The step sequence of a SMT machine controls the process when it is running, such as the arrangement of feeders, the order of picking up materials and the order of placement. Unreasonable program sequencing will cause long waiting time, low placement speed and waste of machine resources. Reasonable program sequences make full use of the components of the mounter, so that its efficiency can be higher and its capacity can be maximized.
Therefore, how to optimize the different structure of the mounter?
I. Rotary high-speed SMT machine optimization
Each mounting head of turret-type high-speed mounter has a nozzle suitable for various component sizes, which can be automatically replaced after each mounting cycle, and will not take up the machine's mounting time. Therefore, the optimization of turret-type high-speed mounter is relatively simple. Generally speaking, when optimizing the turret-type high-speed mounter, the factors and methods that should be considered are as follows.
1. Feeder switching time
the feeder switching time is generally greater than the theoretical placement unit time. Therefore, in the optimization, try to put the components with more material forward to reduce the movement of the feeder platform.
2. Turret rotation speed
in order to prevent the components in the brick tower rotation shift, for the larger the components, the lower the set rotation speed, and in the whole turret, there is a component of the rotation speed is low, will make the other components of the speed is also reduced. Therefore, in the optimization should be placed in the high-speed components together first, and low-speed components in the back of the paste.
3. X, Y table movement distance
in the unit rotation time of the turret, the table can move a certain distance, if the table moves more than this distance, the mounting head in the rotation after the need to wait for the table to move to the mounting position. Therefore, the placement of the step sequence should make the total distance of the table to move the smallest, if the same kind of components of the distance is far away, you can consider the first paste the next feeder components and then back to the last feeder to reduce the distance of the table.
II. Optimization of Arch Multi-Nozzle Side-by-Side SMT machine
The arch frame structure is different from the turret structure in that it takes up time for component pickup, identification, placement, nozzle replacement and X and Y movement of the placement head. Therefore, when optimizing the arch-type SMT machine, the main consideration should be to reduce the number of placement cycles. In general, the factors and methods to be considered when optimizing the arch-type mounter are as follows.
1. For multi-nozzle side-by-side SMT machine, try to do simultaneous suction to reduce the suction time when suctioning material. Generally, the distance between the feeders with a width of 12 mm or less is the same as the distance between the nozzles of the patch head. When the feeders are arranged, the feeders with a width of 12 mm or less should be placed together so that the nozzles can be sucked at the same time. If there are more bits of a component, multiple feeders can be used to increase the possibility of simultaneous suction. If simultaneous pickup is not possible, the pickup order should be from farther away from the camera for pickups recognized by a fixed upward-facing camera. For the use of a moving camera with a mounting head, the feeder with more positions should be positioned as close as possible to the board. For single-beam machines, pick up components from only one side of the machine's feeder in a placement cycle.
2. Identify components with the same camera and light as much as possible in the same placement cycle to minimize the time spent on camera and light changes. Smaller than the size of the camera's field of view of a component and larger than the camera's field of view of a component should be placed in a different placement cycle, otherwise the identification of components will take too much time.
3. The placement position of the components in the same placement cycle should not be too far away from each other, otherwise the X and Y movement of the head will take too much time during placement.
4. As the replacement of the nozzle needs to put down the original nozzle, and then pick up the new nozzle, it generally takes 1.5 ~ 2 s, so in the programming should minimize the replacement of the nozzle. For machines with a large number of nozzles on the head, the ratio of the number of different nozzles can be determined according to the ratio of the number of components using different nozzles.
5. For machines with dual beams and dual placement heads, consider the balance of the two placement heads. First, the placement cycles of the two heads should be approximately the same, with one head sucking up material while the other head is placing it. Second, the suction time of one head and the mounting time of the other head should be the same as much as possible to minimize the waiting time.
6. For multi-tray tray feeders, minimize the number of tray changes in the same placement cycle. On the material transfer track, the material should be transferred more than once to reduce the waiting time of the patch head.
III. Optimization of rotary head composite chip mounter
Rotary head composite mounter program optimization of the basic principles and the arch structure of the same mounter, should try to reduce the number of placement cycle. However, due to the different structure of the placement head, the optimization should also consider the following aspects.
1. The rotary head only picks up components in one position, but the y-axis movement takes time on different feeders. Therefore, the more component positions in a feeder, the better. If the number of feeders is too large, the pickup time will be reduced. You can minimize the y-axis travel time by using as many dual-rail feeders as possible.
2. Some rotary mounting heads recognize components on fixed upward-viewing cameras, and some recognize components on moving cameras on the mounting head, so there is generally no need to waste time for smaller components. But if there are larger components level rotary mounting head, it is necessary to squeeze 'off some of the suction nozzle.
3. As the rotary mounting head in the mounting process generally does not replace the nozzle, so the number of various nozzles on the mounting head should be configured according to the number of components using different nozzles first, the mounting head will be in the beginning of the mounting program to replace the nozzle.
IV. Optimization of Modular SMT machine
A modular chip mounter is equivalent to a production line consisting of two or more arch-type mounters. When optimizing the entire machine, the placement times for each module should be as close to the same as possible to reduce the wait time between modules, much like line balancing on a SMT machine. Optimization of the individual modules requires the same considerations as for a SMT machine in a gantry configuration.
Company Profile
Zhejiang NeoDen Technology Co., Ltd. has been manufacturing and exporting various small pick and place machines since 2010. Taking advantage of our own rich experienced R&D, well trained production, NeoDen wins great reputation from the world wide customers.
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