Vacuum Metallization
Plating & metallizing on plastics · Vacuum deposition
Vacuum metallization evaporates aluminum or another metal onto prepared plastic to create a reflective or conductive-looking film.
What is Vacuum metallization?
The v1 injection-moulding and 3D-printing entries are one finish, typically 0.1–1 µm before protective topcoat.
How it works
A plastic or printed part is cleaned, smoothed, and usually sealed with a basecoat. In vacuum, resistance or electron-beam heating vaporizes metal, commonly aluminum, which condenses on exposed surfaces. A clear or tinted topcoat protects the extremely thin film. Coverage is line-of-sight, and the polymer itself does not become a load-bearing metal.
Why specify it
- Mirror-like appearance at 0.05–1 µm
- Low added mass
- Works on moulded and printed polymers
- Can support reflector or EMI functions
Where it falls short
- Needs a smooth sealed substrate
- Line-of-sight shadowing
- Thin metal scratches without topcoat
- Not structural plating
Vacuum metallization at a glance
Vacuum metallization is strongest on cosmetic quality (94 of 100), at a high cost. Surface hardness is not rated: the finish leaves the part's own surface.
Each score is 0–100 against every finish in this catalog. Corrosion comes from salt-spray life (ASTM B117, log scale) and hardness from the finish layer's Vickers or pencil hardness; cosmetic, lubricity and cost are FabDigit's engineering assessment. Economy on the radar is the inverse of cost.
Vacuum metallization key numbers
Typical values from the governing specifications and shop practice; bars are this finish against the highest value among plating & metallizing on plastics finishes.
- Thickness
- 0.05–0.5 µm decorative aluminum; up to about 1 µm when continuity or EMI is specified, plus organic basecoat and topcoat
- Electrical
- Conductive
- Colours
- bright aluminum
- chrome-look
- gold tint
- custom tint
- Appearance
- Highly reflective mirror metal when the base surface is smooth; printed layer lines remain visible unless filled.
Specifications for Vacuum metallization
The documents a drawing cites to define this finish, with the Type / Class rows that apply. Each links to a page explaining the standard.
Drawing call-out
VACUUM METALLIZE VISIBLE SURFACES WITH ALUMINUM, 0.2–0.5 µm METAL THICKNESS, BRIGHT CHROME APPEARANCE; APPLY CLEAR PROTECTIVE TOPCOAT; MASK SNAP FITS AND BONDING SURFACESWhich materials take Vacuum metallization?
Verdict per material family, with the grades that behave differently. Each family links to its datasheets in the material library.
| Material family | Verdict | Notes |
|---|---|---|
| Yes | Injection-moulded polymers require compatible basecoat.
| |
| Yes | Cure, sand, and seal before coating. | |
| With care | Seal fibers and qualify adhesion. | |
| With care | Layer lines and porosity require extensive smoothing. | |
| With care | Porosity requires sealing before a bright film. | |
| With care | Porosity requires sealing. | |
| Limited | Possible for reflectors, but polishing or anodize is usually preferred on bulk aluminum. | |
| No | This process is specified for polymers, not brass. | |
| No | This process is specified for polymers, not copper alloys. | |
| No | Metal AM is not vacuum-metallized; finish the metal directly. | |
| No | This process is specified for polymers, not magnesium. | |
| No | This process is specified for polymers, not stainless steel. | |
| No | This process is specified for polymers, not steel. | |
| No | This process is specified for polymers, not titanium. | |
| No | This process is specified for polymers, not zinc alloys. |
How Vacuum metallization is applied, and what it does to the part
- 1Smooth and seal
- 2Apply basecoat
- 3Vacuum clean
- 4Evaporate metal
- 5Apply protective topcoat
- 6Inspect reflectivity or resistance
| Dimensions | The metal film is only 0.1–1 µm, but basecoat and topcoat can control fit; define total paint-stack allowance separately. |
|---|---|
| Build-up per side | 0.05–1 µm — Metal alone is 0.05–1 µm; basecoat and topcoat dominate total buildup. |
| Masking | Usually needed. Mask bonding areas, snap fits, contacts, and optical zones not designated for metal. |
| Electrical | Conductive |
| Temperature limit | 80 °C (176 °F) continuous |
| Appearance | Highly reflective mirror metal when the base surface is smooth; printed layer lines remain visible unless filled. |
| Added lead time | 7–14 working days on top of the bare part |
Design rules for Vacuum metallization
What to decide on the drawing before the part goes to the finisher.
- Seal printed porosity and layer lines.The metal reproduces every substrate defect.
- Provide line-of-sight access.Deep recesses receive little vapor.
- Specify topcoat.Bare submicrometre aluminum scratches and oxidizes.
- Separate metal and total stack thickness.Organic coats dominate dimensional buildup.
Vacuum metallization versus the alternatives
Finishes engineers weigh against Vacuum metallization, and when each wins.
| Finish | Corrosion | Hardness | Cosmetic | Cost | Thickness | Choose it when |
|---|---|---|---|---|---|---|
Vacuum metallization this page | 45 | — | 94 | $$$$ | 0.05–1 µm | — |
| 72 | 71 | 98 | $$$$ | 20–50 µm | a thicker Cu-Ni-Cr decorative system is required | |
| 58 | 39 | 60 | $$$$ | 5–15 µm | uniform conductive coverage is primary |
The radar overlays Vacuum metallization with Chrome Plating on Plastic, its most common alternative — chosen a thicker Cu-Ni-Cr decorative system is required. Scores in the table are 0–100 across every finish in the catalog.
Cost, lead time and compliance
Relative cost
Vacuum Metallization is a high-cost finish ($$$$): more expensive than about 73 % of the finishes FabDigit quotes.
Finishing is priced per part with a lot minimum, from FabDigit's own China-side rates. The exact figure appears on the instant quote once the part is uploaded.
Lead time and compliance
| Added lead time | 7–14 working days |
|---|---|
| RoHS | Compliant |
| Notes | Aluminum metallization is generally RoHS-compatible; topcoat chemistry controls final compliance. |
What Vacuum metallization is used for
- Headlamp reflectors
- Cosmetic caps
- 3D-printed display models
- EMI shielding films
Vacuum metallization — frequently asked
How thick is vacuum metallization?
The metal itself is typically about 0.05–1 µm and often 0.05–0.5 µm. Basecoat and topcoat are much thicker and control total buildup.
Can 3D prints be vacuum metallized?
Yes after sealing, sanding, and priming. Any visible layer lines will be mirrored by the thin metal film.
Is vacuum metallization real chrome?
Usually no; bright aluminum under clear coat creates the chrome-like appearance. It is much thinner than Cu-Ni-Cr plating.
Is vacuum-metallized plastic conductive?
The metal film can conduct if it is continuous, but seams and masked areas interrupt it. EMI designs need a measured sheet-resistance requirement.
Vacuum metallization vs chrome plating plastic?
Vacuum metallization uses about 0.05–1 µm of evaporated metal and is light and reflective. Plastic chrome uses etched ABS or PC-ABS plus electroless and electrolytic Cu-Ni-Cr layers totaling tens of micrometres.