Quick Project Overview
Hobbing is the machining process for gear cutting, where the cutting edge and work piece turn simultaneously in a machine to create a specific gear design. Gleason Works is one of the leaders in the hobbing business and has asked our team to help develop a solution to one of their problems. If the machine is not stiff enough between the cutting edge and the work piece, it can cause issues during the hobbing process. Currently, Gleason uses a test fixture in which the load is manually applied to the arbor in one static direction and it is tedious, strenuous, and time consuming to run the test.
Our mission is to develop a new device to make their testing easier and more effective. Gleason Works has asked us to develop a way to apply a force up to 1000lbs (400lbs minimum) in the x, y, and z axes, so they can test the stiffness of their newly design hobbing machines in a timely fashion; meanwhile, making the device light enough to carry, easy to install, and small enough to be an accurate representation of the forces that occur during the hobbing process.
Gleason's Current Testing Apparatus
Systems DesignIn our systems design review, we brainstormed ideas to help develop a rough draft solution for the problem. Using morphological charts to identify various possibilities and combine ideas we developed a few different concepts. After comparing the various concepts using Pugh charts, we determined that our best option was the "Pivol Swivet," a device that clamped onto the arbor rod and was able to rotate by having 2 joints, one ball joint at the work piece and pivot joint connected near the arbor rod, with a hydraulic ram and loads cell connected linearly in between the two joints.
Subsystems DesignIn the subsystem design phase we expanded upon our “Pivol Swivet” fixture. During that phase we performed various simulations and determined that the subsystems still needed to be modified in order to avoid interferences and withstand the load caused during operation. It was our first attempt at physically analyzing the capability, mechanical movements and strength of the Pivol Swivet.
Preliminary Detailed DesignMore simulations were done to prove that the design would work, we started working on our drawing package, constructed preliminary test plans and a rough BOM.
Based on our previous design review we were advised the following objectives:
- Invest money into good electronics, it will help in the future.
- Make sure we purchase a conditioner for the load cell.
- Identify what parts we're purchasing and making ourselves in the BOM
- Make as many parts in the machine shop as possible. It will save a lot of money.
- Create a more developed drawing package.
- Test Plans need to be more developed.
Team Vision for Detailed Design Review
What We Planned to Do
- Finalize the Drawing Package to have as much detail as possible.
- Finalize Test Plans
- Finalize BOM to include as much detail as possible. Reduce prices by determining what can be made in the shop.
- Create a preliminary MSD II schedule with a heavy focus on Phase 1.
What We Did
- Completed the drawing packed for all customized parts. We determined what components are possible to make in the shop.
- Created two important tests to ensure that our results are accurate. The first test plan focuses on the load cell's capabilities and the second test plan focuses on the system outputs all together.
- The BOM has been finalized and now includes category, suppliers, part number etc.
- Purchase orders have been completed and are awaiting approval.
- The MSD II preliminary schedule has been completed and contains a general outline of everything through May 7th, 2016 (Imagine RIT).
Drawings, Schematics, Flow Charts, Simulations
Whole System Design Exploded View
Customized Components Package
Ball Joint Subsystem
Part No. 01 - Outer SocketDrawing
Supplier/Source: Morgood (Outsourced Machined Component) - $270.00
Part No. 02 - Inner SocketDrawing
Supplier/Source: Morgood (Outsourced Machined Component) - $290.00
Part No. 03 - Ball RodDrawing
Supplier/Source: Morgood (Outsourced Machined Component) - $150.00
Entire Pivot Sub Assembly
Load Cell and Ram Subsystem
Part No. 04 - Load CellDrawing
Supplier/Source and Model Number: Futek LTH350 FSH00361 - $560.00
Part No. 05 - Load Cell Block
Supplier/Source: In-House | Raw Materials from McMaster-Carr - $30.00
Part No. 06 - Retainer PlateDrawing
Supplier/Source: In-House | Raw Materials from McMaster-Carr - $8.00
Part No. 07 - #4-40 X 5/8' Socket Head Cap ScrewSupplier/Source and Model Number: McMaster-Carr 91251A112
Part No. 08 - RamDrawing
Supplier/Source: Enerpac RSM-50 - $330.00
Part No. 09 - #8-32 X 3/8' Socket Head Cap ScrewSupplier/Source and Model Number: McMaster-Carr 91251A192
Entire Load Cell Sub Assembly
Load Cell and Ram Sub Assembly
Part No. 10 - Outer SlideDrawing
Supplier/Source: In-House | Raw Materials from McMaster-Carr - $6.00 For Two Parts
Part No. 11 - Inner SlideDrawing
Supplier/Source: In-House | Raw Materials from McMaster-Carr - $6.00 For Two Parts
Entire Slide Sub Assembly
Slide Sub Assembly
Part No. 14 - Pivot BlockDrawing
Supplier/Source: In-House | Raw Materials from McMaster-Carr - $40.00
Part No. 15 - Rotary EncoderPicture
Supplier/Source and Model Number: US Digital MA3-A10-125-D - $70.00
Part No. 16 - Encoder PinDrawing
Supplier/Source: In-House | Raw Materials from McMaster-Carr - $10.00
Entire Pivot Sub Assembly
Clamp Machining Early StagesStage One Drawings
Stage One Assembly.
