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Do SMD resistors have to be reflowed black side up, or is black side down okay?
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I reflow my own boards in a toaster oven. When I drop my resistors off the paper tape, I always flip them over to black side up before I place them. Should I bother if it doesn't really matter?
resistors surface-mount reflow
asked 2 hours ago
BSEE
1,27211829
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up vote
2
down vote
favorite
I reflow my own boards in a toaster oven. When I drop my resistors off the paper tape, I always flip them over to black side up before I place them. Should I bother if it doesn't really matter?
resistors surface-mount reflow
asked 2 hours ago
BSEE
1,27211829
The main reason I flip them over is so that I can see the numbers for post-assembly inspection. That's why I hate the fact that capacitors aren't labelled.
– Dave Tweed♦
2 hours ago
Most of the resistors I use have no markings due to size and cost restrictions.
– isdi
2 hours ago
add a comment |Â
up vote
2
down vote
favorite
up vote
2
down vote
favorite
I reflow my own boards in a toaster oven. When I drop my resistors off the paper tape, I always flip them over to black side up before I place them. Should I bother if it doesn't really matter?
resistors surface-mount reflow
asked 2 hours ago
BSEE
1,27211829
I reflow my own boards in a toaster oven. When I drop my resistors off the paper tape, I always flip them over to black side up before I place them. Should I bother if it doesn't really matter?
resistors surface-mount reflow
resistors surface-mount reflow
asked 2 hours ago
BSEE
1,27211829
asked 2 hours ago
BSEE
1,27211829
asked 2 hours ago
BSEE
1,27211829
asked 2 hours ago
BSEE
1,27211829
asked 2 hours ago
BSEE
1,27211829
1,27211829
The main reason I flip them over is so that I can see the numbers for post-assembly inspection. That's why I hate the fact that capacitors aren't labelled.
– Dave Tweed♦
2 hours ago
Most of the resistors I use have no markings due to size and cost restrictions.
– isdi
2 hours ago
add a comment |Â
The main reason I flip them over is so that I can see the numbers for post-assembly inspection. That's why I hate the fact that capacitors aren't labelled.
– Dave Tweed♦
2 hours ago
Most of the resistors I use have no markings due to size and cost restrictions.
– isdi
2 hours ago
The main reason I flip them over is so that I can see the numbers for post-assembly inspection. That's why I hate the fact that capacitors aren't labelled.
– Dave Tweed♦
2 hours ago
The main reason I flip them over is so that I can see the numbers for post-assembly inspection. That's why I hate the fact that capacitors aren't labelled.
– Dave Tweed♦
2 hours ago
Most of the resistors I use have no markings due to size and cost restrictions.
– isdi
2 hours ago
Most of the resistors I use have no markings due to size and cost restrictions.
– isdi
2 hours ago
add a comment |Â
1 Answer
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up vote
5
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There are several reasons to put the alumina (white) side down. For small production/hobby runs it may not matter.
You can tell if the resistor has been overloaded for whatever reason as the passivation/element color will generally change under high continuous heat.
Depending on the technology, the contact dimensions may not be the same on the top as on the bottom. Pad geometry assumes alumina side is placed into the paste.
It's a little easier to clean which can be an issue in high resistance components. Passivation layers typically have varying heights/roughness, unlike the flat alumina base.
Wear and tear under mechanical stress, passivation layers are not as tough as the alumina substrate so if the board rubs against it it will eventually get damaged (usually only a problem on thin board under mechanical loads).
answered 2 hours ago
isdi
1,31618
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
5
down vote
There are several reasons to put the alumina (white) side down. For small production/hobby runs it may not matter.
You can tell if the resistor has been overloaded for whatever reason as the passivation/element color will generally change under high continuous heat.
Depending on the technology, the contact dimensions may not be the same on the top as on the bottom. Pad geometry assumes alumina side is placed into the paste.
It's a little easier to clean which can be an issue in high resistance components. Passivation layers typically have varying heights/roughness, unlike the flat alumina base.
Wear and tear under mechanical stress, passivation layers are not as tough as the alumina substrate so if the board rubs against it it will eventually get damaged (usually only a problem on thin board under mechanical loads).
answered 2 hours ago
isdi
1,31618
add a comment |Â
up vote
5
down vote
There are several reasons to put the alumina (white) side down. For small production/hobby runs it may not matter.
You can tell if the resistor has been overloaded for whatever reason as the passivation/element color will generally change under high continuous heat.
Depending on the technology, the contact dimensions may not be the same on the top as on the bottom. Pad geometry assumes alumina side is placed into the paste.
It's a little easier to clean which can be an issue in high resistance components. Passivation layers typically have varying heights/roughness, unlike the flat alumina base.
Wear and tear under mechanical stress, passivation layers are not as tough as the alumina substrate so if the board rubs against it it will eventually get damaged (usually only a problem on thin board under mechanical loads).
answered 2 hours ago
isdi
1,31618
add a comment |Â
up vote
5
down vote
up vote
5
down vote
There are several reasons to put the alumina (white) side down. For small production/hobby runs it may not matter.
You can tell if the resistor has been overloaded for whatever reason as the passivation/element color will generally change under high continuous heat.
Depending on the technology, the contact dimensions may not be the same on the top as on the bottom. Pad geometry assumes alumina side is placed into the paste.
It's a little easier to clean which can be an issue in high resistance components. Passivation layers typically have varying heights/roughness, unlike the flat alumina base.
Wear and tear under mechanical stress, passivation layers are not as tough as the alumina substrate so if the board rubs against it it will eventually get damaged (usually only a problem on thin board under mechanical loads).
answered 2 hours ago
isdi
1,31618
There are several reasons to put the alumina (white) side down. For small production/hobby runs it may not matter.
You can tell if the resistor has been overloaded for whatever reason as the passivation/element color will generally change under high continuous heat.
Depending on the technology, the contact dimensions may not be the same on the top as on the bottom. Pad geometry assumes alumina side is placed into the paste.
It's a little easier to clean which can be an issue in high resistance components. Passivation layers typically have varying heights/roughness, unlike the flat alumina base.
Wear and tear under mechanical stress, passivation layers are not as tough as the alumina substrate so if the board rubs against it it will eventually get damaged (usually only a problem on thin board under mechanical loads).
answered 2 hours ago
isdi
1,31618
edited 2 hours ago
answered 2 hours ago
isdi
1,31618
answered 2 hours ago
isdi
1,31618
answered 2 hours ago
isdi
1,31618
1,31618
add a comment |Â
add a comment |Â
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The main reason I flip them over is so that I can see the numbers for post-assembly inspection. That's why I hate the fact that capacitors aren't labelled.
– Dave Tweed♦
2 hours ago
Most of the resistors I use have no markings due to size and cost restrictions.
– isdi
2 hours ago