What Is a Mounter?
Mounters are devices that mount electronic components on the surface of printed circuit boards.
Also called a surface mounter or chip mounter, it mounts components of various shapes and sizes at high speed and with high precision. There are two types of mounters: rotary mounters and modular mounters. In recent years, modular mounters, which are compact and have faster mounting speeds, have become the mainstream.
Surface mounting, also called SMT (Surface Mount Technology), is one of the board mounting methods. Electronic components such as IC chips and capacitors are mounted on the surface of a printed circuit board, and the electrodes are fixed in a reflow oven by bonding them with solder paste.
Compared to insertion mounting, where component leads are inserted into holes, this method saves space and has become the mainstream mounting method in recent years. For small-lot production with a small number of boards and components, manual solder mounting by hand is also possible.
Usage of Mounters
There are many boards that are surface-mounted using Mounters, and they can be found almost anywhere that requires boards for electrical circuits. Examples of surface-mounted boards in use are as follows
- Cellular phones
- Smart phones
- Game consoles
- Home appliances
- Automotive substrates
- Airplanes
- Rockets
They are used in many familiar objects that require circuit boards for electrical circuits. Surface mounting consists of a printing process, a mounting process, and a reflow process. In the printing process, adhesive is applied to the printed circuit board by cream solder printing or dispensing, and Mounters are required to mount electronic components on it. Heat is then applied in a reflow oven to blend the solder and adhesive with the components and adhere the components.
In recent years, the size of electronic components has become less than a few millimeters, making it difficult to mount them by hand. Mounters, which can realize accurate and high-speed mounting of components, are indispensable equipment for board mounting. Mounters that can handle a wide variety of electronic components, including odd-shaped and large components, are available.
Principle of Mounters
Mounters are devices that mount components on printed circuit boards to which solder printing or adhesive has been applied in the previous process. Components set in the feeder are picked up by the suction nozzles in the device and mounted at the designated positions on the board. The structure of the Mounters is as follows
- Head section
The nozzle picks up the electronic components. - Drive section
Moves the head section on the XY axis - Supply section
Supplies electronic components to be mounted. - Recognition section
Recognizes the positions of substrates and electronic components with a camera. - Transport section
The printed circuit board is transported.
Mounters are used for mounting electronic components by surface mounting, so after the components are placed using the mounter, the soldering process takes place. Depending on the soldering process, pretreatment before using Mounters is different. In most cases, solder is applied using a cream solder printer or adhesive is applied using a dispenser as pretreatment.
After the board has been pre-processed, electronic components such as chips to be placed are grouped together and placed in the mounter’s feeder. The electronic components are automatically fed from the feeder, and the nozzle of the device sucks the components under negative pressure. The suctioned nozzle moves directly to the top of the board, and the electronic components can be placed and positioned at the set location on the board.
Mounters can be divided into rotary mounters and modular mounters. The mainstream is the modular mounter, which has become smaller and more convenient in recent years. Rotary mounters use a rotary head to pick up and place electronic components. Modular mounters use XY robot axes to move the head to pick up and place the components.
Mounters in recent years have made it possible to mount electronic components in place with high speed and accuracy. The improved performance of the component recognition camera enables highly accurate mounting by measuring and correcting the position of the board and the mounting position of components.
Types of Mounters
There are two types of Mounters: modular type and rotary type.
1. Modular Type
Modular type mounters are currently the most common type of mounters, with a suction header attached to the end of an XY robot, which picks up the component to be mounted and carries it to the mounting position on the board.
While the equipment can be made compact, the disadvantage is that the suction head must be moved in the XY direction each time a component is picked up, resulting in a longer tact time than with the rotary type.
2. Rotary Type
The rotary type has multiple suction heads on a rotating rotary section and can pick up multiple parts in a single pick-up operation. While the rotary type has the advantage of high-speed mounting, it has the disadvantage of large equipment and high maintenance costs.
In addition, it is necessary to set a large number of parts at a time, which is no longer suitable for today’s market, where small-quantity, high-mix production is required. For this reason, most mounter manufacturers have now discontinued production of the rotary type.
How to Select Mounters
The following are things to consider when selecting a mounter.
1. Speed
The speed of mounting a single component varies from about 0.1 second to about 1 second, depending on the mounter model.
2. Mounting Accuracy
For mounting technologies that require miniaturization and high density of components, such as boards for smartphones, an error of about 0.1 mm is required. For circuit boards that do not require high density mounting, a mounting accuracy of about 0.2mm is sufficient.
3.Component Types
When not only chip components wound on tape but also large tray-supplied surface-mounted components are to be mixed on a circuit board, a large mounter capable of setting a special parts feeder is required.
Other Information on Mounters
Mounter Feeder
Mounter feeders are automatic parts feeders that feed electronic components into the equipment. Electronic components are delivered in reel or tray packaging and set in the feeder.
The parts are fed through the feeder into the equipment, and the feeder is an important device for ensuring that the parts are loaded in a constant direction without tilting. The use of a batch feeder exchange cart allows the feeders to be removed and attached from the main unit in a batch, and optimization can be achieved for each cart, thereby reducing the number of setup man-hours.
The feeder size should be selected to suit the packing configuration of the following parts.
- For reel tape sharing
- For stick feeding
- For separate parts
- Tray feeding
In the reel tape-sharing type, which is the most common delivery form, electronic components are attached to paper tape or plastic embossed tape, which is covered with a thin plastic film tape called cover tape. This mechanism feeds components into the equipment while peeling off the cover tape inside the feeder.