How to save money on pcb manufacturing via correct documentation?

An Ultimate Guide to streamline pcb making process

Pcb manufacturing is an important and much underestimated phase when it comes to speed in the creation of electronic boards and the preparation of efficient documentation for assembly. Often it is not considered how much correct documentation saves.

Frequently the documentation we receive presents problems, files with the same name but referring to different board.

The purpose of this article is to explain, accompanying our customers in the steps to be taken to prepare documentation before assembly or pcb manufacturing.

How can proper documentation in pcb manufacturing save you money?

Producing efficient assembly documentation is certainly time-consuming. Clear documentation prevents unnecessary email exchanges, which generate misunderstandings starting from the offer phase.

During the following procedures: screen printing, assembly and testing, the technicians will not be forced to exchange continuous information. It will proceed in a linear way, benefiting from a considerable saving of time.

How does correct documentation make pcb manufacturing easy?

As an example, think of a change made to your card and not updated on the documentation as a new revision.

In this situation the boards would be mounted automatically and only later would the problem be noticed.

The resolution of the problem would require intervention by a specialized operator, increasing costs. The worst eventuality would be revealed with the total rejection of the batch and the need to produce a new one.

Human error is another point to consider if you have to put your hand to the BOM, because it is not correctly drafted or impossible to import.

Let’s now see how to make correct documentation.

How to create a complete file package?

Creating a clear file package in pcb manufacturing may seem complicated. In reality it is only a matter of ‘good practice’. Once established as a “working method” you will not think about it anymore and everything will be smoother and more efficient.

To make a package of files for the production of electronic boards complete and efficient, the following files must never be missing:

• BOM (Bill Of Material)
• Topographic drawings
• Gerber files
• CAD
• Wiring diagrams

Now let’s see in detail these types of files in order to be clear about what we are talking about.

BOM (Bill Of Material)

The BOM represents the list of all the components that mount on the board. It follows that the file must be as detailed as possible.

The recommended format for this file is the classic .xls or .csv considering the wide diffusion of excel for professional use.

As known, the BOM automatically generates by the CAD drawing programs. It is always good to pay attention to the information entered during the export phase.

The information necessary for a correct import and analysis of the file are:

• Part Number Manufacturer
• Drawing reference
• Quantity
• Value
• Description
• Your internal Part number

This is the information that should never be missing, in order to speed up the work of the purchasing department and of the entire production process. It is a clear example of how proper documentation can increase speed of pcb manufacturing.

The BOM can also enrich with further information, such as the vendor code and the case of the components.

Gerber files creation in pcb manufacturing

This type of file has use for two purposes, the production of the printed circuit board and the part related to the screen printing of the PCB.

Thanks to Gerber files, the PCB manufacturer can implement a series of checks to prevent problems in the production phase.

An example is the control of component shapes and criticalities such as adjacent nets, which could create criticalities related to low impedances.

In addition to the production of the PCB, the Gerber file has use for the creation of screen printing frames and programs for screen printing machines with JetPrinter technology.

The file format types supported by our systems are as follows:

• Gerber data format: RS-274X (extended format with aperture table incorporated);
• Drill data format: Excellon or Sieb & Mayer 3000 (with package tool released).

CAD file

The CAD file plays a decisive role in the production process. It allows the development of programs for pick and place machines and for test systems.

Speaking of CAD files managed by us, we specify that the possibility of importing them on different systems should be considered.

Precisely for this reason we recommend ODB ++ as a standard CAD file. It is perfect for any type of system. In this regard, we suggest reading the article on the ODB ++ file which explains its advantages.

Alternatively, for the Pick and Place systems we can import coordinate files with extensions: .txt, .csv, .xls, .pkp, .mnt. with inside them:

• XY coordinates
• Drawing Reference
• Orientation of components

We recommend using the CAD file to ensure faster development times.

The right documentation saves you money by using it quickly in the SMD Assembly Line Also as regards the test systems; we have the possibility to import various types of CAD files.

In the case of test systems, another great advantage generated by the CAD file is the ability to view individual nets and increase the speed during repair. It will also help in pcb manufacturing accurately. 

Our test systems can import all types of CAD listed in the previous table, also in this case we recommend the use of the ODB ++ file.

Wiring diagrams for pcb manufacturing

The wiring diagrams are not completely indispensable, except for the implementation of in-circuit or functional tests or to draw up any manual modifications in a more exhaustive way.

in-circuit tests use cad files

Let’s say that after a functional test the board fails and therefore needs to repair, the technician in the absence of wiring diagrams would not be able to identify the problem.

Another typical situation is the creation of spinning mills or modifications. Even in this case, thanks to the wiring diagrams, doubts are easy to resolve, saving time in unnecessary emails or calls.

For these and other reasons, we always recommend inserting the wiring diagrams in the documentation file package. In this way misunderstandings throughout the production process will be minimized.

We also remember that for the development of in-circuit tests for pcb manufacturing the wiring diagrams are indispensable.

Pdf is essential as a file extension, with the possibility of searching inside the drawing references, so as to facilitate their reading.

Topographic drawings

Topographic files commonly called drawings are nothing more than the representation of the positions of the components on the printed circuit board.

As you can well imagine, having them in front of your eyes during the assembly and verification phase is very useful for the operators, greatly facilitating the work, with a consequent saving of time.

These files are essential as they have use throughout the production process.

Also in this case it is advisable to always use files with .pdf extension activating the possibility to search for the component inside it.

It is advisable that the topographic files represent both the TOP and the BOT side of the card.

In conclusion, does correct documentation really make you save money in pcb manufacturing?

In light of the considerations made, it immediately catches the eye that good management and accuracy on documentation leads to greater efficiency. This is how correct documentation saves you money in pcb manufacturing.

As we all know, efficiency in the production of electronic boards is synonymous with savings and speed, considering the need for ever faster delivery times.