Based in Wareham, Dorset, CSM Electronics specialises in contract electronics manufacturing and surface mount technology. They also offer through hole and box building capabilities. The company has grown steadily from a small start-up in 1990 to its present operation comprising seven SMT assembly lines and throughput capability of 300,000 placements an hour.
Achieving customer satisfaction through quality has always been a priority for CSM, but how best to do this has, in their experience, changed over the years. The changing nature of customer demand, evolution and size reduction of components, higher density PCBs and significant advances in inspection and test technology all present their own particular challenges to quality control. Accordingly, CSM decided to review these factors as a basis for updating their quality strategy. This review process resulted in their purchase of a Nordson YESTECH BX series benchtop Automated Optical Inspection (AOI) system from Cupio Yestech-Europe.
CSM’s decision was based on the production, financial and business benefits available from the BX system. To understand these, we can review the resources CSM had been working with and how these became inadequate to meet the above ‘challenge factors’, and then show how the BX system provided the solution – and additional benefits too.
AOI as a concept was not new to CSM; they had a pair of AOI scanners dating back 8 or 9 years. Their functionality and throughput were becoming growing issues as newer components appeared. For example, the scanners could no longer read logos and part numbers reliably as they became laser etched rather than printed. They also could not read information from through hole passives, as this is visible from the side rather than above, and the scanners only have overhead cameras. Additionally, the scanners could not easily spot problems with solder joints. As a result, manual inspection was still required to supplement the scanners’; this was becoming increasingly time-consuming as components shrank and boards became more densely populated.
CSM’s quality strategy involves testing as well as inspection, using ‘bed of nails’ testers. However these require a new jig for every board, costing around £5000 each; an amount that becomes more difficult to amortise as customers’ production volumes drop.
Benefits of the new technology
CSM was well aware that AOI technology had advanced significantly since their last scanner purchase, so they attended a production exhibition for an update on its possibilities and suppliers. Following this, they invited a short list of three AOI suppliers to propose solutions, from which they selected the BX machine. Their decision was based both on the BX’s capabilities and on the quality of service and training provided by Cupio Yestech-Europe. From the start, CSM was impressed with Cupio Yestech-Europe’s ability to program the BX in 1½ hours for a board not previously seen, using X-Y CAD data supplied by CSM.
After programming, the BX proved able to check the areas described above as invisible to the scanners. This was due to its top and side-mounted cameras, RGB lighting system, and more advanced hardware and software computing capabilities. The trial also included simulation of solder web and lifted leg faults. These were successfully spotted by the BX. The existing scan systems were not equipped to capture these faults; neither were the BX’s two competitors, which also only had overhead cameras. They could spot solder joint problems, but not raised legs, incorrect component heights or information on the side of vertically mounted components. By comparison, the BX provided the cameras and the functionality required by CSM at little or no extra cost.
In CSM’s view, productivity with the BX is considerably enhanced by its programming mode – the machine can be accessed remotely from a PC and programmed for a new board even while performing AOI on the live production line. When a new product is ready for manufacturing, first article inspection becomes easy with the BX, which compares the first production board with either a ‘Golden Board’ or with previously entered CAD and BOM data. This allows CSM to spot any production line problems before they can translate into a faulty production batch.
The BX has made tracking and management of faults easier through its bar coding system. The machine reads the bar code for each board, and any faults it detects are logged against this. Another operator at a rework station can then enter the bar code reference to see these faults as the inspector saw them – either an hour later, or a year later if there should ever be a requirement to do so. The bar code reference also logs the ID of each inspector, so issues such as an individual inspector needing further training can be identified and acted on. The BX also flags multiple occurrences of a fault, allowing CSM to identify the root cause and improve their process.
The new AOI installation improves and streamlines CSM’s overall quality strategy. As it can handle every aspect of inspection, including solder joints, human inspection is greatly reduced. Additionally, only one inspection stage is needed instead of two as previously. Meanwhile, false failure rates are greatly reduced. CSM no longer needs another inspector. They now have 6 people qualified for AOI, 3 for rework and 5 for programming and operation inspection. This setup allows them to comply fully with their customers’ quality requirements; customers will accept either an AOI report, or an AOI report together with evidence of functional testing, depending on the application.
CSM believes the benefits of their AOI installation arise from the quality of Cupio Yestech-Europe’s training as well as that of the BX. They feel that the training provided both for their operators and their programmer has been excellent; Cupio was very generous with their time, shared their deep understanding of the technology and its application, and remained focused on ensuring that CSM staff were comfortable with the system rather than limiting themselves to predetermined time schedules. Onsite training is supplemented by webinar links allowing CSM to access Cupio’s expertise for problems they cannot solve themselves.
“The benefits of this new AOI system to our production and process improvement are obvious” commented Dave Barton, General Manager at CSM Electronics, “We have faster throughput and reduced load on our inspection staff with better documentation and traceability. Also, our false failure rate has dropped dramatically, from 40 - 50 events per board to just two.” He continued “We see the system as good for business too. Its fast set-up time means we can be more flexible in changing our production runs, and the level of data generated by the BX improves our confidence in our QA status. These both improve the service we can offer our customers”