An experienced CEM should have close to 100 per cent yield
size of the board. Thus allowing for a smaller overall product.
In order for a CEM
to effectively print the solder paste through the stencils during the surfacemount technology (SMT) process, it is imperative that the rightmaterials and machinery is used to
meet themuch smaller dimensions of HDI designs. For this to happen it is critical that the solder resist registration accuracy is constrained within 0.1mmand this can only be assured if the manufacturer of the bare PCB uses laser direct imaging (LDI).
Experience counts
A CEMwith experience inmanufacturing HDI PCBs will work closely with its supplier to develop the production tools required for a successful assembly process and procure the right components for individual projects.
OEMs should be aware that some CEMs claimtomanufacture
HDI designs, but don’t necessarily have the experience to effectively assemble themand they almost certainly won’t have characterised their processes required for the job.
This can result in the accuracy of the solder paste being
compromised with increased likelihood that the finished product will not be effective or will need repairing at a later stage. Rework or repairs on HDI PCBs can be difficult and expensive.
To ensure that these problems do not occur, there are a couple
of questions that an OEMcan ask its CEMto determine whether they can effectively produce the HDI design.
What to ask?
Firstly, ask what HDI designs they currently build. Although they may not be able to discuss specific clients, they should be able to talk through their processes in general terms. Secondly, ask to see their yield data and howmany defects they have for each product. An experienced CEMshould have close to 100 per cent yield.
CEMs should also be able to
provide evidence ofmaterials and process characterisation for HDI PCB designs. If they can’t it is an indication that they do not have the necessary experience in this area. Ask yourself: do you really want your product to be their guinea pig?
www.axiom-ms.com
One Stop!
To form a new manufacturing partnership
Its easier than you think to fulfil the needs of your customers. But you’ll need a partner with a reputation for producing the goods. Reliability, consistancy and efficiency are everything.
Dynamic EMS specialise in electronic manufacturing services and can provide:
• Finished goods business model to meet your demand.
• High mix low to medium volume SMT and PTH circuit board assembly and test.
• Product assembly and test.
For more information please contact: +44 (0)1383 822911 Fax: +44 (0)1383 824740 or see our website at:
www.dynamic-ems.com FM26874
March 2011 | 23
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76