Elastomeric Coating

Basics

• A term for the Coating of a Product (or Structure/Vehicle, although that may be better addressed on another page) in an Elastomer
• In Product Design/Advertising, it is often Called:
  • ”Rubber Armor”
    • Although this can be a BIT misleading as Latex is rarely used
  • ”Non-Slip Coating”
    • The “grippy-ness” of the Elastomer can help prevent dropping something etc
    • Also can help with the Ergonomics / Accessibility of things, OXO Good Grips is an example of this
    • The Oily/Wet Non-Dominant Hand Test is an interesting test that simulates dexterity issues quite well for otherwise able bodied people
      • Link to the product reviewer’s videos here

Options

Overmolding

• This is the highest quality (industrial) method
• A specialized Injection Molding machine is used such that one “shot” is done shortly after, and directly OVER the previous “shot”
• Often done for the handles of Power Tools etc
  • For instance a “core” of Glass Filled Nylon surrounded by a TPU of some sort
• Features/Finishes can be designed into the elastomeric surface via Injection Molding Design

Dip Molding

• This produces a smooth coating, and can be done with many products (even aftermarket)
• Main issue is it requires some surface prep, is more limited in how it cam be used, and can ONLY be used for a smooth surface

Spray Coating

• Essentially uses an Elastomeric Paint (Akin to that used along with Crumb Rubber in Playground Surfacing (The material used in Playgrounds / Splash Pads etc
• Can form a thin layer + get into “nooks”
• May also be able to be foamed if a Blowing Agent is included
• Depending on coating quality/number of coats etc may present more of a flaking risk than dip coating
  • Especially so if Foamed
  • This also ties into MNP Pollution concerns

Multi-Material Printing

FDM

• A Toolchanger 3D Printer or Hotend Changer 3D Printer can print not only different colors, but also different materials
• For instance PLA and TPU
• Joinery -like features can also be used to interlock the materials

MJF

• Different “inks” could be used
• Similar joinery like structures could be used also

SLS or SLA etc

• These processes do not lend themselves to Elastomer use, short of as a separate part
• SPD could potentially do so if the powders flow well enough to the toolhead+melt/consolidate sufficiently

Concerns

Product Lifespan Concerns

• Rubber Reversion occurs on many older tools and such
• Since it is typically a coating/overmold, removal of the decayed coating is difficult/impossible
  • Also in the process generating M/NP Pollution which isn’t great
    • Flaking Pleather on a Seat or Headphone Ear Cup is a decent analogy, although rubber reversion tends to be “goopier” / sticky at that point

Potential Solutions

Routine Removal+Reapplication

• This would most likely need to be done as a service at a makerspace etc, BUT
  • Pry Off/Rotary Tool Drill Out/Media Blasting wear away/Ablate away the coating/overmolding
  • Depending on design and state of decay may be quite labor intensive
  • Also would generate a ton of MNPs which would need to be captured+disposed of properly

Alternative Fulfillment of the Same Goal

• A Silicon Case / Elastomer Case (if designed properly) could fulfill much of the same functionality/goals (Non-Slip/Skid, “Grippiness”, Shock Protection (from dropping/crashing etc), etc)
• It would be removable, and depending on Product Life Cycle / Spare Parts Availability (re: Phone Cases ; rarely any good/major brand cases for OLD phones etc), User Replaceable
• Main potential issues would be:
  • Difficulty in getting the case on
    • As was the case with “Wiimotes” and their Elastomer Cases, especially those with the “Wii Motion Plus” brick
  • Poor Bond/“Cling” of the case
    • Given that they are not chemically/mechanically bonded, ESPECIALLY if poorly designed/made, they may slide around/have a gap of air that debris could get into etc
    • This could POTENTIALLY be solved via some sort of Adhesive
    • Also via Magnets, although these would add some issues
      • Threaded Inserts may work well in a similar manner while being easily reversable (just remove the sc