Pre-Thanksgiving Rush

Well, last week was a very productive week for our team. We managed to complete our MCM in time to demonstrate it for Mark, our GSI, and while it needs some tweaking (mostly in regards to tensioning the belt system) it worked surprisingly well. We also finished all of our machining drawings--a good thing, too, considering that our machining needs to be completed this week in order to test our finished machine next week. Even though most of our parts are brackets and axles, we anticipate needing a lot of machining time this week to complete all of them. Thankfully, the chassis will be laser-cut from a sheet of plywood...the difficult part of that (positioning the holes correctly in our CAD model) is already completed!

So, this week's goal: to finish manufacturing all of our necessary remaining parts in order to test our machine's operation next week.

Only one week of machining time remains!

Week 11/22 - 11/ 29

This past week, which was abbreviated for Thanksgiving Break, we were completely focused on finishing our MCM (assembly of all the parts we made so far) and all the engineering required for the rest of the design.
When assembling our MCM, we ran into a few things that we were not aware of. First of all, delrin, which is not porous material, does not stick well to ANY types of adhesives, especially the epoxy in our kit (which by the way, does not support shear leads). Our (temporary) solution to this, when were fastening our cap and other parts together was to rough up the delrin first with sandpaper. This works OK for now, but we made need to revisit and modify it if we have time at the end.

Photos and update

Hey all,

Last week was a pretty efficient time for us as a team....We managed to fabricate all of our MCM components, and are now working on assembling a working mechanism. Here are some pictures that Dan took at his house...On top we have the scoop, which was laser-cut from a piece of 1/4" acrylic. In the middle we have the bottom axle of our arm with a pulley mounted to it, and the bottom picture is of our fabricated arm with a drilling block for drilling axle holes. Our goals for this week include completing our MCM module and machining some parts for the machine chassis. After that, we're all headed home for some good food & much needed sleep!

Week: 11/5 - 11/22

This past week has been very busy as we have been concentrated on manufacturing our MCM. We now have all the parts made for this and will assemble them on Monday, Nov. 23. The biggest part of our manufacturing this week was the arm because we had some difficulties with the possesses. First of all, when we went to cut it out on the water jet (out of 16” aluminum sheet), we were not aware that the water jet only cuts a maximum of 23.5 inches long…. our arm was 23.75 inches. We ended up modifying the dxf file and just cutting the last .25” out on the bandsaw.

When it came time to bend the arm, we also realized that the bender in Bob’s shop would not be adequate for such precision bends on a large piece. Thanks to Anna’s connections at Washtenaw Community College, we got access to a large, industrial bender, and were able to create our good bends. This shows the arm after it was bent:

Tentative Schedule Through Thanksgiving Break

Here's the tentative schedule for the next nine days. If we can stick to it this week, we should be able to complete manufacturing of the MCM on Monday next.

• Monday (today): complete waterjet code, axle dimensioning, scoop sketch (laser cut, 1/4" acrylic), final MCM dimensioning/sketching(?) What remains to be done?
• Tuesday: EXAM 1:30-3pm, lathe time [lathe #3], 4:20-6:30pm; work on arm pulleys, MCM axles
• Wednesday: lathe time [lathe #3] 4:20-6:30pm; complete arm pulleys, MCM axles (?) AND waterjet time, 1:30-2:30pm; cut out arm structure, laser-cut scoop?
• Thursday: (many of us have Friday exams....do we need to meet for 250 this evening?)
• Friday: 3 parts manufactured (DUE) (arm pulleys, motor mount (drill holes), MCM axles (top & bottom), arm structure, scoop?)

** looks like we need to have another blog post completed by the end of this week, as well. Thanks, Dan, for posting last night. I'll try to put some pictures up tonight as well**

• Saturday/Sunday:
• Monday: Build MCM in lab
• Tuesday: continue design/dimensioning of machine chassis, arm mount mechanism, rack & pinion system, drive system, gearbox placement, etc. Begin building?
• Wednesday: DEMONSTRATE MCM
• Thursday-Sunday: Thanksgiving break

Week: 11/08 - 11/15

Over this past week we were very busy working on our MCM and the motor assignment. Our MCM work involved revising the design a bit after multiple design conversations with Professor Hart and the GSIs. The biggest thing we determined was that our MCM (arm) was too weak and needed some reinforcements. Also we needed more support for our bushings. Our solution was to make a cap for the top (out of delrin which is smooth enough to act as bushings) and make some braces inside the arm to support across the entire length. The cap (shown here on the arm without the top piece) will also support the motor (which turns a pulley that rotates our scoop) when the top piece is in place.

The cap component was the first part we made this week, on the laser cutter (pics coming soon). It should be noted that it took us a few tries (on small test pieces) to get the correct power and speed settings for the laser, for delrin (to make the correct fits between the notches of the walls of the cap).

In regards to the motor assignment, well... that didn't go well because we burned up our motor. A small miscommunication that led to misalignment in assembly of the gearbox cost us our motor when we put 5 volts to it and noticed it was not spinning. The motor got hot quickly, and smelled like burnt plastic after that. Once the misaligned gears were corrected, the motor still did not work, so we are getting a new one.

Next week: 11/15 - 11/22
- Finish assembly and manufacturing for MCM
- Exam
- Finish engineering for rest of design