RoHS & Lead-Free PCBs
SUNNY PCB's RoHS Solution
SUNNY PCB Circuits has been making lead-free boards since 2005. Our lead-free boards are made with laminate that have a higher Td to withstand the increased temperature and dwell times required during assembly. The surface finishes that we can offer are also RoHS compatible.
Lead-Free PCB Boards
We provide lead-free material like IS410 or R370HR and we use lead-free finishes like Immersion White Tin, Immersion Silver, Immersion Gold, or Lead-Free HASL. If you are not sure about how to proceed, Talk with us..
High-Reliable Lead-Free PCB Board
We produce lead-free printed circuit boards that can withstand up to 2000 thermal shocks from -45ºC to 145ºC. These special purpose lead-free boards are produced through our proprietary, patent-pending process. The dependability of these lead-free circuit boards has been proven through rigorous HATS testing and our own solder float testing.
How Does This Affect My PCBs?
In certain instances, tin-lead solder is no longer allowed. For many years the electronic industries used tin-lead solder to join the components and as a surface finish to protect the copper from corrosion. Lead-free solder requires materials with a high Td (decomposition temperature), as thermal profiles and dwell times increase.
Lead Free MCPCB Assembly Services
Lead Free PCB Assembly Services That Meet Global Requirements
SUNNY PCB support customers who are concerned about the environment by providing lead free pcb assembly services. Our lead free assembly processes are designed to meet all the requirements and regulations of RoHS and WEEE Directives.
Comprehensive Lead Free PCB Assembly Services
At SUNNY PCB, we not only provide lead free printed circuit boards for your industrial applications, but also help you migrate to lead free and RoHS compliant MCPCB assembly services.
We provide the following lead free MCPCB assembly services:
• Lead-Free Materials Analysis
• SMT Lead Free Board Assembly
• Single or Double Sided Assemblies
• Lead Free Selective Soldering
• Encapsulation and Conformal Coating
Our automated assembly processes as well as the use of high grade materials and parts ensures that the quality of the circuit boards never diminishes. We utilize the following materials for our lead free board assemblies:
• Halogen Free ‘Green’ Boards
• High Temperature Tg and Td Materials
• Lead Free Compatible Solder Paste
• Dicyandiamine (Dicy) Hardening Materials For Epoxies
SUNNY PCB can supply you with a RoHS compliant board using laminate materials that can be matched up with the exposure to high temperatures during your assembly processes. It is important to keep in mind that some lead free assembly processes will require the laminate base material to withstand temperatures in excess of 260 degrees C or 500 degrees F for extended periods of time. To resolve this, we have high temperature laminates in our inventory so that our customers will be able to meet the higher temperature cycling requirements of some lead free assembly applications.
SUNNY PCB buys those materials which met the UL testing for 130°C maximum operating temperature, solder limits of 288°C for 20 seconds, 94-V0 flame rating and direct support of current carrying parts. Each of these laminate systems meets the minimum requirements for IPC 4101 specification sheets 21, 26, 28, 98, 99, 101, 126 or 129. Individual manufacturer's material types may exhibit variations in electrical, thermal and physical properties. Normally a single manufacturer's material will be stocked for use. If you have specific questions please talk with SUNNY PCB
Which PCB Surface Finish Should I Use?
At the most basic level, a PCB surface finish is plating or coating that is applied to the exposed copper of a circuit board. The surface finish not only protects the copper from oxidation, but also forms the foundation of connectivity between a PCB and a component. Before choosing a service finish, you should have an answer to the following questions:
• How important is pad flatness for assembly?
• How solderable/ wettable does my circuit board need to be?
• Does my circuit board need to be lead free/ RoHS Compliant?
• Does my circuit board need gold or aluminum wire bonding?
• How many solder cycles will my circuit board be exposed to?
• Is the cost of surface finish a deal breaker?
• What's the minimum shelf life of my circuit board?
• What kind of storage conditions will my board be kept in?
Once you have a pretty solid idea of how you want your surface finish to perform, SUNNY company pub’s Surface Finish Comparison Chart below will come in handy:
In conclusion there is no "best" surface finish for all of your circuit board needs. PCB surface finishes should be selected based on the intended functionality of the end product.