Stage Two Drawing
Part No. 18 - Primary ClampDrawing
Supplier/Source: Morgood (Outsourced Machined Component) - $330.00
Part No. 24 - Clamp PinDrawing
Supplier/Source: In-House | Raw Materials from McMaster-Carr - $10.00 DOUBLE CHECK
Part No. 25 - Secondary ClampDrawing
Supplier/Source: Morgood (Outsourced Machined Component) - $275.00
Part No. 22 - Clamp BoltDrawing
Supplier/Source: McMaster-Carr - $10.00
Part No. 21 - Clamp NutDrawing
Supplier/Source: McMaster-Carr - $4.00
Part No. 19 - InclinometerPicture
Supplier/Source and Model Number: US Digital A2T-A-S-D - $350.00
Entire Clamp Sub Assembly'
External Load Application Components Subsystem
Part No. 32 - Pump
Supplier/Source and Model Number: Enerpac P-392 - $0.00 (Product is being supplied by Gleason Works)
Part No. 31 - Pressure Release Valve
Supplier/Source and Model Number: Brand Hydraulics RL50-2000 - $65.00 (Product is being purchased from Northern Tool and Equipment)
Part No. 27 - DAQ
Supplier/Source and Model Number: Measurement Computing USB-201 - $100.00
Part No. 28 - Strain Gage Signal Conditional Amplifier
Supplier/Source and Model Number: Futek FSH03863 - $425.00
Part No. 30 - Strain Gage Signal Conditioner Power Supply
Supplier/Source and Model Number: US Digital PS-24 - $66.00
Part No. 29 - Inclinometer Power Supply
Supplier/Source and Model Number: US Digital PS-12 - $20.00
GUIGUI produced using Microsoft Visual Studio.
Additional code required for program provided with DAQ.
Bill of Material (BOM)
Total Expenses: $3,470
Total Budget: $4,000
Percentage Used: 86.75%
Test PlansThe following tests will be performed in the manner described to establish proof that the device works as intended given the engineering requirements. This will include demonstrating the data collections components, user interface (GUI), and loading components perform as desired. In addition, showing that the device as a whole accomplishes it intended purpose, force application for stiffness testing.
The load cell used in conjunction will be tested off line of the test hobber initially to determine GUI accuracy in load measurement. The full device, with all data collection components and GUI, will be testing in the machine under typical testing example testing conditions.
The initial test will require that the load cell be placed into a device capable of applying its own load and measuring it. The device to be used for this test will be one of the several tensile/compression tester available in the COE. The GUI will be fully connected to the load cell as would be under typical operating conditions. The load cell will be placed in the tester so to load it in the typical operating fashion.
The primary test will require the completed device be installed in the test hobber in in the typical operating manner. The load cell, rotary encoder, and inclinometer will be fully linked to the GUI. The hydraulics will be fully connected as in typical operating conditions. Gleason will need to provide the measuring equipment they utilize in determining deflections.
The parameters to be measured in the initial test are as follows:
- Load applied as measured by the testing machine, LM
- Load applied as measured by the load cell through the GUI, LG
The parameters to be measured in the primary test are as follows:
- Time to install the device fully, TI
- Angle of pivot measured offline, PO
- Angle of pivot measured with rotary encoder through GUI, PG
- Angle of arbor clamp measured offline, AO
- Angle of arbor clamp measured with inclinometer through GUI, AG
- Load applied, measured through the GUI; L
- Load components, measured through the GUI, in x, y, and z machine directions; LX, LY, LZ
- Time to produce the given loadings, TL
- Deflection arbor relative to workpiece produced by original Gleason device, DO
- Deflection arbor relative to workpiece produced by Pivol Swivet, DP
The procedure for performing the initial test will require first establishing which testing machine will be used. Then it will need to be determined of the machine can provide compressive loading or if a simple rig will need to be constructed to adapt a tensile force into a compressive application to the sensor.
