How to ensure documentation for the EMS company is accurate.

Electronics assembly documentation includes files such as design schematics, assembly drawings, test procedures, bills of materials and more. Problems or omissions in this documentation result in delays and, in extreme cases, may lead to product deficiencies and quality issues. The following best practices will help ensure that documentation to be sent to the EMS company is in good order.

Documentation is typically provided to us in a .zip file that contains documentation related to details of the PCB, assembly work required, materials required, design schematics, test procedures, special instructions, and more. Ideally, the documentation files should be separated into discrete folders. As an EMS company, we prefer either:

• A distinct .zip file for each type of data (e.g. schematics, bill of materials, assembly, test), or
• One .zip with an embedded directory structure that keeps these types of data discrete.

The following are common errors related to manufacturing documents. Avoiding these errors will improve delivery time and quality.

CAD data. Not every contract manufacturer has the systems to handle CAD data. For those that do, accurate CAD data improve information flow and can reduce manufacturing time and design errors. For example, the manufacturer can query CAD data for accurate dimensions and other product details.

If using a third party for CAD layout, request the CAD layout data from that company. If producing CAD layouts in-house, follow these guidelines:

1. ASCII CAD is the preferred data format. ODB++ and GenCAD are acceptable alternate formats.
2. Ensure the correct version of the data is sent. Double-check the version, or rely on a rigorous documentation control program to ensure the correct versions are employed.
3. Send Gerber data in only one format, rather than multiple formats. At many firms, RS-274x is the preferred format for Gerber data.
4. Verify that the aperture data you send are correct; documentation sometimes contains aperture dimensions of “0”, requiring the CM to halt the process and request clarification.
5. Avoid sending redundant data, such as sending both Gerber files and apertur data containing aperture data separately. RS-274x Gerber files already contain the aperture data.
6. In the Gerber data or a separate PCB document, include specifications for copper weight, surface finish and laminate.

Schematics and drawings. Adhere to these three best practices when preparing schematics and drawings for a contract manufacturer:

1. Include PCB schematics. These tell the contract manufacturer how parts on a board are to be connected. CMs refer to these drawings to ensure interconnect is accurate and to solve problems, if they arise. EDIF format is preferred because an EDIF file carries intelligence that can be cross-referenced with CAD data and assembly drawings to speed debugging. PDF format is also acceptable, but does not contain intelligence. If the contract manufacturer will perform testing, providing a schematic is essential for debugging.
2. Include assembly drawings in the documentation package. An assembly drawing provides higher-quality information about board assembly than Gerber data.

Reference a workmanship standard to which the manufacturer must adhere. If special assembly steps or requirements exist, indicate these on the drawing. PDF format is acceptable for assembly drawings.

Bill of materials. Follow these guidelines when preparing BoMs for the contract manufacturer:

• Send a BoM in only one file format. A spreadsheet is preferred to a text or PDF file.
• Always include alternate parts in the BoM, as this ensures the benefit of lower pricing or reduced lead times on parts.
• Always include complete manufacturer part numbers in the BoM; not doing so can cause delays.

Functional specification. A functional specification of how the product is meant to function is helpful if testing is being undertaken. This information cannot be conveyed by a schematic or CAD data. A functional specification should describe how the product is designed to work and its acceptable limits. This, in combination with the other documentation, allows technicians to understand the product quickly and move on to efficient testing and debug.

George Henning is vice president of manufacturing at OCM Manufacturing (www.ocmmanufacturing.com); This email address is being protected from spambots. You need JavaScript enabled to view it..

Figure 1. Working from the CAD system offers the best chance at accurate data.

Figure 2. The assembly drawing provides higher-quality information about board assembly than do Gerber data and should
be included.

How working in tandem applies to barbecues, car washing and PCB design.

