Introduction: Stamping Machine for Small Series EVA Foam Phone Case

EVA foam is great for DIY projects. In addition to its shock absorbing qualities, it’s cheap, easy to form and lightweight. The perfect material for a phone case if you ask us!

In this Instructable, we will explain how to make a stamping tool to easily produce a small series of EVA phone cases. The stamp is a steel die that creates a flat pattern on the foam when heated.

If you design your own stamp, you could use the same principle to make a broad range of different patterns and products.

Step 1: What You Need

- Materials (all sizes are in mm, unless stated otherwise)

  • 1 m² triplex wood panel - thickness: 8
  • 340 x 160 steel plate - thickness: 2
  • Steel plate - thickness: 1
  • 380 x 380 deal wood beam - length 1,8 m
  • Ø10 steel bar, length 900
  • 12 mm door seal brush (12 being the length of the brush without the solid plastic part) - overall length: 330
  • 2 small handles
  • 2 medium handles
  • 480 x 290 plexiglass plate - preferably stiff, about 5 mm thick
  • A few pieces of scrap wood
  • Some wood screws & nails

- Tools:

  • Screwdriver
  • Drill
  • Jig saw
  • Grinding wheel
  • Welder
  • Heat gun
  • Glue gun
  • Laser cutter (optional)

Step 2: The Frame

The frame is made out of the triplex panel and connected by the beams.

Cut the panels to size (check the PDF files in attachment if you are using a laser cutter):

  • Front & back (A & B): 500 x 300mm (x2)
  • Left & right (C & D): 290 x 300 (x2)
  • Bottom 1 (E): 480 x 290
  • Bottom 2 (F): 480 x 215

Cut 4 beams to size: 160

Cut 2 rectangles out of the side panels C & D as shown in picture 1. The distance from the horizontal rectangle to the bottom is 16 mm.

Join the panels with 3 nails in the corners by placing the beams inside of the box. The side panels should be within the front & back panels (picture 2).

Glue the 2 bottom panels together (hot glue or wood glue work great). Put the frame over the bottom and connect with 4 nails (picture 3).

Finally, cut small 2 strokes (width 10) from the triplex wood and stick them to the bottom, 155 mm apart. Make sure to add compliancy to the left side where the foam is to be introduced (picture 4).

Step 3: The Stamp Die

The die will determine the pattern produced on the foam. We sized it for an iPhone 5 or similar size. Simply adjust length and width to fit your phone size.

Cut the 1 mm steel plate to small strokes (height 9 mm) and weld them to the 2 mm plate (picture 5). The outer line is in one piece and can be obtained by folding it to the right shape.

Fold the Ø10 steel bar to shape (picture 6).

Cut 3 beams to 16 mm lenght. Drill a 10 mm hole in the middle of each one. Stick the steel bar through the holes, you can fix it by having screws holding it to the beams (picture 7)

Drill 6 holes in the 2 mm steel plate and screw it to the beams (picture 8).

Step 4: The Cover

Cut a 30 x 50 triplex panel with a 20,5 x 40 rectangle hole in the middle (picture 9).

Cut the profile shape of the beams (38 x 38) out of the corners of the plexiglass panel and glue it to the frame (picture 10).

Screw the handles.

Step 5: Final Details

Screw the medium handles to the sides of the frame to make it easy to carry.

To lock the foam once it's in working position, we used the vent hole of the frame of an old computer and glued it to an EVA foam strip (picture 11).

Make a holder for the steel bar (picture 12). This is necessary to hold the die in the right position when heating it. The deign here isn't very 'elegant', let us know if you come up with a better solution!

Glue the brush seals to the sides and place a small triplex strip at the top (picture 13).