By papascott October 17, 2013
Thanks for the GREAT service...Building has never looked cleanerRick ...read more
By AmyBob October 01, 2012
business is doing well and its even better since its been kept clean. thank you all for such a terrific job keeping things sparkly clean. ...read more
Circuit Board Rework The complexity of board assembly, limitations of the printed circuit board assembly process and the finite quality of electronic elements and materials all lead to the need to rework components on printed circuit boards. Rework, as defined by the industry IPC 7711 standard,is the act of reprocessing noncomplying articles, through the use of original or equivalent processing, in a manner that assures full compliance of the article with applicable drawings or specifications.In other words rework is the process of removing and replacing components due to any number of root causes with the outcome being that the printed circuit board is functioning as designed and comes with all of the applicable discrimination attributes as prior to the rework being performed. Circuit board rework, in its truest sense, attempts to mimic the original manufacturing process so that the PCB meets the original manufacturing process standards. In this manner, the stresses on the board due to thermal and other environmental parameters are limited to those seen by the components in the original manufacturing process. With the added complexities of the board being previously exposed to a variety of operating conditions circuit board rework needs to take in to account these previous processes. For example, the laminate and solder mask may only be designed to be able to accept a finite amount of heat cycles. This means that there will only be a finite number of “tries” in circuit board rework as the thermal stress of the reflow cycles will limit the heat excursions. In addition, the same or superior materials should be used in the remanufacturing or printedcircuit board reworkprocess. Figure 1-Typical hand soldering operation in rework The need for circuit board rework coms from a variety of problems. For example, in the original assembly of the circuit boards, components can be misplaced in the feeder. This means that the devices will have to be desoldered, the site location prepped and the device re-soldered and inspected. In other cases devices can fail electrically or the interconnections be mechanically broken requiring circuit board rework to be performed to replace the device or resolder the interconnection. Whatever the case, circuit board rework requires that original specifications of the board be met. There are numerous challenges associated with modern printed circuit board rework including both logistic and technical issues. The technical challenges of printed circuit board rework are too numerous to mention but several of the most challenging and often repeated ones are outlined below: BGA rework of very small footprint devices requiring a high degree of skill and great deal of experience is a challenge Ultra fine pitched part rework such as 0.4mm spaced leaded devices or ultra small package devices like 0201s is of concern Leadless devices with very small standoff distances requires fine process controls and ability to clean underneath low standoff heights and the ability to read x-ray images Handheld devices with shields around the RF transmission chips Underfilled devices requiring finesse so as not to scratch the solder mask or lift the pads In addition to these technical challenges there are many logistical challenges associated with circuit board rework. In many cases the volume of rework is extensive for consumer oriented products. This means that pressure to get the “problem” fixed, especially with very long supply chains, is extensive. With nameplate holders in many cases in Europe, America or Japan it is a long distance between the warehouse with the defective product and the home base or factory of origin. Due to the timing pressures in order to get the factory performing the rework “up to speed” in many cases performing the rework back in the country of origin takes too long. In addition, the components may not be as readily available in the market where the rework is being performed as it may not be as plentiful as the country of manufacturing origin. The complexity of board assembly, limitations of the printed circuit board assembly process and the finite quality of electronic elements and materials all lead to the need to rework components on printed circuit boards. Rework, as defined by the industry IPC 7711 standard,is the act of reprocessing noncomplying articles, through the use of original or equivalent processing, in a manner that assures full compliance of the article with applicable drawings or specifications.In other words rework is the process of removing and replacing components due to any number of root causes with the outcome being that the printed circuit board is functioning as designed and comes with all of the applicable discrimination attributes as prior to the rework being performed. Circuit board rework, in its truest sense, attempts to mimic the original manufacturing process so that the PCB meets the original manufacturing process standards. In this manner, the stresses on the board due to thermal and other environmental parameters are limited to those seen by the components in the original manufacturing process. With the added complexities of the board being previously exposed to a variety of operating conditions circuit board rework needs to take in to account these previous processes. For example, the laminate and solder mask may only be designed to be able to accept a finite amount of heat cycles. This means that there will only be a finite number of “tries” in circuit board rework as the thermal stress of the reflow cycles will limit the heat excursions. In addition, the same or superior materials should be used in the remanufacturing or printed circuit board rework process. Figure 1-Typical hand soldering operation in rework The need for circuit board rework coms from a variety of problems. For example, in the original assembly of the circuit boards, components can be misplaced in the feeder. This means that the devices will have to be desoldered, the site location prepped and the device re-soldered and inspected. In other cases devices can fail electrically or the interconnections be mechanically broken requiring circuit board rework to be performed to replace the device or resolder the interconnection. Whatever the case, circuit board rework requires that original specifications of the board be met. There are numerous challenges associated with modern printed circuit board rework including both logistic and technical issues. The technical challenges ofprinted circuit board reworkare too numerous to mention but several of the most challenging and often repeated ones are outlined below: BGA rework of very small footprint devices requiring a high degree of skill and great deal of experience is a challenge Ultra fine pitched part rework such as 0.4mm spaced leaded devices or ultra small package devices like 0201s is of concern Leadless devices with very small standoff distances requires fine process controls and ability to clean underneath low standoff heights and the ability to read x-ray images Handheld devices with shields around the RF transmission chips Underfilled devices requiring finesse so as not to scratch the solder mask or lift the pads In addition to these technical challenges there are many logistical challenges associated with circuit board rework. In many cases the volume of rework is extensive for consumer oriented products. This means that pressure to get the “problem” fixed, especially with very long supply chains, is extensive. With nameplate holders in many cases in Europe, America or Japan it is a long distance between the warehouse with the defective product and the home base or factory of origin. Due to the timing pressures in order to get the factory performing the rework “up to speed” in many cases performing the rework back in the country of origin takes too long. In addition, the components may not be as readily available in the market where the rework is being performed as it may not be as plentiful as the country of manufacturing origin. ...read more
