallic foil (0.001 to 0.011 in thick)
Common materials: Hastelloy-X, Hastelloy-S, Inconel, Stainless Steel, Haynes alloys (214, 224, 230, 233)

Manufacturing Process:

Corrugation & Welding:

Foil is corrugated and laser spot welded at nodes to form hexagonal cells

Cell Sizes:

Standard sizes: 1/64″, 1/32″, 1/16″, 3/32″, 1/8″, 3/16″

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Appendix: Honeycomb Overview

Processing & Assembly:

Shaping & Cutting:

Shaped using EDM (Electrical Discharge Machining)�

Attachment Methods:

First tack welded to backing members
Then brazed for final assembly

Application in Turbines:

Formed into rings and brazed onto turbine components

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TACK WELDING

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Appendix: Gas Turbines

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F_lift=C_liftv²Aρ

F_thrust=C_thrustv²Aρ

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Appendix: Intro to Gas Turbines

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Air Intake

Fuel Injection

Compression Stage

Combustion & Expansion

Exhaust

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Appendix: Characterizing Gas Turbines

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Appendix: Why are fluctuations important?

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F_lift=C_liftv²Aρ

F_thrust=C_thrustv²Aρ

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Appendix: Designing Turbine Blades

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Appendix: Gas Turbines

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Rotor

Stator

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Appendix: Gas Turbines

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Stator

Honeycombs are fitted inside stator

Fitted Honeycombs in the stator

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Appendix: Gas Turbines

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Honeycombs create a seal that allow smoother pressure and velocity distributions!

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Gas Turbines

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38 Parth

Rotor

Stator

Rotor

Stator

If we take a step back and take a look at what a gas turbine looks like. A gas turbine is characterized by 4 stages, the compression stage, the combustion stage, the expansion stage and the exhaust stage. Useful is extracted from the expansion stage.

The propelling nozzle system that extracts mechanical work consists of two main parts.The stator, acts as a capsule to retain the fluid, while the rotor extracts useful mechanical energy. But because the stator is a capsule, and the fluid has high entropy and velocity coming into the turbine, this incudes a back flow of the fluid, that decreases the efficiency of the engine and adds to the fluctuations of the velocities, creating unstable drag and lift forces. That is where our Industry Partner comes into play. By fitting honeycomb shaped rings inside the stator, which are structurally sound shapes, the fluid particles get trapped within the honeycombs creating seals, effectively reducing the black flow of the fluid and also reducing the entropy of the fluid.

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How are Honeycombs made?

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39 Parth

Step 1- Sheets of Metal alloys are corrugated

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How are Honeycombs made?

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Step 2- Corrugated sheets are spot welded to create honeycomb sheets

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How are Honeycombs made?

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Step 3- Honeycomb sheets are bent using a roller machine to create rings

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How are Honeycombs made?

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Step 4- The ends of the rings are manually tack welded together to create the final product

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Manufacturing Honeycombs

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43 Parth

4

3

2

1

Corrugation

Automated

Laser Spot Welder

Roller Machine

Manual Tack Welder

Brazing process

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Resistance Tack Welding

What are its shortcomings?

44 Rohan

HTH receives hundreds of orders per day. This means they have to carry out thousands of resistance tack welds daily.
The employees develop chronic wrist and thumb pains.
HTH previously attempted to resolve this issue by creating soft silicone grips but they still require a permanent solution.

Figure. Silicone hand grip for the Amada THP Tweezer Handpiece

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Future Work

45 Rohan

Manufacture our current prototype with copper, and test its welding capabilities.
Research the power supply and the feasibility of introducing transformers to its circuitry.
Transition to a more automated mechanism with either a Mill or Waffle Maker System.
Try to model our system for a Parallel/Series Electrode Configuration for Resistance Welding instead of the existing Pincer Configuration.

Figure. Various possible configurations of the electrodes used in Resistance Welding