Solder Bridging Issues, Causes and Recommendations during PCB Assembly

By | Date posted: | Last updated: April 20, 2021
Solder Bridging Issues

With smaller and more compact electronic appliances here to stay, one problem that is increasingly being faced by manufacturers is to do with solder bridging. A common defect, as it name suggests, it occurs when solder flows between the connectors, causing a bridge. With two points in a circuit board that are not meant to be connected, being connected by solder, an electrical short can result, which in turn can create havoc.

Bridging can occur in different stages of the PCB manufacturing process. Some of the common causes of bridging include:

  • A poorly designed PCB where the large components are placed on one side and therefore there is an issue of unequal weight distribution
  • Lack of proper orientation of components
  • Lack of enough space between pads
  • Setting of the reflow oven
  • Placement pressure of a component, and several other causes

Some of the commonly known Soldering Bridging issues include:

  • Tombstone- This refers to a condition where a component is lifted up during wave soldering and resembles a tombstone. This is often caused on account of having an incorrect lead length or using components that have different solderability requirements.
  • Excess Solder- As the name suggests, this results from an excess build up of solder. This could be on account of a fast conveyor belt or an incorrect lead length to pad ratio.
  • Solder Balling- This is a result of solder attaching itself to the Printed Circuit Board during wave soldering. Solder balling can result on account of the temperature being too high or on account of the solder splashing back onto the board.
  • De-wetting and non-wetting- De-wetting refers to when the molten solder covers a pad and retreats, leaving behind a mound of solder. Non-wetting on the other hand refers to the solder leaving behind exposed copper. This is often on account of the fact that the flux needs to be changed or that the brass components haven’t been plated well.
  • Lifted Pads- This is known to occur when a soldered component needs to be removed and results in the pad being lifted from the PCB. Lifted pads are often a result of an overworked pad joint or even an uneven layer of copper plating.
  • Pin holes and blow holes- These are caused on account of excess moisture in the board or even poor copper plating.

Irrespective of what solder bridging is on account of, the fact is that it can pose a host of problems. While we cannot ensure that solder bridging never occurs, there are certainly some key measures that can be taken to reduce the risk of soldering significantly. Check out the complete guide on how Solder Bridges becoming a major challenge during PCB assembly.

Here are some handy tips to reduce solder bridging:

1) Printed Circuit board design.

A close look at the circuit board design can be an effective step in reducing bridging. Common areas to watch out for include adjusting the aperture width or looking at area ratios. Often adding solder mask dams can also arrest bridging

2) Reflow profile.

Broadly speaking, liquid solder tends to flow towards warmer surfaces. If leads are warmer than the pads, that is where the solder heads first. To change this, it will work if the soak time is increased. What this will do is that it will equalize temperatures.

3) Off-contact solder paste printing.

This can be prevented by changing the stencil as well as the board design so that there is no off contact printing.

4) Solder paste volume

Bridging can also be reduced by reducing the solder paste volume. Using components with increased leads also goes a long way in not allowing the solder to flow between the leads.

5) Solder masking

Proper application of solder mask goes a long way in reducing the risk of solder bridging

6) Correct lead lengths

Long leads with through-hole components often lead to soldering bridge. What needs to be done, therefore, is to use correct lead lengths depending on the size & thickness of PCB, type of soldering etc.

7) Fiducials

Fiducials or precisely designed markers that are put into the PCB design can go a long way in aligning the components on the board. Typically three marks are recommended. Poorly placed marks can lead to improper alignment of parts, which in turn can lead to solder bridges.

While you may not be able to control the manufacturing process what you can definitely control is the choice of a partner that has enough experience and hence can take the necessary measures to control solder bridging. Armed with the knowledge of how solder bridging can be prevented, you could ask the PCB Assembly House, pointed questions about their process, board design, reflow profile and more so that you are sure about their expertise in stemming the issue of solder bridging.

Technotronix offer high quality and defect free PCB Assembly and PCB manufacturing services as per customer specification. We also offering dedicated SMT PCB Assembly, Prototype PCB Assembly, Led PCB Assembly, Overseas PCB Assembly, Mastering Mixed PCB Assembly and more services as per customer requirements and specification. To know more, please explore our PCB Assembly!

Right Choice of “Cable Assembly” and “Wire Harness” in Electrical Components: What is the difference?

