Adhesive Curing Fixture

generally rectangular sections that are 25 mm x 100 mm x 1.6 m-

Overall To-do: -apply feedback to the confluence, detailed and clear manufacturing plain

Designed by: Ethan Sobkowich, Yanshen Zhou, Winnie Lin

Supervised by: Tommy Tran

Purpose: Fixture for preparing adhesive test specimens of similar sizes (25 mm x 100 mm x 1.6 mm)

Needs statement: There exists a need to create a fixture that can hold specimens a stationary position for adhesive curing while being adjustable to different specimen sizes.

Constraints:

Functional Requirements

• All three adhesive joints curing at the same time

• Constrained movement in three axis

Criteria:

• Maximize number of specimens that can cure at the same time

• Can be machined in-house

• Minimize time required to manufacture

• Maximize adjustability to different size

• Minimize costs for materials and manufacturing

-constraints: needs, functional, non-functional

*can organize into checklist

Testing between:

• Steel to steel

• Composite to composite

• Steel to composite

The idea behind this design is to create a “tray” (Fig. 1) to constrain movement in the outer edges of the specimens. Multiple specimens can be cured at the same time in this tray. The spaces between each individual specimen will be separated with ladder-shaped 3D printed jigs (Fig. 2) as well as the spaces between each adhesive joint on a specimen (Fig. 3). A flat board/weights will be placed on top of all specimens to add pressure.

Fig. 1: An image of the base tray for the testing jig

Figure 2, seen below, is a side view of one test specimen. This is how they will be aligned in the jig.

Fig. 2: Side view of specimen in tray

Figure 3 is an example of how the jig will clamp the test specimen. The green planks are aligned as seen in Figure 2. A flat board should be placed on the ground first and then the specimens should be placed on top of it. Then, a flat board (like a piece of plywood for example) will be placed on top of the specimens and weights will be placed on top of the board to apply downwards pressure on the z axis (purple). There will be four longer boards, two per axis, that run parallel with the sides of the specimens on the x and y axis. These boards are in place so that pipe clamps can apply pressure from the sides (red). The idea is that the blue square-shaped pieces will ensure that the test pieces line up properly under clamping force. It is possible that more thin brown square pieces may need to be added in the middle section. Nine of these specimens can be lined up at once inside of this tray.

Fig. 3: Example of how specimen will be placed in tray

Adhesive Anti-Sticking Solution

Adhesive to be Used: 3M DP 420 and Henkel EA E-120HP (both epoxy adhesives)

For Epoxy:

• Parchment Paper

• Wax Paper

• Polyethylene sheeting (saran wrap)

• Mold-release compounds for epoxy

• PTFE Tape

Criteria Overview:

*ranked in order of most important to least important

1. Effectiveness

• how well the solution prevents the adhesive from sticking onto the fixture

2. Ease-of-Use

• how quickly the solution can be applied and removed from the fixture

3. Feasibility

• how easy is it to obtain the solution; is it widely available?

4. Affordability

• how much the solution costs

5. Maintenance

• how often does the solution need to be replaced on the fixture

Source: https://www.youtube.com/watch?v=uLH1MsaHnX4  

-create eng. design spec. chart

-define effectiveness

Overall: Saran wrap is the best material to use due to its ease-of-use and effectiveness. It is also one of the more affordable options and is easy to maintain.

-other factors: interference with test specimen (wrap thickness)

Assembly Procedure 

Step 1: Printing

1. Use PrusaSlicer to print 2 CAD models on the same tray. The follow CAD files are to be printed in this step: one with three sides of a rectangle and one with a remaining, detached side of the triangle.

2. Remove the printed pieces and print multiple support beams.

Step 2: Anti-stick Solution

Tray

1. Cover the inside of the tray with saran wrap

2. Press down on the inside edges and corners to try and flatten the wrap as much as possible

3. Trim excess saran wrap off the sides of the tray if needed

4. Tape down sides of saran wrap to the outside of the tray to prevent movement of the wrap

Ladder 

1. Double wrap ladders with saran wrap

2. Tape off loose ends 

Step 3: Placing Specimens in Place

1. Align first specimen in a corner with the longer side of the specimen touching the shorter side of the curing fixture.

2. Wedge a support fixture along the specimen to hold the individual pieces in place.

3. Place two support fixtures perpendicular to the first specimen to provide support for the next one. Continue placing specimens down until the tray is full.

4. Place a flat board on top of the tray and specimens. The flat board should also be wrapped in saran wrap. Place a weight on top of the board.

-pictures with assembly

-bill of materials w/ quantities + descriptions

-some explanation for procedure (decision behind assembly process; why?)

Material Specifications