Biggest name in musical mixing
07 November 2006
The company Allen & Heath, situated in Falmouth, has been creating, developing and manufacturing audio mixers and soundboards for 35 years. Many of the big names in today's music rely on the company's systems - and the company's systems' quality is assured by a state of the art AOI system.
The world of entertainment has changed from analogue to digital. This is most commonly seen in the new generation TV, DAB radio or DVD equipment. These changes have also been occurring in the world of public music performances. Allen & Heath was hand-building mostly analogue sound boards until the 90's, and they still do, but more and more digital equipment has been deployed and built. At PCB level this is seen by the presence of device types such as DSPs, FPGAs or BGAs which are found in digital mixers by Allen & Heath. The PCBs are in-house produced by Allen & Heath by their own SMT line.
In former analogue days the production volume was higher; nowadays, there's lower volume but high-mix of types. About 800 different boards with a maximum size of 350 x 550 mm are produced every day. The reason for high-mix is the variety of applications the PCBs are produced for - about 300 different PCBAs. For example, Allen & Heath is producing multi-channel analogue mixing desks. Such a console might include 24 input cards plus 12 boards in the master section; an additional six boards are utilised as backplanes for connection. One analogue input channel board has about 500 different components; a digital input card could have twice that number of components.
Modern mixers have become light and transportable; however, the dimension of the PCBs has decreased as well. This means that the net density on the board has been getting increasingly higher. In previous generations the analogue boards were tested by an In-Circuit Tester but on the new generation boards, Allen & Heath utilises the latest AOI technology. The most significant reasons are ever decreasing physical access for test probes and rapid product development.
Roger Hand, Test Development Engineer for Allen & Heath, explains: "Since we no longer produce large volume-single type boards, flexibility became the magic word. And this flexibility could only be assured by a fixtureless test system." Roger offers an example, that they might need to test less than half a dozen of a particular OCB per day. Additionally, the PCB designs are changing so quickly it is difficult to produce cost-efficient test where physical access if required.
"Because of the flexibility, zero fixture costs and ability to cope with design updates and changes quickly, and AOI system offers the most economical, yet thorough test for low-volume, high-mix production," says Roger.
When the change in test strategy became necessary, a group of engineers discussed alternative technologies and finally decided for Automated Optical Inspection, Allen & Heath found that some AOI technology had significantly improved in recent years. Additionally, it offers a short Return-on-Investment because the only costs relate to the capacity of the AOI machine and not for test fixtures.
First, they started their research on the internet - ending up with a shortlist of three different vendors. These vendors were asked for benchmarks. Both Roger and Steve Benney, Allen & Heath's Quality and Improvements Manager, visited a contract manufacturer in Portsmouth to be given a demo of a stand-alone AOI system by Goepel Electronic. Goepel Electronic's UK distributor Cimbian UK Ltd was able to show how the system would be used in practise and could be deployed at Allen & Heath; Allen & Heath engineers were also given demos by other AOI vendors.
The critical points for purchasing an OptiCon BasicLine system from Goepel were:
OptiCon BasicLine is an entry level system
"It looked more substantial - more like a machine," says Roger.
Linear motors mean high speed but low maintenance
Latest technology illumination and optics for today's and tomorrow's technology
Fast and easy to program and neutral network object recognition
Software and hardware better than competition
Best price-performance ratio
The whole package or performance, service and support
Minimum future expenditure - no calibration costs, no maintenance costs. Steve Benney says, "We pay once for the machine and there's a lot of capability for the future.
The OptiCon BasicLine AOI system is used for typical inspection tasks such as checks for presence, polarity, value, solder joint quality and shorts & opens. However, Allen & Heath have also used the 'neutral network' driven software to inspect more diverse components, each of which is now mapped to an Allen & Heath part number so that future programs are generated in the minimum of time.
For the Allen & Heath test engineers it is very important hat the system is able to inspect both top and bottom sides of the PCB because numerous THT components are still used. The AOI system's test coverage is up to 99% of the inspected areas - particular importance was laid on the inspection of THT components. For smaller boards it takes half a day to generate and debug a test program. Roger Hand, though, is looking to the future.
"In a couple of months we'll be generating test programs in just one day for out biggest boards too," he said.
Steve Benney adds: "We've invested a lot of money in new product designs, the quality of which can only be assured by a high-quality test machine. Because the AOI can cost-effectively test even prototypes, a faster product introduction is possible now. It takes 1-2 days to create a test program with AOI compared to 2-3 weeks with a fixture based test."
Since the purchase of their OptiCon BasicLine, Allen & Heath has successfully been working with the system. And whenever problems occurred, support is at hand.
Says Steve Cooper; "Never leave a non-working machine or dissatisfied customer." His philosophy of ideal customer support is consistent with Goepel's, that the most powerful product is of little value if the vendor can't ensure proper support which helps guarantee customer satisfaction.
Roger Hand and Steve Benney agree in saying that Cimbian UK's knowledge of the system and support has been very helpful.
"But also the Goepel people are responding and acting very quickly - it's a high level of customer support all round," explains Roger Hand. Another feature that Allen & Heath is happy about it the support policy of free software updates for life that can be easily downloaded from the Goepel Electronic customer website. "We are very happy with the system."
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