Design and Manufacture Guidelines for Surface Mount Technology

Ralba

Involved In Discussions
#1
Hello all,

I am working with an SMT electronics CM, and we ran into some issues with problematic designs for manufacture from customers, such as lack of rails or poor component placements. Some inside my organization mentioned their previous companies would issue a "Guidelines to Design for Manufacture" type of document to the customer detailing characteristics necessary to make a board reliably manufactureable. Many of our customers are small or are not part of a compliance system, so I cannot do something like PPAP.

Does anyone have a document they issue to customers for this kind of purpose? While obviously an electronics related document would be great, I am mostly looking for a format, so this type of document from any industry would be helpful.
 
Elsmar Forum Sponsor

outdoorsNW

Involved In Discussions
#2
The IPC 22xx series of documents cover design. There are general documents for rigid and flex PCBs and documents for more specialized design needs. I would ask customers to use these documents.

However the reality is only some customers will. Even our large customers (Forture 500 types) sometimes have poor designs when there are easy ways to improve the design that will not hurt performance or cost. And one of our engineers, a former PCB designer, complains about how often he is ignored when he makes easy to implement design recommendations to customers early in the design process.

The reality is most electrical engineers receive little to no training on how to design a good PCB for manufacturability.

Your only solution may be to charge the customers your added cost and highlight the cost saving if they improve their design.
 

John Broomfield

Staff member
Super Moderator
#3
Being as better manufacturability results in lower costs (and better reliability?) how about selling your design expertise?

I’d recommended designing your design enhancement service and validating it with your favorite customers first.

This new design support service may increase the sales of your manufacturing services too.
 

Ralba

Involved In Discussions
#4
The IPC 22xx series of documents cover design. There are general documents for rigid and flex PCBs and documents for more specialized design needs. I would ask customers to use these documents.

However the reality is only some customers will. Even our large customers (Forture 500 types) sometimes have poor designs when there are easy ways to improve the design that will not hurt performance or cost...
Well that is disheartening, but not surprising. I doubt there is any industry that never skips over something that would make everything easier on everyone. I will try to get the IPC 22xx documents you mentioned. I was just wondering what some example "design for manufacture" documents might look like so I could communicate effectively when I craft one for things we commonly run into (e.g. 'yes, you must have a complete gerber file with the solder mask included. No, you cant put parts at the edge of the PCB with no rails.')

If anyone in this industry was willing to share, I was also wanting to see what they include on it so I do not miss something obvious.
 

outdoorsNW

Involved In Discussions
#5
There is a lot to consider, hence the multiple documents. You may not need all of the 22xx series documents.

Things that often cause us problems are rails-wrong size, customer wanting a non standard condition after rails removed (sometimes the customer does not understand the natural break lines of the various ways of attaching rails), the customer fails to allow for a worse case tolerance condition, or forgets that scoring is a v groove and not the centerline on the drawing. We ask to design the panelization ourselves whenever possible.

Other common problems are components too close to the edge, wrong land size or pattern, lack of soldermask between lands (some soldermasks have better resolution than others). I have seen a couple of cases of through hole parts on both sides (difficult, may mean hand rather than selective solder is used) and one case with where to board is threaded rather than using an insert (not going to hold over time). Bottom termination components are best avoided as well. Balanced stack up and design helps maintain flatness.

Large boards need to be thick to maintain coplanarity. A .062 thick 16 inch wide board can be designed, but it will move and flex from reflow heat and create problems with BGAs, especially those with non-collapsing balls. When the PCB cools, it can be flat again. The hypothetical 16 inch wide board probably needs to be at least .096 inches and possibly thicker to have enough rigidity for anything other than a small BGA. A long narrow board may have similar problems; I don't have enough experience to be sure. Even with a fixture, keeping a wide board flat can be a problem. Possibly if fixture attachment points were designed into the board middle in the correct places and a rigid enough fixture could be fit through the reflow oven, cheating the thickness might be possible. Otherwise low yields are likely and the big expensive BGAs will be the ones causing problems.

Fiducials need to be in different locations on each side and between similar parts. We had a case where a PCB was loaded upside down but because the fiducials were in the same place, the machine accepted the part. Some newer SMT equipment can switch products by reading the fiducials if the components are in the machine. If you run product families, there is potential for time savings especially if you can either rapid change your stencil or have jet print equipment for your solder paste.

Gerber is outdated as a format and should not be used for new designs. ODB++ is better than gerber, and IPC 2581 is taking over (45+% of our business, growing every year) and is the best format until someone develops something even better.

If you are purchasing IPC-2223 for flex and rigid flex PCBs, make sure you get the E version. I got an email from IPC today saying it had been released, along with 6012 E for bare PCB manufacturing and quality.
 

Ralba

Involved In Discussions
#6
That is one impressive post! I will be meeting with the production team and some very experienced operators to build our list, and I will keep what you said here with me to make sure we include it.

We have asked all of our customers to use ODB++. That said, some of them, especially some of the smaller companies, do not have that capability yet, so we get many gerber files.

And thank you for the heads up about the revision changes.
 

Ralba

Involved In Discussions
#7
OutdoorsNW , could you perhaps help me with another thing? I have made this document and I am in the process of having my co-workers review it, but there is one aspect of the design that I can't seem to locate. Is there a chart/matrix somewhere that shows the relationship between board size and board thickness? That is, what is the minimum recommended thickness for boards with X surface area?

I found a table in one of the IPC standards that says there is a risk, but it doesn't attribute any numbers to it. I am mostly looking for a general guideline on maximum panelization for small boards, as the savings in throughput of a highly panelized board eventually will be overshadowed by the sag and coplanarity risk of a very large, thin board with many V-scores/mousebites.
 

outdoorsNW

Involved In Discussions
#8
I am not aware of a chart. I just know about cases where my company has had problems. Factors are board size and thickness, BGA size (smaller is easier, bigger is more likely to have problems) and BGA ball type, collapsing (easier) vs non-collapsing.

