A Checklist For Improving Product Design

There is a saying that what costs $10 to fix in design, costs $100 in production and $1000 out in the field. Good designs are more cost efficient to produce, have less defects in manufacturing and are generally more reliable in the _FBP5218-2field. What common design mistakes should you avoid in your next product development effort? Here are eight issues we’ve seen:

Issue 1: Lack of Proper Protection on I/O (Inputs/Outputs).  Most devices need to take input signals and output a signal to other devices out in the field.  These are generally connected via hard wiring.  This hard wiring can be susceptible to external electrical noise or power surges due to other devices or lighting strikes and electrostatic discharge (ESD).  When this happens, it is very possible for this unwanted noise to be induced onto the wiring going back into your system.  Sometimes minor, but sometimes major damage can occur making the product malfunction.  To prevent this, it is vital to design protection circuits that shunt the unwanted energy to ground.

Issue 2: Lack of Proper Power Conditioning.  For any electrical product, it is important that the incoming power is conditioned to accommodate fluctuations in power, brown out conditions, missing AC cycle and power outages.  There are a number of ways to accomplish this.  Many active ICs have some power conditioning built in and some even have the ability to monitor the power.  Otherwise, utilizing simple resistors, capacitors and inductors in various topologies accomplishes sufficient power conditioning for most designs.

Issue 3: Design for Manufacturability (DFM) Guidelines Ignored. As I always say, you only design a product once, but you build it many, many times.  Following good guidelines not only controls cost, but also ensures good quality.  Follow proper spacing when routing traces, placing vias/pads, and placing components.   Maintaining minimum distances to stay within “standard” capabilities for both fabrication and assembly results in good quality at a lower cost.

Issue 4: Design for Test (DFT) Guidelines Ignored. Process control requires a mechanism to monitor the process.  Electrical test can serve as that mechanism.  Providing at least one testable-sized via for each net on your design is good practice.  Test fixturing has become more of a commodity these days so the cost of fixtures has dropped significantly.  Keep the test pad (which can be a via) at least 35 mils diameter size and minimum 75 mils diagonal spacing to adjacent test pads.  Keep test pads minimum 75 mils from body of component and 25 mils from a component lead.  Following these two design guidelines will allow for good test coverage utilizing a lesser cost fixture.

Issue 5: Insufficient Filtering of Integrated Circuits (ICs). Placing filter capacitors (aka bypass caps) onto each IC is required to provide enough localized potential energy to allow the IC to switch properly.  The other function they serve is to filter out AC (or DC ripple) voltage as not to interfere with the function of the part.  Not having bypass caps in place may cause the IC to switch states unintentionally.

Issue 6: Insufficient Bulk Capacitance. Bulk capacitance is required to maintain proper voltage levels throughout the entire board.  Depending on board size, there may be multiple sets of bulk capacitors used.  Because the power source or power supply may not be able to provide sufficient power to all parts of the board, the bulk capacitors help provide the additional energy as needed. In other words, they help load level the supply(s).

Issue 7: Insufficient Protection for Uncontrolled Incoming Power Loss. Linear regulator protection is required to account for uncontrolled incoming power loss.  When this occurs with insufficient protection, the current will want to go through the regulator in the wrong direction, possibly damaging the component.  Ideally, a diode should be provided to shunt the current around the regulator instead of through it.

Issue 8: Failure to Utilize PCB Design Good Practices. Most products sold into market need to comply with certain agency standards, i.e. U.L., FCC, CSA, CE, etc.  In order to pass many of these standards, employing sound EMC (electromagnetic compatibility) practices is key.  The compatibility part of EMC means that a design cannot emit any electromagnetic interference nor be effected from induced electromagnetic interference.  Following the practices mentioned previously will all help with ensuring the product complies with EMC requirements.  Additionally, if you remember what was taught in basic circuits class, current (I) flowing through a wire will create an electric field.  As a result the more wires carrying current, the more fields are produced.  And a trace on a board is really nothing more than a wire.  So keeping all wires a short as possible with the least amount of resistance reduces the magnitude of the electric field(s).  These can be mitigated by providing sufficient power and ground planes which ultimately reduces ground loops.  And one more thing to remember, a loop of wire with current traveling through it is really an antenna!  This is not good for passing EMC testing.

