Spitfire Controls Moves to New Engineering Center
In mid-June of this year the Spitfire Controls Division (the design arm of SigmaTron International, Inc.), moved into its new engineering center in Elgin, Illinois. SigmaTron acquired this facility in May. The facility, which was originally built as an engineering center for Emerson Electric, has test capability labs and electric power that conforms to standards of all regions of the world. Products for the Japanese market can be tested at 100V 50/60Hz and European Standard products likewise can be tested at 220 Volts 50Hz just as easily as those products meant for North America. The engineering section has areas for bread boarding, prototyping and electrical, as well as, environmental testing.
In addition to improved lab area, a new CAD facility was added, which gives this department capability to support more projects.
This move puts Chicago area design staff with-in one facility.
Strategically, Spitfire Controls enhances SigmaTron’s portfolio of manufacturing service offerings by adding complete product development engineering services.
Spitfire’s product development expertise includes software-driven controls, analog controls, microprocessor controls, switching power supplies, LED lighting applications, human interface user I/Os, variable speed drives for small frame motors, industrial designs and packaging.
Spitfire Controls’ advantages include:
- Reduced time to product realization
- Design for manufacturability/testability expertise
- Extensive expertise in appliance control design and manufacturing
- Lowest total cost through a combination of design focus on minimal component count, competitively priced supply chain and efficient manufacturing operations
- Access to a global network of manufacturing facilities providing customized, high quality manufacturing solutions
Suzhou Facility Supports Local Market
Nearshoring has become a popular term of late. And while it is most often used to refer to the practice of sourcing in the U.S. or Mexico to support North American markets, the reality is nearshoring is often taking place anywhere a company has a market.
Not surprisingly, manufacturing in China is a logical way to service the Chinese market. SigmaTron International’s facility in Suzhou, PRC is licensed for both production of domestic product and export to Asia and export markets.
One of the biggest challenges to foreign companies planning to sell domestically in China is finding partners who understand their quality and intellectual property protection concerns. Customers using SigmaTron’s Suzhou facility for domestic production see the same high level of systems visibility and controls in place in any other SigmaTron facility.
A comprehensive ERP system combined with SigmaTron’s internally-developed iSCORE suite of supply chain management tools provide close linkage with the supply chain on forecasted requirements, actual demand, material on order and inventory on hand, and automatically adjust as demand trends change. The Suzhou facility’s internal procurement team includes a Green Product Compliance Service Center and in-house Customs staff. The team is supported by SigmaTron’s global procurement network which also includes an International Purchasing Office in Taiwan. In short, all the resources are in place to ensure that the logistics advantages and response speed associated with nearshoring are achieved.
Proprietary systems monitor real-time production status, quality trends and shipments. SigmaTron’s SCORE customer portal gives customers 24/7 project status visibility.
Agile and Valor software are used to speed New Product Introduction (NPI) and design for manufacturability/testability (DFM/DFT) analysis.
SigmaTron’s Suzhou facility has been a pioneer in some of the Company’s continuous improvement initiatives. For example, as a pilot project in China, the production team converted to an electronic standard operating procedure (ESOP) system that enables operators to view visual aids, detailed work instructions and historic defect data, plus participate in in-line video training via monitors at each workstation. The system en
sures documentation integrity, speeds changeovers and gives operators the tools they need to fully understand the processes they support. After testing in Suzhou, it was rolled out to other facilities.
The quality system includes real-time data collection and process feedback. There are robust preventive and corrective action processes. Six Sigma tools are used to drive improvement in both manufacturing and administrative processes.
SigmaTron’s Suzhou, PRC facility offers a high quality solution for companies wishing to build product in China for domestic sale.
Five Common DFM Mistakes and SigmaTron’s Solutions
Ensuring optimum design for manufacturability (DFM) is a key part of SigmaTron International’s New Product Introduction (NPI) process. Since Product Engineering teams often are primarily focused on product form, fit and function, it isn’t unusual to find potential DFM issues with the initial design. According to Yousef Heidari, Sigmatron International’s V.P.
Engineering, the five most common are:
- Layout land pattern to component footprint mismatch
- Lack of solder mask web in between SMT pads and the connected through-hole vias creating potential for insufficient solder joints
- Insufficient spacing near through-hole components for selective soldering No thermal relief connection to copper planes for through-hole components’ plated through-hole (PTH) lands
- No tear-drop transitions for through-hole components’ PTH lands to narrow escape-out traces.
