Properly prepared assembly documentation enables and at the same time speeds up offer preparation as well implementation of a production order. That is why, we have prepared quidelines which will help you to prepare correct and clear documentation.

Documentation for paste stancils

The following information is needed for stencil manufacturing:

    • stencil’s technology (laser, chemically etched, drilled),

stencil’s size and specified requirements when it comes to stencil’s edges, for laser and digested stencils – the thickness of stencil,

  • providing a paste layer in gerber file (when it comes to laser stencils it is advised to inform us whether the view is on the squeegees or plates’ side – it is crutial as laser stencil’s holes should have a trapezoidal cross).

When you order a comprehensive service, i.e. manufacturing of a stencil is a part of our company’s comission – the stencil will be adjusted to the standards of our production machines.

Documentation for printed circuit boards

The following information is needed for PCB manufacturing:

  • number of layers (their order, if it’s a multilayer board, n>=4)
  • soldermask – one-sided or two-sided – its colour (TOP and BOTTOM)
  • description unilateral or bilateral, its colour (TOP and BOTTOM)
  • panelizing, other requirements imposed by smd assembly (if the PCBs will be assembled in our company – we will make them in such a way which is suitable for assembly on our machines
  • gerber files (with TOP layer view).

Attention! If you already have a supplier of printed circuits and you have decided to assemble in our company, the panel is advised to be constructed in a particular way which is presented here pcb_panel_requirements.pdf.

Documentation for SMD and THT

The following files are needed for electronic assembly:

Detailed remarks for bill of materials

FORMAT– BOM should be in table where components are written in lines and columns convey information about them. Preferred formats: XLS, ODS, DOC.
CONTENT – BOM should convey all components which are necessary for the order, even those which are not soldered to the plate, e.g.:

  • radiators, nuts, washers, screws, cables, cable connectors, cable labels, thermally conductive silicones, glue, fuses, batteries, LED lenses

DATA – in order to identify components easily, the following information should be provided (in columns):

  • VALUE – i.e. exact parameters describing components, e.g.
    • Integrated circuit – full name with suffixes, e.g. 74AHC1G14DBVR
    • Resistors – information about the value, housing, tolerance, e.g. 10k 0603 1%
    • Capacitor – capacity, dielectric, working voltage 10nF X5R 50v
  • TYPE – description of components’ type, e.g. “Cap.tantal.size.3”, “resistor 0603”, “transistor NPN”, “power reactor SMD”
  • SMD/THT (optional) – it is advised to mark the difference between SMD and THT. It can be done by marking them in different colours or by adding a column with SMD and THT,
  • SUPPLIER (optional) – this information is necessary especially when we are to buy components and they are difficult to access because it does not occur in the main polish suppliers’ offer. In that case, the following information can be added:
  • quantity – the number of identical elements for one board
  • designators – markings of components on the board, e.g. R12, R24, capacitors C5, C7; integrated circuits: U7, IC5; quartzses X1, Q2; transistors Q6, T3; coil L3, DL2 etc. Designators should be sepatared by space, semicolon or comma. Components which are not assembled in a particular project should be marked as  “not mounted”, e.g. in brackets.
  • REMARKS – any information which might be helpful, e.g. “not mounted”, “R15 not mounted”, “temp range -20+115degC”, “provided by the client”, “mount 1%”.

Other reguirements

  • It is advised to put the identical elements in one line in BOM. Separating identical components into different lines because of different functions is a common mistake, e.g. the red diode LED POWER and identical red diode LED sygnalizing ACTIVE LINK. The other example of identical components, which are often separated, are signal connectors. Taking assembly into consideration, componets’ function does not matter, therefore it should be ignored and identical components ought to be put in one line. It is enough to differentiate those components using designators.
  • marking of components in documentation provided by a customer (SMD assembly) should be in accordance with BOM, i.e. they should match the components in BOM.

An example of properly prepared BOM is here: BOM_example_1.xls.

Software freeware
for viewing gerber files we recommend gerbv, you can download it here
http://sourceforge.net/projects/gerbv/files/gerbv

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