The required procedures for the machine will need to be followed but the process will be relatively simple.
1) Connect load cell (free) to the DAQ and the DAQ to the computer running the GUI, as per typical operating conditions.
2) Run the GUI, ensuring that the load cell is registering a zero load, note any variation.
3) Insert load cell into testing machine. Load cell x-section
4) Bring the testing machine software online.
5) Ensure that the machine is applying a zero load to the load cell.
6) Run the GUI, ensuring that the load cell is registering a zero load, note any variation.
7) Operate the testing machine, applying the loads detailed on DS1 as per typical operating conditions.
8) Note the LM and LG for the given loading condition.
9) Return testing machine to zero load.
10) Note any variation from zero for machine and GUI.
11) Repeat 7-10 5 times for each of the 4 loads with 3 different operators.
Test Plan 1 Data Sheet
The process for the primary test will require information from Gleason as to the loading conditions they have previously tested on the test hobber. This will include the results of the deflections.
1) Allow each of the three testers to perform the following as per typical operating conditions to gain experience and understanding of the setup.
a) Mount the device to the test hobber as per typical operating conditions.
b) Connect the hydraulics to the device.
c) Connect the device to the DAQ and the DAQ to the computer running the GUI.
d) Run GUI
2) Repeat above, collecting TI.
3) Repeat this 2 times with 3 different operators.
4) Position the device into the “zero” position, the device orientated only in the machine x direction.
5) Using a digital level, positon, as per typical operation, the pivot, then the arbor clamp, into the specified conditions as per DS2-1.
6) Note the angle measured by the digital level and the GUI.
7) Repeat 4-6 5 times with 3 different operators for each condition.
8) Position the device into the “zero” position, the device orientated only in the machine x direction.
9) As per the listed conditions in DS2-2, enter the loading condition into the GUI.
10) Position the device as per typical operation into the orientation indicated by the GUI.
11) Apply hydraulic pressure until the desired load is reached, as indicated by the GUI.
12) Note the total, L, and component (LX, LY, LZ) loads given by the GUI.
13) Repeat 5 times with 3 different operators for all 4 conditions.
14) Given previously tested loading conditions by Gleason, follow steps 8-11, replacing the DS2-2 conditions with the Gleason conditions.
15) Measure the time to accomplish 14 (TL) and the same deflections measured by Gleason (DP).
Test Plan 2 Data Sheets
Risk Assessment Chart
MSD II Schedule
MSD II Phase 1 - Build and Test Prep
MSD II Phases 2-5
MSD I Lessons Learned
- Do not procrastinate. You will not enjoy it.
- By making products in the machine shop, it will reduce cost tremendously
- Having a good Gantt chart to follow makes it much easier to understand what needs to get done.
- Meeting with Gary regularly gets you on the right track, as opposed to being sidetracked by things that don't really matter.
- Creating tasks based on risks in MSD I makes it so that you have to tackle them directly.
- Stick to one CAD program.
- Regular meetings with team help make sure everyone is on the same page.
- Put your money into the electronics, because that's the hard part for a mechanical engineer.
- Double check information with faculty, because they will be able to tell you if you've gone astray.
- Allow people ample time to complete drawings and CAD drawings.
- The more documentation the better.
Feedback to MSD Program
- If Nick and Peter didn't take Design Project Leadership, we don't know if we could have produced the same results, because the first 6 weeks would have been hard to figure out.
- Last minute changes to room for presentations are cumbersome.
- Teams that go on Thursday definitely have an advantage (Not that we're complaining), but it would help our peers if you alternate them.
Post Detailed Design Review ItemsAfter presenting our final design review, we were given some suggestions on how to improve our drawing package, electrical devices layout, BOM and MSD II schedule. The final versions of each item are listed below.
Drawing PackageFinal MSD I Drawing Package
Electrical Devices LayoutAfter the review we have determined to create a platform for the electrical devices that are external to the Pivol Swivet. To do this we are going to contain the devices inside of watertight plastic enclosure seen below here:
We were also asked to show wiring and strain relief devices. The links for which are below: