Then, you will be better prepared to decide whether you should use lead free PCB assembly. During the assembly of your boards, the components, either surface mount technology SMT or through-hole , are attached through a soldering process. These higher temperatures have implications for board construction and component selection.
If board materials are selected with a decomposition temperature that is too low, irreversible damage may occur following exposure to the elevated temperatures involved in lead free PCB assembly.
Care must also be taken when choosing components to ensure there is no damage, especially during reflow where high temperatures are present on the board for extended periods of time. From a PCB manufacturing perspective, the major concern for lead free PCB assembly is board damage due to higher temperatures. Rework is also more difficult. Materials are another consideration as substrates and laminates must be selected based upon their temperature attributes. If any entry in the list below describes your situation, you will likely benefit from using lead free PCB assembly.
Today, for compliance with the RoHS directive , the following substances may only be present at the levels shown. Ensuring that your boards are built to meet the RoHS requirements means that you must ensure the contract manufacturer CM that you select has a defined lead free process, including soldering, materials, components, solder mask , and surface finish. Active Oldest Votes. I have seen tons of high-density black boards which didn't have more issues compared to e.
I mentioned in my answer not-green may have worse specifications. The PCB fab will usually tell you about it if it's an issue. If they have black as stock, it's unlikely to be a problem or at least they have clearances you need to use. Also lots of flagship phones I think it's just if some shitty board shop decides to use some budget black soldermask colored with carbon black that you'd have problems.
This minimum width went up to. Apparently due to the pigment used. This appears to have been based on their experience with their manufacturer and may be anecdotal.
It is possible newer formulations of non-green solder mask resolve this issue. Add a comment. DerStrom8 DerStrom8 However, when you are dealing with those kinds of situations you often omit the solder mask entirely. I imagine it is a high-price item though. I often wonder why OSHPark chose that for a color. Show 3 more comments. Barleyman Barleyman 3, 8 8 silver badges 21 21 bronze badges. The main color of a PC board comes from the solder mask. The "just paint" layer is the silkscreen, which is usually white.
Silkscreen has nothing to do with PCB colour. Wrt solder resist, I have worked with PCB fab that will actually mix you colour you want if you pay extra. Obviously you don't want that as it costs extra and black resist materials are widely available if not everywhere. Its color is merely a side effect to that main functionality. For industrial, it becomes important for compliance and lifetime. Show 1 more comment. Peter Green Peter Green Spehro Pefhany Spehro Pefhany k 12 12 gold badges silver badges bronze badges.
As I said, regular solder resist mixed white can turn out pink.. And it's much lighter shade of pink than that. Probably red mixed with a bit of white. I'm doing that for one of my PCBs and it's working pretty good so far.
PCB colors - what's available, and why? Ask Question. Asked 4 years, 2 months ago. Active 1 year, 11 months ago.
Viewed 16k times. Would any of this affect color blind tech people who work on the board? Dirk Bruere. Dirk Bruere Dirk Bruere It adds a bit cost but makes it harder for the bad guys to find my stuff. Also, if you do low volume or only prototyping and use an IR reflow oven not convection for soldering red and black PCBs you will need to adjust the thermal profile the first time I tried red PCBs, I burned the first batch.
I guess the opposite applies for white PCBs I have not tried those. I've heard that some colors make the flux residues stand out more than others in case you don't clean it because you use no-clean flux but I haven't had that problem. Show 7 more comments. Active Oldest Votes. I have seen tons of high-density black boards which didn't have more issues compared to e. I mentioned in my answer not-green may have worse specifications.
The PCB fab will usually tell you about it if it's an issue. If they have black as stock, it's unlikely to be a problem or at least they have clearances you need to use. Also lots of flagship phones I think it's just if some shitty board shop decides to use some budget black soldermask colored with carbon black that you'd have problems. This minimum width went up to. Apparently due to the pigment used.
