Week 7

Overview of Status of Analysis, Design, Fabrication, Tests, etc.

· Magnet and frame design agreed upon and and CAD drawings have been drawn up. Found a source for metal and stepper motor.

· Utilizing a magnetic field simulation software called Vizimag, we have modeled magnetic field lines of several design solutions and have decided on pursuing permanent magnets using a slider/threaded device to change the size of the air gap.

· Machining of iron components has begun.

Accomplishments from Previous Week

· Machining of iron components has commenced and frame is almost complete.

· All parts and components have been ordered. Orders have started arriving this week.

· Have gained access to a gaussmeter capable of measuring greater than 1 Tesla courtesy of Professor Jin

· Determined correct press fit specification for support shaft to be 0.0027” delta to provide 100 pound press for a factor of safety of 5 for the 20lb magnet.

Goals for Next Week

1. Finish machining iron & aluminium components = Sam and James

2. Cut acrylic motor mount and UI panel - Phil

3. Determine other options for measuring magnetic fields = Thomas and Michael

4. Begin correlating Tesla values with separation of threaded iron blocks using calipers = Thomas and Michael

Sponsor Comments from Last Meeting and Actions Taken to Address these Comments

· “I have concerns with the stepper motor bearing the entire load of the iron. Maybe you can have a Lazy-Susan type device to take the load of the iron off of the motor and onto the frame. Especially since the motor will be in tension instead of compression.” – Michael Porter (2-9-12)

Actions taken: We have included a thrust bearing into the design of our apparatus. This is in part to Michael’s concerns with the stepper motor failing first if required to carry the entire load on the iron alone, also in part to the motor not being able support the 9 kg load of the iron. With this design, the motor can be easily replaced without having to detach the iron components.

· Regarding our purchase of the Gaussmeter: “Yeah, I don’t think spending $500 on a Gauesmeter would be a good use of the budget. We probably won’t be needing it when you guys are done with your project. Maybe look into using the Hall-effect sensors you do have with small magnets and find a trendline. Use that to predict the values of larger Tesla readings.” – Michael Porter (2-9-12)

Actions taken: We have inquired around campus about borrowing a gaussmeter and have successfully been granted access to Professor Jin’s gaussmeter for the remainder of the quarter.

Pier Comments from Proof of Concept Presentation:

· “You can maybe use an inductance coil to measure the magnetic field strength” – Pauel Kozlouski (2-15-12)

Actions taken: We have taken his suggestion with great thought. This could be the best way of determining the magnetic field strength if we are unable to locate a gaussmeter that we can have access to. Gausemeter found so inductance coil measuring is not needed.

Instructor Comments from Last Meeting and Actions Taken to Address these Comments

· “Maybe you can use a pre-loaded compression spring on the threaded iron blocks such that there will always be iron to iron contact at the threads” – Dr. Delson (2-8-12)

Actions taken: We have performed a risk reduction regarding the air gaps present at the threads and have determined that the reluctance of the air gap is negligible.

· “Think about the assembly and designing for manufacturability” – Dr. Delson (2-8-12)

Actions taken: We have composed an assembly process and have taken note of safety concerns as well. In terms of manufacturability, we have purchased and received the aluminum tubing for the frame. The aluminum tubing comes together really easily. The feet on the frame can also be adjusted and leveled out.

· “Is there room for misalignment with the motor shaft?” – Dr. Delson (2-15-12)

Actions taken: Using a spirit level mounted to the motor in conjunction with adjustable frame feet to determine motor straightness to +-1 degree. We then replaced solid coupler with flexible coupler to allow +- 1 degree of motion. We calculated the radial movement of the shaft relative to the framing to be +- 0.051” given this one degree motion and assuming the motor pivots around the center of its mount. Allowing for an extra 0.05” play to compensate for manufacturing error, the clearance hole in the frame must be 0.4676” (15/32”) diameter with a 0.3125” shaft running through. This will work with the 0.625” OD thrust bearing.

· “Have you done literature to find sensors for high Tesla magnetic field sensor?” – Dr. Delson (2-15-12)

Actions taken: We have done multiple searches regarding high Tesla magnetic field hall-effect sensor on vendor sites. The gaussmeter really caught our eye in terms of ease of use bu We are still conducting literature searches.

Risks and Areas of Concern

· Now that a guassmeter capable of measuring Tesla values greater than 1, we do not have to worry about accurate measurements of generated magnetic fields. We can proceed accordingly.

Milestones

· Receiving ordered parts (7th week)

· Finish machining the iron components and begin assembly of frame. (7th week).

· Have remaining components arrive and build magnet potion in preparation for testing (7th-8th week)

· Test device and create more samples (8th week–end)

Budget

Total spent = $736.45

Remaining budget = 3000 – 736.45 = $2263.55

Michael Porter Purchases = metallic powders = __________

Progress on Report and Webpage

· Website has been updated with any progress made by the team

· Proof of Concept Presentation has been uploaded to website for sponsor scrutiny

· Changes are being made to the website accordingly