Whether designing a PCB, cleaning the car or cooking a meal, we all look for ways to do things faster. Of course, at work there’s more at stake than, well, steak. Concurrent engineering introduces parallelism into our design process so that we can shorten, accelerate or recover our schedules. It permits different disciplines to have a positive impact on costs, quality and performance earlier in the design cycle – when it matters. A recent study by the Aberdeen Group found that best-in-class companies focus on improving communication and collaboration. They achieve this by working concurrently and collaborating across the extended PCB development team, and some report up to a 60% decrease in design cycle time.

Concurrent engineering is a widely used term and anyone who appreciates motherhood and apple pie will surely claim to practice it in their design process. I love my mother and enjoy apple pie as much as the next guy, but let’s get a bit more specific.

Consider two approaches to concurrent engineering:

1. A meal consisting of a salad and grilled hamburgers can be created quicker if one person makes the salad while in parallel another grills the burgers. With this approach, the time saved would be equivalent to the shortest time taken by either task. This is an example of independent concurrent engineering across disciplines: The two activities do not affect each other, but the overall schedule is shortened.
2. Two people can wash a car much faster than one person. Each person will not bother to wash what has been already washed by the other, but there will be overlap at the edges. With this approach, two people will not wash the car in half the time taken by one person, but they will definitely be much faster – say, a 40% elapsed time savings. This is an example of collaborative concurrent engineering within a discipline: Each activity is done in the context of the other and requires real-time communication in order to be optimal.

In PCB design, independent concurrent engineering is widely practiced because it can be achieved somewhat independently of a design tool’s capabilities. It is true, however, that a change or problem in one activity can affect other activities. For example, the most common form of independent concurrent engineering is schematic design in parallel with the PCB layout. A change in the schematic netlist requires an update of the PCB netlist. Communicating and managing changes between activities is critical for this approach.

Collaborative concurrent engineering in PCB design is much less common and usually enabled by tool capabilities. Historically, PCB design tools have been designed for use by a single user at a time. Innovative users have figured ways to apply concurrent engineering to single user activities. They do this by eliminating codependency in the form of a partition-and-reassemble approach.

For example, PCB layout can be partitioned into two pieces, effectively creating two new designs. Two or more designers work on them independently, and then reassemble the two designs back into the original design. Next, the boundaries of the partitions need to be cleaned, taking into account placement changes, physical connectivity and constraints. A placement change in one partition could cause a violation with the other partition’s components. Physical connectivity refers to the actual hooking up of traces that cross the boundaries. Constraint violations could occur once the partitions are reconnected, and must be dealt with.

The problems with this approach include overhead of partition and reassemble, risk of error and suboptimal use of resources. On top of this, partitioning by area is not always ideal; it may make sense to assign different nets or busses to a designer, or different layers. On top of these problems, this approach is only useful for the routing portion of the layout design.

Let’s examine how concurrent engineering can be applied in a couple of areas of PCB design, namely schematic design and PCB layout.

Schematic design is sheet-based and can be flat or hierarchical. Usually, different engineers can work on different sheets, with an agreement about the interfaces between those sheets. Mismatches between the sheets would be found through design reviews, schematic checking or, worst case, during PCB layout. Even so, mismatches in connectivity may not be found until a prototype is built. Another fly in the ointment is the increasing need to specify electrical constraints on the nets. Constraints for more than 80% of nets are quite common, hence the need to collaborate on constraint definition. There are currently different approaches to this design challenge:

• Specify the constraints in a separate specification, backed up with verbal communication, several prayers and hope the layout designer gets it right.
• Partially specify the constraints on the schematic using available but limited properties, backed up with written instructions. (Not much better than the first option.)
• Fully specify the constraints on the schematic and use these constraints to drive PCB layout.

This is where concurrent engineering is enabled by the tool’s capabilities. For starters, not all schematic design tools have a constraint management system. Of those that do, most enforce a serial approach such that only one person can edit constraints at any time. This restriction arises from the fact that constraints go across the design and so are held in a single database accessible by one person at a time (back to that single-user architecture discussed earlier).

