Adhere to customer's specifications to avoid mistake is necessary in PCB manufacture and assembly process. Such specifications determine the general operating characteristics of a Printed Circuit Board. To do this, we ensure that we understand what each customer wants. However, to avoid discrepancies and poor work output due to wrong designs, we recommend that double-check your order to prevent delays due to holding in the assembly stage, sometimes, communication takes time and customer may need it urgently. Here are some common mistakes in PCB assembly files.
Mismatch between the footprint and the BOM
In this case, a component placed in the Bill of Materials (BOM) happens to be too small, too big or simply the wrong component for the designated position. This could include the size of a drill bit to be used to create holes or the size of copper layers to be used. The BOM is usually accompanied by the Excellon drill file which defines the drill. The drill file specifies where the holes are to be placed. In some cases, there is a conflict between the components in the BOM and what the design needs. To avoid confusion and design of the wrong board which does not meet your specifications, we hold the assembly process until clarifications are made.
Mixing different orders
As an international and one of the best PCB manufacturer, fabricator in the world, we deal with thousands of orders in a day and we welcome customers to place as many orders as they can. However, care should be taken to ensure that the components in one order in the Bill of Materials are clearly differentiated from the others by marking by a tape or a reel or placed in a single troy come bag. This eradicates chances of confusion which may lead to PCB assembly holds since we cannot assembly a PCB whose components are not clear. Do you have any question so far or would you wish to know us better? Please Contact Us .
Missing components
Customers provide the list of tools or components which they need the manufacturer to use in coming up with their design product. A tool list is embedded in the Excellon drill file or it can be sent as an independent file. Using the tool list which is provided on the fabrication is not professionals since it eliminates automatic verifications and may cause some errors in data entry. We highly recommend that you provide minimum overages so as to compensate for any assembly attrition. Failure to do this might lead to holding of the assembly of the board.
Failure to update the Bill Of Materials to meet recent design changes
After coming up with a clear idea of what one needs to design, there are some changes which one might need to incorporate in the design to make it more appealing or effective. We welcome any design changes from our customers provided they don’t interfere with an already ongoing PCB assembly for the same board. We, therefore, encourage our customers to ensure that design changes in the BOM, assembly files, materials and instructions are updated on time so as to give us humble time while designing the board. However, we consider the interests of our customers so in the event that you find yourself in such a situation, we will listen to you and find the best way out.
Non-marked polarities
In PCB assembly, there are many components used like the diodes and batteries which have polarities. These polarities ought to be clearly marked so that our experts might distinguish between the cathode and anode. This is because connecting the wrong polarity to the wrong terminal leads to a short-circuit which might blow up the whole circuit or destroy some components due to thermal discharges. Always ensure that the polarity of each component you provide is clearly marked.
Insufficient inner clearance
Inner clearance is the minimal distance from the edge of any hole to the next unconnected inner layer of copper. In PCB design, it is vital to ensure that inner clearances are sufficient so that the drill does not short the inner copper layers which might lead to wastage of copper. This applies for both non-plated and plated holes. Most of the inner clearances are 0.010-inch inner clearance
Inner Clearance = Spacing+ Annular Ring
If you provide the above specifications, please ensure that they fit your board precisely otherwise we will have to hold the PCB assembly process. However, we advise our customers in advance if we see some of such errors.
Missing Aperture List and Excellon File
The aperture list gives a specification of what shape and size of an object should be drawn in a given Dcode (location). A comprehensive aperture list doesn’t have to be in the 274X format files. Different from that, the Excellon file is majorly accompanied by the drill file. This is crucial in identifying the areas which need drilling. It is significant that you provide these files to avoid the holding of your PCB in the assembly stage.
