Electronics Forum | Wed Jan 29 17:19:50 EST 2003 | albertoh
Hello!! I need to know the land pattern specs for a melf resistor with dimensions length 0.415(+/-0.02) and width 0.144 (+/-0.008) inches. Because i have tombstone problem. My stencil design is 10 mils thickness in order to avoid the issue but it hel
Electronics Forum | Thu Jun 26 07:44:07 EDT 2008 | kmeline
Hello, we are having issues with two assemblies where the Melfs will lift or not solder on one end of the components. Has anyone had issues with this in the past? What can be done to help this? Thanks
Electronics Forum | Thu Jun 26 08:20:42 EDT 2008 | cyber_wolf
Check your pad spacing on the board. Look at the IPC specs for pad design.
Electronics Forum | Thu Jun 26 09:33:11 EDT 2008 | realchunks
Yes, try slowing it down. It will indicate if your ramp up is too fast.
Electronics Forum | Thu Jun 26 09:47:12 EDT 2008 | kevinjm
Hi Mark, Are these lead free parts on a leaded process? If so, that could be your problem. We had the same issue in my place a while back.
Electronics Forum | Thu Jun 26 07:53:39 EDT 2008 | realchunks
Depends on a few variables. Could be the part, your profile, your paste, your stencils..... many things affect it.
Electronics Forum | Tue Nov 27 10:56:42 EST 2001 | jmathis
Hello, Our company has been successfully using Loctite 3612 for screen printing glue. Resently there has been a HUGE issue with the melf components falling off or tumbstoning during the wave process. It's apparent that these components were cured
Electronics Forum | Tue Nov 27 11:24:55 EST 2001 | jmathis
Only the melf's. These PCB's are in pallets, so there should not be a obstruction issue. Thanks for the responce.
Electronics Forum | Tue Aug 24 16:11:21 EDT 1999 | Scott Cook
| Hello everyone, | We found many cylindrical diodes missing during SMT process. Could someone tell us how to prevent this problem? Is it effective to change the shape of stencil apture or reduce fan speed in reflow oven? Thanks in advance. | | Gyve
Electronics Forum | Thu Jun 26 09:09:27 EDT 2008 | kmeline
The pad size is okay. I have also requested the manufacturer's recommend reflow profile. I have seen some issues with 0402 caps that we run also but for the most part solder paste does okay. I think the cap issues is stencil related. Still trying to
