Updated Schedule

Updated Schedule :

http://spreadsheets.google.com/ccc?key=0AofiS4ctRuXxdGgzeGFTeGMxSU55TzZEZjNEZlpMUUE&hl=en

To do: Week of Nov 30- Dec 4

Lathe 4 cart wheel axles for the e-clip grooves and attach wheels to the axles.

Laser cut holes in top of cart for lead screw and to attach scissor arm base.

Drill holes in cart horizontal pieces for the wheel axles to go through to connect to the motor.

Make Motor base to mount the motor for the wheels and coupe to shafts

Finish all lead screw machining that was started last week

We recently discovered that is it very hard to lift the scissor arms up so we need to engineer and machine a pulley system to help lift and retract scissor arms.

Assemble everything/ epoxy anything else that can’t attach using screws

Week of November 23rd

This week, we finished assembling the MCM (hopper+scissor arms), we cut and drilled holes in the cart bases, we finished drilling holes in the L-connectors, and we started manufacturing the leadscrew module.

We already had the springs/spring flaps secured to the hopper columns, and all of the columns secured to the hopper top. We finished the assembly of the hopper by weaving the kevlar thread in a Z-pattern through the hopper columns, so the PPBs would not fall out of the sides of the hopper once it was raised out of the slot. This Z-pattern keeps the columns from spreading too far apart. We secured the scissor arms to the scissor arm base that is screwed on to the hopper top with two of our scissor arm axles. The caps on the pins were interfering with the retraction of the scissor arms, so we had to cut out small notches in the scissor arm base with the mill to allow the scissor arms to retract more completely. We put washers on the pins in the scissor arm base to keep the two ends of the scissor arms from sliding to the opposite side from where they are supposed to be. We demonstrated our MCM for MS8 in the slot, and we realized that we also need to have something constraining the hopper columns from compressing toward eachother. We decided to add spring steel to the sides of the hopper to reinforce it.

We cut the cart bases to length out of the square tube stock, using the band saw, and we drilled holes in them using the drill press. We also used the drill press to finish drilling holes in the L-connectors.

We cut the brackets that will be holding up the leadscrew with the band saw, out of the aluminum 1/2" square stock. We then went to the mill with these brackets and started the process of tapping holes in them in order to secure them to the cart top with a screw. We are using the #8-32 screw, so we used the #29 screw (from the drill/tap chart), and we drilled holes in them. We then took these brackets to the tap, and used the #8-32 tap.

Next week we will have to finish manufacturing and assembling the leadscrew module, turn the wheel axles and couple them to the wheels, and couple the motors to the leadscrew and wheels.

Scissor Linkage Video!

Week of Nov 16th

This week we finished the scissor arm bases, drilled holes in our vertical supports, made our L shaped supports for the cart, cut holes in the cart top, and assembled most of our MCM.

We made the scissor arm base with the mill. The holes in the vertical supports and the in the L shaped supports for the cart were made on the drill press. The holes in the cart top were made on the laser cutter.

To assemble the MCM (the hopper plus scissor arms) we first threaded then glued the torsion springs to the velcro/spring steel flaps and attached them with kevlar thread and glue. We then wove the kevlar thread in X shapes around the hopper columns and cross pieces and glued the thread in place. We also screwed the scissor arm base to the top of the hopper. We then glued the column supports in the hopper top.

We then found out we put the spring flaps on the wrong way. Therefore, we carefully extracted the hopper supports from the hopper top and turned them 180 degrees. We also had to take the spring support off the smallest column to put it on the column that was previously empty. We found out that including the glue and kevlar thread the column supports were too wide to fit in the arena so we now have to shave down the width so that it will fit in the arena.

Next week, we will cut and drill the holes in the horizontal cart pieces since we traded for more square tube stock with Ram Rod. We will finish drilling the holes in the L shaped connectors and weave the kevlar around the column supports. We also need to drill the holes in the cart top for the lead screw.

Laser Cutter Video

Week of November 9

This week was the beginning of the long process of manufacturing our machine. On Sunday, we met as we usually do in the Undergraduate Library where we came up with a schedule for the week. We wanted to get all of our engineering for the entire machine done, as well as update our CAD drawings and solid model with this. We also wanted to make our scissor arms, hopper top, pins, hopper columns, cross pieces and horizontal supports, and the spring plates. This collection of parts and pieces required a great enough variety of machining processes that it would fulfill our requirement for MS7.

On Monday, we went for it all and decided to cut our scissor arms and hopper top out of the acrylic on the laser cutter. We were pretty excited, but we had some trouble with scaling in the Bobcad program for the laser cutter. After having to entirely redraw our parts on the computer in the machine shop, we successfully cut out the scissor arms, but the hopper top came out very wrong, with holes way too small and edges not parallel. Luckily, we had extra acrylic, so we decided we would work out those problems and try again later in the week. We were also able to cut out all 13 of our 1" pins for the scissor arm joints out of the 1/4" aluminum rod on the band saw.

On Wednesday, we came prepared with another file for the hopper top, with everything saved in english units (which seemed to be our problem from Monday), and cut the hopper top out with relative ease. We also cut out the longer pins for the scissor arms that go through the scissor arm bases, and cut the scissor arm bases to length on the band saw. We also spent a lot of time working on the motor assignment.

On Friday, we cut out the top of the cart out of plywood on the band saw and set up for the holes in the scissor arm bases. We were hoping to have gotten those cut, but we didn't have some of the correct drawings with us, so we had to wait until this coming week.

Throughout the week, we were busy setting up trades to get some of the extra materials we need. The Victors agreed to give us 6" of 1/4" rod for 4" of the 90 degree angle stock, and Team 42 gave us their 24" of aluminum tube stock for the remaining 8" of our 90 degree angle stock. We also purchased a package of caps for our 1/4" pins for the scissor arms from McMaster-Carr.

Please enjoy this video of the laser cutter. It is awesome.

Updates from the Week of Nov 2

This week we finished all the engineering for the MCM since it was due on Friday. Our MCM consists of the five column hopper and the scissor arm linkages. This week we decreased the height of the scissor arm linkages so that we were able to add height to hopper columns. The added height allows each column to hold nine balls, this way we can pick up all of our balls and some of our opponent's balls. For the engineering of the MCM, we had to figure out which materials we were going to use. The scissor arm links and the hopper top will be made out of acrylic since it is light and strong, this will also be easy to cut out on the laser cutter. We are using the welding rods for the columns since they are thin and will bend a little allowing the balls to move around within the structure and they won't break if they have a slight impact on the bottom of the slot. Torsion springs that we ordered from McMaster will be at the bottom of each column holding up the balls attached to the columns by horizontal welding rod. We are using pins to link all the scissor arms together (hopefully using caps to constrain them, if not eclips). The scissor arm base will be made out of the square tube stock using the mill.

We also decided to work in the machine shop on Monday to use the laser cutter for the scissor arms and hopper top. We will hopefully have enough time to use the bandsaw to cut the pins as well.

Next week we will hopefully finish all the engineering for the rest of our machine and revamp our schedule. We now realize that some of our timetables cannot be met given the time and machines available in the machine shop, especially since 250 is not allowed to use the mill at all next week. We hope to have most of the manufacturing for our MCM done this week as well.