Selecting Contract Manufacturers 101

When evaluating an onshore contract electronics manufacturer, one of the things you will consider is whether it has the equipment and the experience to handle the smallest surface mount components you will use on your printed circuit boards.

One of the first questions to ask in this situation: Do you need a contract manufacturer that can handle today's smallest components? These are exceedingly small; state-of-the-art 01005 components measure only 0.01 x 0.005 inches, and 0201s are about 0.02 x 0.01 inches. To put this in perspective, 0.005 inches is about the thickness of a sheet of copy paper.

Obviously, parts this small can't be placed on printed circuit boards by hand. Manufacturers use pick-and-place machines to put them on boards at speeds of up to 60,000 parts per hour. A lot of US contract manufacturers don't find it worthwhile to invest in SMT lines that can handle the smallest components. Z-Axis does have this capability, but we're rarely asked to use it.

Why? The components are just too small! The 01005s and 0201s are great in products such as hearing aids and smartphones, where users demand the smallest product possible, and every hundredth of an inch of board space matters. Most of these products are produced in very high volumes (millions of boards a month) at offshore facilities.

We manufacture a lot of electronic products here, but the boards we make usually go into medical instruments, commercial products like LED lighting, or industrial products like motion control systems for factories. Production volumes range from tens to thousands of boards per month. Compact size is often important for these products, but it's not usually the absolute driving factor. Other considerations — such as the ease of laying out and routing traces on the board and the ability to make and test prototypes by hand — are more important than saving a few tenths of an inch of board space.

Tiny components such as the 0201 are usually just not worth the trouble for most designers. If you don't plan to use 0201 or 01005 components in your design, does it matter if your contract manufacturer can handle them? The answer depends on two related packaging trends:

  1. Micro ball grid arrays (MBGAs):
  2. They typically have six to eight connections (balls) located on the bottom of the package, with a ball-to-ball spacing (pitch) of 0.4mm (0.02 inches) or less.

  3. Micro lead frame (MLF) or “leadless” packages:
  4. They have connections arranged along the edge of the package, similar to a traditional SOIC package, but the connection is flush with the package, rather than extending horizontally at the base. A 3 x 3mm package with 12 connections may have a pad size of 0.25mm (0.01 inches) and a pitch of 0.5mm (0.02 inches).

In our business, we have seen the use of MBGA and MLF packages grow tenfold over the last five years. Although MBGA and MLF packages are larger than 0201s, they're still small enough to blow away with a sneeze. Significantly, the lead size and pitch is about the same as a 0201. These tiny feature sizes require more sophisticated manufacturing processes to place and solder the components reliably with good product yields.

If your designs use MBGAs or MLFs, look for a manufacturer with experience placing 0201 components. The ability to work with the tiniest packages is a good indicator that the manufacturer can handle the fine pitches of your MBGA and MLF packages.

8 comments on “Selecting Contract Manufacturers 101

  1. Barbara Jorgensen
    September 20, 2012

    Are there any niche EMS that specialize only in these tiny products/boards, or is it just not profitable enough? I guess I am surprised that this capacity isn't being used that much as “smaller, faster and less expensive” is the credo for the electronics industry.

  2. Cryptoman
    September 21, 2012

    Michael, this is a very useful post. İt emphasizes the importance of handling tiny components. Do you have more general suggestions for more ordinary manufacturing process? As you know most of the electronic production deals with parts that are larger than those mentioned in the post. What are the important tips to bear in mind when choosing a manufacturer? İ would be grateful if you could provide a few reference links or papers. İf you are able to provide another post that covers more general aspects of electronic manufacturing that would be even better. Regards…

  3. AnuvaJim
    September 21, 2012

    We recently did a study for a customer that was considering use of smaller (0201 and 01005) parts when there really wasn't a need to.  For a standard 10K 5% resistor, the 0201s were roughly 150% the cost of the more common 0402 and larger parts and the 01005 was a whopping 1800% more expensive.

    If you need them, you need them.  But, if not, why increase cost and process challenges?

  4. bolaji ojo
    September 21, 2012

    I wonder what other factors OEMs consider when reviewing a contract manufacturer. You addressed a specific market requirement but I believe this may not be the key factor an OEM would consider when picking a partner.

  5. Michael Allen
    September 22, 2012

    We certainly have produced boards that were designed with 0201's for no good reason as there was plenty of room for 0402's.  The difference in cost from $0.004 for a 0402 to $0.006 when placed with our 60,000 part an hour pick n place is $120.  This is not much considering the value of the product produced.

    We also see a lot of boards now that contain micro BGA's and lead-less packages with the same feature size as an 0201 so having the equipment and processes to put down 0201's allows us to put them down with a high yield.

  6. Brad hudon
    September 22, 2012

    Software systems, integration capabilities and process transparency would be high on the list. That would probably apply to any supply chain partner, not only CMs.

  7. Himanshugupta
    September 24, 2012

    Is manufacturing capability only and foremost criteria for selecting a contract manufacturer? I think other characteristics such as expendability, reliability and cost can be other criterias. With outsourcing practices, maybe other factors are also there to consider.

  8. Michael Allen
    September 25, 2012

    Bolaji, Brad, Himanshugupta – you are correct, there are hundreds or even
    thousands of factors that go into selecting and maintaining a relationship
    with a contract manufacturer. The post title was probably a little
    misleading: this was not meant to be a comprehensive selection guide
    (although that might make a good future topic). Rather, for each post I
    planned to pick one factor that I have found is often overlooked or not well
    understood, and provide a little depth on that factor. You all have pointed
    out several additional factors that might make good future topics. Thank

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