Author Archives: Erin

Restriction of Hazardous Substances (RoHS) Directive

Perhaps the greatest reliability issue to come out of the Restriction of Hazardous Substances (RoHS) Directive is tin whiskers. This residual effect of RoHS is nothing new to electronics manufacturing. Tin whiskers were first been reported in the 1940s and credited with taking down satellites and military planes, causing critical failures to pacemakers and space shuttle systems and even the shutdown of a nuclear power facility.

Tin whiskers cause their fair share of headaches, but they can’t be solved by keeping them out of water and not feeding them after dark. Tin whiskers, their causes and how to prevent them, typically bring more questions than answers. These are the answers Dr. Werner Hügel, Robert Bosch GmbH, has been seeking for years and will discuss during his presentation, “Whisker Prevention and the Relevance of Plating Conditions” during the CALCE Annual Tin Whiskers Symposium at IPC TechSummit, October 28-30, 2014 in Raleigh, N.C.

Dr. Hügel is responsible for the backend technology, galvanic surface finishes and solderability requirements for the automotive electronics division at Robert Bosch. The electronic packages his group is responsible for are found in such areas as: airbag, engine management and transmission control systems, all of which ensure driver and passenger safety. High reliability and low failure rates—especially those caused by tin whiskers—are essential. An electronic short to one of these systems could result in potential harm to people or costly recalls.
Hügel will discuss: four basic whisker growth mechanisms, the relevance of the properties of the tin-finish on whisker formation and whisker mitigation. He will also share insights and data on the influence of plating conditions and plating parameters on whisker performance. Attendees will also learn an approach for effective whisker prevention supported by a modified testing procedure.

The following is a preview of the data, findings and recommendations Hügel will share.

Why whiskers grow

Why tin whiskers grow is a question that has boggled minds for decades. Hügel, however, does have his own theories—on tin whisker formation. According to him, whiskers will grow if there is an overall compressive stress (close to the yield limit of tin) in combination with a stress gradient (- 50 MPa/µm) toward the surface. This situation can be achieved by four basic mechanisms:

•       Growth of irregular intermetallic compounds (IMC) between Cu and Sn
•       Mismatch of coefficient of thermal expansion (CTE) between the base material and tin plating (e.g., delta CTE > 8 ppm)
•       External mechanical force on the tin layer over a long period of time (in press-fit, clamping) not bending
•       Corrosion-induced whisker growth (humid environment)
Why tin finish properties are important
Whisker growth can compromise the functionality of applications; therefore, the risk due to whisker growth has to be minimized, so it’s understandable why tin finish properties themselves are so important. Hügel indicates that tin finish properties are highly relevant to tin whisker growth in terms of:
•       Tin plating process (preparation)
•       Process parameters (process window) (temperature, concentration, agitation, current density, etc.)
•       Electrolyte (type)
•       Maintenance (process conditions such as agitation and current density)
•       Texture of the plating and the robustness of the texture against variations of current density, agitation, etc. The texture itself is the relevant factor regarding whisker growth of the tin plating (impact on CTE, chemical potential, etc.)
Minimizing risk
To minimize the risk of whisker growth, the root cause of whisker growth has to be identified and countermeasures have to be implemented.
According Hügel, “Conformal coating is not seen as the mitigation strategy because of the different side effects and the effectiveness of the coating in case of whisker growth. Third-generation electrolytes can provide excellent performance if the process is well defined and maintained.”
This only scratches the surface of the many parameters that go into whisker formation and prevention. Hügel will delve even deeper into these topics and others.
He will explain why maintenance is a major critical point for tin plating and the necessity for tin plating layer systems to fulfill minimum requirements (thickness, plating system setup, type of plating). He will also share how, by arming yourself with the knowledge of the robustness of the plating, a no-whisker, tin plating can be achieved.
For more information on the CALCE Annual Tin Whiskers Symposium at IPC TechSummit 2014, and to register, go to www.ipc.org/TechSummit.

Bare Board

Electronics Printed Circuit Board (PCB) Fabrication

Electronics Printed Circuit Board (PCB) Fabrication

In this Technological era, more and more, fast and faster, new products are being developed to help humanity have better envelopment and better life.  All development of electronics stuff needs to use Printed Circuit Board (PCB) fabrication services to make their products.  Selecting the right Printed Circuit Board (PCB) fabrication house can make for a difficult challenge, it all depends on what type of product you are planning on working with.  If you are one of those companies that have more than a few products that have different requirements ACME PCB Assembly can assist you with all your needs.

ACME PCB Assembly will help you select the perfectly matched Printed Circuit Board (PCB) fabrication house for each of your new jobs.  We currently are working with over 10 Printed Circuit Board (PCB) fabrication houses, so we can closely match all new incoming inquires to an Electronics Printed Circuit Board (PCB) fabrication house.

Each Printed Circuit Board (PCB) fabrication house has strengths in different areas.  All offer great economic cost, flexibility of service, quick turn-around lead time.  There are a variety of factors to help you choose a great Printed Circuit Board (PCB) fabrication shop for each different project needs, but it is one of ACME PCB Assembly’s specialty.

