-
- News
- Books
Featured Books
- smt007 Magazine
Latest Issues
Current IssueBox Build
One trend is to add box build and final assembly to your product offering. In this issue, we explore the opportunities and risks of adding system assembly to your service portfolio.
IPC APEX EXPO 2024 Pre-show
This month’s issue devotes its pages to a comprehensive preview of the IPC APEX EXPO 2024 event. Whether your role is technical or business, if you're new-to-the-industry or seasoned veteran, you'll find value throughout this program.
Boost Your Sales
Every part of your business can be evaluated as a process, including your sales funnel. Optimizing your selling process requires a coordinated effort between marketing and sales. In this issue, industry experts in marketing and sales offer their best advice on how to boost your sales efforts.
- Articles
- Columns
Search Console
- Links
- Events
||| MENU - smt007 Magazine
What SMT Component Shortages Mean for Design and Manufacturing Engineers
September 13, 2018 | Russell Poppe, JJS ManufacturingEstimated reading time: 4 minutes
Much has been written about the increasing shortages of multilayer ceramic capacitors (MLCC), surface mount (SMT) resistors and other semiconductor devices. Right now, we are seeing price increases and greatly extended lead times. In some cases, the delivery time is so long that the component is all but unavailable, and there has been a vast increase in devices notified as "end of life" and due for obsolescence.
Where components can be found, it is quite possible that they will be offered in smaller package sizes than before. According to a recent TTi MLCC Market update, manufacturers are migrating to smaller package sizes. We might find, for example, the popular 100nF capacitor soon only being available in 0201 or 01005 packages.
It seems the situation is likely to get rapidly worse rather than better. Given that product still needs to be manufactured and sold, it going to be down to design and manufacturing engineers to come up with solutions, and fast.
So, what are our options?
1. Can we fit smaller SMT components on PCB pads designed for larger devices?
Maybe. Unfortunately, there is no straight answer as it very much depends on the overall PCB design. The component size and the PCB pad design will determine how much of the device can sit on the pad and how good the solder joint can be. Standard sizes for components and pads or ‘land patterns’ are defined by IPC 7531, but for a variety of reasons designs can be slightly different, and maybe more or less favorable to using ‘wrong size’ components. As a worst case you might find something like the following for the smaller components:
If it does appear possible, it will probably be necessary to re-design the solder stencil. Careful stencil design, very accurate component placement and reflow profiling can reduce the risk of unwanted defects such as ‘tombstoning’. Without a change to the stencil aperture, the applied solder will try to ‘wet’ over the whole pad, which being too large for the device can pull it away from the pad.
It might be possible to get the PCB manufacturer to alter the solder resist to cover more of the pad, but again this can present printing problems.
Smaller components might also make it necessary to reduce the stencil thickness from say 5 to 4 thou. A ‘stepped’ stencil could be required to ensure the right amount of solder paste is applied to the right areas of the PCB, or perhaps use solder paste jetting instead of printing.
If you are looking to comply with IPC-A-610 standards, then you might find this approach is unsuitable. There could also be implications for longer term product reliability due to the solder joints being less than ideal.
Inspection and test also need considering. In particular, automated optical inspection (AOI) will need to be adjusted. First time pass yields are likely to decrease, and a larger amount of rework may be necessary.
Of course, when specifying alternative components their performance characteristics need to be correct too; smaller components may well have different operating voltages, heat dissipation etc. making them unsuitable for your circuit. ‘Track and gap’ requirements might need to be considered.
It is also worth checking that your SMT assembly equipment is capable of placing smaller components as 0402, or even larger, could be the limit for older equipment.
2. Can we re-design the PCB for smaller components?
Yes, and this is probably the preferred option, though much of the above still applies in terms of checking production capability, component characteristics and the need to amend stencils and inspection. Of course, testing and approvals processes will also need to be considered.
It might be possible to replace a few components with smaller parts, and keep the rest the same, by using a stepped stencil as discussed above. However, if the new smaller components are widely distributed across the PCB, decoupling capacitors for example, then a more extensive re-design might be required to ensure all components are small enough to use the same stencil thickness. Alternatively, it may be necessary to consider jet printing the solder paste.
If space allows, designing pads to accommodate two component sizes could help. This could be by having parallel components (with one not fitted) or by adjusting the pad size and gap; though of course consideration needs to be given to the solder joint that can achieved.
What should we do now?
In summary, the best approach is to discuss and evaluate what is possible with your manufacturing engineers before committing to any smaller components, as they will most probably raise some challenges—and costs—if indeed the parts are useable at all.
Ensuring the electrical integrity of the circuit is maintained is also vital, and, of course, any testing and/or approvals processes must be planned in.
Most important of all, though, is to start planning now. Your electronics manufacturing services (EMS) provider may have done a great job so far shielding you from this issue and securing stocks on behalf but there’s a limit to what they will be able to achieve as the months roll by without your input.
Suggested Items
AIM to Highlight NC259FPA Ultrafine No Clean Solder Paste at SMTA Wisconsin Expo & Tech Forum
04/18/2024 | AIMAIM Solder, a leading global manufacturer of solder assembly materials for the electronics industry, is pleased to announce its participation in the upcoming SMTA Wisconsin Expo & Tech Forum taking place on May 7 at the Four Points by Sheraton | Milwaukee Airport, in Milwaukee, Wisconsin.
Hentec/RPS Publishes an Essential Guide to Selective Soldering Processing Tech Paper
04/17/2024 | Hentec Industries/RPS AutomationHentec Industries/RPS Automation, a leading manufacturer of selective soldering, lead tinning and solderability test equipment, announces that it has published a technical paper describing the critical process parameters that need to be optimized to ensure optimal results and guarantee the utmost in end-product quality.
Empowering Electronics Assembly: Introducing ALPHA Innolot MXE Alloy
04/16/2024 | MacDermid Alpha Electronics SolutionsIn the rapidly evolving electronics industry, where innovation drives progress, MacDermid Alpha Electronics Solutions is committed to setting a new standard. Today, we are pleased to introduce ALPHA Innolot MXE, a revolutionary alloy meticulously engineered to address the critical needs of enhanced reliability and performance in modern electronic assemblies.
New Book on Low-temperature Soldering Now Available
04/17/2024 | I-Connect007I-Connect007 is pleased to announce that The Printed Circuit Assembler’s Guide to… Low-temperature Soldering, Vol. 2, by subject matter experts at MacDermid Alpha Electronics Solutions, is now available for download.
Inkjet Solder Mask ‘Has Arrived’
04/10/2024 | Pete Starkey, I-Connect007I was delighted to be invited to attend an interactive webinar entitled “Solder Mask Coating Made Easy with Additive Manufacturing,” hosted by SUSS MicroTec Netherlands in Eindhoven. The webinar was introduced and moderated by André Bodegom, managing director at Adeon Technologies, and the speakers were Mariana Van Dam, senior product manager PCB imaging solutions at AGFA in Belgium; Ashley Steers, sales manager at Electra Polymers in the UK; and Dr. Luca Gautero, product manager at SUSS MicroTec Netherlands.