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 Nov 6 at 23:05
BSEE
1,29511829
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up vote
5
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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 Nov 6 at 23:05
BSEE
1,29511829
3
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♦
Nov 6 at 23:22
Most of the resistors I use have no markings due to size and cost restrictions.
– isdi
Nov 6 at 23:31
1
@davetweed just mark them yourself, can't be that hard
– PlasmaHH
Nov 7 at 7:41
add a comment |
up vote
5
down vote
favorite
up vote
5
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 Nov 6 at 23:05
BSEE
1,29511829
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 Nov 6 at 23:05
BSEE
1,29511829
asked Nov 6 at 23:05
BSEE
1,29511829
asked Nov 6 at 23:05
BSEE
1,29511829
asked Nov 6 at 23:05
BSEE
1,29511829
asked Nov 6 at 23:05
BSEE
1,29511829
1,29511829
3
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♦
Nov 6 at 23:22
Most of the resistors I use have no markings due to size and cost restrictions.
– isdi
Nov 6 at 23:31
1
@davetweed just mark them yourself, can't be that hard
– PlasmaHH
Nov 7 at 7:41
add a comment |
3
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♦
Nov 6 at 23:22
Most of the resistors I use have no markings due to size and cost restrictions.
– isdi
Nov 6 at 23:31
1
@davetweed just mark them yourself, can't be that hard
– PlasmaHH
Nov 7 at 7:41
3
3
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♦
Nov 6 at 23:22
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♦
Nov 6 at 23:22
Most of the resistors I use have no markings due to size and cost restrictions.
– isdi
Nov 6 at 23:31
Most of the resistors I use have no markings due to size and cost restrictions.
– isdi
Nov 6 at 23:31
1
1
@davetweed just mark them yourself, can't be that hard
– PlasmaHH
Nov 7 at 7:41
@davetweed just mark them yourself, can't be that hard
– PlasmaHH
Nov 7 at 7:41
add a comment |
1 Answer
1
active
oldest
votes
up vote
10
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 Nov 6 at 23:22
isdi
1,466110
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
10
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 Nov 6 at 23:22
isdi
1,466110
add a comment |
up vote
10
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 Nov 6 at 23:22
isdi
1,466110
add a comment |
up vote
10
down vote
up vote
10
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 Nov 6 at 23:22
isdi
1,466110
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 Nov 6 at 23:22
isdi
1,466110
edited Nov 6 at 23:29
answered Nov 6 at 23:22
isdi
1,466110
answered Nov 6 at 23:22
isdi
1,466110
answered Nov 6 at 23:22
isdi
1,466110
1,466110
add a comment |
add a comment |
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3
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♦
Nov 6 at 23:22
Most of the resistors I use have no markings due to size and cost restrictions.
– isdi
Nov 6 at 23:31
1
@davetweed just mark them yourself, can't be that hard
– PlasmaHH
Nov 7 at 7:41