Buying individual precut pieces of styrofoam is not cost effective in a mass production scenario. A variety of polystyrene bulk sheet products are readily available either from local building supply stores, or online. Cutting polystyrene is easy and can be done using a variety of methods.
12" X 12" X 1" = $3 to $6 each | Bulk Sheet
32 square feet X 3/4" = $8 = $.25 each
1. Utility Knife & Straight Edge (rough edges, messy)
2. Circular Saw, Table Saw, or Band Saw (flat edges, fast, but messy)
3. Hot Wire Cutter (flat edges, fast, no mess)
When cost per unit is a priority consideration, comparative shopping and a willingness to choose a generic instead of brand name is helpful.
750 square feet = $135 = $.45 each | Generic Extra Heavy Duty Foil
750 square feet = $46 = $.14 (prices don't include S&H)
You pay more for convenience, buying small rolls of tape on a disposable dispencer with cutter is not cost effective in a mass production scenario. Bulk rolls can be dispenced by hand, and cut with scissors or a knife.
66' = $3 = $.05/foot | Bulk Roll
327' = $4 = $.01/foot
The styrofoam that I used for this experiment is bead-type expanded polystyrene which is denser and more rigid than the floral foam that is currently being used. It appears that the floral foam crushes more easily and retains the shape of the impacting object with more resolution than the bead-type polystyrene. The main sensing element however is the malleable aluminum foil surface layer which records the impacts by becoming embossed with a negative of the impacting object.