-
- News
- Books
Featured Books
- pcb007 Magazine
Latest Issues
Current IssueThe Growing Industry
In this issue of PCB007 Magazine, we talk with leading economic experts, advocacy specialists in Washington, D.C., and PCB company leadership to get a well-rounded picture of what’s happening in the industry today. Don’t miss it.
The Sustainability Issue
Sustainability is one of the most widely used terms in business today, especially for electronics and manufacturing but what does it mean to you? We explore the environmental, business, and economic impacts.
The Fabricator’s Guide to IPC APEX EXPO
This issue previews many of the important events taking place at this year's show and highlights some changes and opportunities. So, buckle up. We are counting down to IPC APEX EXPO 2024.
- Articles
Article Highlights
- Columns
Search Console
- Links
- Events
||| MENU - pcb007 Magazine
Understanding MIL-PRF-31032, Part 4
October 20, 2020 | Anaya Vardya, American Standard CircuitsEstimated reading time: 3 minutes
Overview
Continuing with Part 4 of the discussion on understanding the military PCB performance standard MIL-PRF-31032, the next step in the process is to create four new procedures to address the unique requirements of the military.
Qualification and Add-On Procedure
This process provides the guidelines for the initial qualification of the company, as well as a path for future add-on qualifications. The first thing that needs to be included is the process for developing the qualification test vehicle. This is the specific PCB design that will be used to build the qualification boards. The documentation required must also be identified, such as production traveler, test vehicle design, drawings, multilayer layup, etc.
Test Vehicle
A company will qualify for specific technology and will need to develop a qualification test plan, which is a document that specifies the following minimum attributes of the qualification board:
- Max. Number of Layers and Dielectric Type
- Max. Panel Size
- Max. Board Thickness
- Min. Drilled Hole Before Plating
- Aspect Ratio
- Min. Conductor Width
- Via Structure
- Min. Conductor Space
- Hole Preparation
- Hole Wall Conductive Coating
- Copper Plating
- Solder Resist
- Silkscreen
- Final Finish
- Additional Fabrication Capabilities
- Controlled Impedance
It is important to note here that the qualification “flows down” but not “up.” In other words, if an 18-layer is qualified, layer counts less than 18 layers can be built as long as the other above parameters are the same, but a 20-layer would not be allowed.
Sample Size and Data Requirements
The next section would be to establish the lot size of the qualification lot and the sample sizes that will be used for testing. The data recording and retention of all qualification records must be defined, including coupons and any extra boards left over from the qualification lot.
Failure Analysis and Resubmission
A DLA-approved third-party testing lab must be selected to use for the initial qualification as well as the ongoing monthly testing. Should a submitted sample fail any tests, this procedure needs to have a provision for failure analysis and corrective action. This typically leverages the existing processes already in place. The rules for resubmitting new qualification boards must also be defined here, particularly that additional extra samples from the failed lot cannot be used.
Qualification Test Summary and Reporting
This section outlines the components for the summary that is needed to be submitted to the DLA after all tests and inspections have been successfully performed, including the third-party lab). This includes things like the travelers, internal and external test and inspection results, lot conformance forms and results, failure mode for any rejections, dimensional and electrical test parameters and measurements, and a copy of the qualification test plan.
Add-On Qualification
MIL-PRF-31032 allows for the expansion of the qualified technology through the add-on qualification process. A technology that falls within 25% of the current qualified technology can be built with a new qualification test plan and TRB approval. For example, with a qualified 18-layer, a 22-layer could be qualified through the add-on process.
The same would apply to line width, hole size, etc. There is no need to wait for DLA approval in these cases; they will verify the add-on qualification data during their next regular visit/audit. Anything greater than a 25% technology change will require a new full qualification like the initial qualification.
Conclusion
This wraps up qualification and add-on procedures. Part 5 will focus on the next unique procedure needed to produce MIL-PRF-31032 PCBs.
Editor’s note: Read Part 1, Part 2, and Part 3.
Anaya Vardya is president and CEO of American Standard Circuits; co-author of The Printed Circuit Designer’s Guide to… Fundamentals of RF/Microwave PCBs and Flex and Rigid-Flex Fundamentals; and author of Thermal Management: A Fabricator's Perspective. Visit I-007eBooks.com to download these and other free, educational titles. He also co-authored “Fundamentals of PCB Technology.”
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.