PCB layout is a tougher nut to crack. Unlike a schematic that naturally is divided into sheets, a PCB layout is a flat representation in a single database. Most PCB design systems can partition a design, creating a new layout for each partition. Normally this would only be done once placement is complete; otherwise, how would you calculate the areas and size of the partitions? Ad hoc rules are put in place regarding the interfaces between the partitions so that they can be reassembled into the complete design.

Troublesome questions arise with this approach. What about nets that traverse partitions? What if a partition needs more space due to fanout and breakout? What if the agreed on partition interfaces are suboptimal? (Bit optimization of busses at the interface present a special challenge.)

The answers involve reassembling the board, making the change and then restarting the partition process. Then, having finished the partition design, the whole design is reassembled. Now we have to clean up the interfaces and complete any of the design that spans the partitions – for example, the global nets, power and ground planes.

As you can see, this approach is complex, and while users and the tool suppliers endeavor to automate and control the whole process, these problems are really just symptoms of the real underlying issue: the architecture of the tools. Many were designed in the ’80s and early ’90s. The only way to achieve concurrent engineering with tools designed for a single user is to somehow turn the problem into one of independent concurrent engineering. Clearly, collaborative concurrent engineering would make more sense.

The problem has been solved in industries such as IT and even video gaming by the use of a client-server architecture. Today’s video games allow multiple players in the same game, played over the Internet. The server provides access to the game’s database for multiple clients, ensuring data integrity and real-time game feedback and communication between the players. There are many other examples, such as video and voice conferencing, instant messaging, financial reporting – isn’t it about time PCB tools took advantage of this technology?

A client-server architecture allows multiple engineers to work on the same design data in real-time. Those engineers can be distributed across organizations, geography, and even companies.

Revisiting our examples, multiple engineers can work on the schematic such that they see their work in the context of the whole design in real time (including the system-wide connectivity model), not as a snapshot. If an interface changes, they see it immediately – no need to wait for a design review or schematic check. They can enter constraints and see where others are entering constraints without stepping on each other’s toes. Need to modify a net that crosses multiple sheets or hierarchy? No problem. They can make the change, and the team sees it in real time. Because there is a single schematic database, there are no error-prone re-synchronization steps.

A client-server architecture when applied to the layout allows multiple designers to work on a single layout design without the need for the partition-reassemble rigmarole. Each designer can see where the others are working; the possibilities are endless and can be applied from placement to routing to power distribution to manufacturing prep. Now, multiple designers can work on different areas of the board, or on different layers. Engineers can join a design session offering advice on critical placement and routing. Note also that engineers could include specialist disciplines such as RF, analog, FPGA, ASIC and IC package. Design consultants could work on the layout without the design data ever leaving the company’s server. 

Unlike the independent workaround approach, there is no duplication of design data, and there is real-time communication of changes and visibility of the whole design context.

The biggest benefit of collaborative concurrent engineering is the ability to accelerate schedules (and to claw back a slipped schedule). Other important benefits include:

• Ability to apply idle resources. (Not to be taken the wrong way! There are peaks and troughs with workloads in many situations.)
• Increased communication across the design team.
• Data integrity – no overhead of disassembly and reassembly; one copy of the design data.
• Promotes a team approach – team members learn from each other.
• Flexibility in management and utilization of engineering resources.
• Leverage of expertise across the team, even if not at the same location.
• If you like video games, it’s kind of cool and fun, and you have more time to barbeque with your family!

Companies are realizing quantifiable gains due to collaborative concurrent engineering. These statistics are not calculated projections, but data compiled by companies using this approach in actual design situations:

• Alcatel Lucent saw a 60% reduction in layout design time, from 13 to 7 weeks.
• Fujitsu Technology Solutions was able to eliminate expensive night shifts.
• Kontron has reduced layout time by 25%, even as designs became more complex.

Collaborative concurrent engineering offers major gains in productivity and design cycle time reduction, made possible by today’s client-server architectures and fast networking infrastructures.

