In some manufacturing applications, accuracy up to 99% is not of high value, and a dispense of 0.10 gram of material on one product and a 0.101 gram dispense on the next product rolling down the assembly line doesn’t matter all that much.
However, for some applications, especially those where maximum speed and premium quality is vital, such a high degree of variation could lead to a lot of expensive scrap and costly downtime.
Such was the case for a large multinational electronics manufacturer that recently contacted Techcon. Working to meet the demand for a hot new premium electronic device, they had high-speed potting lines going in several facilities throughout Asia, and on each line at each facility, the problem was the same. They were using a series of time/pressure valve dispensers, and from product to product on the line, the volume of silicon being dispensed varied from inadequate to overflowing.
In fact, their extensive quality control procedures were rejecting device after device where not enough silicon entered the cavity, leaving the printed circuit board assembly on the innovative new product open to prying competitive eyes as well as vulnerable to vibration damage in shipping and in use. And, they also found themselves continually having to reject devices where the silicon was actually oozing out of the case, making the product unsalable and even creating a clean-up need on the line. To compensate, they were frequently stopping the lines to adjust settings, but, with lowered yields and high waste levels, they knew that they needed a better solution long term.
Variations in viscosity don’t have to be a problem anymore
As folks familiar with dispensing applications likely conjectured, the environments were subject to ambient temperature and moisture fluctuations, a very common issue. In an open system like a time/pressure valve, this can wreak havoc on the consistency of the flow of any material, changing viscosity—and the resulting size of the bead dispensed—minute to minute. And, since these valves—and all dispensers for that matter—are unable to compensate, a wide variety in the amount of material dispensed each time is the inevitable result.
The exception is the progressive cavity pump. It differs dramatically in operation from a time/pressure valve, which is simply an “open and close” type of mechanism—whatever volume of material has happened to flow into the cavity during the set time interval is what the pump dispenses when it fires. As a result, variations can be as high as ±5%-±10% or more, which was the variation this manufacturer was being challenged with.
The progressive cavity pump works differently. It is a closed system with the precise volume of material fed under positive pressure to a series of rotors/stators, and so it is impervious to changes in viscosity or any other variables that can impact dispense volume. Indeed, whether dispensing anything from plain water to high viscosity materials rating 300,000 centipoise or more, dispense rates have been shown to be up to 99% accurate, which is what this company quickly enjoyed, instantly increasing their yields and slashing their scrap rates.
Vigorous testing beforehand proves out ultimate success
Well, I say “instantly,” but, truth is, there was some reasonable degree of “prove out” time invested beforehand. Like many strategically run companies, especially large multinationals, this organization needed to be sure of the efficacy of a new potential solution before making such huge changes to their global production infrastructure. This started with a demo at our facility using the Techcon progressive cavity pumps and the actual silicon material in use at their facilities. The results were excellent, so this was followed by a six-week test run at their main factory, and only when these results were also excellent—the difference was clearly night and day—did they implement the progressive cavity pumps on all of their mass production lines. By now, they are running several hundred pumps at every assembly line throughout Asia and the results are universally outstanding—consistently meeting up to 99% volume goal over thousands and thousands of devices.
It is also worthy of note to mention that, although it was the demonstrated consistency that drove their evolution to these pumps, they are finding that some other factors are working to further increase their yields. For example, since progressive cavity pumps are continuous flow, they no longer have to stop the line to refill the material, as they did with the incumbent time/pressure pumps. Further, although flow rates don’t need to be constantly tweaked as they were before, the occasional need to do so can be accomplished by adjusting the motor speed on the controller, so the operation doesn’t have to be stopped for that either, further ensuring against downtime.
Are progressive cavity pumps for you?
Progressive cavity pumps are in successful use in dozens of applications at industrial facilities around the world, not just in electronics manufacturing but in medical, aerospace, and automotive production facilities, and many more. The common denominator is a desire for dispensing consistency where such tight tolerances will help increase yields and minimize waste, and certainly there is no shortage of such premium, quality-focused products being manufactured in these industries and many others.
If this is something that seems like it might solve a challenge in your facility, contact Techcon now to find out more and test out samples. Issues are rare, but for highly corrosive fluids, for example, stator material must be considered, so this type of vetting and pretesting is definitely something we always encourage. And, we are glad to work with you on it. Just give us a call and let’s get rolling.