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Reducing Test Cost – Five Areas to Evaluate

Is product testing costing more than it should? That is one of the first questions test engineers at Burton Industries, Inc. ask when evaluating new projects. Printed circuit board assembly (PCBA) complexity, project volumes and defects per million opportunities (DPMO) estimates all factor into what tests should be required.  But here are five key areas to check in analyzing whether or not there may be opportunities for cost reduction:_FBP4942

  • Can a faster tester be used? Case in point, Burton Industries’ CCI automated functional test platform reduces typical functional test time from 5 minutes to under a minute, over older similar functional test platforms.
  • Can NRE be reduced through use of connector-based testing? The CCI functional tester can use either bed-of-nails fixtures or do connector-based testing, provided the PCBA design allows test access via the connector.
  • Has the product been evaluated for the best test and inspection strategy? Burton Industries’ team analyzes the right mix of inspection and test steps for each customer’s goals. The Company’s current inspection and test capability includes automated optical inspection (AOI), 2D x-ray inspection, a Checksum manufacturing defect analyzer (MDA) tester, in-circuit test, automated functional test and custom functional testing, providing a wide range of options in inspection and test step combinations.
  • Are test point accessibility issues driving higher cost? In-circuit testing can cut test costs in higher volume PCBA manufacturing when the PCBA is accessible enough to ensure good coverage, however, when that isn’t the case the solution is often greater levels of inspection or longer functional test cycles. Self-tests such as boundary scan testing can help improve test coverage in PCBAs with limited test point access. To achieve maximum benefits boundary scan cells need to be included on all pins.
  • Is there a final program, test, pack and ship station? Combining testing and programming can save some time over separate processes. Having that work cell also pack and ship the product enhances configuration management by minimizes the opportunity for mislabeling or mispackaging products that are configured to order.

The team at Burton Industries is focused producing products at the lowest possible costs and routinely evaluates these areas to better optimize test strategy.

Visit Burton Industries at AMCON Novi, Nov. 10-11

The Burton Industries team will be exhibiting in booth 111 at AMCON Novi (Detroit), MI in the Suburban Collection Showplace on Nov. 10-11. Click for Your Free Registration

Visit Burton Industries at the Covington Kentucky Design 2 Part Show

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Burton Industries team will also be exhibiting at the Design 2 Part in Covington, Kentucky at the Northern Kentucky Convention Center, Nov. 4-5.

Click for Your Free Registration

Visit Burton Industries in Booth 1054 at MDM Minneapolis

MDM Minneapolis will be held at the Minneapolis Convention Center on Nov. 4-5. Burton Industries’ team will be there in Booth 1054. The show is co-located with five other manufacturing related events.

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Click for Your Free Registration.

Burton Industries Enhances its SMT Capability

Burton Industries Adds Universal Fuzion Line PR_Page_1Burton Industries is continuing to invest production enhancements. The Company recently added a Universal Instruments’ Advantis Fusion SMT line which includes a Fuzion1-30 high-speed placement machine and a Fuzion1-11 flexible platform. The new system supports fast line changeovers, plus has integrated inspection tools which help Burton’s team consistently deliver superior quality. Read more in our recent press release.

Supporting Variable Demand: Four Key Areas to Analyze

525123-Global SMT Jun_Burton Industries Variable Demand_Page_1As systems have created better real-time visibility in terms of end market demand trends, and raw material availability and production status in the supply chain, original equipment manufacturers (OEMs) have reduced finished goods inventory levels. The upside of reduced inventory is faster inventory turns and reduction of the non value-added costs associated with excess inventory. However, the downside is that a supply chain interruption or unanticipated spike in demand could result in empty shelves. One strategy to avoid that is simply to require the electronics manufacturing services (EMS) provider to carry a finished goods Kanban. However, pushing the costs of excess inventory safety stock down to the supplier doesn’t truly eliminate the cost. A better strategy involves working with the EMS provider to create a system that provides the needed flexibility, but minimizes the non value-added costs associated with material or finished goods in an extended “wait state.”

At Burton Industries, we have a number of customers with highly variable demand. The four areas our team focuses on optimizing to support variability efficiently are:

  • Design for procurement (DFP)
  • Forecasting
  • Stocking programs
  • Production throughput.

Read our latest article in Global SMT & Packaging which goes into more detail on this topic: Supporting Variable Demand: Four Key Areas to Analyze here.