A fully functioning electronic device is not just a result of an overnight design and manufacturing process. These fancy devices that we know contain working printed circuit boards (PCBs) that act much like the command center of the system. If the PCB has a fault, the electronic device will malfunction in the field. Before the PCB goes into the final packaging, it has to go through rigorous designing, prototyping, manufacturing, and quality testing.
Once the PCB design and layout have been established, the next step is to produce prototypes to check in a few quantities if the PCB is functional. The prototyping stage of the PCBs prevents unforeseen issues and guarantees a functional device with a long service life. This article will talk about the benefits, considerations, main steps, and key factors of PCB prototype fabrication services.
Table of Content
- Benefits of PCB Prototyping Fabrication
- Considerations in PCB Prototyping Production
- PCB Prototype Fabrication Service Steps
- Key Factors in PCB Prototype Fabrication Services
Benefits of PCB Prototyping Fabrication
The standard process for qualifying electronic products requires going through the prototype phase before full deployment to mass production. Especially for the critical part of any electronic device: the printed circuit boards (PCBs). Aside from the benefit of being able to identify potential design issues and risks, prototyping activities can also help gauge the manufacturability of the printed circuit boards. Samples are built after a series of design reviews to ensure quality output. It’s better and less costly to address product issues at the early stage of development rather than to produce high-volume parts with issues. The highest importance is given to safety, quality, and reliability. You must look for a prototype PCB fabrication facility partner that will help you actualize your requirements.
Considerations in PCB Prototype Production
The end in mind in PCB prototyping is to be able to have a reproducible and well-functioning prototype in terms of clock speed, temperature, noise, signal integrity, and other output characteristics. The prototype should be able to withstand the environment and movement during normal and extreme handling conditions, depending on the device application.
Several iterations of the design are expected during the prototype PCB fabrication phase. The boards should have available provisions and allowances for test probes like oscilloscope probes and connectors for convenient isolation, connection, and replacement.
The Bill of Materials (BOM) has a significant impact on the final cost. Selecting the right BOM combination for your PCB prototype is very critical to the overall performance and functionality of the PCB. Important material characteristics of PCB materials are thermal coefficients, glass transition temperature, dielectric constant, conductivity, and dissipation factor. It’s also important that the PCB prototype fabrication service has a second or alternative outsourcing supplier for their raw materials as mitigation for any supply chain or shortage issue.
PCB Prototype Fabrication Service Steps
Layout and Schematics
The PCB design engineer must generate the circuit board schematics which show the traces and points where the electronic components will be placed. A PCB layout software is used to complete the design, usually in a CAD format. After fixing the PCB design, Gerber files are produced for each PCB layer, which is a recognizable format that is used to fabricate the circuit board. After the layout and schematics, parameters and requirements are submitted to the prototype fabrication service as the basis for manufacturing. The project requirements should include PCB drawing, dimension, number of layers, thickness, surface finish and solder mask.
PCB drilling selectively removes the copper layer to create insulation and holes. There are rapid PCB prototyping services that have specialized equipment. The drilling locations are specified in the Gerber files along with the essential criteria like the diameter and coordinates of the holes. Drilling can be done through mechanical or laser mechanisms.
Through Hole Plating
After drilling, the cylindrical holes are made conductive through the plating process. The drills are first deburred to remove the unwanted debris from the holes. The holes are then plated with conductive copper to make conductive paths. Copper plating is very critical in prototype PCB fabrication.
Panels consist of several boards combined in an array to make manufacturing more efficient since several boards can be manufactured simultaneously. PCB depaneling, otherwise known as singulation, is the process of separating the assembled printed circuit boards into individual boards. There are various depaneling methods such as punching, sawing and laser cutting. Laser depaneling has the highest precision of all methods and can be useful for measurements with limited tolerances. We can try to choose the best method in the prototype PCB fabrication stage.
In the Surface Mount Technology (SMD) process, the electronic components are mounted on the PCB. This is the most preferred and used method due to its high speed and accuracy. The SMT process flow includes solder printing, component placement, reflow, inspection and testing. This process is favorable for small and sensitive components to be mounted to high-density boards. SMT assembly is th most widely prototype PCB fabrication and assembly method.
Inspection and Testing
The prototype samples are being visually inspected and tested to know the electrical performance of the PCB. The functional test can be done by simulating an input signal to the PCB and measuring the electrical results. Probes are being connected to the circuit board to check for shorts, opens, resistance, capacitance, and other output parameters. The responses are being compared to the expected range or criteria to know if the PCB prototype has good quality.
Key Factors in PCB Prototype Fabrication Services
Enlisted below are the qualities and factors you need to assess in looking for a prototype fabrication service.
The chosen PCB prototype fabrication service partner should have an expert engineering resource to be able to communicate design results and reviews. Since the fabrication of prototypes requires specialized mechanical equipment, the fabricator should also have the manufacturing capability to produce prototypes.
The printed circuit boards must be tested during the PCB prototyping phase to know if the design meets the established requirements. Aside from the functionality, the boards must also be tested for reliability by subjecting them to certain operating conditions under specific time and environmental parameters.
The printed circuit board prototyping facility should have stringent measures to ensure the quality of the products. Before proceeding to large-scale production, the PCB must be qualified based on a requirements checklist, reviewed by a team of technical experts and a quality team. Quality certificates like ISO and IPC standards help manufacturers comply with quality and testing requirements, material regulations and efficiency measures.
Design For Manufacturability
Design for Manufacturability (DFM) sets guidelines at the early phase of the product design to assess potential issues and abide by design rules to reduce risks during the High Volume Manufacturing (HVM) stage. The circuit board design should refer to manufacturing requirements and limitations like PCB area, trace width, spacing, thickness, etc. In DFM, the materials should also be studied and evaluated in accordance with IPC and customer requirements. Different materials have different properties, cost, and quality. It is important to select a prototype fabrication facility that has DFM guidelines so that any issues can be planned, consulted, and evaluated. The PCB prototype manufacturer must be able to provide a DFM report during the prototyping phase which highlights any design violations, gap analysis and compatibility check with respect to manufacturability.
Cost and Timeline
The chosen PCB prototype fabrication service provider should have a sound and reasonable quote for prototyping. You can compare the engineering charges and sample build costing and the supplier should be able to provide the breakdown for these costs. Timeline is also a key consideration for your prototype project. The fabrication facility should follow the committed timeline for the design freeze, procurement of materials, prototype samples submission, testing and reliability checking.
As we know printed circuit boards are the most important part of any electronic device. A minor mistake in mass production will cause a huge loss. So, fabricant PCB prototypes before mass production is extremely important. This article gives us a comprehensive guide of the benefits, steps, considerations, and key factors in PCB prototype fabrication.