By | Date posted: | Last updated: April 19, 2023
cable-assembly-and-wire-harness

In common parlance we often land up using the terms “ cable assembly” and “wire harness” interchangeably. The fact however is that these components are quite different with distinct functions. Here is an overview on what each of these are and the individual purposes they serve:

Cable Assembly

Essentially these are groups of wires with an exterior covering made of a protective material such as thermoplastic, thermoplastic rubber, or vinyl. On account of this exterior coating, it is possible to use cable assemblies for outdoor applications as they can withstand harsh environmental conditions. Cable assemblies find use in industries such as -military, aerospace, security installations, oilfields and more.

Cable assemblies are largely meant:

  • To protect the cable from environmental conditions
  • To provide protection from electrical flow
  • Overall it helps to organize the electrical systems

The advantage with cable assembly is that:

  • The wires in the cable can be in twisted pairs or even in triads
  • In case of HDMI cables or Ethernet cables where the wires need controlled impedance, these are very helpful.
  • A metal strand can run with the wires which in turn can provide electrical connectivity between the connectors
  • In order to ensure easy assembly and handling by technicians, the jacket can be color coded.
  • The wire can be cut at length so it does not require zip ties.
  • They can be designed to meet the specific demands, including shape & size constraints
  • They are designed for outdoor application
  • Are durable and can withstand harsh environmental conditions

Wait !! Do you want to hire cable assembly manufacturer? Then check out Tips for Choosing the Perfect Cable Assembly Manufacturers!

Wire Harness

A wire harness is a single cable covered by an exterior sheath, which is made from the same material that is used in cable assemblies. Several coated wires are bundled together with an external covering to form a wire harness. Wire harnesses however are not known to protect the wires from a range of environmental factors. Harnesses are therefore suitable for use in applications where there isn’t too much exposure to harsh environmental conditions- be it extremes of temperature, moisture or more. Harnesses are therefore best used in equipments such as cars, computers, airplanes and more.

Advantages of a wire harness

  • They are a low cost option
  • They are suitable for indoor applications

Also checkout: Wire Harness Manufacturing Process

The commonality between wire harnesses and cable assemblies is that both of them help organize wires, however their usage differs greatly.

Here are the major differences between cable assemblies & wire harnesses

Look & function

Cable assembly consists of multiple wires bound together by an outer sleeve. Each cable may function separately but the final product looks like a single thick wire. Wire harness, on the other hand, is separately sheathed wires grouped together.
Cable assemblies can be used in tight, small spaces while wire harnesses tend to be bulky and cannot be maneuvered around so easily.

Durability

A cable assembly is extremely durable and stress resistant and is designed for outdoor applications as it can withstand harsh environmental conditions. A wire harness on the other hand is best suited for indoor use.

Application

While cables are used in industrial applications, harnesses work well for indoor usage.

Both cable assemblies and wire harnesses therefore come with their own pros and cons. It is important to have a thorough understanding of them to be able to make the correct choice.

Building and testing Cable Assembly and Wire Harness

When it comes to building wire harnesses and cable assemblies the process is pretty much similar. It requires wires to be cut, soldered to connector pins while some require potting at the connector end. What is also required with both wire harnesses and cable assembly is extensive testing. One needs to be sure that connectivity is correct and there is no scope of shorts. They also need to be tested for compliance, insulation resistance as well as for any passive components. It is therefore important to choose a provider who has enough domain expertise in these areas.

Overall knowing whether to use Cable Assembly and Wire Harness will go a long way in mitigating manufacturing costs as also protecting yourself against costly mistakes.

Why Start-ups or Small Businesses Should Choose Full Turnkey PCB Assembly?

By | Date posted: | Last updated: April 8, 2022
Full Turnkey PCB Assembly

There are several significant advantages for a full turnkey PCB Assembly for businesses of all sizes & scales. After all the convenience of outsourcing a crucial part that enables smooth running of your product is sizeable. However when it comes to start ups and small businesses, the advantages that accrue from choosing a turnkey PCB supplier, can have a significant strategic business impact.

What is Turnkey PCB Assembly?

Before looking at some of the advantages, it will be worthwhile to define what full turnkey PCB Assembly actually implies. Simply put, turnkey PCB assembly means that the PCB supplier takes care of all aspects of the PCB project. This would mean procurement of components, manufacturing and assembly. The right electronics contract manufacturer with an experienced team and wide variety of capabilities will classify cost-effective and responsive communication practices. There are two types of turnkey PCB assembly available including full turnkey PCB assembly and partial turnkey PCB assembly. Additionally, A full turnkey PCB assembly can be your best investment compare to partial or consigned assembly.

