Week 13: Final Report, Third Presentation

The third presentation and final report rough draft were the focus this past week, and will continue to be so throughout the week, and possibly next weekend as well. Owing to Thanksgivings break and not being in town, no work was done on the bender this week. However, as stated last week, bender results that matched expectations gave great confidence that the work that we have done thus far is going in the direction we need it to. Therefore, it seems that we have overcome the greatest obstacle in our path, which was the creation of a proper die to produce results exactly as we needed them.

The track improvement team has provided the team with some updated information, as well as their expectations for next semester. They informed us that they intended for us to create the corners for the improved track, but were considering reusing the station sections from the previous year. It so happens that work on the corner sections (in terms of dies) has progressed the furthest, which is beneficial for us. Additionally, corner sections were assumed to be potentially the most troublesome, given the bender type. Comparatively, bends for the station sections are seen as simply smaller versions of the full corner bends that were prepared for and tested, so all signs on work performed thus far are positive.

Week 12: More Positive Results, Foreseeable Future

Recent work includes the creation of one finalized die with radius and arc angle calculated from equation addressing material springback and wanted dimensions for the final track. The bender was able to reliably and repeatedly bend around the die, producing very uniform results. New holes had to be drilled in the aluminum baseplate, both for the die and for the material hold block as well.

The results produced by the bender confirmed that all calculations used are true representations of what to actually expect. This is significant because it means that every other final die that is made according to calculated numbers should work exactly as planned, so work will proceed in that direction.

Less time was spent working on the project this weekend, owing mainly to accumulated fatigue (and lightheadedness on one of the days).

This particular die was for the top corner rail,

with the intent of creating the corner bend in one go.

The baseplate was drilled for the die and material

hold block. All parts are ready to go in this pic.

And it was raining outside.

The first bend from the die was just about 90 degrees

(matching the concrete lines on the floor) and at the

radius intended. Couldn't have gone better, and

successive bends had the same results.

Week 11: Somewhat Positive Results, Work Still Needed

Utilization of the wheel on the bender arm worked as planned, producing the curve that was shown in last week's post. Upon using the wheel to bend a second piece of test material this last weekend, the bender failed to produce the same result. Investigation revealed that the 5/16" bolt used to hold the wheel in place was not strong enough, and had deformed due to the shear stress applied. A 3/8" bolt was subsequently tested, and subsequently failed as well. A simple design using 3/4" aluminum bar stock instead of a bolt, and 2" aluminum bar stock instead of a wheel fared better, resisting the shear force applied. Interestingly enough, the plywood die did not appear to deform in shape in spite of the loads applied.

Free, sturdy table legs were acquired over the weekend, and plans have been made to create a table for the bender for the Spartan Superway workshop. The table will be made '2x4's and aluminum diamond plate or plywood (all of which was free), along with some bolts purchased from the local hardware store (Lowes).

As a side note, the bill of materials for the project was due on November 15th. The many materials used in the build thus far have been free or have been scrap left over from previous years. Owning the many tools used and doing the work myself, labor and tooling costs are zero. As things currently stand, the cost for our material bender may be no more than the nuts, bolts, and washers that are used to hold everything together. This would be a large win for the Superway project, without even needing to calculate what would have been the comparative cost had the work been done externally.

Taken during the actual bending of material.

Comparison pictures of a sketched radius and actual bent material.

The match is fairly close, need to ensure a total 90* bend.

See above picture.

Bent bolt after material bend.

Table legs, to be used for Spartan Superway workbench.

Dies made thus far.

Replacement roller, with 3/4" aluminum bar stock.

Required new holes in the aluminum bar.

Week 10: Work Revision, But Progress As Planned

Work continues on the build of the bender and necessary dies. Utilization of a sample die and bending of material by hand resulted in a bend very close to what calculations determined, being 10.4” radius die for a 20” radius bend of 6061 aluminum flat stock of 1.5” by 0.25”. The main work completed this weekend included the manual bend of material as proof of concept and verification of calculations, the viability of the current design, and that work yet continues according to plan.

There is a general update to the specific tasks listed on the Gantt chart, resulting from realizations during the build process. Instead of planning for two separate builds for benders and die creation in between, work will be put towards utilizing the single design made thus far, with an emphasis on die revision as necessary.

Looking forward to bender use in the Spartan Superway workshop (away from my home, where I am currently working on it), a means of support will be required. At present, the bender sits atop an old lathe stand, which has both the size and the weight to accommodate the forces applied to it, and resist movement. The lathe stand was obtained with the intent for personal use, so an alternative support will be investigated for permanent installment in the Spartan Superway workshop.

The bend on the 1:1 die, resulting in a radius too large to be useful. 

 Size of the die (10.3") according to calculations to match the 20" radius.

The material bent on the 10.3" die compared to the 20" radius. 

The 10.3" die attached to the table, with holding block clamped. 

Milling flat of the aluminum holding block.

Reaming of the aluminum block hole after drilling.

The aluminum block bolted to the table with corresponding pin.

Some of the many drill bits used thus far, as well as calipers.

Week 9: Prototype Problems, Course of Action

The group presentation can be seen in the week eight post for the group. As was calculated and shown in the presentation, the current bend radius should have been much too large to create a permanent bend as intended and necessary. The results were confirmed when the material was bent around the radius by hand, with minimal permanent bending occurring. The calculated radius for a 20" bend was found to be 10.4" for the die, which will be attempted this coming weekend. The overall design of the bender has yet to be disproved, however. This past week, less effort was put towards the project, owing to obligations for other courses, including test preparation.

The die, with a radius of approximately 20".

Material after having been forced about the die.