In mold labeling
The packaging version of the same idea.
In mold labelingProcess guide
In Mold Decorating
Wood grain on a car trim strip, the brushed metal ring around a washing machine dial, the icons on a rice cooker lid. Many of these were decorated inside the mold. The trouble is that IMD is used as a name for two quite different processes.
The naming problem
One acronym, two processes
Suppliers, film makers, and buyers do not use the terms the same way. Sort out which one is meant before comparing quotes.
In the first process, a long foil runs through the mold from one reel to another like a typewriter ribbon. Each shot presses resin against the foil, the decoration layer sticks to the part, and the carrier film peels away when the mold opens. Some people call this IMD. Others call it IMR, for in mold roller or release, to make clear that nothing but ink stays behind.
In the second process, the printed film stays on the part for good. It is printed flat, formed to shape, trimmed, and placed in the mold as an insert, and the resin is molded against its back. This goes by IMF, INS, film insert molding, and, just as often, IMD.
In both cases the decoration is molded in rather than added later. They differ in how deep a shape they can cover, how the surface wears, and how much tooling sits outside the mold.
Side by side
Foil transfer and formed film inserts compared
IML is included because it is the same idea applied to packaging.
| Point | Foil transfer (IMD / IMR) | Formed film insert (IMF / INS) | In mold label (IML) |
|---|---|---|---|
| What stays on the part | Ink and a thin protective layer | The whole printed film | The whole printed label |
| Shape it can cover | Flat or shallow, gently curved faces | Deeper three dimensional shapes, since the film is formed first | Surfaces that unroll flat |
| Work outside the mold | Foil feeder on the press; very little else | Printing, forming, and trimming before molding | Printing and die cutting; robot placement |
| Surface wear | Depends on the hard coat in the foil | Print sits under the film, so it is well protected | Print sits under the label film |
| Where you see it | Appliance panels, phone and laptop shells, trim strips | Car interior trim, instrument lenses, deep bezels | Tubs, lids, pails, and cups |
Foil transfer
Where the ribbon method runs into trouble
Foil transfer is quick once it runs. Most of the problems come from asking a flat ribbon to follow a shape.
- Registration: the foil has to index to the same spot every shot, or the icons drift off their windows
- Draw depth: past a shallow curve, the foil wrinkles or tears before it reaches the bottom of the cavity
- Edges: the transfer stops at the part edge, so returns and side walls usually stay undecorated
- Ink wash: a gate aimed at the decorated face can smear the ink layer before it sets
Formed film
The film insert route, one stage at a time
Each stage can scrap the part, and most of them happen before the press.
The film is printed flat, usually on the back so the film itself becomes the wear surface. It is then heated and formed, by vacuum or high pressure, into roughly the final shape. Anything printed flat has to be distorted on purpose so it looks right after forming, which means the artwork and the forming tool are developed together.
After forming, the film is trimmed to its outline and loaded into the cavity, where resin is molded against its back. The film has to fit the cavity closely. If it is a little too big it creases at the parting line, and if it is too small the resin shows at the edge. Any artwork change means reprinting, reforming, and possibly retrimming, so this route suits designs that are frozen.
Quote review
Questions to ask when a quote just says IMD
Answers to these make two quotes comparable.
Does the film stay on the part, or only the ink?
Who prints, forms, and trims the film, and who owns those tools?
How deep a draw is the decoration expected to cover?
What abrasion or chemical tests does the finished surface have to pass?
What does an artwork change cost, and how long does it take?
Keep reading
Related guides
Other ways to put color and graphics on a molded surface.
In mold electronics
Printed circuits carried on a formed film.
In mold electronicsPainting vs molded in color
When paint is worth the extra step.
Painting vs molded in colorHot stamping
Foil marks applied after molding.
Hot stampingInjection molding textures
Grain and pattern cut into the steel.
Injection molding texturesAutomotive interior trim
Grain, gloss, and fit on cabin parts.
Automotive interior trimBezels
Frames around displays and controls.
BezelsSecondary operations
Printing, marking, and assembly after molding.
Secondary operationsProcesses hub
Every molding process and secondary operation.
Processes hubFAQ
Questions about in mold decorating
Is IMD better than painting?
It depends on the part. IMD moves the decoration into the molding cycle and can hold fine graphics that paint cannot. Paint is easier to change, covers any shape the gun can reach, and needs nothing special in the mold.
Can foil transfer decorate the sides of a part?
Only a little way down. The foil comes in flat and can follow a shallow curve, but steep side walls and returns usually stay plain.
Why print the film on the back?
The film then covers the ink and takes the scratches and cleaning chemicals. It is also why formed film parts often hold up better than foil transfer parts on surfaces that get handled.
Does the mold have to change for IMD?
Yes. Foil transfer needs space and mounting for the foil feeder and a parting line that lets the foil pass. Film inserts need a cavity that locates the film and gates that keep resin off the printed face.
Next step
Mark the faces that carry graphics
Upload CAD with the decorated areas noted. The review looks at painting, pad printing, hot stamping, or laser marking after molding for the graphics. NetProto manufacturing is ISO 9001 certified.