PCB layout - avoid errors

Footprint and component labelling
We require the following documents to be able to successfully assemble your printed circuit boards:

  • Placement plan
  • BOM
  • Pick & Place file if Gerber format is used

Initial problems often occur at the PCB layout stage which can affect the entire project.

-  Please make sure that the footprints (land pattern), that is the component landing points of the components to be assembled, comply with the specifications of the respective manufacturer.

- The IPC-7351 offers alternative recommendations and design specifications: http://www.ipc.org/

- Footprints from the standard libraries such as Eagle "rcl.lib" are suitable for manual assembly, but not for automatic machine production, as we do.

Solder drained into a via

Tombstone effect

QFN housing with exposed pad

Reference marks

- Please avoid placing vias on the soldering surfaces of components pads, this causes the solder paste to flow during reflow and will not guarantee a reliable solder joint.

This error is unfortunately made quite frequently and may lead us to identify this site as an error using AOI (Automatic Optical Inspection).

This can also cause the "tombstone effect" where components are lifted vertically during reflow.

Paste data
A component also includes the correct paste data in addition to the footprint.
Unfortunately, it happens time and time again that e. g. in QFN housings the exposed pad in the middle  of the component is forgotten. Since the paste data is used to manufacture an SMD stencil required for PCB assembly we recommend that you double-check the paste data before ordering to avoid any errors.

Stencil
Based on your paste data, the stencil is created. Therefore, you should definitely check if all solder pads have been included.
If you order a partial assembly, please note that all pads that were created in the paste data are also printed with solder paste.

When mounting THR components, the corresponding holes and residual rings need to be included in the paste data, as these locations must also be cut out just like normal SMD solder pads.

For logistical reasons we do not send you the SMD stencil.

Reference points
Please include at least two or more preferably three reference points in your PCB layout. There is often a corresponding library within the PCB layout program with such reference marks (Eagle = marks.LBR).
 
If this is not the case, simply place 2 or 3 reference marks/fiducials (Ø = 0.5 mm - 2 mm), which should not be covered with  solder mask, as far away from each other as possible. Generally, these should be placed diagonally in the corners of the PCB.
 
The pick and place machine finds these points using a camera and all components are placed on the coordinates relative to these points.
 
If during the PCB assembly stage, we notice that components do not match the designated location in the layout, we reserve the right not to place these components, meaning they are not to be assembled.
 
 

Component placement plan - briefly explained

BOM - listing components perfectly

MAGIC-BOM - the fastest way to assemble

Components - each one is important

Pick & Place file - perfect placement

Soldering process and methods

Panelizing made easy

Instructions for BOM and component placement plan

Assembly lead time explained

Terms and Definitions - for your information