Here is the comparing between normal Polydome/Polyester dome and metal dome array, so that you can easy to see the different between Polydome and metal dome array and choose suitable dome into your products.
Please to be noted that only round/circle metal dome was compared and bigger size metal dome than 6mm excludes comparing, and not special metal dome involved in too, and no special function of metal dome was listed too.


Normal Polydome VS Metal Dome

Specification

Poly Dome

Metal Dome

(Conductive area)
Raw material

silver + carbon ink

SST (stainless steel)

raw material thickness

Silver: 0.004-0.006mm
Carbon: 0.005-0.006mm

0.05-0.08 mm

Force

100-300g

100-280g

Click

40~75%

40~60%

Life Cycle

>300,000 times

>1,000,000 times

Fading Rate < 20%

Fading Rate < 10%

Environment Test

72 Hours

72 Hours

80°C

80°C

80RH

80RH

Fading Rate < 20%

Fading Rate < 10%

Dimension

Diameter

Custom-made

3, 4, 5, 6mm

Design Welcome

Total Height

0.4~0.65mm

0.25-0.36mm

Max Working Voltage

30 VDC

24 VDC

Max Working Current

20 mA

40 mA

Contact Bounce

Make 1 msec, break 20 msec

Voltage

250 VDC

250 VDC

Contact Resistance

< 10 ohm;
<100 ohm(special one)

0.1-10 ohm

Operation Temperature

-20° C to + 45° C

-40° C to + 85° C

Storage Temperature

-40° C to + 60° C

-40° C to + 85° C

Humidity

0%  to  85%

0%  to  85%

Height

0.35-0.45mm

Vibration

10g @ to 2000Hz

Min dome to edge distance

1.50 mm

1.00 mm

Dome to dome tolerance

± 0.15 mm

± 0.20 mm

Dome to edge tolerance

± 0.25 mm

± 0.25 mm

Structure & stack up comparing:
The structures of Polydome and metal dome array are similar to each other and there’re different material combination and stack up. Click to see Polydome structure.

stack up of Polydome 
(stack up of Polydome)

stack up of metal dome array 
(stack up of metal dome array)

Working method: It is similar between Polyester dome and metal dome.

Polyester dome working 
(Polyester dome working)

metal dome working 
(metal dome working)

Cosmetic looking:

material: carbon ink polydome bottom view          polydome top view

Polydome: you can see the conductive area color is black (material: carbon ink) in top view, and is silver grey (material: silver ink) in bottom view, and conductive area is only in the center area of embossing half circle shape.

Metal dome array

dome array top view             dome array bottom view

Metal dome array: whole conductive is metal dome made of stainless steel and color is silver white from top or bottom view

PCB PAD comparing:
The PAD of circuit board will be much different for Polydome and metal dome. Here are PCB PAD pictures for polydome and metal dome.

Polydome PCB PAD 
Polydome PCB PAD (anode and cathode trace are mixed into the same area)  

Metal dome PCB PAD Metal dome PCB PAD (anode and cathode trace are separated layout in the same area)

And bellowing is circle metal dome put on membrane switch, you can see from the bottom view that the PCB PAD layout which is much different from Polydome.

Metal Dome on Membrane Switch (bottom view)      (top view)

Here are you can find the PCB PAD design guide for metal dome and polyester dome (Polydome).
If you want to know more, or has any questions about the difference between Polydome and metal dome, please write contact us with your question, requirements, and we will make it easy for you to understand it.