Paste dispensing and the bad tempered dog
27 November 2007
The dream of the ‘lights out’ factory was never going to work, somebody once told me. A ‘lights out’ facility being one where everything was fully automated and requiring no manual intervention would never work because it would always require, at the very least, one man and his dog.
The man was there as the ‘insurance’. Somebody who could make that uniquely human and subjective decision about whether the process was running out of control, if the facility was in danger and so on. The dog was there to bite the man if he tried to touch anything!
The dream of a fully automated production facility has, of course, had a set back in recent years in that in the majority of cases there are parts of the assembly line, most notably at the end of the line, that can be done more cheaply by low-cost manual labour.
But there has also always been one process hurdle to overcome if the ‘lights out’ dream can become a reality – the stencil. The printing process is the one aspect of the production line that is not fully programmable. It needs a stencil and when the product changes it needs a different, manual loaded stencil, in its place. Efforts to automate stencil changes have proved cumbersome and not financially viable, but several companies have looked at the possibility of completely changing the way in which solder paste is deposited on a PCB.
In fact the one man and his dog story above was first recounted to me about seven or eight ago, shortly after Cookson had bought Camelot and were using its materials dispensing expertise in tandem with MPM’s (another Cookson company at the time) paste printing capabilities to come up with the first production speed ‘jet printing’ machine. They came close, but ultimately it came to nothing.
Then along came Mydata with its MY500, launched two years ago at Productronica. In my column last week I bemoaned the fact that there was nothing that really turned the head at this year’s exhibition. Two year’s ago there was – The Mydata MY500. Was this machine the key to a fully automated process? No it wasn’t. More than anything else it had a price tag that was double what you might pay for a top of the range stencil printer. And it was not as fast, or at least certainly not for bigger boards. Even dispensing at 1.8 million dots per hour, a dispenser obviously takes longer the more paste it has to dispense, whereas a stencil printer has a standard print time.
The MY500 is a good machine – it can react quickly to the demands of low volume and high complexity, particularly in development environments, but it is not going to enter the mainstream as a replacement for the stencil printer. At this year’s Productronica Mydata released the second generation of the machine which was a bit cheaper (at around US$320k) and features off-line programming and whenever I walked by the Mydata stand then it was still creating a fair amount of interest. I covered this machine in our Productronica preview ( click here ).
Another machine, along a similar vein, that did catch my eye at Productronica was the Essemtec CDS6700, even though it was tucked away in corner of its stand. A dedicated solder paste dispensing platform, Essemtec have firmly placed this as a prototyping machine. But none the less, it is an option at the ‘bottom’ end of the market. ( click here for more information). On further enquiry Essemtec say a more suitable machine for production volumes is the CDS6250 featuring the NanoJet. This claims the capability of over half a million dots per hour and is approximately 20% of the cost of the MY500. So if you have a production floor the size of a football pitch and were considering buying the Mydata machine then you could buy four of these and save yourself US$40k!
But despite this technology already having made one false dawn, the fact that the Mydata machine was worth developing for a second generation and other companies are expanding the potential of dispensing systems to use as dedicated solder paste dispensing platforms, implies that this is a part of the surface mount process that could undergo a radical, if gradual, change in the future. And these applications are far more likely to appear in prototyping and low volume, high mix environments than in the ‘lights out’ scenario that was anticipated in the past.
Just as a footnote, we will be closing our win a laptop promotion shortly. If you haven’t done so already, please register (all you need to do is supply your email address) and you can ensure that you receive this newsletter every Tuesday and you stand a chance of winning a laptop computer that we will draw at random from all new registrants.
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