Component Land Patterns
Land pattern choices are critical because they drive the spacing. The pad size must support the density requirement of product as well as the formation of the correct solder joints. SigmaTron International’s DFM review process verifies the footprint (from the Valor Part Library) of all the components specified in the bill of material (BOM) to match the land patterns used in the layout. Once potential issues are found, i.e., if the pad size appears incorrect for the specified component, the manufacturer’s datasheet is referenced. Most of the time, the problem is resolved by slight change in the manufacturer part number (MPN) specified in BOM. In addition the component-to-component spacing is also analyzed as part of the DFM review using the actual component’s body size and shape.
Solder Mask Design-Related Issues
Via-in-pad (VIP) can wick part of the limited solder out of the SMT terminations/solder joints. Similarly, if there is a PTH via connected to the SMT pads that does not have the solder mask web in between, there will be potential for insufficient solder joints and even open solder joint formation.
PTH vias once exposed by solder mask openings can be very useful as test access points for electrical testing such as flying probe test. However exposed PTH vias that are underneath and very close to low-standoff components could get shorted during soldering operations.
Insufficient Spacing of SMT and Through-Hole Components
Selective point-to-point soldering is an overall better process in terms of through-put and repeatability, than manual soldering. The proximity of SMT components’ body and terminations located on the solder side of the through-hole components determine whether the manufacturing process should utilize either selective wave soldering pallets and/or selective point-to-point soldering equipment. The layout is also checked for sources of mechanical interference and to ensure that adequate spacing around the printed circuit board assembly (PCBA) is present for automated handling.
No Thermal Relief Connection to Copper Plane
Through-hole components require thermal
relief pads to connect them with the surrounding copper. This design element restricts heat flow which improves soldering. When this element is not present and the component is connected directly to the copper pour, the high thermal conductivity of copper can cause the heat to dissipate from the pad, resulting in a cold solder joint and insufficient PTH barrel fill.
Tear Drop Transitions to Narrow Traces
Narrow traces that are connected to PTH lands used for through-hole components could be thermo-mechanically stressed during soldering operation. When smaller traces must be used, tear drop transitions or equivalent structures at pads can reduce stress.
Focusing on common DFM issues early in the design process helps shorten the product development cycle. SigmaTron International can support customer product development teams with design guidelines and detailed DFM recommendations.
SigmaTron International’s Processes Help Protect Products
Moisture, chemicals, salt fog, dust and extreme temperatures are just some of the conditions faced by the products SigmaTron International builds. Fortunately, the Company offers protective coating options for printed circuit assemblies (PCBAs) that include conformal coating, parylene coating, potting and encapsulation.
Depending on the facility and application, there are both automated and manual spray booth conformal coating options. Curing ovens are used for heat-cured products and to reduce dry time. Coating options include urethane, acrylic and heat-cure silicone.
“Requirements are often been ‘locked in’ in the product qualification phase. For example, while urethane represents an upgrade over acrylic, customers who have done reliability tests using acrylic don’t want to change. While the majority of our customers use urethane and silicone, we offer acrylic as well to ensure the broadest range of customer needs are addressed,” said Dennis McNamara, Vice President, Engineering, Acuna, Mexico facility.
Parylene coating is also an option. One of the disadvantages of conformal coating is that there can be small pinholes or voids in the coating. For most applications, this isn’t an issue, however for products that are continually exposed to driving rain or other severe conditions, a more robust coating may be required. Parylene coating is applied using a vacuum deposition process. Parylene elimi
nates the possibility of voids. In addition, because this is an omnidirectional process, it goes under ICs and all other components providing a perfectly sealed coating. Coating thickness is determined by the amount of dimer placed in the machine.
Parylene coating does require a more complex preparation process than conformal coating. The PCBA must be cleaned of all flux in a water wash process. Then it must be primed with a mixture of xylene, silane and alcohol. After that step, the PCBA is dried in a vacuum oven at 85 degrees C to remove any moisture. Connectors and unsealed
switches are masked by hand. The prepped PCBAs are then placed in the vacuum chamber and coated. Following coating, PCBAs are manually demasked.
Epoxy and silicone potting and encapsulation are also offered via an automated process.
“Coatings can be critical in ensuring continued product performance in hostile conditions. Our mix of options ensures that customers can select the process best aligned with their application needs and cost goals,” added McNamara.