As per increasing demand and complexity, most of electronics contract manufacturers allow users to select types of PCB assembly, low to medium and high volume production, customization and services. If you are looking at a new launch, new product prototype, a low volume PCB assembly can be your absolute choice. Alternately, you can contact small batch PCB manufacturer who produce small batch PCB quickly and affordably without sacrificing on quality. If you are looking at entering in the market at some certain scale, your requirements of circuit boards must be higher than usual. High volume PCB assembly finds their application when your production is ready to take off the market. It can also benefits with faster turnaround time and cost-effective service. In a full turnkey PCB assembly, customer needs to send design files to manufacturers; the rest part from parts procurement to assembly would be taken care by your turnkey PCB assembly manufacturer.

Advantages of Full Turnkey assembly for businesses:

Time saving

With a turnkey manufacturer taking care of the entire PCB Assembly, the obvious advantage that accrues is in terms of saving the client team precious time to focus on other aspects of business, one in which their expertise lies. As a client, you need not spend time and energy looking for individual component cost effective quotes, undergoing the hassle of procuring them and then putting all of them together efficiently. This is also efficient from the cost standpoint as turnkey services are priced far more effectively as bundled services.

Proof of Concept

Ever so often, a professional proof of concept can go a long way in garnering investor interest. Turnkey PCB Assembly providers ensure that you get high quality boards without having to assemble them yourself, thus leaving you with precious time. What you get from turnkey manufacturers is also the fact that they deliver finished, professional looking boards with your company name and logo that adds to its look & feel. Also particularly if you are using surface mount components, manufacturers use automated placement, which is extremely hard to do by hand particularly when the components are small in size. The high quality final product goes a long way in inspiring confidence in investors that you are ready to start mass production.

Helps identify problems at the outset

A major advantages of turnkey PCB Assembly at the prototype stage, is also that any problems can be identified early. In fact once you share a netlist file with the turnkey manufacturer he will be able to point out errors, if any. These errors can then be corrected in the design stage itself, instead of making costly changes later once you are ready to roll your entire production or worse still when you have already done the production and need to make changes.

Better management

significant advantage with Turnkey assembly is also the fact that you do not have to deal with multiple vendors. This has many advantages other than time saving. What you are also saved of is the possibility of miscommunication when you are dealing with multiple vendors. With a turnkey supplier, you are likely to have a single point of contact, which makes the process seamless. With delivery timelines being of utmost importance, the slightest miscommunication between vendors can turn the entire timeline awry and lead to costly repercussions. With a turnkey supplier, peace of mind is a given as the entire accountability of timely delivery lies on them.

Helps in estimate PCB manufacturing costs

If there is one skill that is imperative for a start up, it is that of accurate financial planning. This is also something that can be done well using the services of a turnkey supplier. In fact the early prototype cost can go a long way in estimating your future manufacturing costs. Since unit costs are higher, simply indicating the quantities you require can get the turnkey provider to give you the costs. In fact more often than not, manufacturers can also quote effective costs if you indicate the number of units you need per month instead of one large batch, as you may not want to do one large production run at the very outset. Turnkey supplier also give you the advantage of combining several small orders into a large one and therefore help you enjoy economies of scale, that could independently not be available to you.

Turnkey manufacturer provides additional services

Turnkey suppliers also often offer additional services that could include inventory & shipping among other things. For small businesses and start ups the importance of these services cannot be overstated, as you do not have to expend time, energy and manpower on these aspects and can keep your costs under check and thereby offer you competitive advantage.

At Technotronix, we have over 4 decades of experience in offering high-quality custom boards. Our state-of-the-art machinery and experienced manpower can offer you products that are way ahead of the curve. Additionally, we have a huge vendor network when it comes to sourcing components. What that means for you, is that we offer you high quality products with a quick turnaround time and at optimal costs. A range of clients across industries have gained a competitive edge with our turn key PCB Assembly, California with our consistent delivery of high-quality, on-time, price-competitive products.

You can use Complete or full Turnkey PCB Assembly quote request form and submit information. Alternatively, you can email us BOM and Gerber files along with information of Complete PCB Turnkey Assembly volume and type of Turnkey PCB Assembly testing requirements you might have on [email protected] or call us on 714/630-9200 in case any other clarification is required in respect to our Full or Partial Turnkey PCB Assembly services.

