Wave

A pan-tipping assistant that transforms and makes cooking accessible to those with limited hand strength or wrist mobility.
CHALLENGE
My mother loves cooking, but with age, she experiences increased wrist strain that makes it challenging to hold a pan, especially in one hand while the other hand is serving.
SOLUTION
  • Design and manufacture a stand capable of holding and tilting a pan
  • Relieve stress placed on wrist and improve cooking accessibility for those with limited hand strength or wrist mobility
MATERIALS
Aluminum 356, Thermal Oak Wood, Threaded Brass Inserts, Stainless Steel Machine Screws
ROLE
Product Designer
DURATION
5 weeks (April - June 2022)
SKILLS
Design Sketching, CAD Modeling, Rapid Prototyping, 3D Printing, Manufacturing
SKILLS
Patternmaking, Casting, Milling, Woodworking, Finishing

01 | Overview

Revolutionizing Cooking with Effortless Control

ME103: Design and Making is a mechanical engineering course at Stanford where students are tasked with designing and manufacturing a product of their choosing. This involves creating sketches, product use-stories, rapid prototypes, 3D printed models, CAD documents, manufactured test models, and ultimately, a customer-ready prototype.

Within this course, I developed "Wave," a pan-tipping assistant designed to make tilting a pan effortless, much like riding a wave.

02 | Ideation

Concept Exploration

I envisioned having two hooked stands that would support the pan, assuming the pan had two handles.

Hooked design allows both main and helper handles to rest on stand while preserving rotational motion.
Experimented with different bases (eg base with opening for plate to sit in).
Played around with varying thicknesses and depths, resulting in intricate pattern design.

03 | Rapid Prototyping

Bringing Ideas to Life

Fabricated two stand prototypes from pink foam to assess functionality and visual appearance.
Created simple base from cardboard and assembled stands on top to evaluate complete product assembly.
Intended as gift to mom, I replicated her favorite wok with cardboard and the exact dimensions. The wok could successfully tilt while resting.

04 | CAD Modeling

Digital Fabrication

  • Sketched critical part with spline tool on Fusion 360
  • Extruded sketch 0.375” (half of desired width)
  • Filleted and drafted all angles by 5° to get easier pull when casting
  • Mirrored entire body over yz-plane to get entire part
  • Full assembly consists of wooden base and two critical parts. Critical parts are fastened to ends of base.

Challenges

One significant challenge during the CAD modeling process was filleting and drafting all the edges. I encountered frequent error notifications, especially because there were multiple depths in my pattern.

My original approach was to create and extrude sketches on top of existing extrusions to increase the thickness of specific parts, but this didn’t work as the overlaid sketches and the original sketch would often be slightly misaligned. After much trial and error, though, I ended up creating my entire design in one sketch and then extruded each enclosed space by a unique amount.

05 | Sandcasting

Patternmaking

Printing the Pattern

    • 3D printed half of my critical part twice with polylactic acid (PLA), resulting in two mirrored parts, each half the desired width
    • 3D printing double-sided pattern would ensure consistency among the two parts, especially since the shape was so organic
    • Included two holes for easy alignment when attaching to the patternboard

    Making the Patternboard

      • Used drill and table cutter to create board out of 1” “no void” plywood
      • Positioned pattern on one side and marked where to drill alignment holes
      • Inserted 3/16” dowel through holes to secure other half of pattern onto other side of the board
      • Cut out general shape of gate & runner with bandsaw from 1” thick scrap wood
      • Drafted gate & runner with disc sander, spindle sander, and sandpaper at 10° angle

      Finishing the Patternboard

        • Sanded and sealed everything with shellac to fill pores in the wood and pattern

        Ramming

        Each ramming session to sandcast my critical part required 100lb of sifted and mulled sand.

        Challenges

        It took several tries to get a successful pull. The sand would often break at the grooves, the edges where the pattern caved inwards, and near the gate and runner. To avoid the latter challenge, I could have used one runner instead of two. This would have gotten rid of the enclosed space between the pattern and gate, which was susceptible to breaking.

        examples of unsuccessful pulls: common areas of sand breakage are seen in the grooves, edges, and near the gate and runner

        In the initial pours, the metal was very porous, suggesting that a higher temperature was necessary. It was also apparent that sand broke and entered cavities that should have been filled exclusively with metal. As a result, the grooves of the pattern were lost, resulting in highly textured casted parts.

        Key Changes

        Changes to Board

        Increased pattern draft by heating wax and making fillets around the entire pattern/grooves to pull the pattern from the sand

          Changes to Ramming Technique
          • Added more parting compound before ramming up to help remove pattern from the sand. Worked but some parts of sand still broke off, especially in the grooves
          • Brushed on graphite in the grooves and edges of the pattern to help remove it
          • Used less force when ramming up lower layers of sand so each layer could still latch on to each other but not be so packed that board is difficult to remove
          graphite and wax fillets added

            Successful Pulls

            06 | Post-Machining

            Facing

            To smooth the casted parts’ surfaces, I used a strap clamp setup with angle blocks to secure the casted part to the mill. I then used a shell mill tool to face off the front and back faces of the part and repositioned the clamps in between to face off the areas initially covered by the clamps.
            Since the casted parts would be fastened to a base, I needed to smooth out the bottom of the stands as well. To do this, I used a level tool and the right angle block clamp setup to ensure the part was straight and then used the shell mill tool to face the bottom.

            Drilling & Tapping

            The stands would be secured to the base with fasteners, so I drilled two holes into the bottom of each part and tapped threads for 10-24 machine screws.

            07 | Woodworking

            Cutting

            Used 0.75” thick thermal oak wood to make the base. Cut down to size with the table saw so that there was a 0.5” margin. Then used router to cut out nice design along edges.

            Drilling & Countersinking

            Marked where casted parts would stand on base according to the holes in my parts. Drilled corresponding holes into the base and used countersinking tool to countersink each hole and have machine screw flushed with the wood. Then screwed in threaded inserts to fasten the machine screws.

            07 | Finishing

            Sanding and Buffing

            1
            Since the pattern needed a lot of draft, there was excess metal around the part after casting. I used a metal file and belt sander to clean off the edges as much as possible.
            2
            I sanded the faces and edges with an orbital sander up to 600 grit. After, I transitioned to using sandpaper and sanded up to 1200 grit on a granite table for a flat work surface.
            3
            After sanding, I buffed and polished all the faces and edges so that everything had a shiny, polished finish except the grooves, which kept the casted finish.
            4
            I finished the wooden base with mineral oil since food could potentially make contact with the stand.

            08 | Delivery

            Final Product

            09 | Reflection

            Key Takeaways

            This was the first opportunity I had to design and manufacture a product of my own. Having come into the class with no prior experience in manufacturing, I was intimidated by the amount of knowledge and skill I would have to pick up, but as I spent more time in the lab, I was able to learn how to weld, machine, cast, and woodwork, becoming more comfortable with the various tools, machines, and manufacturing processes.

            I also learned the importance of iteration and troubleshooting. Failure was inevitable during this process, but working through these challenges provided me constant opportunities to discover, problem solve, and brainstorm various solutions. This project has left me with a valuable set of personal skills and an impressive knowledge of new manufacturing and design techniques.

            faithkzhang@gmail.com
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            © Faith Zhang