POM vs PBT.

[Oobly]

why do people care about toughness for keycaps?

Because they don't want their keycaps becoming shiny within weeks of usage. "Hard-wearing" would be a better word.

i wasn't talking about shining.  i was talking about crushing pressure.

So is POM a stronger plastic than ABS or PBT?

What exactly do you mean by "stronger"?

In terms of pure tensile strength, POM is strongest (68MPa), then PBT (50MPa), then ABS (40MPa).

However, there are different measures of "strength". Tensile strength, compressive strength, fracture resistance, surface hardness, etc. PBT has low fracture resistance for instance, even though it has higher tensile strength and surface hardness than ABS. This is why it doesn't handle being hit with a hammer as well as ABS like in that ridiculous Ripster hammer test image: http://deskthority.net/wiki/File:Hammer_Time_-_PBT_versus_ABS.jpg

In simple terms, POM is the "toughest" (highest tensile strength and fracture resistance). PBT is hard wearing, but brittle, ABS is the softest and it's fracture resistance is somewhere in between POM and PBT.

[rowdy]

why do people care about toughness for keycaps?

Because they don't want their keycaps becoming shiny within weeks of usage. "Hard-wearing" would be a better word.

i wasn't talking about shining.  i was talking about crushing pressure.

So is POM a stronger plastic than ABS or PBT?

What exactly do you mean by "stronger"?

In terms of pure tensile strength, POM is strongest (68MPa), then PBT (50MPa), then ABS (40MPa).

However, there are different measures of "strength". Tensile strength, compressive strength, fracture resistance, surface hardness, etc. PBT has low fracture resistance for instance, even though it has higher tensile strength and surface hardness than ABS. This is why it doesn't handle being hit with a hammer as well as ABS like in that ridiculous Ripster hammer test image: http://deskthority.net/wiki/File:Hammer_Time_-_PBT_versus_ABS.jpg

In simple terms, POM is the "toughest" (highest tensile strength and fracture resistance). PBT is hard wearing, but brittle, ABS is the softest and it's fracture resistance is somewhere in between POM and PBT.

No idea.

Whatever tbc meant by "crushing pressure".

[yjfknt]

I prefer PBT because of the texture and I dislike both ABS and POM textures I feel like they feel pretty similar.

[tbc]

why do people care about toughness for keycaps?

Because they don't want their keycaps becoming shiny within weeks of usage. "Hard-wearing" would be a better word.

i wasn't talking about shining.  i was talking about crushing pressure.

So is POM a stronger plastic than ABS or PBT?

What exactly do you mean by "stronger"?

In terms of pure tensile strength, POM is strongest (68MPa), then PBT (50MPa), then ABS (40MPa).

However, there are different measures of "strength". Tensile strength, compressive strength, fracture resistance, surface hardness, etc. PBT has low fracture resistance for instance, even though it has higher tensile strength and surface hardness than ABS. This is why it doesn't handle being hit with a hammer as well as ABS like in that ridiculous Ripster hammer test image: http://deskthority.net/wiki/File:Hammer_Time_-_PBT_versus_ABS.jpg

In simple terms, POM is the "toughest" (highest tensile strength and fracture resistance). PBT is hard wearing, but brittle, ABS is the softest and it's fracture resistance is somewhere in between POM and PBT.

No idea.

Whatever tbc meant by "crushing pressure".

keycap vs hammer.  or more likely, other packages on top of them when they're being shipped.

[lilky]

I think each plastic material has it's own pros and cons. Try using different plastics with different switches...the combinations are endless!