Why contactless cleaning sweat quickly replaces manual cleaning
13/07/2015
Today, the manufacturers of printed circuit boards (PCB) much on quality, but also between the operations that are increasing linked able yields close to or even more than 99%, the vast amounts of applications, such as smartphones and tablets could still with thousands of sheets per week leave them damaged from the assembly line and revised needs. Since the cost of these PCBs may be far above $ 200 each, most manufacturers and suppliers feel it is important to recover an effective process of working these tips and minimize PCB to develop scrap - and earnings losses.
In fact, the current environment is far from the days of limited functionality "candy bar phone" when the value of PCB rework faulty joints was not very clear. But while the Council sophistication and scale costs and global consumer demand continues to rise, it will manually clean for manufacturers of defective cards more difficult when returning to work. Instead, contact cleaning a specialized process previously only a small -Market Segment wins not only integrated, but mandatory for most PCB manufacturers often not only by the need to remain competitive, but motivated for employers, by the inflexible demands of its OEM customers as well as.
Traditional hand cleaning process can cause many types of damage
The recovery process has long consisted of three steps: removing the failed component, the cleaning of waste solder ball grid array (BGA) tablets that the component age available, and its replacement by a new component to create a profitable PCB. The first and third stages of the removal and installation have long automated and is carried out in time recovery machines with operator assistance. Step Cleaning media undoubtedly the most delicate and important step when it. Around a table, often by qualified personnel that comes recover completely damaged by hand The cleaning is done with hand tools carried out, usually a mesh of wire and a soldering using standard or specialized advice. Obviously, the efficiency of the operation to a large extent on the skill of each operator, in particular with emphasis often placed on the speed at which damage to the card is a relatively common.
* (See Figure 1)
For example, a common scenario in the manual cleaning is the destruction of a buffer by adhesion when the heat of the soldering iron temporarily discharged by the Bank, making it sensitive to keep the wick pad and chipped or completely eliminated when the operator panel tool away. Overwhelmingly, the destruction of the tablet results in a waste board.
To help today in the drive, the smart phone or other end product offer more functionality, manufacturers create thicker multi-layer circuit boards with copper inside. This, unfortunately, is that they dissipate heat to more rapidly with manual cleaning tools that the Union will be challenges even more problematic in the future.
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Additional risks for the mounting of the circuit board when the manual cleaning is performed, there are many BGA. To name a few, can the molten solder connections and electrical pathways causing flow shorts advice. Lot can be removed from inconsistently between tens or hundreds of wafers, which. In poor adhesion of the new component And may be inadvertently removed from the wick parts of resistance welding, whereby the solder to flow into the electrical connections when placed the card in the recovery engine, which bridges and short circuits.
Another perhaps more insidious problem is that, or during many of the problems of manual cleaning can be caught in the inspection process, and the Board, now the need for expensive waste in the market, not visible is another common source of damage perceptible same-ray inspection. Pad crater in fiberglass under the pillow due to restrictions by mechanical pressure from the operators press too hard with the soldering tip or superheated something be created caused too long in power against the board.
* (See Figure 3)
With this type of damage the cushion and the solder balls are always connected to each other, but the keyboard is not completely attached to the circuit board, leaving them vulnerable vulnerable to the slightest vibration of the consumer and the brand reduces end product reliability and consumer dissatisfaction. The smaller the buffer, the more prone to this kind of hidden columns, which means that the situation be more frequent and in the future even more common, as the size of the buffer are further back.
Trends in the industry, which makes it even more difficult for manual cleaning
In fact, it is important to note that, as usual, as all of these and similar scenarios in the past to much more have become. Tips and thicker the buffer size and the field size is in recent years, significantly reduced, with many smart phones and other devices now with pad sizes as small as 5 mm intervals .25mm mil. It is in the industry, the new chips for release over the next two to three years planned with drawings calling sizes as small as .1mm without .3mm cushions are known. With adjoining rooms so close together, avoiding with lock for manual cleaning and the creation of another cycle of recovery is likely to be impossible to hit for the most qualified.
Furthermore, the traditional methods of cleaning can even less effective when it comes to integrate the cleaning PCB chips advanced technologies. For example, fourth generation of Intel Core processor technology provides outstanding improvements in security that order data is almost impossible for criminals, stored in the processor. However, due to factors such as size pads and unequal volumes welding, manual cleaning can be a challenge.
Another technology, ceramic ball grid array, specific procedures in the aerospace industry, military industry and other high-reliability applications is used, is another case of great value to the point. These cards, the individual components of that cost tens of thousands of dollars and can be a million or more half use cost to manually own success and get back to work, and generally, if defective, are very difficult discarded. The problem is that the two different types of solder is used for the production, associated with a melting point of 183C and 302C. Incorrect manual cleaning can change the melting temperature of the solder pads, so that when the new part is applied with solder paste, the temperature may not be high enough to form an intermetallic seal, and could result in the dry seal these connections.
