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

6. Degree of Obtrusion

• How much the anti-stick solution will alter the dimensions of the fixture and specimen (how thick is the solution)

Results:

Parchment Paper = 41 pts, Wax Paper = 38 pts, Saran Wrap = 45 pts, PFTE Tape = 27 pts

In conclusion, Saran Wrap is the best anti-stick solution because it is the most effective and easy to use, a well as being thinner than all the rest of the materials.

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

https://www.seattletimes.com/life/food-drink/wax-paper-and-parchment-paper-are-not-interchangeable-plus-a-recipe-parchment-baked-salmon-with-orzo/

-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 an array of support pieces on the tray. Two of the longer spacing supports are required per specimen and 3 of the spacing supports are required between two specimens.

   1. You may need to change the dimensioning of the support beams to customize it to your specimen.

   2. Print according to the number of specimens that are cured.

2. Remove the printed pieces.

Step 2: Machining Cover

Step 3: 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

5. Place saran wrap on the flat surface where the curing fixture will sit. Tape down saran wrap to surface.

Spacing supports

1. Double wrap supports with saran wrap

2. Tape off loose ends 

Step 4: 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. Correct placement shown in fig. 4.

   

   Figure 4: The adhesive specimen is shown in blue. The support material is coloured in orange and labelled. They hold pieces on the same level in place.

3. Place three support pieces perpendicular to the first specimen at each joint to provide support for the next one. Continue placing specimens down until the tray is full or until you are satisfied with the number of specimens. If the tray is not full, wrap a flat piece of wood in saran wrap and place it flat against the last specimen. Put a weight behind the piece for support (i.e. a piece of steel, a block of MDF, a rock, etc.)

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.

Bill of Materials

-pictures with assembly

-bill of materials w/ quantities + descriptions

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

Material Specifications