Archive for August, 2016

Programming for PCB Production: Overview of Programming Methods in Electronics Manufacturing

Written by Rush PCB Inc on . Posted in PCB, PCB Design, PCB Manufacturing

Programming for PCB Production

There are several options for programming for PCB production. The choice of which option to use will generally depend on the form factor of the device being produced, and the size of the assembly run. Each method has strengths and weaknesses.

Dedicated Headers

The most common way to program devices is using dedicated programming. The process provides the option for the end user to change the software reasonably simply. Using dedicated headers provides an easy connection to the program. The weaknesses include the cost and the assembly of the connector part. The connector is generally one of the more expensive parts of a PCB to assemble. Therefore, reducing the demand for connectors is worthwhile. The connector has to be keyed. If this isn’t done, issues can arise with connectors being installed backwards. When this happens, false negatives can occur when programming and testing the PCB. USB connectors are in the same category. When USBs are used they can provide an effective option for programming, and the result is usually a good quality and repeatable outcome.

Programming Integrated Circuits from the factory

Possibly the easiest method for programming integrated circuits is having them pre-programmed from the manufacturer or the distributor of the parts. When the ICs are pre-programmed, there is no additional charge from the assembler for programming. Choosing this option also means that there is no need for a programming connector. Similarly, there is no requirement for a footprint on the PCB. This means that there are lower manufacturing costs.

The process involves placing the integrated circuit into a Zero Insertion Force (ZIF) socket. This socket connects to the program of the integrated circuit, allowing it to function. The circuit is then programmed, and packaged for assembly.

There are risks associated with pre-programming. Issues such as firmware bugs or changes in features mean that all integrated circuits will need to be reprogrammed. Similarly, if there is a need to put an update through in the middle of the production run, reprogramming will also be required. Choices that have been made earlier in the development may impact changes at this stage. If programming headers have been removed, then the PCBs will need to be re-worked to remove chips with the faulty code. As such, the use of pre-programming is a relatively inflexible option for programming assembled PCBs. If the process is for bootloaders, the risks are lower as they very rarely change. It is worth noting that manufacturers or distributors will generally charge a setup fee and a charge per unit of production.

Manufacturing and Test Jigs

When the production run has a higher volume, a programming jig can be an effective tool. The process involves the use of spring loaded contacts called pogo pins. These make electrical contact between PCBs. They are used to press into contacts on the PCB that need to be programmed. The jig is then set up to program entire panels at the same time. This speeds up both production and testing. Jigs are a more expensive option, with higher costs for both development and building. As this tooling cost is higher, they are generally only used for medium to high production runs.

Universal Headers

The final option available is using universal headers. This can be considered to be something between programming headers and jigs. Cables are used that have built-in pogo pins. The cable has one end connected to the program, while the other end is connected to the PCB contacts. This provides an effective process for lower volume production runs, as there is no need to tool a dedicated header or to build a programming jig.


The Advantages of On-Demand Manufacturing

Written by Rush PCB Inc on . Posted in PCB

The Advantages of On-Demand Manufacturing

To understand the advantages of On-demand manufacturing, the first step is understanding what this process is. When a customer places an order for a custom-made product that can be immediately fulfilled, the process is called On-demand manufacturing. Within the scope of the facility and process, a nearly unlimited range of products can be manufactured in a short time frame. This contrasts with traditional manufacturing, where pre-set tooling uses raw materials that are held in inventory to manufacture products.

For a manufacturer, it is generally more challenging to offer on-demand services using traditional manufacturing processes. The budget required to provide a range of products is a constraining factor. Similarly, the production configurations and tooling will need to be pre-set to meet standard processes.

For customers, there are many benefits for on-demand manufacturing. If a customer were to seek an on-demand outcome from a manufacturer that hadn’t established on-demand protocols, they may receive special treatment with urgent processing and accelerated manufacture, but the manufacturer would be challenged to deliver the product within time and specifications for the customer.

