P16682: AATech GE90 Tube Trim

Detailed Design

Table of Contents

Team Vision for Detailed Design Phase


The overall goal of this phase's activities was to prepare for MSD II.

The following activities were planned to be completed for this phase:


The following activities were completed for this phase:


The following activities were not completed for this phase:

Action items:

Phase Schedule

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Prototyping, Engineering Analysis, Simulation


Inner Tube Clearance

Tolerance Stack-Up

Cutting Speed

Push-Plate Force Rate

Ergonomic Assessment

Inner Tube Centering

The spring-mounted push-plate consists of a flat, stepped plate connected to the tool mount by two springs. These springs are identical and are separated by 2.5 inches, centered on the axle of the tool. Under design conditions, the inner tube is expected to contact the plate equidistant from the two springs, but the nature of the part is such that this cannot be guaranteed.

The purpose of this analysis is to determine the effect on the push plate when the inner tube is off-center relative to the plate. For the purposes of this analysis, each spring is given a spring constant of 11 pounds-force per inch. The inner tube is represented by a force between 5 and 10 pounds-force applied perpendicularly to the spring plate at the point of contact.

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With D=2.256in; k=11lbf/in; and P=5lbf:

Angle (degrees) Distance from Center (inches) Effective Compression (inches)
0 0.000 0.227
1 0.098 0.229
2 0.195 0.234
3 0.292 0.242
4 0.390 0.254
5 0.487 0.269
6 0.585 0.288
7 0.684 0.310
8 0.783 0.335
9 0.884 0.364
10 0.985 0.398

The effective compression is a measure of how much the push-plate moves at the point of contact with the inner tube. By design, when the compression is less than 0.250 inches for a new disk or 0.500 inches for a disk due for replacement, the inner tube will be clear of the cutting disk.

As long as the inner tube can be controlled to within 0.36 inches on either side of the center of the push-plate, there will be no issue with the clearance.

Height Requirements

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Requirement Required Value Expected Value Acceptable?
Centering Tolerance 0.0175 in 0.0120 in Yes
Vertical Tolerance 0.005 in 0.001 in Yes
Plate Centering 0.36 in 0.0120 in Yes
Cutting Speed 916 in/s 916 in/s Yes
Plate Force Rate 10 lbf/in 11 lbf/in Yes
Ergonomic Score 26 24 Yes

Drawings, Schematics, Flow Charts, Simulations

Full Exploded View

Click the link below to explore our system


link=https://edge.rit.edu/edge/P16682/public/Detailed Design Documents/Drawings/PDF's/Full Assembly Pages.pdf|Full Assembly

Tool Mount

https://edge.rit.edu/edge/P16682/public/Detailed Design Documents/Drawings/PDF's/Right Angle Dremmel Holder.pdf|Tool Mount


https://edge.rit.edu/edge/P16682/public/Detailed Design Documents/Drawings/PDF's/slider assembly full.pdf|Slider


link=https://edge.rit.edu/edge/P16682/public/Detailed Design Documents/Drawings/PDF's/Containment Assembly.pdf|Containment

Bill of Materials (BOM)

public/Detailed Design Documents/Bill Of Materials/BOM 3.PNG

Test Plans

The test plan is meant to address all of the engineering requirements. Tests will be run on the completed process assembly. The team will be provided with a number of parts that have failed inspection and are thus not fit for production, but the relevant dimensions are correct for this operation. Because these parts cannot be used for production, they can be used for testing. The provided parts will be run through the cutting process and the dimensions called out on the data sheets will be measured and recorded using the specified gauges.

The outer tube radius will be measured by fixing a circularity gauge to a stationary surface and rotating the nozzle with the outer tube in contact with the gauge. The gauge will show a variance as the tube rotates, and the minimum and maximum values will be recorded.

Tube heights will be measured by mounting the part in the base plate fixture and measuring the vertical distance between the flat surface of the inner or outer tube and the reference plane of the fixture; this distance corresponds to the tube height specified in the drawings and on the data sheets.

Features such as the presence or absence of burrs or other cosmetic defects will be measured on a pass/fail basis by visual inspection. A passing grade for cosmetic defects means that no marks, scratches, or blemishes are visible to the naked eye. A passing grade for the presence of burrs means that no burrs are visible to the naked eye that can affect a process dimension, cut or otherwise injure an operator or inspector, or be removed by hand.

Testing will be completed in two steps: the first step will be to collect data after the bending operation to make sure the parts are within the allowable ranges for the cutting operation.

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The second step will be to run the same parts through our process and collect data on the final dimensions.

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The values obtained through testing will be used to evaluate process performance and capability. Typically, a process is deemed acceptable if it can meet a process performance index of at least 1.33, calculated as follows:

public/Detailed Design Documents/Proof Of Concept & Test Plan/Performance.PNG

The requirement for this process is based on the first-time yield, rather than the performance index. To meet a FTY of 99.5% on a sample of 30 parts, no parts can fail any dimensions. The performance index will still be calculated, as it provides insight into the level of process control.

An additional stage of testing will be undertaken to measure the rate of tool wear. While parts are being run for testing of dimensions, the diameter of the cutting disc will be measured twice after each operation. If the disc needs to be replaced during the tests, the average tool life will be recorded; otherwise, the rate of wear will be recorded and used to calculate the expected tool life.

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Code Requirement Required Value Test
S2, S9 Defects None Visual Inspection
S3 FTY 99.5% Capability Study
S4 Process Time 85 seconds Stopwatch
S7 Tube Separation 0.090-0.140 inches Height Gage
S8 Outer Tube Height 1.275-1.285 inches Height Gage

Design and Flowcharts

Subsystem Decomposition

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Process Flowchart

Risk Assessment

public/Project Management/risk and problem management/Risk Assessment 5.PNG

Plans for next phase

Preliminary Plan for MSD II

Preliminary Plan for MSD II

Lessons Learned

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