New customer special discount on 2 & 4 layers printed circuit board fabrication. Trust our high-quality standard is the main reason we always have return customer. ACME Printed Circuit Board Assembly has over 25% customers are over 10 years relationship.  Over 25 years in the printed circuit board assembly service business, ACME Printed Circuit Board Assembly knows how to make customer satisfied.

Printed Circuit Board FabricationACME PCB Assembly is in Carson, California and provides the following services and more.

ACME PCB Assembly is an ISO 9001:2008 certified EMS provider, we make sure that you get the best price without compromising the quality. We take full responsibility for your printed circuit board order since we only use ACME PCB Assembly certified suppliers as our domestic and offshore partner.

Contact us today to find out about our other services and how we can help your business.

 

 

 

 

 

 

CNC punching machine

How does Metal Punching Differ from Stamping

Often times, people who are not strictly linked with metal works fields, can confuse between the sheet metal punching and the sheet metal stamping.

This happens because, at first glance, the meaning of these two words might seem the same. On the contrary, the sheet metal punching and the stamping are really different starting from the equipment required to achieve punching and stamping.

The first ones, are metal forming processes realized with automatic CNC machines that use punch presses and dies realizing any kind of hole. The punch pass through the sheet metal while the dies, located on the other side of the metal piece, work as support and help punches to put more force ensuring the non-breaking of metal.

Otherwise, the stamping is the set of operations performed to obtain specific shapes and it includes our sheet metal punching. Stamping is in fact a consequence of others metal processes such as punching, blanking, sheet metal deep-drawing and bending. It’s the ending process useful for giving to metal pieces a specific shape to the entire piece.

To be clear, there’s a third metal process which often is confused and it’s called pressing. The metal pressing, contrary to the sheet metal punching is processed to give shape without breaking the metal piece. For example, pressing process is used to realize corners.

Contact Us today to inquire about our services.

Proud to Be a Lead-Free PCB Assembly Provider

Is lead-free (Pb-Free) also on your mind? It should be. Lead-free (Pb-Free) will impact almost everyone in the electronics industry – from suppliers of component, board and materials like paste and flux to manufacturers and users of electronics products and equipment. Also expect considerable investment both in human resources and capital equipment. Your relationship with your suppliers and customers will also be tested.

There’s a reason that in the United States we no longer allow lead in paint or in gasoline. Though lead is a naturally occurring element, it can be highly toxic to humans. It has been connected with behavior and learning problems, lower IQ, slowed growth, anemia, and even coma and death in severe cases. Children and pregnant women are the most at risk of lead poisoning.

Printed Circuit Board FabricationFor a long time, lead has been part of the soldering process, which is critical to making printed circuit boards. Here at ACME PCB Assembly, we have made the commitment to adopt lead-free solders. Replacing lead solders requires more than just replacing equipment. Lead-free solders have a higher melting point, which means we have had to revise our entire production and assembly process. This required re-training our workers.

Lead-free solder and assembly reliability is achieved if trained specialists carefully implement several process requirements. There are a number of variables that must be taken into consideration to achieve lead-free solder assembly joint reliability.

ACME PCB Assembly is flexible in meeting your requirements. We have offered Lead-Free (Pb-Free) soldering since 2005. Please review Design to Avoid Tin Wiskers for RoHS compliant (Lead-Free) assembly. Though the change was difficult, it was worth it to remove the risk of lead exposure from our facilities.  Now, when you work with us, you know that you are working with a lead-free PCB assembly provider.

 

Printed Circuit Board Fabrication

What You Actually Need to Make a Printed Circuit Board?

What Do You Actually Need to Make a Printed Circuit Board?

Printed circuit boards are in all manner of electronics. If it has computing power, then it is likely to include a printed circuit board. What is a PCB actually made of, and what components does it include? Surprisingly, PCBs are not too complicated.

The first ingredient you’ll need is the printed circuit board itself. The board won’t be of much use until you assemble it. To do that, you’ll need electronic components, soldering materials, soldering flux, and the soldering equipment.  Using the soldering equipment, printed circuit board assemblers, like Acme PCB Assembly, solder on the electronic components. The soldering equipment includes things like solder wire, solder paste, solder bar, and solder performs.

The Components Involved in Printed Circuit Boards

If the copper traces behave like the skeleton of the PCB, acting like the basic structure – then the components are the vital organs. Each component used has a different function. Using all these different components gives the circuit the unique qualities that it needs to fit for its intended purpose. Depending on what the device is or what the electronic item is, a PCB is designed for a variety of different components that will be needed for different circuits. These components can consist of a wide range of electronic parts. Some common PCB components include:

Battery: Provides the voltage to the circuit.

Resistors: Control the electric current as it passes through them. They’re color coded to determine their value.

LED’s: Light emitting diode. Lights up when current flows through it, and will only allow current to flow in one direction.

Transistor: Amplifies charge.

Capacitors: These are components which can harbor electrical charge.

Inductor: Stores charge and stops and change in current.

Diode: Allows current to pass in one direction only, blocking the other.

Switches: Can either allow current or block depending if they are closed or open.

Of course, there’s a lot more to printed circuit board assembly, but we’re not about to give away all of our secrets! If you want to work with a trusted and experienced printed circuit board assembler, contact us today!