Which is Better — Plate Mounted or PCB Mounted Switches.
Rush PCB Inc. makes various types of PCBs, including those for keyboards. Many customers would like to know what makes a better keyboard, and whether they should use plate mounted or PCB mounted switches. Both types of switches are meant for mechanical keyboards, and the difference between the two can be somewhat confusing. Therefore, we will discuss the merits and demerits of both PCB vs. plate mount switches.
The difference in PCB vs. Plate Mounting
The major difference between the two switches is in their mounting. Printed circuit boards meant for PCB mounting switches have five holes, as the PCB mounting switches have two metal pins and three plastic pins. One the other hand, printed circuit boards meant for plate mounting switches have only three holes, as plate mounting switches have two metal connecting metal pins and one plastic pin. Therefore, it is always possible to use PCB mounting switches in printed circuit boards meant for plate mounting switches by cutting off the extra plastic pins of the former.
PCBs for PCB mounted Switches
PCBs meant for PCB-mounted switches have five holes in total. This is because each PCB-mounted switch has five projecting pins. Among these, two are metal pins that are meant for switch connections. There are two plastic side pins for providing stability and a middle pin to act as a mounting guide.
As their name suggests, PCB-mounted switches are meant for direct mounting on the printed circuit board. This is a relatively simple installation, as the PCB has plated through holes for switch fixing.
The guiding pin helps install the switch on the board, as it is difficult to see the holes when inserting the switch. Installing this type of switch on a board offers a lighter feel to the keyboard, but also allow the key to bounce a little more. Mostly smaller keyboards use the PCB mounting keys, as they do not flex much and therefore, need fewer support arrangements.
PCBs for Plate Mounted Switches
However, modern heavy-duty keyboards come with a supporting plate. It is always possible to build a printed circuit board for plate mounted switches that will not use a plate. However, the stability of the switches will then depend only on the soldering quality.
As the name suggests, plate mounted switches require a supporting plate for providing stability. These switches have only three pins, two for the switch operations, and one for guiding the switch when mounting on the PCB. As these switches do not have the stabilization pins, they require an additional metal plate. The plate prevents the switches from wobbling when the keyboard user presses them.
PCB vs. Plate Mounting
Plate mounting requires mounting the switches to a plate before inserting them in the PCB. The operator then moves the plate and switch assembly over the printed circuit board, and solders the pins of the switches. The plate allows the Printed Circuit Board assembly to feel more rigid and secure.
Larger keyboards use plate mounted switches as the plate offers them more support. The extra size of the keyboard makes them flex more. Adding the plate makes the keyboard more rigid, even when the user is a heavy typist.
Plate mounted switches do not need a guiding pin, as operators mount them first on the metal plate, before soldering them on the printed circuit board. This makes it very difficult to remove the plate once the operator has soldered all the switches.
To remove the plate, it is necessary to de-solder all the switches. Therefore, Rush PCB Inc. recommends using PCB mounting switches if the customer is planning on making several modifications and changes.
Overall, plate mounted switches make higher quality keyboards that tend to last longer than keyboards with PCB mounted switches do. This type of keyboard offers a more stable operation, a finger-feel for the switches, and less rocky feeling. However, this configuration of the keyboard is more expensive on account of the extra component—the metal plate—and its assembly.
Although both plate and PCB mounting switches are similar in performance, mounting a plate mounting switch without the plate means there is less support, making the switches rock sideways during operation. Heavy-handed typists or those who enjoy stable keyboards prefer to add a plate in the keyboard for stability.
Keyboards with PCB mounted switches are cheaper as there is no reinforcement plate to assemble. As the switches have only three pins, hot-swappable keyboards find them beneficial. Customers building custom keyboards may find PCB mount switches more convenient as they can select the PCB they want to use.
Converting a 5-pin to a 3-pin switch is easy, as the user can easily cut away the two extra plastic pins, taking care to not cut the metal pins.
PCBs for Keyboards
As the printed circuit board forms the foundation of a keyboard, it is equally important as the motherboard of a computer. Switches soldered to the printed circuit board send electrical impulses to the computer when the user presses the keys. Broadly, there are a few types of PCBs for keyboards:
- Soldered Printed Circuit Board
- Hot-Swappable Printed Circuit Board
- Through-Hole Printed Circuit Board
Soldered Printed Circuit Board
A soldered PCB is the default for a custom mechanical keyboard. The assembler needs to solder the switches when building the keyboard. They can either use plate mount switches along with a metal plate, or use PCB mount switches. These PCBs may also have holes for mounting LEDs along with the switches.
Hot-Swappable Printed Circuit Boards
Printed circuit boards meant for hot-swappable keyboards have hot-swap sockets mounted on them. Mounting switches on these keyboards does not require soldering, as the assembler can simply push the switches into the socket.
Beginners new to mechanical keyboards can use hot-swappable keyboards to check out different types of switches. They can experiment to find out the switch type that suits them the best. The user must exercise caution when swapping switches, as excessive force can damage the sockets. Hot-swappable keyboards can handle both 5-pin and 3-pin switches. However, most hot-swappable keyboards are plate mounted types, as they need the extra support for stabilizing.
Through-Hole Printed Circuit Boards
A through-hole printed circuit board is another variation of the soldered PCB for keyboards. More advanced types of keyboards use these through-hole PCBs, and they require a more skillful soldering for mounting the switches.
Most through-hole PCBs for keyboards use the 5-pin plate mount switches, but using the plate is optional.
Materials for Metal Plates
The metal plate offers extra support to plate mount switches. Mounted on top of the PCB, it prevents the board from flexing when the typist operates the keys.
Keyboard manufacturers use several materials for making the plates, as they add newer metals to the list.
Aluminum and brass are the two most common metals manufacturers use. Among them, aluminum is more extensively used for keyboards. It provides moderate rigidity and sturdiness necessary without adding excessive weight.
Although brass is more rigid compared to aluminum, it requires a chemical treatment to prevent oxidation and tarnishing.
Some manufacturers have tried using non-metals like polycarbonate and carbon fibers with good results. Polycarbonate, being a plastic material, adds more flex and makes the keyboard feel bouncier.
Carbon fiber is a very durable material and lightweight. The advantage of using carbon fiber is it allows the keyboard to flex when using, providing a bouncy feeling.
In PCB vs. plate mount keyboard switches, the number of pins of the switches do not matter much, as the user can cut off the extra pins as necessary. Rush PCB Inc. recommends choosing the type of keyboard carefully to achieve the best performance from the keyboard. Although a plate is not essential, using one offers rigidity and a feeling of sturdiness.