Jamie Metcalfe is market development manager at Mentor Graphics’ Systems Design (www.mentor.com); This email address is being protected from spambots. You need JavaScript enabled to view it..

Figure 1. The partition and reassemble approach is complex, limited in application and error-prone.

Figure 2. A client-server approach allows multiple designers to work on a single layout design with real-time updates and no reassembly required.

Altium today announced plans to acquire Morfik Technology, a provider of cloud-based software applications, in an all-stock transaction worth an estimated AU$3.3 million. The deal is pending due diligence. Within the next fiscal year, there will be no significant impact on Altium's revenues.

PRINTED CIRCUIT DESIGN & FAB spoke with Altium’s Alan Smith this morning:

Altium's Alan Smith

PCDF: How many employees does Morfik have? How many are software designers?

AS: Twelve in total, nine of which are software developers. 

PCDF: When is the deal scheduled to close?

AS: We expect this to be in the next few weeks, but we can't be precise because of the due diligence that forms part of the process. Having said that, we are also accelerating the acquisition by bringing the Morfik development team into Altium's offices to work with the Altium team on the development of the ecosystem infrastructure that we now plan to build into our software.

PCDF: What specifically made Morfik so attractive to Altium?

AS: Altium has been working with Morfik for a number of years, so Morfik's attraction, based on what it has done with the development of tools to create dynamic cloud-based ecosystems, is well understood. It has to do with Morfik's software engineering approach to the creation of object-oriented connectivity to the Internet. The two key phrases here are dynamic and object-oriented. These are essential for managing large amounts of content, which is what you have in electronics design: content down to the scale of individual components.

PCDF: What are the top technical challenges behind moving electronics design to cloud-based architectures, and how does the Morfik acquisition help Altium overcome them?

AS: Two points: 1) Tactical: helping Altium establish its ecosystem today for subscription-based content delivery. 2) Longer term: Morfik is about developing cloud-based applications; these are the applications that will be the highest layer, running on the “sea of connected devices” in this ecosystem. If we are to deliver the tools and solution to help the designer move from device design to ecosystem design, then cloud-application development is a fundamental part of this solution.

PCDF: When it comes to cloud computing, Altium is on record as seeing Google as being superior to Microsoft. Will *customers* have to choose a platform based on one or the other, or will electronics design in the cloud be platform-independent?

AS: We don’t really know. Amazon (Amazon Web Services) is more significant than either Google or Microsoft because it provides a much broader industrial-scale infrastructure for cloud-based application that is provided as a utility service for organizations that want to provide these kinds of solutions.

PCDF: Would a cloud-based infrastructure force any change to the subscription model that most ECAD companies now rely on?

AS: Not specifically. Cloud-based (Internet-based) models allow a real-time connection between customers and suppliers, as well as between customers and customers. This creates the possibility of having a much stronger and timelier value exchange between these parties. In the future, they can move the basis of software subscriptions away from being primarily based on software upgrades (new features, etc.) to a much stronger focus on content that can be delivered over time. In electronics design this includes component models, designs, price and availability from part suppliers, as well as feature upgrades being delivered in a “plug-in” model.

PCDF: Would cloud-based electronics design help resolve the persistent library and documentation issues that today cost designers extraordinary amounts of time?

AS: An emphatic yes. Vastly improved data management is already a big focus of the next release of Altium Designer, in Beta today, and cloud-based data exchange is a big part of this. Initial focus is on management of data between the board-design process, and the fabricators and assemblers of those boards, especially when the parties are in different regions and speak different languages.