This appears to have been based on their experience with their manufacturer and may be anecdotal. It is possible newer formulations of non-green solder mask resolve this issue. Add a comment. DerStrom8 DerStrom8 However, when you are dealing with those kinds of situations you often omit the solder mask entirely. I imagine it is a high-price item though. I often wonder why OSHPark chose that for a color. Show 3 more comments. Barleyman Barleyman 3, 8 8 silver badges 21 21 bronze badges.
The main color of a PC board comes from the solder mask. Two assessment criteria are used to assess p olychlorinated biphenyl concentrations in sediments Table 3 :. Table 3. Background Assessment Criteria and Environmental Assessment Criteria for polychlorinated biphenyls in sediment.
A number of samples exceeded the thresholds and these were local in nature and close to the sources, particularly in industrialised estuaries and coasts HM Government, The mean concentrations across the monitoring stations used were below the Environmental Assessment Criteria values for p olychlorinated biphenyl s in the Greater North Sea, the Celtic Seas and the three sampled biogeographic regions. Figure 4 gives an overview of the different polychlorinated biphenyl congener assessments failing the Environmental Assessment Criteria in the different biogeographic regions.
CB was the only one that failed in one out of three sampled biogeographic regions. Figure 4. A value of 1 indicates the average concentration is equal to the Environmental Assessment Criteria. Blue: statistically significantly below the Background Assessment Concentration; green: statistically significantly below the Environmental Assessment Criteria: red: the estimate of the mean concentration is not significantly below the Environmental Assessment Criteria.
One Northern North Sea in three sampled biogeographic regions showed significant downward trends, taking the mean of all polychlorinated biphenyl congeners into consideration.
Individual p olychlorinated biphenyl congeners trends for each region can be seen in Figure 5. Figure 5. Upward trends upwards triangle , downward trends downwards triangle , no change circle. Trends in p olychlorinated biphenyl concentrations were assessed in UK regions where there were at least 5 years of data, each containing at least one measurement above the detection limit.
Overall p olychlorinated biphenyl trend by region and trend by individual compounds can be found in Figures 6 and 7. The percentage yearly change for each polychlorinated biphenyl in each region is shown in Figure 7. Figure 6. Figure 7. More data are available for p olychlorinated biphenyl s in sediment, but this data was from estuarine stations and therefore excluded from the assessment.
Mean regional p olychlorinated biphenyl concentrations relative to the Background Assessment Concentrations are shown in Figure 8, all regions were classed as being above background for p olychlorinated biphenyl s in sediment.
Figure 8. Blue : statistically significantly below the Background Assessment Concentration ; green: statistically significantly below the Environmental Assessment Criteria; red: the estimate of the mean concentration is not significantly below the Environmental Assessment Criteria.
Figure 9. A value of 1 indicates the average concentration is equal to the Background Assessment Concentration. Blue: statistically significantly below the Background Assessment Concentration; green: significantly below the Environmental Assessment Criteria; red: the estimate of the mean concentration is not significantly below the Environmental Assessment Criteria.
Concentrations were below the Environmental Assessment Criteria for all p olychlorinated biphenyls in all regions, except for CB in the Irish Sea, potentially resulting in adverse effects. Mean concentrations in the final year of available data variable by station is given in Figure Figure A value of 1 indicates the average concentration is equal to the Environmental Assessment Concentrations. Blue: statistically significantly below the Background Assessment Concentration; green: statistically significantly below the Environmental Assessment Criteria; red: the estimate of the mean concentration is not significantly below the Environmental Assessment Criteria.
Average polychlorinated biphenyl concentration in sediment in each biogeographic region in the final year of available data, which varied based on station. A very high percentage of stations met the UK target for this indicator.
The exception is one of the most toxic polychlorinated biphenyls CB , which is above the environmental assessment criterion in one Irish Sea of the three assessed biogeographic regions, and therefore adverse effects on marine organisms may still be possible in this region. Additional information can be found in the following publications, as well as sources cited throughout the text:.
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