By BEST Inc April 10, 2017
IPC Training for PCB The IPC, the trade organizations for the PCB and electronics, has developed a series of both inspection criteria and hand skills courses related to PCB s and their assembly. Industry consensus within the IPC has driven the desire for a training program. For theIPC trainingprograms involving inspection criteria the classroom teaching involves being able understand the specification and being able to look up the material. For the hands on IPC solder training program skills in the subject matter like soldering, rework and repair of printed circuit boards need to be demonstrated along with proficiency in the specification. TheseIPC trainingcourses are based on the industry specifications assembled via the IPC trade organization based on member input and cover a variety of topics. These along with IPC member input drive the training programs. Specifications are created for the given topic through the input of members at committee meetings based on volunteer support. The supporting members are training centers, consultants to the industry and end users. These working groups, chaired by an industry member and organized and guided by IPC staff members, reach agreement on the specification. After a final vote by industry the document is published and subsequently translated into a variety of different languages. These documents are on the basis for the IPC training program. A separate training committee is then established and drives the training program content. After a few trial classes and one or more rounds ofIPC trainingprogram, the IPC training program is then released. The IPC training programs are administered by the IPC, the industry trade organization. Administration of the IPC training program entails keeping track of instructor credentials, verifying the training center’s competence as well as printing and distributing the materials and maintaining the web site. In addition to maintaining the web site, the IPC administers the testing portal. TheIPC certificationtraining programs are taught by subject matter experts from industry using IPC coordinated and industry-approved materials. IPC credentialed, authorized and licensed training centres make sure that their instructors are vetted requiring a minimum amount of classroom and industry experience. In turn, the IPC training centers make sure that the newly-licensed instructors going back to their locations are able to teach the materials for the class to their own associates as part of the IPC training. An IPC certification, which is the result of a successful outcome of IPC training, is governed by a set of agreed guidelines and rules. These rules are setup in a living document called the “The IPC Governing Policy and Procedures for Training”. Members of this committee drive policies and requirements for IPC training. There are several drivers for the need forIPC certification training. One of the drivers is the desire and requirement by space, governmental bodies as well as international companies from having their products built to and by people knowledgeable in industry standards. These standards are accepted worldwide and allow the owner of the design to have choices in where their products should be built. The IPC certification in many cases faces a requirement for those who will be building, assembling and testing their products. On the flip side, the industry in then driven by this requirement and demand to have certified and trained personnel in order to participate in these contracts. A second driver for companies to have their employees participate in the IPC certification program in order to meet the ISO and QS quality system requirements for having a 3-part certified training program. Each of the IPC certification training programs matches these requirements as they are linked back to the ANSI standard. The IPC certification program is constantly evolving its requirements. The local licensed training centers with their subject matter, experts are there to help users and companies to navigate the requirements. In addition, the IPC training centers are able to teach the standards and hand skills as their staff teaches full time and has the commensurate experience to bring the training to life. Look to your local IPC training center to bring these requirements and standards to life. ...read more
By BEST Inc April 07, 2017
BGA rework process covers the development and criteria of establishing profiles for BGA removal and replacement. There are several technologies which can be used as the heat source in removal of a BGA including but not limited to hot air and IR. The BGA rework process can be methodically worked out on guidelines though difference in printed circuit boards and devices populated on those boards. The increased use of BGAs and the underlying trend of ever-smaller package sizes, finer pitches and their placement on to ever denser printed circuit boards has led to greater and greater challenges in BGA rework. In addition to these challenges there are many others that have made the job of BGA rework technicians more and more difficult. One of the trends in making BGA rework more difficult is their ever-increasing usage in handheld device. Due to the drop test requirements of these products in many cases the BGAs and other higher density devices need to be underfilled. Underfilled BGAs have the challenge of the tacky material “squirt out” causing solder shorts underneath the BGA. In addition, the tacky nature of this material tends to lift pads as well as destroying the underlying solder mask underneath the BGA. This makes theBGA rework processeven more challenging. The ever-thinning device packages of BGAs cause the packages to warp. This too makes BGA rework difficult. ...read more
By BEST Inc January 31, 2017
Design consulting businesses are those businesses which require your expertise and creativity in designing something for your client. This category includes graphic design, interior design, landscape design and many more. It is a vast field with lots of opportunities. There are a few creative ideas yo... ...read more
A green consultant is an individual who has completed specific training in one of several environmental or ecological areas of specialty. Green consultants work professionally to assist homeowners, business owners or corporations to create a more environmentally conscious and sustainable set of practi... ...read more
