Ron: Phil, you have likely visited more assembly factories than anyone I know, hundreds for sure. What are some of your observations on how folks address or don’t address productivity?
Phil: Ron, there are so many bad practices that result in low productivity. More often than not, when we enter the manufacturing floor (for a process audit or other reason) we see a sea of red and/or orange light towers – rather than PCBAs in process. Most managers have no concept of the capacity they are operating at and usually feel that adding another line (with faster equipment) will increase capacity. However, there are three top “sins” that should be addressed – immediately!
The first is set-up time. Unless you’re an OEM building the same PCBA day in and day out, this is something you have to master. And the higher the product mix, the more line change-overs prevail, and the more this impacts throughput. There are a number of things that can be done to “expedite” set-up and they all add up. Any facility with more than one active line can benefit from a systematic approach toward set-up. I tend to favor (and have had excellent luck with) the “Pit-Crew” approach. Note that the operators and set-up crew are working together. Sequential changeover goes a long way: as soon as the last PCBA in a run passes through a machine center the crew commences changing over that machine (stencil, feeders, programs, etc.) rather than waiting for that last PCBA to clear the reflow oven.
Usually, hand-in-hand with this situation is a lack of adequate feeders for the different components that need to be changed over. Having a feeder already loaded with the component and “popping” it in rather than having to remove a reel and replace the component reel goes a long way. Feeder carts go even further. But this costs money and management usually “doesn’t get it”. In fact, we’ve encountered situations where there is such a shortage of extra feeders that, when the tech or engineer discovers that a feeder is malfunctioning, they don’t have a “spare” and are forced to continue using it, continuing to produce defects that have to be attended to (more time, expense, etc.).
Ron: Phil, I have observed similar practices as, noted in my book “The Adventures of Patty and the Professor” .
OK, what is the second sin?
Another common situation is a lack of balance in the line. Particularly predominant in the placement machines, if one machine is waiting a disproportionate time for another machine, the line is unbalanced. Components can and should be shifted from one machine to the other. While most of the placement machines come with software for calculating this, it is very simple math – single variable algebra (like we learned in 8th grade). But the “math phobia” we seem to suffer from is a subject for a different day….
Ron: I agree. The engineers will tell me that the line is balanced, but when I go out to the shop floor and check with my watch, the lines are almost never balanced, even though, in theory, the placement machines will easily handle it.
Now, we are holding our breath, what is number 3?
Phil: I’d finally like to comment on, to use a term you originated, “Floundering Time”. This is where the operator or tech comes across a problem or situation and has no idea what to do. She is not sure of the reporting system and “who to call”. It could be a machine problem, a tooling problem, a component outage, or a variety of other things. But, they all result in unscheduled downtime and severely impact productivity.
That’s just the tip of the iceberg, Ron. But just addressing these areas can improve productivity and cost a lot less than adding another line.
By the way Ron, I know you have thoughts on how materials can affect productivity. What's a top example?
Ron: Obviously the main consideration for materials is that they perform their material function well. As an example, you would want your solder paste to form a reliable solder joint. However, solder pastes can affect productivity. I have seen cases where the poor response to pause of a solder paste was so bad that, if the line was idle for more than 20 minutes, the paste would stiffen up and have to be wiped off the stencil and replaced with fresh paste. These types of issues are discussed in “The Adventures of Patty and the Professor” in Chapters 9, 10 and 21 and can affect productivity and profitability more than you might expect.
Phil, thanks for the nice chat!