Meeting the CEMs' demands - Brief Article

Electronics Times, May 15, 2000

David Buckley sees how equipment suppliers are meeting the needs of CEMs

The demands placed on PCB assembly equipment suppliers by contract electronics manufacturers (CEMs) are different from those made by OEMs. Not radically so, but the CEMs' tight margins make high operating speed, high throughput and flexibility key requirements. OEMs need these features too, but they have other opportunities, notably in design and marketing, to add value. The CEM relies on its production efficiency for its profitability and, indeed,

for its very survival.

Adrian Freakes, chairman of the Association of Contract Electronics Manufacturers, said: "Today most OEMs are divesting themselves of their manufacturing plants; few are investing in equipment. It is the CEMs that are driving the equipment market." So what is it these contractors are calling for from the equipment suppliers?

In addition to speed and flexibility, CEMs' requirements include accuracy, reliability, the ability to handle new components and the occupation of the smallest possible amount of factory floor space. But as Freakes points out, the weight given to these demands depends on the CEM's size.

"The smaller companies are looking for flexibility; the big ones want speed," he said. Freakes has observed that the bigger, high-volume CEMs tend to dedicate production lines to particular customers, while the small and medium-sized CEMs like his own - Freakes is MD of Hampshire- based Surtech Interconnection - probably have to change a placement machine set-up several times a week. For these lower volume producers, flexibility and rapid reconfiguration are crucial.

The SMD placement machine has long been considered to be the bottleneck in surface mount line output, but the latest offerings from the assembly equipment suppliers are changing all that. Placement machines are getting ever faster, while other equipment, and materials such as solder pastes and chip bonding adhesives, are being similarly upgraded to meet the CEMs' demands for increased speed.

Placement machines are generally categorised as either high-speed or flexible, although these terms need not be mutually exclusive. Examples of high-speed types include the familiar chipshooter format, employing a revolving turret equipped with a number of component pick-and-place heads under which the PCB is moved in X and Y, and the more recently introduced machine format in which multiple X/Y-moveable heads each place components only on to specific areas of the PCB as it is indexed along beneath them. Philips manufactures such a machine, designated FCM, and to illustrate its high-speed capability quotes the experience of one customer which, having two FCMs in line, is able to place no less than 110,000 components per hour (cph).

Both high-speed machine types are seeing performance enhancements. Japanese equipment manufacturer Fuji has upped the specified speed of its latest chipshooter, the model CP7-31E, to 55,000cph, an increase of 37.5% on its previous model's already substantial rate of 40,000 cph.

Robert Murphy, UK sales manager with Nissei Sangyo, said: "The buzzword in the industry has always been cph, and that is rising."

His company expects to be launching a chipshooter model in the UK later this year. Dubbed the TCM X200, the machine will be offering enhanced cph capability together with greater flexibility in terms of the component types handled. The increase in speed has been achieved by designing the turret head to function with fewer moving parts. Compared to the current and previous Sanyo models, moving parts reduction on the TCM X200 machine's turret comes in at 40% and 80% respectively.

But while the very fast chipshooters are increasing both their flexibility and their speed, the machines offered by the conventional flexible placer (fixed position PCB; moveable X/Y head(s) format) suppliers are also getting quicker. And by pairing up two of these medium-speed machines in a single production line, with `balancing' software ensuring that they `talk to each other' and thereby share the workload efficiently, extremely fast and flexible configurations can be achieved.

A variation on the conventional flexible machine configuration is provided by Siemens' Siplace series, which employs a turret head mounted on an X/Y gantry moving above the static PCB. The high-speed version, the Siplace HS50, has a specified placement rate of 50,000cph and, when linked together in a group of two, three or more, extremely high placement rates are achievable. Indeed, according to Ray Bruce, Siemens' business manager, these machines are used "in very high-volume mobile phone assembly".

They appeal to CEMs both large and not-so-large. Falling into this latter category is Siemens' own contract manufacturing operation, Siemens Manufacturing Services, based in Nottingham, where the Siplace platform is established and where production throughput is enhanced by the installation of automated handling equipment for transporting boards between the various assembly processes.