You have a basically flat, rigid BGA that you are trying to solder to a potentially slightly curved PCB surface. Anything that minimizes the effect of or conforms to a slight curve is helpful. You are trying to keep everything within .006 inches of flat within the BGA area.

Bare PCB design (balanced vs unbalanced construction and amount of copper in an area) is also a factor but is hard to predict ahead of time.
 

Ralba

Involved In Discussions
#9
I had hoped there was a guideline resource, but after looking into it more, it appears there are just far too many variables for a usable matrix like I wanted. Thank you for all your time in your responses.
 
Thread starter Similar threads Forum Replies Date
B Supplier of design and manufacture process ISO 13485:2016 - Medical Device Quality Management Systems 10
L Contracted Manufacture Company wanting to be able to design and manufacture own product. 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 7
K Does company who manufacture but does not design or carry out clinical trials is responsible for CE marking for single use medical devices? ISO 13485:2016 - Medical Device Quality Management Systems 3
J Is Design Validation required for fixtures or test systems used to manufacture a product? AS9100, IAQG 9100, Nadcap and related Aerospace Standards and Requirements 4
C Addition of Design & Manufacture - CE Mark Reissue? EU Medical Device Regulations 1
G Cell Design - Use DFMA (Design for Manufacture & Assembly) Analysis Lean in Manufacturing and Service Industries 2
C Design and Manufacture of Tortilla Production Machines Manufacturing and Related Processes 5
J Tooling Design & Manufacture ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 3
S Product Development Program - Design, develop, approve and manufacture new products Design and Development of Products and Processes 6
I Design & Development - Exclusion of 7.3 - We Manufacture to Customer Prints Design and Development of Products and Processes 14
A Design History File - Not ready to share the design drawings or Bill of Material US Food and Drug Administration (FDA) 2
W Need for current design or process control FMEA and Control Plans 2
A What is the difference between Design Process, Process Design and Design Control? 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 2
D Test summary report example for design validation wanted - ISO 13485 ISO 13485:2016 - Medical Device Quality Management Systems 1
B Why the Greek god Hephaestus should have done a design FMEA (DFMEA) on his giant robot APQP and PPAP 1
S Documenting Design Verification Test Results (ISO 9001) Design and Development of Products and Processes 1
DuncanGibbons Understanding the applicability of Design of Experiments to the IQ OQ PQ qualification approach Reliability Analysis - Predictions, Testing and Standards 0
S Requirement to Conduct New Shelf-life Testing? (re-do testing for design change) EU Medical Device Regulations 3
A Sample Agreement available for Outsourcing Medical Device Design activity? ISO 13485:2016 - Medical Device Quality Management Systems 1
DuncanGibbons How is the arrangement between Design and Production organisation envisaged? EASA and JAA Aviation Standards and Requirements 4
L Design & Development of a SERVICE Service Industry Specific Topics 13
C Documentation for items used for Design Verification 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 4
P Design verification driven by new equipment. How is this different than process validation? 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 1
A AS9102B - 3.6 Design Characteristics and form 3 AS9100, IAQG 9100, Nadcap and related Aerospace Standards and Requirements 3
P Design FMEA - Detection Rating criteria ISO 14971 - Medical Device Risk Management 3
U Medical Device Design finalization testing ISO 13485:2016 - Medical Device Quality Management Systems 2
S MDR Delay - MDD design Change? (before new MDR DOA) EU Medical Device Regulations 8
J Iterative design and production for custom made products ISO 13485:2016 - Medical Device Quality Management Systems 3
T Design Input detail & specificity ISO 13485:2016 - Medical Device Quality Management Systems 4
J Design file for pre-existing products - Inputs and Outputs ISO 13485:2016 - Medical Device Quality Management Systems 5
D Design Transfer Template capturing Customer Specific Requirements Other Medical Device Related Standards 3
T Design Control Procedures later in the Development Process ISO 13485:2016 - Medical Device Quality Management Systems 6
M Looking for a Presentation on Design for Excellence (DfX) Manufacturing and Related Processes 2
K Old medical devices -> 7.3.7. Design and development validation ISO 13485:2016 - Medical Device Quality Management Systems 1
optomist1 Design Exclusion, but now we might have an outsourced Product Design ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 5
Q Relabeler for patent expired product - design control responsibilities? 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 2
I Does anybody use Detection in medical device Design FMEA? ISO 14971 - Medical Device Risk Management 18
A Design process goal for ISO 9001 Manufacturing and Related Processes 23
Z Definitive definition of design? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 4
A UDI and Design Controls - Labeling change via the Design Control process 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 1
P Design FMEA for Industrial Machinery FMEA and Control Plans 3
M Design Development MDR Design and Development of Products and Processes 0
C Essential Design Output(s) and Design transfer 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 11
O How can I justify excluding the R&D group and the design and development clause? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 4
N Design Verification & Process Validation - Statistical sample sizes Design and Development of Products and Processes 2
D Design Verification - Is testing required? Design and Development of Products and Processes 5
D DHF Responsibility after design handover Document Control Systems, Procedures, Forms and Templates 4
K Completing Design Controls after 510(k) Clearance Other US Medical Device Regulations 11
C Design and implementation of process audits as defined within IATF 16949 IATF 16949 - Automotive Quality Systems Standard 2
R Design Verification Documentation ISO 13485:2016 - Medical Device Quality Management Systems 19
Similar threads


















































Top Bottom