Environmental Regulations

“Asian Chemicals Regulations”

Author: Gregory Dripps; This email address is being protected from spambots. You need JavaScript enabled to view it..
Abstract: Asia is adopting core elements of REACH, although the region is not adopting the regulation itself. Registration and reporting are based on tonnage bands, with mandated testing requirements (physical/chemical plus toxicity). Possession of data packages will become a currency of the future as management controls consider a substance’s potential hazards and use, not just hazards. A philosophical shift is underway, whereby the notion that existing or new materials are safe is being abandoned, and comprehensive analysis and testing data are required to demonstrate an acceptable hazard profile. In many nations, rules will go into effect as early as this year. (IPC Symposium on Electronics and the Environment, July 2010)

“Recent Developments in the Implementation of the EU REACH Regulations”

Author: Michael Kirschner; mike@designchain-associates.
Abstract: More than 140,000 substances have been preregistered, almost five times more than expected. To date, there are 38 candidate substances of very high concern (SVHC), and the Commission expects 165 by 2012. Until a listed substance is authorized or restricted, it remains a Candidate SVHC. To use an SVHC, make sure your supplier is legally authorized if your supply chain goes through the European Environment Agency. Furthermore, compliance in the EU does not mean compliance elsewhere. (IPC Symposium on Electronics and the Environment, July 2010)

“Halogen–Free: A Regulatory Overview”

Author: Susan Landry; This email address is being protected from spambots. You need JavaScript enabled to view it..
Abstract: Combustion gases generated during fires (whether or not flame retardants are present) that contribute to acute toxicity include CO, HCN, HCl, and acrolein. Carbon monoxide is responsible for more than 90% of all fire-related deaths. The most important pollutants generated in fires are polycyclic aromatic hydrocarbons (PAHs) and polyhalogenated dibenzodioxins and furans (PHDDs/PHDFs). Measurements made in large fires have shown that the PAHs have an up to 500 times higher cancer risk than the PHDDs/PHDFs. PAHs are generated in all fires, and many are carcinogenic compounds. In the US, the “Chemicals of Concern” Action List includes phthalates, short-chain chlorinated paraffins, polybrominated diphenyl ethers (PBDEs), and perfluorinated chemicals, including PFOA. An upcoming DfE will review Deca-BDE alternatives. The Department of Toxic Substances Control is called on to scientifically and systematically identify and prioritize chemicals and consumer products for manufacturers to conduct alternatives assessments, and DTSC could impose regulatory responses for alternatives selected by manufacturers. In June the European Parliament Environmental Committee voted to support amendments that require further evaluation instead of a ban on the use of certain organobrominated materials and PVC in electronics and electrical equipment, with certain exclusions for materials for military purposes and vehicles. (MEPs also called for a ban on nanosilver and carbon nanotubes, and that other EEE material containing nanomaterials should be labeled.) Amendments will now be considered by the full plenary session of the European Parliament. (IPC Symposium on Electronics and the Environment, July 2010)

Laminate Environmental Testing

“The Combustion Testing Phase EPA DfE Project on Flame Retardants for Circuit Boards”

Author: Dr. Emma Lavoie, et al; This email address is being protected from spambots. You need JavaScript enabled to view it..
Abstract: Goals of this work, a partnership of the US EPA and various industry suppliers, included identifying and characterizing commercially available flame retardants and their environmental, health, safety, and fate aspects in FR-4 printed circuit boards. The work applied lifecycle thinking to consider hazards and exposures, and used EPA New Chemicals Program criteria to evaluate hazard and environmental fate concerns. Methods included comparing the combustion byproducts from FR-4 laminates and PCB materials with different flame retardants during potential thermal end-of-life processes, including open burning, incineration, and smelting. Testing is designed to be a first step in providing industry with a comparative analysis of combustion byproducts from these materials, and to help inform further studies to better understand these byproducts in real-world scenarios. Investigations covered combustion testing of printed circuit board laminates, including materials containing phosphorus, TBBPA and no flame-retardant additives under temperatures of 300°, 700° and 900°C, with and without oxygen. (IPC Symposium on Electronics and the Environment, July 2010) CA

This column provides abstracts from recent industry conferences and company white papers. With the amount of information increasing, our goal is to provide an added opportunity for readers to keep abreast of technology and business trends.