1. Product
2. Polydome
3. Polydome VS Metal Dome Array

     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 metal dome array)

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

 
(Polyester dome working)

 
(metal dome working)

Cosmetic looking:

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.

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

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.

(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.