Some of the biggest influences that affect PCB Manufacturing Cost

By | Date posted: | Last updated: January 18, 2023
PCB cost

When it comes to Printed Circuit Board Assembly, there are a host of factors that determine its cost. Beginning with the technology used to the number of components, there are an array of aspects that directly impact the cost. However what is often forgotten are a number of indirect factors that also add to the PCB Assembly Cost. These factors include areas such as lack of testing equipment for example or even lack of trained manpower. Best practices such as lack of Design for Assembly as well as design for Manufacturing can also go a long way in positively impacting efficiency and negatively impacting cost. At the design stage itself, components need to be chosen with utmost care. Similarly the placement of these components can have a bearing on costs. Ensuring that you Design for Manufacturing, for example also goes a long way in eliminating issues at the design stage itself, as well as keeping costs under control. If not done correctly, aspects such as the design and placement of components could significantly affect costs. Check out the guide on how to reduce PCB assembly cost.

Here is a quick overview of some of the factors that impact PCB Manufacturing Cost:

  • Technology Used in PCB –

    Assembly process may use Surface Mount or Through Hole Technology. Sometimes though some assemblies may require both these technologies to be used, adding to the cost.

  • Single or Double Sided board –

    A Single sided board assembly cost would typically be lower than one where you use a double sided board.

  • Number of placements –

    Costs can typically increase with the number of placements required

  • Size of PCB components –

    Typically smaller components and densely packed assembly boards add to the cost.

  • Availability of components –

    It stands to reason that cost is also impacted by the (non)availability of components.

  • Compliance –

    Often times testing to ensure assembly compliance also adds to the cost. Compliance such as RoHS and non- RoHS, IPC-A-610D Class I, II or III ITAR are often required, adding to the cost.

  • PCB Assembly Process needs –

    Some PCB Assemblies could need a host of processes such as:

  • Wave Solder
  • X-Ray
  • Automated Optical Inspection
  • Hand Solder, and other such processes. These could add to the cost significantly.

  • Flexible or rigid PCB Assembly –

    Typically flexible PCB Assembly cost is higher than that of a rigid one.

  • Coating –

    Cost is also impacted by the coating requirements. Aspects such as whether you are using spray or a brush, the number of coats required, impact the cost.

  • Testing –

    From thermal cycling to in circuit tests, there are a number of tests required before the PCB can be shipped. The testing in turn have a direct correlation with costs.

  • Flexible or rigid PCB Assembly –

    Whether you need special containers or electrostatic discharge bags, once again can add to the costs

  • Delivery –

    In case express delivery is required, costs are likely to increase.

Top tips to be kept in mind so that PCB manufacturing can be kept under check:

  • Look for multiple component sources –

    This will help you to source components at the lowest cost without sacrificing efficiency. It will help to set up a process between the design engineering and purchase departments in order to ensure that conflicting priorities do not lead to a lack of cost optimization. Setting up cost reduction committees for example, could go a long way in identifying opportunities for cost reduction without of course negatively impacting efficiency.

  • Ensure that you do a Design-for-Manufacturing test –

    This will take into account multiple factors at the design stage itself. Optimizing the bare board schematic will mean checking for areas such as:

    • Complexity
    • Number of holes and their size
    • Via tech
    • Material
    • Layer Count

  • Prepare a complete BOM –

    Simply put, the PCB bill of materials (BOM) as it is popularly called,is a list of parts and components used on the PCB. A complete Bill of Materials including details such as part number, manufacturer name, quantity, description, component replacements etc. can significantly expedite the quotation process, as also help source components at the right price. A thoroughly prepared BOM means lesser time spent back and forth and therefore greater efficiency.

  • Order Value and lead time –

    Costs are typically inversely proportional to order value and lead time. Planning well in advance so that you can request for quantities at one go as also ensuring that you have enough lead time will help in controlling costs.

  • Inspection –

    Even though testing and inspection adds to the cost, skimping on the same can have larger repercussions. Some manufacturers can offer in house inspection which can save you the time and hassle of getting a third party to inspect the boards.

Technotronix offers professional PCB Assembly services with 40 years of expertise. Our accurate PCB assembly process meets the quality standards, including ISO-9001:2015, RoHS, and more. You can rely on our PCB design tools that, in turn, lead to that perfect PCB Assembly. Our superior engineering capabilities mean that each board matches your exact requirements and technical specifications. If you have any questions or any requirements related to PCB assembly service, please feel free to contact us via email at [email protected] or call at 714/630-9200.