In addition, many chip package confidence manual methods due to the threat of melting of the final package can not be cleaned in the package. An advanced element of the BVA-POP Invensas promises a quadrupling in the memory and the processing speed reluctance solder balls with hook-shaped connectors 50 microns wide and 90 microns in size, hardly visible, the distance with the naked eye and at a distance of 0.2 mm. Suffice it to say that the manual cleaning is not an option for this innovation.
Contactless mechanical cleaning provides safer options
Fortunately scanning is cleaning or contact a highly effective cleaning these chips with BGA method and the growing challenges of manual cleaning described above significantly reduce. No contact with cleaning an automated software-controlled machine process precisely controls temperature and the placement of a failure, and uses a vacuum to remove the molten solder.
With these characteristics in mind, it is easy to understand how touch less cleaning, the challenges that reduce the manual cleaning, and certainly replace all in many applications. For example, it is not in contact with the roller skate or board, whereby the risk of mechanical damage. Controlled precision tips can try to human operator reasonably clean the shoes too small and too close. The software constantly monitors and thermal professional equipment. And the vacuum collection nozzle automatically removing welding job, are for a more consistent and complete, and less chance of molten solder flows in removing unwanted areas.
Independiente vs all-in-one contactless designs
Until recently, non-contact cleaning machines can be very large peak-guided and / or optional, cultivation of cleaner on the steps of removing and replacing a machine be retrofitted so that the opportunity given. As the demand in the industry is growing for a lower-cost, non-contact, "stand-alone" touch less cleaning machines on the market, eliminating the need for a much less capital investment and a number of other potential benefits.
Perhaps the most obvious and significant, and autonomous machines at a higher rate. As "all-in-one machines can be operated by a single operator, but unlike all-in-one machines, if used, and replace that offer the possibility of setting a cap of standard machine remove an operating" production line "in order to increase speed and performance.
In this scenario, the operator starts by a printed circuit on the recovery machine. After the machine the chip to the adjacent table device for cleaning the machine cleaning is eliminated transferred. Meanwhile, a second card in the recovery machine is arranged to remove the chip, so that the two cards in the production, while. When both are finished, transfer the first card, now clean, the cleaning machine no independent contact of the recovery machine to replace the chip, and transmits the second card, now its chip is removed, regardless of the machine for cleaning. This becomes a continuous process.
Compare that where a map will be processed at a time with the operation of all-in-one sensor, usually by component removal, cleaning and replacement of the components of a serial manner. With a catcher 'stand-alone' revised income cards can be increased by 50% or more. In addition, since the capture tend to single-phase power to a standard while larger machines often use power phase 3, the difference in energy consumption and the cost can be significant, especially in a volume operating 24/7 high and should definitely ROI equation are considered.
It should also be noted that the machine self-cleaning contacts is an opportunity for manufacturers more flexible, fast and cost-effective to add capacity contact operations. If, for example, have invested recently in a recovery machine lacks an add-on option of standard gauge, they can be easily added
Contact cleaning machine to work closely with your current machine rally, regardless of make or model, without investing in a new machine recovery. This is an especially useful option to add contact cleaning skills quickly by customer contract, for example, manufacturers 'forced' suddenly. Similarly, even if the current recovery engine offers a choice catcher supplement, you can choose a separate catcher in place all the advantages of higher performance, as mentioned above.
Characteristics of the machines varies
Another advantage of the non-contact cleaning for manual cleaning machine is that many all-in-one, even retrofitted and the like includes a second programmable preheat under the table to heat the nozzle is arranged in addition. This allows reducing the need to operate for the higher temperatures required when a single heat source, such as a welder, and to contribute to the optimum constant temperature used in combination, whereby the pad and damage board related cleaning endemic hand heat.
However, different manufacturers use different heating techniques for this configuration is the double heating, air heating and combinations of infrared heating elements, including IR / IR, IR / convection combination convection / convection significantly different. In addition, machines that IR with a number of different technologies, such as infrared light red and white quartz. The bottom line is that technology to offer precision control of temperature essential and this aspect should be examined before buying in order to maximize returns.
The machines differ in their level of automation; for example, some require the operator to move the card at certain points that may affect the success rates and the power manually. The machine may vary accepted in the size of the BGA matrices.
They have also differ from the machine, the quality of the automation itself is how easy it is for engineers to efficiently necessary to program the number of steps for the user to -use a sequence of recovery or cleanability GUI perform user, the amount of training that is needed, and so on all aspects that must be considered before making an investment.
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