How should I stock my pcbs?
- It is the popular question. When market or capacity is changed on PCBA factory, they most probably ask it. Here is the summary as following for your reference
- Storage condition for each type PCB
How to process PCB Surface Finishes
Among all the PCB (printed circuit board) fabrication craft, surface finish plays an extremely role in PCB assembly and utilization. Copper layer on PCBs tends to be oxidized so that generated copper oxide layer will seriously influence soldering quality. However, surface finish is capable of preventing pads oxidizing so that excellent solderability and electric performance will be ensured. Surface finish, or surface coating, is the most important step in the process between PCB manufacturingand PCB assembly with two main functions one of which is to preserve the exposed copper circuitry and the other of which is to provide solderable surface when soldering components to the circuit board. As is shown in Figure 1, surface finish is located at the outermost layer of PCB, playing a role as a "coat" for the board.
Surface Finish Types
Basically, there are two main types of surface finishes: metallic and organic, each of which has the specific categories as the display of Table 1.
- 1. HASL (Hot Air Solder Leveling) HASL is a conventional type of surface finish used on PCBs. The PCB is typically dipped into a bath of molten solder so that all exposed copper surfaces are covered by solder. Excess solder is removed by passing the PCB between hot air knives. Usually, HASL follows the procedure below:
- To reach the standard concerning environment, HASL develops with an environment-friendly category that is lead-free HASL that increases lead-free solderability plate of choice. 2. ENIG (Electroless Nickel/Immersion Gold) ENIG consists of electroless nickel plating covered with a thin layer of immersion gold, which protects the nickel from oxidation. Among all types of surface finishes, ENIG is the most expensive but provides the best characteristics for PCBs. Usually, ENIG follows the procedure below:
- The electroless nickel step is an auto-catalytic process that involves depositing nickel on the palladium-catalyzed copper surface. The reducing agent containing nickel ions must be replenished in order to provide proper concentration, temperature and ph levels necessary to create a consistent coating. During the immersion gold step, the gold adheres to the nickel plated areas through molecular exchange, which will protect the nickel until the soldering process. The gold thickness needs to meet certain tolerances to ensure that the nickel maintains its solderability. Table 3 below shows the pros and cons of ENIG.
- Similar with ENIG, ENEPIG (electroless nickel electroless palladium immersion gold) is the development of ENIG. The difference between ENIG and ENEPIG is the palladium layer that is capable of stopping the nickel corrosion and copper migration to nickel layer. 3. ImAg (Immersion Silver) ImAg consists of thin immersion silver plating over the copper traces. Usually, ImAg follows the procedure below:
- ImAg is a good type of surface finish for soldering and testing. Creep corrosion is its major weakness. Table 4 below shows the pros and cons of ImAg.
- 4. ImSn (Immersion Tin) ImSn is mostly the same as ImAg except tin is used in ImSn while silver is used in ImAg. In terms of the advantages of ImSn, it provides an extremely planar finish on the copper pads, making it very suitable for SMT applications. Besides, ImSn provides a surface that is easily detectable by common AOI (automated optical inspection) techniques. 5. OSP (Organic Solderability Preservatives) OSP is a transparent organic material surface finish. It uses a water-based organic compound that selectively bonds to copper and protects the copper until soldering. Usually, OSP follows the process below:
- In summary, each type has its own advantages and disadvantages. In the process of selection, some main elements must be taken into considerations including cost, corrosion resistance, ICT (in-circuit test) and hole fill. Based on the features of PCBs and utilization purposes, suitable surface finish type is selected. More considerations concerning surface finish selection will be discussed in the second part of this article. Comparing these types of surface finishes, generally speaking, in terms of COST, ImAg and OSP are the most inexpensive while ENIG is the most costly. In terms of CORROSION RESISTANCE, HASL and ImSn have the best corrosion resistance capacity while ImAg has the worst. In terms of ICT, only OSP is the worst while others are just similarly good. In terms of HOLE FILL, HASL and ENIG are better than other types.
Table 5 below shows the pros and cons of OSP.
