Errors which cause PCB Assembly Holds

Mistakes Which Cause PCB Assembly Holds

As an international PCB manufacturing and design company, RUSHPCB is determined to ensure that its boards adhere to customer’s specifications. Such specifications determine the applicability thus 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 hold a job if there are any differences between an order and the parts or files which the customer provided.

This protocol is used in the entire PCB design and manufacturing industry since all PCBs design demand explicit precision. Moreover, Design Rule Check (DRC) errors should be avoided to ensure specifications like minimum via hole diameter and copper-to-copper spacing are given. It is for this reason that we recommend that you double-check your order to prevent delays due to holding in the assembly stage. Fortunately, we are all proud when your product is delivered to you on time with no errors at all. This is why we came up with some of the most common errors which lead to PCB assembly holds. Please join us as we discuss or visit us at for questions or to place a quote. We are always ready to serve you.

  • 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 and designer 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 design 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. Please note that we have most of the PCB assembly components in our stores so to avoid such dubious mistakes, please pay us a visit at and place your quote.

  • 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.

Please don’t be scared by the above points and procedures which one should adhere to so as to ensure that their board is manufactured without delays. We are professionals in the Printed Circuit Boards world thus we assure you of the best. Our team of experts goes through your orders, BOM and design specifications to ensure everything is in order. They contact you and clarify and confusing procedure before the final assembly commences. Serving you is our pleasure and we will always focus on quality and uniqueness.

Please pay us a visit at or contact our sales team or 0203 750 0201