DFM Analysis for Beginners Using NextDFM

Unlike my other blogs, In this one we'll focus more on what to do prior to sending you files for manufacturing.

In order to minimize expenditure on PCB manufacturing, one has to do so called "DFM testing". In this blog I will show how to do DFM analysis of your PCB design using NextDFM Software made by NextPCB.

DFM analysis stands for "Design for Manufacturing" which basically means analyzing your design if it fits the nominal charge requirements of your manufacturer.

Every PCB has mainly two types of problems in manufacturing, one where the design itself is flawed and other where the manufacturer requires extra effort or resources to manufacture it. For ex. 60 mil via is normal hole size, hence can be drilled/plated by any manufacturer easily, however a 10 mil Via is a uncommon hole size, requires different equipment to be drilled/plated. Hence can increase the design's production cost.

To avoid this, one can do DFM tests beforehand and know what are the errors in the PCB that maybe either design issue or manufacturing problem.

However, not all software are that user friendly and beginners might find DFM analysis difficult. NextDFM makes DFM analysis easy and is Free to use.

Steps to download and install NextDFM:

1. Head on to NextDFM homepage and download the software.
2. Unzip and install the software using the setup file.
3. Once installed, log in with the same account as made on NextPCB website or sign up with an email.

Steps to import the PCB/Gerber files in NextDFM:

1. Click on File tab and then Open
2. Browse and select the gerber files or PCB file

That's it! NextDFM is now ready to do DFM analysis of the design.

Individual Gerber files can be viewed and the software will automatically align all files and the drill files. The physical renderings of the PCB and change its soldermask color along with finish can be checked by clicking on Design/Simulated button. In the bottom right side of the window we can view Real-time pricing based on the analyzed data, and price details are also given, so that users can predict the cost when designing, making the cost more "transparent" and the direction of cost reduction is clearer.

DFM analysis can be done by clicking on the button on the left.

NextDFM will analyze the whole PCB and show more than 20 tests done for same.

One-click analysis of common design "pits" can be done, it can accurately locate the problem, combined with design-side problems or production-side problems and factors affecting prices, etc., giving various optimization solutions. In the images attached it can be seen that Dangling track and Hole to track spacing are displayed red and rest are green. It shows that there is major issue with these two tests, however copper to edge gap test is yellow, which means it less critical error as that of dangling track.

When clicked on the Dangling track error, we can see that this track is not connected to the resistor. This is a design issue and not manufacturing problem. However the hole to track error is due to USB port vias which can cost more to manufacture.

Here are some comparisons of NextDFM with other softwares that are used for DFM analysis:

• It can cover CAM350 and Gerbview's picture viewing function, fool-like operation, and supports physical simulation renderings.
• It can output Gerber, BOM list, coordinate file of Altium Designer, Protel 99se, pads file type with one key, so that technical novices can become technical experts.
• Impedance calculation is simpler than SI9000

I used this software to find out mistakes in my design and hence save both time and money. Do DFM tests beforehand and get your designs manufactured at lowest cost!