Control PCB Fabrication Costs by Thinking about Panel Sizes
While designed-in features are the predominant driver of PCB manufacturing costs, the more subtle factor of panelization efficiency can also have a dramatic impact. One of the key things to understand about your PCB order is that the manufacturer (some would say "fabricator") probably doesn't build individual boards. For the sake of automation and repeatability, their machinery and processes are setup to handle uniformly-sized "panels" of material. Unless your board is large, or requires special processing, it's likely it will flow through the manufacturing process on panels with other designs.
The second key thing to understand is that the cost of manufacturing panels is basically fixed for a given set of technology. This obviously doesn't include non-reoccurring charges (i.e. the "one time" setup required for a new design) but it is the case for the actual fabrication processes. Other than the price of materials and labor, not much varies from panel to panel.
Working from a fixed panel cost, you can quickly see that more boards packed into a set of panels mean more efficient (less costly) manufacturing. And, generally speaking, the more boards that fit on a panel the lower the per-board price. This works out well for both customers and fabricators. However, it's one of those things that seem to be missed during PCB layout. Costs can skyrocket when your design differs from "what everyone else is doing" because your boards will need to be on panels all by themselves. Boards that are done using "common" technology are easily aggregated; meaning the cost of manufacturing the panel can be spread among multiple customers. This can be a huge cost saver. But if you're boards are going to be on panels by themselves, you have to take a close look at penalization efficiency.
To make the best use of the available space on a panel (and thus lower your cost), carefully choose the size of your board. Ask you manufacturer for the details of the panel sizes they prefer, and if possible pick board dimensions that are an integer divisors of the length and/or width of the panel size. Don't forget to account for the margin around the edge of the panel and spacing between the boards. Your manufacturer should be able to provide specific instructions for sizing your board for maximal efficiency -- if they can't (or won't), you may want to consider a more cooperative manufacturer.
The math behind finding the best board size isn't complex, but it's tedious. Here I want to volunteer a couple examples of PCB penalization scenarios:
The point of the above examples is that size really does matter when it comes to effectively using the space on panels. Assuming panels have fixed cost (and they should, when they are identically built), then size choices can also impact your price. The difference between getting 2 boards per panel and 4 boards per panel may be a tiny fraction of an inch. The designer of the board in the third example above could cut their per-board price by as much as 50% by shaving a tiny bit off each dimension. Here are another couple examples, this time with the exact same size board and panel, but with the board rotated 90 degrees: And, finally, keep the spacing between boards in mind. You might be temped to think that smaller boards would always lead to better panelization, but that isn't the case. As the board size gets closer to the inter-board spacing, efficiency drops like a rock. Consider these three cases:
This is obvious stuff, You may talk with SUNNY PCB in mail :email@example.com
Extend The Useful Life of LED by Aluminum PCB
LEDs generate a significant amount of heat as a by-product of the visible light they produce. If not managed properly the heat generated by these LEDs can cause an early demise for the consumer electronics in which they are commonly found. The use of Insulated Metal Substrates can help manage this problem and extend the useful life of products. The PCB design is printed on an Insulated Metal Substrate (IMS) laminate, which consists of a very thin dielectric layer sandwiched between a metal baseplate (generally made of aluminum) and a thin layer of copper. LEDs and other components are only mounted on the thin copper side.
The life and efficiency of a LED is a direct result of correct dissipation of the temperature generated by the emitter through the surface on which it is mounted. Keeping the LED temperature under 90ºC will guarantee full luminosity and a long-lasting useful life that can reach over 100,000 hours. Dielectric plays vital role in the dissipation of the temperature. Ideally, the dialectical strength of a 3 mil layer can stand in laboratory conditions of 6kV, but no supplier can guarantee that 100% of their 3 mil layer will withstand 6kV. This is because mass production will always produce some impurities and impurities cause dielectric failures.
SUNNY PCB has the solution for this problem. We provide PCB's which can stand 100,000 hours at 118 ºC while keeping 50% of the initial dialectical strength value. The initial dialectic strength of IMS was 10kV. After 100,000 hours it can be seen that IMS will stand. By guaranteeing these values it can be assured that LEDs will dissipate their heat to the aluminium or copper substrate correctly and the IMS material will not be the cause of failure for the LED.
SUNNY PCB provides such solutions which can ensure most effective thermal management in the PCB's. Contact us to know more.