Episode 9 Design Tip; PCB Assembly – Manufacturing Data Requirements

In today’s episode, we are going to look at our data requirements in
order to process your job, and how providing the correct standard of
data can reduce queries and opportunities for error.
Applicable to all documentation:
• Our preference is to receive Electronic documents
• Documents should have a unique version/revision in order to track
changes
• Customers should update the version if they make even minor changes
to documentation that they have provided us to view (even if those
documents were provided just for quote purposes)
BOM
• Electronic format – our preference is spreadsheet (MS Excel)
o Most straight forward for us to work with
• Obvious stuff – circuit ref’s, description, quantity
• Customer part numbers
o Useful for using as a unique reference during communication
o Can be useful for identifying common parts across multiple assemblies
• Manufacturer and Supplier part numbers
• Non fitted parts (NF/OMIT)
PCB manufacturing files – Gerber data
• Usually supplied as single image, and we would step and repeat to
suit our processes.
• Ensure that gerber data includes manufacturing specifications
o Legend colour
o Resist colour
o Copper weight
o PCB thickness
o plating finish
• Breakout positions – highlight critical area of board outline?
Placement Data – ASCII CAD
• More useful than the standard centroid data (see picture)
• Many formats of output, but there are two generic formats:
o ODB++
o GENCAD
Placement drawing
• Mandatory for Fast Track
• Needs to be complete
o Showing every circuit reference
o Clearly showing polarity of polarised components
Mechanical drawings
• Require 2D CAD drawings for bespoke parts (even if free-issue – for
inspection purposes)
• Mechanical assemblies may require an exploded assembly drawing or
photo board assembly process
• Acceptable formats:
o AutoCAD DWG or DXF
o Solidworks eDrawings
o PDF (including the new 3D PDF format)
Test / Device Programming
• Firmware for programmable devices (inc. configuration bit settings
and checksum if poss.)
• Schematic diagrams
• Test instructions
More detail can be found in our Manufacturing Data Requirements
document, which can be found on our website, at www.Cogentcem.com.

source

Specialist circuit board assembly service made available by circuit board suppliers

circuit board suppliers

Greatest things about experienced circuit board assembly

If you’re considering performing the circuit board assembly in-house at a professional level you’re easily going to find out the actual investment expenditure is really large. You absolutely need at a minimum: one pick and place machine, one stencil printing machine and one reflow oven. You most likely would also like various other equipment for examination work and hand soldering instruments. Additionally , you will need manpower and expertise that will expand the investment cost greatly. And then finally when you observe there’s little or no ROI from this form of expenditure you’ll quickly tend to use outside agencies for the circuit board assembly service. Quite often contracting out the circuit board assembly service to an outward firm should be less expensive.

Then there’s the facet of quality; a provider specialized in circuit board assembly services should have the specialist knowledge and manpower to supply great quality. They’ll also put money into their development by consistently having the latest technology so the customer gets all of the advantages of the spanking new assembly technologies. It’s quite possible that you will hit a equipment related limitation doing in-house assembly if you fail to up-grade the equipment regularly, as an example ,, you might end-up in a predicament where you can not easily assembly the latest BGA package for a brand-new processor.

There’s also the element of quality control. A dependable circuit board assembly house can also get a proper established quality control service which you might make use of by not being forced to do the quality control in-house. Of course, you would like to do one more quality control step in-house but it is good to know at any rate the pcb’s are all performing the right way when they walk out of the assembly line.

Problems of expert circuit board assembly

A good reason you wouldn’t want to delegate the assembly of your project is to safeguard intellectual property. For those who are concentrating on some top secret project or the most up-to-date concept that will revolutionize something, you should keep that as secret as possible so in that case you could do the circuit board assembly internally.

There are also cases when the turnaround time of a prototype is very important so you might not afford to wait a week for your circuit board to send back from a expert assembly line. If so it may make more sense to accomplish the assembly in house.

Expense is additionally a crucial cause you may not desire to pick a professional circuit board assembly plant, especially for small companies or enthusiasts. Prices for circuit board assembly services have lowered somewhat during the past couple of years so this is less of an issue presently but nonetheless you may not see a large amount of buyers sending their one off hobby projects to a circuit board assembly plant.

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