Ehem...(clearing my voice as I climb on the soap box) With tracking efficiency, you are essentially trying to get the most amount of product out of a set of machines that you possibly can. To figure that, you want to know what is theoretically possible and how close you come to theoretical. Since many brands of pick and place machines keep a record of what state they are in, you can query that data and get some eye opening results. I have found that cycle times can be figured three different ways, giving very different results. First, looking at a 24 hour period, how many boards came out of that machine. This is real world cycle time planning should use, and is the ultimate bottom line. This time includes set up time and any decreases in change over will positively affect you cycle time. Second, looking at the time that the line is actually running divided by the number of board produced. This is the cycle time that determines your constraint and paces the line. Third is the time it actually takes for the machine to assemble the board. This is the theoretical cycle time. I'm guessing here, but you probably do 2-3 change overs per 24 hour period. Not using docking carts, change overs could be as high as two hours. Assuming you get it down to 10 minutes, that means you gain 5 1/2 hours of number two time. That would be awesome, and would improve efficiency by 25%. This is probably an extreme case, so adjust the numbers accordingly. However, if you look at the numbers between number two time and number three time (theoretical time), you will typically find a difference by a factor of three or more. This is the "mother load". Your efficiencies are lost by not focusing all attention on your constraint and keeping that machine fed, up and running. In other words, any time the constraint "waits" for product to arrive so it can start working, you have lost time. Any time the machine stops for any kind of error, you have lost time. Any time the machine stops for a feeder to be reloaded, you have lost time. These time losses are only a dozen seconds or a minute or two, but they add up over a 24 hour period. As a constraint, there is no reason that machine shouldn't be able to run continuously at near its theoretical limit. I'm not talking about improving the placement time, just keep that machine busy. By improving the "working" time on your constraint, there is an easy 100% improvement in line efficiency, and it doesn't cost anything. Just an attitude change from management down to the production line to identify the constraint and focus on keeping it working. I have worked in factories where this concept has improved output by a factor of three, therefore I'm extremely sold on it. As far as what is possible, I have seen lines where the constraint was "working" 80% of the time the machine was plugged into the wall. What is realistic... I have heard reports from machine manufactures that the CM industry is at about 20-40% machine working time. Of course, those at 80-90% working time are not high mix, low volume. Not that improving change over time is bad, I just think that attention should be focused on the place with the greatest potential for improvement. Ryan Grant -----Original Message----- From: Howard Watson [mailto:[log in to unmask]] Sent: Tuesday, November 05, 2002 3:47 PM To: [log in to unmask] Subject: [TN] Efficiency / Effectivity of your SMT lines Dear TechNet subscribers, I am curious about the level of productivity of your SMT lines, particularly for those in a high mix environment. We are getting pressure to reduce changeover and cycle times, as I am sure most of you are too, and I am curious as to what level of effectivity (hours available in the day do you actually build product) that you are at. Would 80% be reasonable? Also, how efficient are you at building your product to standards, for those who track efficiency? As far as changing over from one job to the next, what are your average times? It was suggested to me by management that the goal for changeover should be 1 minute or less. I am a reasonable person, and I believe that single digit (SMED) changeovers, like 8 or 9 minutes might be reasonable, but 1 minute is a stretch that I can't see happening, even when using docking carts for the feeders. Thanks in advance for your input. Howard Watson SMT Manufacturing Engineer --------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- AMETEK/Dixson --------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------