A New Product - Designing the Circuit board
If a company needs to develop a product that will need elements of logical control, then some appropriate hardware must be found to do the job. Often there are no off-the-shelf devices that can do this, or if there are, they can't be sourced for a low enough price to make the end product marketable.
It makes sense to have a dedicated control module that performs exactly the functions needed in the smallest possible space , for the lowest possible price. Getting a dedicated circuit board to control a product also means that the company retains control the product. No other company can just go out and copy the equipment without making significant investments of their own.
Producing the Design
Depending upon complexity, it may take about two weeks for a quality circuit board design to be generated from the previously described circuit diagram. Shape is important. The circuit board must fit inside something. Before the artwork process commences, the appropriate enclosure must be selected. It will use most of the available space in the selected enclosure. mounting holes on the circuit board must align with mounting posts within the enclosure. Sometimes cutouts are required for cables to pass through the side or rear of the box. Thought must be given to the types of screw terminals being used and how those terminals will be labeled. Some circuit boards have low voltage D.C. and 240V A.C. on the same panel, so appropriate barrier regions and relay choices must be made to comply with electrical clearance regulations. Hole sizes must be selected so that all parts that must pass through the board will actually fit. The thickness and width of copper tracks must be considered and must match loads being controlled. (It is not a good thing to switch a 4 amp motor via a circuit board track that will only carry 3 amps before it burns out!) These are all issues for the designer to resolve, not the customer, but it is appropriate to describe some of the process for customer to appreciate why so many questions must be asked early in the design cycle.
Whats in a PCB?
Circuit boards are made from multiple layers. Some boards are called 'Single Sided Boards' because copper tracks are only on the underside. Double sided boards have tracks on both sides with every hole lined with copper to connect between the layers. Other layers on each board include the green film on both sides called a Solder Mask and white writing on the top of the boards to identify parts and connections called a Component Legend. It is possible to create boards with even more layers of copper, but then costs quickly rise and they can be more difficult to service.
Most boards will be the double sided type as this allows extra solder to flow around the parts,. This makes the finished module more immune to high vibration and mechanical shocks. An extra two dollars per board spent here (in production) can make the difference between a product that works indefinitely and one that requires frequent field service work.
On the artwork sample shown above, the green lines represent tracks on the top of the board and the red lines are tracks on the underside. Yellow dots are holes that pass through the board. All boards will have an identifying project code, version number and the design date. This is necessary to ensure that old versions and new versions are never mixed up in production.
Generating circuit board artwork is true to its name, as moving all the parts around in the confined area, while still completing all electrical connections without having some parts interfering with other parts is something of an art form that can take some years to master.
Getting the prototypes made...
The completed circuit board file is then sent off to a circuit board manufacturing company who turn the file into final boards. If it is a first release of the board, normally only 2-4 boards are produced, as it is often inevitable that small changes will be needed before a production version would be ready. Even for a few prototypes, generating these pcb blanks usually takes two weeks and costs $200-300. When the circuit board blanks return, they are loaded with components and are then ready for software development and testing - but that's another story....
Click here to return to CREATING A NEW PRODUCT
If a company needs to develop a product that will need elements of logical control, then some appropriate hardware must be found to do the job. Often there are no off-the-shelf devices that can do this, or if there are, they can't be sourced for a low enough price to make the end product marketable.
It makes sense to have a dedicated control module that performs exactly the functions needed in the smallest possible space , for the lowest possible price. Getting a dedicated circuit board to control a product also means that the company retains control the product. No other company can just go out and copy the equipment without making significant investments of their own.
Producing the Design
Depending upon complexity, it may take about two weeks for a quality circuit board design to be generated from the previously described circuit diagram. Shape is important. The circuit board must fit inside something. Before the artwork process commences, the appropriate enclosure must be selected. It will use most of the available space in the selected enclosure. mounting holes on the circuit board must align with mounting posts within the enclosure. Sometimes cutouts are required for cables to pass through the side or rear of the box. Thought must be given to the types of screw terminals being used and how those terminals will be labeled. Some circuit boards have low voltage D.C. and 240V A.C. on the same panel, so appropriate barrier regions and relay choices must be made to comply with electrical clearance regulations. Hole sizes must be selected so that all parts that must pass through the board will actually fit. The thickness and width of copper tracks must be considered and must match loads being controlled. (It is not a good thing to switch a 4 amp motor via a circuit board track that will only carry 3 amps before it burns out!) These are all issues for the designer to resolve, not the customer, but it is appropriate to describe some of the process for customer to appreciate why so many questions must be asked early in the design cycle.
Whats in a PCB?
Circuit boards are made from multiple layers. Some boards are called 'Single Sided Boards' because copper tracks are only on the underside. Double sided boards have tracks on both sides with every hole lined with copper to connect between the layers. Other layers on each board include the green film on both sides called a Solder Mask and white writing on the top of the boards to identify parts and connections called a Component Legend. It is possible to create boards with even more layers of copper, but then costs quickly rise and they can be more difficult to service.
Most boards will be the double sided type as this allows extra solder to flow around the parts,. This makes the finished module more immune to high vibration and mechanical shocks. An extra two dollars per board spent here (in production) can make the difference between a product that works indefinitely and one that requires frequent field service work.
On the artwork sample shown above, the green lines represent tracks on the top of the board and the red lines are tracks on the underside. Yellow dots are holes that pass through the board. All boards will have an identifying project code, version number and the design date. This is necessary to ensure that old versions and new versions are never mixed up in production.
Generating circuit board artwork is true to its name, as moving all the parts around in the confined area, while still completing all electrical connections without having some parts interfering with other parts is something of an art form that can take some years to master.
Getting the prototypes made...
The completed circuit board file is then sent off to a circuit board manufacturing company who turn the file into final boards. If it is a first release of the board, normally only 2-4 boards are produced, as it is often inevitable that small changes will be needed before a production version would be ready. Even for a few prototypes, generating these pcb blanks usually takes two weeks and costs $200-300. When the circuit board blanks return, they are loaded with components and are then ready for software development and testing - but that's another story....
Click here to return to CREATING A NEW PRODUCT
