Design For Manufacture (DFM) Article

Working closely with your electronics manufacturing services (EMS) partner early in the design phase of your project will result in a more cost effective product, with shorter lead times, and greater product quality and reliability. As manufacturing experts, with experience across multiple market sectors and product types, your EMS provider is ideally placed to offer you design guidance when it comes to electronics manufacturing.
Whether you are already taking advantage of DFM with your current EMS provider or assessing if this additional service could benefit you, below is a list of 12 common mistakes that are regularly made and how you can easily avoid them.

1. No Consultation
Involve your EMS partner as soon as possible, ideally when the very first draft of your PCB layout is available. With consultation through your prototype and pilot build phases, you give yourself enough time to check the design and correct any part or process difficulties. This an important benefit before committing to ordering all of the components for your first planned production build and committing your design for approvals.

2. Incorrect PCB Panels
The ideal panel layout will depend on the PCB design and what processes the assembly will go through. Thin PCBs (e.g. 0.8mm) will need to be in smaller panels to avoid flexing during the population process. Lack of a waste strip may make PCB conveyor transport and handling during production and test difficult. Having breakouts in the wrong place may mean the assembly is not rigid enough, or difficult to break out without damaging components. Lack of suitable fiducials can lead to alignment issues and increased setup times. Best practice advice is to allow your EMS partner to work with their PCB supplier in order to optimise the panel design.

3. Inappropriate PCB Finish
RoHS Compliant HASL is often specified as a standard finish, but it’s not favourable for fine-pitch components and a silver finish has a shorter shelf life than most. Where possible consider ENIG RoHS compliant finish for assemblies with fine pitch devices or high complexity. Consider the choice of finish could potentially save time and cost during the assembly process.

4. Missing Solder Resist
It may be tempting to have components sharing a pad, or to leave out the solder resist between pads on fine pitch devices. These designs seldom provide a reliable soldering process which adds risk and cost of rework where misaligned components or shorts develop.

5. Vias in Pads
This practice has become more common place to accommodate PCB space constraints but more often than not, results in most of the solder paste on the pad wicking down the via creating a dry joint. To avoid this, via’s should be “plugged” and also plated where required, which unfortunately adds additional cost.

6. Wrong Size or Shape Component Footprints
Double check the component data sheets for the components specified on your bill of materials (BoM) to ensure the correct component pad size and shape has been considered. Also check whether the body of the component will fit at the required location, as often components are placed too close together, or too close to the edge of the PCB. Failure modes such as broken components; component misalignment; and solder defects can result from not adhering to best practise.

7. Stencil Design
Accurate paste print and volume is critical to ensure reliable and repeatable solder joints during the reflow process. You’re EMS and Stencil partners have much experience in this regard and can recommend specific aperture shapes and reductions to ensure just the right amount of paste is applied to avoid solder defects.

8. Complexity
Populating SMT and TH components on both sides of the assembly will add cost to the manufacturing of the product. Unless the design will be compromised, try to avoid double sided assembly as far as possible.

9. Mixing Component Sizes
As 0402 and 0201 sized components become more common in designs, they create manufacturing challenges where they are placed next to larger components, which require more solder paste. The soldering process becomes more challenging where different paste volumes and chemistries need to be considered to avoid process defects such as “Cold Joints” and “Graping”. This also increases the manufacturing cost as stepped stencils and more expensive solder paste types have to be used, which in turn adds risk to the repeatability of the process.

10. Excessive Component Types
The number of component “lines” in your BoM will affect the assembly time and price, so if you can re-use the same component value and/or package size then it’s recommended you do so. Passive components in particular have very little price variation so standardising package size, voltage, wattage and tolerance values can keep the SKU count down.

11. Unnecessary Components
Although having a test point available for every node during prototyping is essential for debug purposes, consider what will be required for the final product in terms of programming and testing and reduce accordingly. Removing any component that is not required for the function of the product will reduce ongoing product costs.

12. Integration
Most electronic designs are presented in some sort of enclosure and the final integration of your product can be equally challenging. Consider reducing the amount of mechanical assembly and fixtures required to integrate your product, this will save time and avoid additional tools. Also consider operator access points to key assembly areas, removing complexity with press-fit solutions will save cost without necessarily compromising reliability.

When it comes to electronic assemblies there are so many variables and therefore countless opportunities for things to go wrong. By working with your EMS provider at an early stage, many of the risks can be reduced. If you are currently working on a new electronics design, looking to upgrade a product already out in the field, or keen to understand how product quality could be improved, let Zyteq Technologies put their expertise to work in assisting you.

ZYTEQ Achieves ISO 9001:2015

ZYTEQ Technologies are proud to announce their achievement of ISO9001:2015 accreditation, our new certiciate is available on our downloads page. Our quality management system has been improved to adopt all of the latest risk mitigation strategies.

ISO 9001:2015 specifies requirements for a quality management system when an organization:
a) needs to demonstrate its ability to consistently provide products and services that meet customer and applicable statutory and regulatory requirements, and
b) aims to enhance customer satisfaction through the effective application of the system, including processes for improvement of the system and the assurance of conformity to customer and applicable statutory and regulatory requirements.

 

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Zyteq Technologies Turns 3!

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On the 1st April 2017 Management and staff celebrated the third anniversary of ZYTEQ Technologies. ZYTEQ was founded on the 1st April 2014 by former management and staff of the Ziton fire detection factory in Cape Town with a vision of using their combined knowledge and experience to create a Contract Manufacturing business capable of providing local and international customers with a world class manufacturing service.

Despite having excellent equipment and vastly experienced staff, ZYTEQ had to prove their worth to demanding potential customers. We started with a small customer base and have continued to show exceptional growth as more and more customers became aware of our capabilities. Now with over 80 customers throughout South Africa representing all industries from high volume, low complexity products to highly complex small batches, ZYTEQ has been able to satisfy their needs and become a serious player in the South African electronics manufacturing space. We are proud that the original team that started ZYTEQ three years ago is still with the Company… with the addition of a few new faces along the way.  Our objective is to continue to grow our customer base by staying true to our vision and our commitment to continuous improvement in all we do.

Thank you to all our valued customers for their ongoing support!

ZYTEQ Technologies TImeline

•    March 2014 – ZYTEQ takes possession of their factory in Wetton, Cape Town
•    April 2014 – Factory Refurbishment completed
•    May 2014 – SMT lines commissioned
•    June 2014 – First production run
•    December 2014 – ISO 9001 (2008) certification achieved
•    May 2015 – Factory officially opened by Minister Rob Davies
•    November 2016 – ZYTEQ host CEO of the IDC Geoffrey Qhena
•    April 2017 – ZYTEQ Celebrate 3 year anniversary

Performance

At ZYTEQ we measure our actual performance against target each month, we are proud of the results we have achieved over the past three years, our historic performance on a few key metrics is given below:
•    On Time Delivery against customer committed date – 92.4%
•    Overall Customer Satisfaction Survey score – 6.5 out of a maximum of 7
(Includes ratings in the following key areas:)
Quality
Delivery
Working Relationship
Responsiveness
Overall Performance
•    Overall Plant First Pass Yield – 99.2%
•    Automated Optical Inspection (AOI) First Pass Yield – 99.5%