DRI: @Aidan Lehal @Salman Rasheed

Project Requirements

There exists a need to design a base that supports the aluminum sheet metal mold and it’s ribs.

Criteria:

• Base needs to be sturdy

• Ribs need to be (perfectly) parallel to each other, and perpendicular to the base in order to ensure curvature accuracy

• Limit cost/try to use material already in the bay

Constraints

• Ribs are being made out of metal

Design Iterations

Aluminum Pipes Base (First Design)

Base Cad: Using pipes already in the bay, a simple frame to support and hold the ribs was crafted. The tubes are 1.25” in diameter and aluminum.

Open

Open

The tubes (grey circular) will be welded together using a jig, and the ribs (Orange) will be welded with the same jig.

MDF Mold:

• Made out of MDF, slots for ribs to be placed, with hardstops at the front and back to prevent movement.

• MDF does not require welding

• MDF base can be reused by removing the ribs from the slots and replacing them with new ones (that fit a different panel)

• MDF will have to be purchased

Aluminum Pipe Mold w/ Slots

• Made out of pipes as cadded above

• Pipes have slots that allow for ribs to be inserted and removed in the event of recycling a mold

• This method uses tube we already have

• This method does not require RIB welding

Aluminum and fully welded/adhered:

• Sturdy and one shape use, very durable

• Requires welding (will need to see what aluminum tubes can withstand) or adhesive

MDF Base (Second Design)

After review of the potential options, an MDF base was cadded. The ability to replace ribs for a different mold was an advantage we wanted to utilize. We also did not require any welding or glue of any sort. We would use cutouts in the MDF to position the planks and wood screws to solidify their position.

MDF base rough sketch:

MDF base submitted for design review 04/13/21:

Next steps:

• Add second screw for the perimeter to horizontal beams (at the slots)

• Add inner and outer 90 degree corner brackets for additional support

• Find out woodshop's CNC envelope

  • 8'x4' (one MDF sheet will fit)

Updated base w outer and inner brackets + screw holes:

Manufacturing Plan for MDF Base:

1. CNC out rib, side, and hard-stop planks

2. Use a 90 degree angle clamp, or two clamps and a square to screw a bracket into a side plank and hard-stop plank. Repeat for all four corners to form a rectangular frame.

3. Screw a bracket onto either side of a rib plank, repeat for all the rib planks.

4. Use the 90 degree angle clamp to screw in the rib planks to the side planks, as well the a bracket on each side of the rib planks to the side plank.

Materials List:

• 8 Rib Planks (cut to length with slots)

• 2 Side Planks

• 2 Hard-stop Planks

• 20 Aluminum Brackets (https://www.homedepot.com/p/Everbilt-2-1-2-in-Zinc-Plated-Double-Wide-Corner-Brace-8-Pack-12434/315016358 )

• >150 3/4” Wood Screws

• Impact Drill/Drill/Screwdriver

• 90degree Clamp/Blocks

• Shims the same height as the clamp/blocks

Aluminum Extrusions Base (Current Design: 2021-06-30)

Based on MDF’s properties, the team was unsure if tolerances between the rib slots and alignment features would be to tight or too loose. Additionally, without a clearly defined way to secure the ribs in place while ensuring all ribs remained parallel to each other, MDF seemed like it would be less precise than required for this application. Moving back to aluminum but opting for an aluminum extrusion base would be ideal because the channels in the extrusions would act as linear slides for the ribs to be aligned correctly, reducing the amount of in house machining we have to do.

Aluminum Extrusion Pros:

• Reusable for any base/project after (no permanent deformations to the tubes)

• Durable

• Little machining required

• Easily adjustable

• Welded or fastened L brackets to the ribs, ensures stiffness and perpendicularity for the ribs

Aluminum Extrusion Cons:

• More expensive than MDF

The brackets are set to the desired location beforehand and tightened in place on the extrusions. Then the ribs would be either welded or fastened to the brackets.

Note: The brackets come with the hardware to attach to both the rib and the extrusion if needed.

The ribs can attached to brackets at multiple points, each colored “X” represents a different row pattern of brackets to be to the aluminum extrusions below. Depending on the amount of welded brackets, aluminum extrusion crossmembers can be added or removed as needed. (e.g. the blue row indicates that each rib has 6 contact points (including ends), and the red row indicates 3 contact points (including ends), etc.).