Procedure on construction of each of the following subsystems:

Transcription

1 Procedure on construction of each of the following subsystems: Chest Cavity with Fittings Diaphragm with wood support Lungs Ribs + Spine Stand (including rib movement system) Section 1: Chest Cavity with Fittings The pressure vessel for the chest cavity was a custom mold crafted from GreenGuard XPS foam available from Lowe s. The link to exact product used is here. The following procedure outlines the process for fabricating the mold using the 3D printed rib cage as a guide for sizing. Cut the foam into 5 panels that are 7 x8 using a sharp edge knife. Glue the faces of the board to the back of the next panel using a thin layer of wood glue. Apply pressure to the assembly and allow 24 hours of drying time to ensure the wood glue has set. Using the 7 edge as the bottom of the model, trace the shape of the bottom of the rib cage onto the top of the foam block. Cut away the foam at a diagonal and fit the base of the rib cage into the foam block. Cut away a channel for the spine to fit into the mold. Ensure that the channel is angled to prevent an extreme draft of 90. Using a large foam grater, slow shape the top of the foam block to match the top of the rib cage. After every use of the grater, replace the rib cage over the foam block to ensure that too much material is not removed between fittings. Ensure that the mold fits tightly within the rib cage. Once the entire rib cage is fit over the foam, remove the rib cage, and sand down the edges to ensure the mold can be released. Once the mold is complete, ensure that the thickness of the plastic that is to be thermoformed is not greater than ⅛ (0.125 in). The plastic sheets used in the thermoform can be ordered here. Contact the Industrial Design Department to obtain access to the thermoformer. Once you have the mold, PETG sheet to be formed and access to the equipment, make an appointment to use the equipment. The instructions for using the thermoformer are provided by the instructor in the design center on the 4th floor of the Vignelli building. Additional information: Fine talcum powder can be used to facilitate the removal of the plastic sheet from the foam mold.

2 Do NOT drop the thermoform on the floor to release the mold. The brittle nature of the plastic will develop cracks that may prevent it from being sealed by the diaphragm. Eye hooks can be screwed into the mold after the thermoforming process to assist in releasing the mold. Ensure that the base of the mold is larger than the overall diameter of the mold. This will ensure a better thermoform with minimal webbing. Use heated(blow torch) metal drill bits to make holes for fittings.

3 Section 2: Diaphragm with wood support Summary: The diaphragm sheet is composed of 2 layers of Ninjaflex with a center attachment point for a load cell and a handle. The top and bottom load cell attachment pieces are connected through a hole that must be cut in the diaphragm. The two parts are fused with a few drops of 99% acetone and sealed with gorilla glue. The top load cell attachment file is placed on the side of the diaphragm that will be inside the chest cavity. This assembly is then overlaid and glued onto the wood frame that is a 9.5in square with holes to allow for bolts to hold the diaphragm sheet and 2 parts of the frame together. Print Parameters: All files are too scale

4 Use same printer parameters as in Rib Cage Manufacturing Guide but with 10% infill Section 3: Lungs Pink Spray Paint Duct Tape 12 x 12 x ⅛ Buna N Rubber Sheet Lung Stencil Bubble Wrap Gorilla Glue Black Permanent Marker Scissors Beaker Whoopee Cushion from Dollar General Clear RTV Silicone Adhesive Sealant (2) 2 long plastic tubing, 1/2" diameter Rubber band or twist ties Procedure: 1. Trace the lung stencil onto the Buna N 2. Rubber Sheet four times with the black permanent marker. 3. Cut the four shapes out with the scissors as shown in Figure L1. 4. Measure out 0.15L of bubble wrap utilizing a beaker for each lung to represent residual volume. 5. Using gorilla glue, attach the bubble wrap to the center of one side of the cut out rubber as shown in Figure L2. 6. Glue the two sides, enclosing the bubble wrap, together. This will result in the creating of two, or one set, of lungs. Allow for a 24 hour drying period as shown in Figure L3. 7. Reinforce the glued edge by cutting small pieces of duct tape and secure around the glued lining and shown in Figure L4. 8. Spray paint the entire with pink spray paint. Allow for a drying period before spray painting the opposite side. 9. Test by blowing air into the lung and feeling for any air leakage. In case of leaks, seal with added tape and re-paint. 10. Repeat steps 3-6 with the whoopee cushion from Dollar General. The stencil does not need to b used as the volume of the whoopee cushion is the same as what is needed for the second set of lungs. Therefore, the whoopee cushion just needs to be cut open, along the seal, and this will suffice. 11. Using the RTV silicone adhesive liberally, secure the ½ diameter tubing inside the opening of each lung. Leave a small portion (½ inch or less) of the tubing exposed to the outside of the lung.

5 12. Wrap the rubber band or twist tie around the rubber surrounding each piece of tubing. Leave on for at least 24 hours to allow silicone to cure. Figure L1. The rubber is cut out via the stencil. Figure L2. The bubble wrap was measured out and secured to the lung via glue.

6 Figure L3. The two sides of the lung are glued together, encasing the bubble wrap. Figure L4. The lining of the lung is reinforced with strips of duct tape. Section 4: Ribs and Spine Summary: The diaphragm sheet is composed of 2 layers of Ninjaflex with a center attachment point for a load cell and a handle. The top and bottom load cell attachment pieces are connected through a hole that must be cut in the diaphragm. The two parts are fused with a few drops of 99% acetone and sealed with gorilla glue. The top load cell attachment file is placed on the side of the diaphragm that will be inside the chest cavity. This assembly is then overlaid and glued onto the wood frame that is a 9.5in square with holes to allow for bolts to hold the diaphragm sheet and 2 parts of the frame together.

7 Rib Print Parameters: 0.5 scale from native.stl,.thing files are to scale and have attachment pieces Makerbot Replicator 2X w/ kaptone print bed Makerbot Print software ABS 235C extruder temp, 110C bed temp 0.2mm layer height 100% infill Raft Extra supports Standard speed Very aggressive ABS/Acetone solution***(experimental) Ligament Print Parameters:.stl is to scale Lulzbot Taz 4 w/ painters tape and purple glue stick on print bed Ninjaflex MatterControl print software Extruder head z offset ~½ that of normal ABS printing Experimentally derived print parameters:

8 Section 5: Stand Flat Screws (10) 9 Wood Posts (4) 16 Wood post 12 x 12 Plywood Black Matte Spray Paint Clear Matte Spray Paint #37 Drill Bit Phillips Head Drill Bit Power Drill Plastic Eye Hooks (2) L-Brackets (2) Procedure: 1. At the machine shop located at KGCOE , ensure the wood posts are cut to 9 and the wood slab is cut in a 12 x 12 square. 2. Secure the wood posts and pieces of plywood utilizing bar clamps.

9 3. Pre-drill two holes for screws into one side of the four posts and piece of plywood. 4. Use an electric screwdriver to secure the 8 screws through the plywood so that the bottoms of the stand is constructed as shown in Figure S1. 5. Cut a wood post to Secure the post to the stand by pre-drilling two holes at the bottom. Utilize two L-brackets and two screws to attach the beam to the piece of plywood. 7. Using a #37 drill bit in the machine shop, pre-screw a hole into the top of the 16 post. Twist the plastic eye hook into the hole until secure. 8. Repeat step 7 and attach the second plastic eye hook 6 up the 16 post. The second eye hook should be facing the innards of the stand. 9. Upon completion, spray pain the built stand utilizing the black matte spray paint. Seal in the spray paint utilizing the clear matte spray paint. Figure S1. The screws being drilled into the predrilled holes. Procedure on assembly of the entire system: