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Common PCB Assembly Design Mistakes

by Josh Biggs in Tech on 30th November 2018

Taking precautions to avoid electronic assembly design errors is vital to manufacturing a product that functions as it’s supposed to and to ensure that your manufacturing process runs efficiently. Keeping that in mind, the following are some of the more common PCB assembly design mistakes that you should take extra precaution to avoid:

Common File Mistakes

Using the wrong files or missing files can be incredibly problematic when it comes to your electronic assembly design. For example, the Gerber file format is used PCB (printed circuit board) industry software in order to describe the images of the printed circuit board, including the copper layers, legend, solder mask, and more.

First of all, you need to provide the correct Gerber file format for your stencil paste, which means that it needs to be RS274X, which is the current industry standard, instead of RS274D. Whereas the RS274D format requires a separate aperture file, the RS274X format includes the aperture information within the Gerber file itself.

Using the wrong format can be problematic, but so will missing a Gerber file for one or both sides of your stencil paste. Paste layers are needed to generate a paste stencil. The typical paste layer or Gerbil will only contain SMT PAD features. Most paste Gerbers will not include the following:

  • Mounting holes with annular rings
  • Holes for axial leads
  • Holes for radial leads
  • Un-tented vias.

One thing to keep in mind is that you can generate your solder paste separately from the FAB layers and named as either a stencil Gerber or a cream using the CAD (computer-aided design) system.

Another important file that is required is the XYRS file. Essentially, the XYRS file is used for machine-placed assembly of SMT parts. Unless SMT (surface mount technology) parts are being hand soldered, an XYRS file will be needed for each CAD program presents in textual XYRS data. XYRS files are in free-form formats and the process of generating the information can differ as well.

Assembly BOM Mistakes

When ordering materials for your electronic assembly, it’s vital that you submit your assembly BOM (Bill of Materials) in CVS format. PDF formats can’t be converted, text formats make it too difficult to analyze, and XLS formats often lose data as a result of cell overflow. Additionally, you need to make sure that you aren’t missing important details for each part. Information that your BOM should contain includes value, description, part numbers, reference designators, and package/decal.

Missing Packing List Documentation

If you’re receiving parts for your electronic assembly design without any kind of packing list documentation, it’s going to cause problems with inventory organization. You should use labels to prevent errors on your incoming inventory. Your clients will need a packing list or invoice for every shipment to compare with your BOM.

These are some of the more common electronic assembly design mistakes that manufacturers make and that you should take extra precaution to avoid to help ensure that your electronic assembly runs efficiently.

 

 

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