What is design for manufacturing?

The “Design for Manufacturing” or “Design for Manufacturability” ( DFM) is a term from product design. The main aim is to develop products in such a way that they can later be produced both error-free and cost-effectively.
DFM is used in almost every engineering discipline, but its exact meaning depends very much on the respective area of application. A sensibly used DFM process begins in the early development phases and takes all critical aspects of a product into account. From the external product design, through the selection of raw materials, the permitted manufacturing tolerances, to the final assembly, all manufacturing steps should be considered.

How does the DFM test work on printed circuit boards?

In the field of circuit board production, the design for manufacturing is primarily used for the production-ready layout of the circuit board. The aim is to design the circuit board in such a way that the circuit board manufacturer can later produce it without errors and with a reasonable amount of effort. There are certain technological limits that must be adhered to in order for the end product to function properly. The following values are typically determined before production and checked for certain minimum values.

What are the problems with DFM analysis?

In today’s development and offer process for printed circuit boards, various tools are used that can already carry out part of the DFM check automatically. However, there are still considerable problems in some cases:

-> Design checks often take a long time
Existing software tools that are used for the automated DFM check are based in part on outdated software architecture and therefore often require a lot of time in the case of complex production data to determine and check all production-relevant parameters. Tools that were designed for use as desktop software at individual workstations are now increasingly confronted with modern web architectures. While analysis times of more than 20 minutes are perfectly acceptable for the internal analysis of circuit board data, a customer in an online shop for circuit boards will be very reluctant to wait several minutes for his analysis result.

-> The DFM test is only carried out by the manufacturer
In the current process, the DFM check is carried out exclusively by the circuit board manufacturer. The development of the circuit boards often takes several weeks or months. During the development phase there are usually no DFM check performed. The CAD software uses a DRC check (Design Rule Check) to identify errors at an early stage. However, the values to be checked for the DRC check are based on the entries made by the developer. If these are faulty or if the export of the production data is different from the development data, problems arise in production. An initial DFM test is only carried out when the development is completed and the manufacturer inquires about the printed circuit board. Structural errors that only become apparent at this late stage can only be remedied with a great deal of effort.

-> Communication in the event of deviations is very time-consuming
If the DFM check at the circuit board manufacturer detects discrepancies, he must communicate this information to the developer. The tools used so far offer the possibility of creating analysis reports in the form of PDF documents. These documents are usually more than 20 pages long and contain all the values and information determined, regardless of whether they are relevant for the developer or not. As evidence of identified bottlenecks, the log is provided with corresponding screenshots, which at best give the developer an idea of where to look for the error.

-> Today’s DFM checks are limited to checking manufacturing tolerances
How already described at the beginning , a Design for Manufacturing test means that all critical aspects that can affect the manufacture or function of a product are checked. However, what circuit board manufacturers check with the tools available today is essentially limited to the manufacturing tolerances. Further important aspects in the production of printed circuit boards arise, for example, from the Layer structures , the materials used or the specific requirements for the respective product. Today, these are not subjected to any automatic testing, but generally depend on the experience and attention of the employees at the circuit board manufacturer.

How does Stackrate help to solve the existing problems?

When designing and developing the Stackrate platform, we carefully analyzed the existing problems and challenges in the circuit board industry. We have created modern software solutions that are able to carry out full-fledged DFM tests in a reasonable amount of time. We have a modern one for visualization WebDFM Create front-end components that support both the developer and the manufacturer in determining and correcting DFM deviations.

What checks does WebDFM perform?


1

Determination of the structure widths

Smallest distance

The distance between conductor tracks is of great relevance for production. Very fine distances place corresponding demands on the precision of the machines used. Finer structures also lead to more rejects in production and are therefore a significant cost driver.

The Stackrate WebDFM module determines the distances and checks them for their feasibility. A modern web component helps developers with corrections and gives useful feedback on possible optimizations.


2

Determination of the structure widths

Finest conductor track

Similar to a very fine distance between conductor tracks, very narrow conductor track structures also place high demands on the manufacturing process and the tools used by the circuit board manufacturer.

The WebDFM module from Stackrate measures all existing conductor tracks and identifies potential problem areas in the shortest possible time. With the help of the innovative Web DFM Viewer, the developer receives valuable feedback with which he can optimize his circuit board in the shortest possible time.


3

Checking the holes

Finest hole

The smallest drilling diameter has a significant influence on the manufacturing process. The finer the smallest drill in the manufacturing process, the fewer layers that can be machined at the same time.

Stackrate checks all existing holes in the circuit board and makes suggestions for possible optimizations. In this way, we ensure that individual bores do not make the circuit board unnecessarily expensive and ensure efficient production.


4

Checking the holes

Restring test

Through-plated holes ensure that current can flow across layers. For this reason, these holes always run through copper surfaces on the circuit board. Similar to the structure width of conductor tracks, certain minimum values should not be fallen below, as this would lead to significantly higher reject rates in production.

The Web DFM module checks all existing vias and ensures that the residual copper ring around the hole is sufficient at every point. In this way, we prevent errors in production at an early stage.

5

Click, select tables and groups

Errors marked quickly

The Web DFM module allows the user to select and ignore errors recognized by the system. Individual errors can be selected with a click or several errors can be selected using a window. This function is possible for every type of defect (remainder ring, smallest distance …).

Active errors are shown in dark red, ignored errors in yellow. This enables the faults to be checked to be identified quickly and easily.

The WebDFM Viewer component

The interactive WebDFM Viewer is a web-based solution for displaying and processing deviations that were determined in the DFM analysis. The right side of the viewer contains a clearly structured list of the deviations. These are grouped according to the respective layers. On the left side of the viewer is an interactive view of the circuit board. Using this representation, the errors can be localized and processed extremely quickly.

WebDFM Viewer

“The fastest DFM check on the market.”

“I’ve failed over and over again in my life. And that is why I succeed. “

We are convinced that analysis processes in the web environment should not take several minutes. The Stackrate Web DFM Check offers analysis times in the range of seconds.

The comparison with the existing tools on the market

We have dealt intensively with the existing products on the market. We are convinced that our analysis algorithms deliver equivalent and in some cases even better results than the existing tools in many projects. What is certain is that the runtime of the WebDFM module is in all cases significantly better than the runtime of existing tools. The following practical examples serve as a reference.

WebDFM 4

4 layers of printed circuit board

Industrial Carrier Board

74.00 x 74.00 mm

Stack rate Market leader
Min. distance 151.51 µm 152.00 µm
Min. Track 111.94 µm 112.00 µm
Min. Residual ring 150.00 µm 147.00 µm
Analysis time 0:35 min 3:42 min
WebDFM 5

10 layers of printed circuit board

System on Module (SoM)

82.00 x 30.00 mm

Stack rate Market leader
Min. distance 1.57 µm unknown
Min. Track 106.60 µm unknown
Min. Residual ring 150.00 µm unknown
Analysis time 1:18 min 2:50 min
WebDFM 6

10 layers of printed circuit board

Single board computer

70.00 x 95.00 mm

Stack rate Market leader
Min. distance 99.94 µm 100.00 µm
Min. Track 100.00 µm 100.00 µm
Min. Residual ring 120.00 µm 125.00 µm
Analysis time 3:41 min 14:14 min
Nils Minor

Sie haben Fragen?

Kontaktieren Sie Herrn Minor und vereinbaren Sie einen unverbindlichen Demo Termin.

+49 6123 7500 623
nils@stackrate.de