A manufacturer that has developed comprehensive on-demand manufacturing will be able to provide many benefits for the customer. Some of these include:

  • Rapid delivery of quotes–On demand manufacturers have systems in place to manage the quoting process. They will be able to provide a quote in a timely manner based on a review of your bill of materials and design documents.
  • Prototype services – an on-demand manufacturer will have processes in place to provide you with prototypes in a timely manner. Of course, this can be done iteratively until the PCB design meets all your requirements.
  • Management of production runs – an on-demand manufacturer will have processes in place to manage production at various scales. Whether your production is a short-run project, or you require bulk production of PCBs, an on-demand manufacturer can manage their processes to meet your needs.
  • Easy sourcing of materials – the on-demand manufacturer will already have relationships in place with a range of raw material suppliers. This will help ensure the materials needed for your PCBs are available when required for your production run.
  • Cost-effective production – while the relationships that the on-demand manufacturer has with raw material suppliers provide benefits in sourcing, it can also help them provide you with cost-effective materials, meaning your PCBs are manufactured at a competitive rate.
  • Control of inventory – the on demand manufacturer can produce your product in line with your requirements, delivering stock as you need, so you don’t end up with a warehouse full of finished goods.
  • Control of process – the on-demand manufacturer will be able to provide an ongoing update of the status of your production, so you will know when to expect your finished product. Some even provide an on-line service where you can log in to measure the progress of your manufacturing process.

These are just some of the benefits of using an on-demand manufacturer. Choosing to use such a provider will reduce the amount of time you need to put into the basics, freeing you up to designing or promoting your product.


The Value of Solder Paste Inspection

Written by Rush PCB Inc on . Posted in PCB, PCB Assembly and component

Solder Paste PCB

Unfortunately, in PCB manufacture there is always the risk of solder joint defects. It has been estimated that over half of all such defects are the result of improper solder paste printing. There are variations based on the print volume. For smaller volume printing, good solder paste printing practices can be acceptable. For larger printing volumes, it will be worthwhile considering using solder paste inspection (SPI).

When you think of the processes involved, surface mount assembly is complex. It relies on solder paste for connecting the leads on the integrated chip to the correct points on the board. The process involves using the stencil to print the paste onto the chip. This is then melted, resulting in a fused connection. There are crucial aspects of the process – the volume of solder used is vital in ensuring an effective fusing, as is the alignment. The complexity of achieving this has increased for two reasons – the density of components has increased in PCBs over time; and the SMT production often involves solder paste that is hidden from view.

Because of the technical issues involved, the solder printing process is responsible for the majority of assembly defects. As an example, if too much solder paste used; OR if too little is used, there is a risk of unreliable joints, leading to the risk of failure. Because of these risks, SPI was developed. It provides a tool that allows manufacturers to monitor the volume and alignment of solder paste, and can be integrated into manufacturer’s quality management systems.

The SPI process uses pictures taken from angle cameras that accurately measure the alignment and volume of solder paste. The pictures are then interpreted using software to provide key data about the printing process. The results help identify any potential errors that can then be addressed and corrected before assembly. SPI works to rapidly identify issues with volume or alignment of the solder. As a result, using SPI can improve the print quality and the yield, helping ensure efficient production of PCBs. The process also minimizes the potential of costs due to re-working of faults.

SPI was originally developed as a two dimensional tool, but has developed from 2D to 3D. The third dimension measures the height of the solder paste, enabling the equipment to accurately measure the volume that is being laid onto the board in the printing process. When 3D SPI is used in conjunction with Automated Optical Inspection, quality control can be ensured for both the placement of components and the associated placement of the solder print.

A sign of a good manufacturer is one who can provide PCBs on time, and defect-free. Manufacturers who integrate 3D SPI and Automated Optical Inspection have systems to ensure they can deliver your PCBs in line with your specifications. It will always be worth your while ensuring that you choose your manufacturer on this basis.