To most clients the method used by a company in manufacturing circuit boards spells the difference between an excellent and a mediocre product. This is the reason we here at PCBNet are very particular about sharing with our clients the manufacturing process of our printed circuit boards.
To give you an idea, below is the step by step process:
Printed Circuit Board Computer Aided Manufacturing (PCB CAM). We start with the production of the printed circuit board fabrication data. This is often generated by CAD using Gerber layer images, Excellent drill files, component information and IPC-D-356 net list. Unlike other manufacturers, we read onto the Computer Aided Manufacturing (CAM) software the Excellent or Gerber files that are in the fabrication data. This makes for a better designed printed circuit board that functions at its optimum.
Computer Aided Manufacturing (CAM) functionality. CAM is the software we use here at PCBNet that inputs the fabrication data first and then follows through with data verification. Once the first two steps are done, CAM proceeds to compensate for misalignments in the process of manufacturing. A good example is when scaling is required to mitigate possible distortions in the lamination process. Once issues are addressed the CAM starts penalization and finishes off with output of tools such as electrical test files, automated optical inspection data, copper patterns, legend image, and solder resists image.
Penalization is an important step in the printed circuit board manufacturing process. It entails assembly of several numbers of printed circuit boards into one ‘panel’, thus the term penalization. Panels can consist of similarly designed PCBs or can be a mix of PCBs with different designs. The two types of PCB panels produced at PCBNet are bare board panels and assembly panels or arrays. When we make panels, we make sure the components are assembled onto the plane and not on individual circuit boards. In terms of design and functionality this is the more efficient and practical approach.
De-penalization is the process of breaking down a panel into individual printed circuit boards with components attached. This is done by creating perforations and drilling on the boundaries of each single circuit board that is in the panel. Another way of separating individual PCBs from a circuit board is through the use of a laser cutter. A far more efficient method because it creates very little stress on the boards and reduces damage.
Copper patterning is that part of the production process where unwanted copper formations on the PCBs are removed using a variety of methods. Essentially the PCB pattern which is found in the CAM system is replicated as a protective mask and placed onto the PCB layers with copper foils. Then the PCB goes through an etching process which removes the unnecessary copper residue.
Below are the very many ways PCBNet accomplishes copper patterning on our circuit boards:
a. Photoengraving creates a photo resist mask that removes any UV sensitive copper coating on individual circuit boards.
b. Silk screen printing is the process of etching resistant ink on the PCB to build a protective mask.
c. Printed circuit board milling uses a milling machine or PCB prototype to remove or mill away the accumulated copper foils on the substrate. It is able to do this because it has a three axis milling system which is powered mechanically.
d. And then there is the laser resist ablation process. It sprays black paint on the laminate which is copper clad. And then the entire PCB is placed on a laser plotter. The laser then scans the entire PCB and as it does so it vaporizes the black paint along with the copper elements that are attached to it. Although this process sounds very efficient, it is still in the beta stage and still requires a bit more fine-tuning.
The choice of copper patterning method, whether photoengraving, laser resist or silk screen, will depend on two things – the resolution required for the PCB that is going to be manufactured and the number of PCBs that needs to be produced. If client requires a large volume of PCBs delivered we recommend to either photoengrave or silk screen print. If we have to deliver a small number of PCBs then milling, laser resist and photo masking would be the best way to go in terms of copper patterning. So, whether our client requires a large shipment of PCBs or just a small package, they are assured we will have the right copper patterning method to ensure the final products are up to standard.