High power desolder station - Page 1
Forum section: electronics / general

author: kaffine
author_rank: Newbie
timestamp: November 05, 2019, 06:23:33 am
content: I am looking for recommendations for a high power desolder station with built in vacuum pump.At work we have been having problems lately with removing through hole parts, we mostly deal with surface mount. Currently we are using solder wick and have hot air tools to preheat the board. In the past I have used Pace desolder equipment and liked it however I wasn't dealing with thick boards with heavy ground planes.We are typically removing multi pin connectors or DC-DC converters. The DC-DC converters typically have 10 signal pins and 4 power pins. It is normal for the boards to have power rails rated for 120 amps or more. This is what has me concerned since I have never used desolder stations with boards with this much copper in them. I know we have a Hakko IR preheater although I have never seen it used normally they just use hot air tools.Thanks in advance.

author: mzzj
author_rank: Super Contributor
timestamp: November 05, 2019, 08:22:34 am
content: In my experience there is no desoldering gun that would be enough alone to desolder thick power boards with super heavy multilayer copper. Worse yet if its already lead-free production.Some telecom power supply boards have been amazingly hard to work. Preheat the board as much as you dare, flux, add solder, desolder, add solder.Never tried but chip-quick style low temperature alloy might help with the most stubborn TH components.

author: Shock
author_rank: Super Contributor
timestamp: November 05, 2019, 03:50:23 pm
content: I'm not sure of the pin size, perhaps attach some images of the board and devices you are removing. Pace also sells thermodrive tips which have more mass up front than the standard desoldering tips.If the thermal dissipation is great enough it can make using any tool challenging no matter what the power. Using a preheater sounds like a solution, it greatly assists all desoldering. A hot air gun alone also tends to heat locally and a lot of the energy is deflected or dispersed. With preheating to allow a greater area to slowly rise, less energy is required from the desoldering tip to bring the target area to melt temp.An alternative is to try slowly bringing the temp up on a variable temp hot air station with the tool mounted in a bracket on an angle or with a broad angled nozzle, allow plenty of time for the heat to soak in. Then use the desoldering tool to come straight in. Or even apply heat from both sides of the PCB if possible with hot air and preheating before desoldering.Ensure there is good contact with the desoldering tip to the pad and a thermal bridge is created. If an oversized tip is used it may miss the pad and heating performance will be reduced. If it's a huge cold ground plane it will likely drag the tip temp down so a high or higher desoldering temperature may also be required, obviously you have to be cautious to prevent PCB damage at the same time.As suggested you could also apply some low temp solder or even leaded solder and flux and freshen the joints, this aids in desoldering. If you get complete melt you also may need to wiggle the pins a bit while vacuuming to break the surface tension around the entire pin.Another trick is to use a solder bath or a custom made desoldering plate.

author: sotos
author_rank: Frequent Contributor
timestamp: November 05, 2019, 04:28:54 pm
content: How about this one.http://www.hakko.com/english/products/hakko_fr400.html

author: PA4TIM
author_rank: Super Contributor
timestamp: November 05, 2019, 05:31:11 pm
content: My Pace MBT250 and SX-100 have never let me down while desoldering big things like a heatsinck soldered to a groundplane. They have special tips desoldering things with thick pins and big groundplanes. I had the SX-70 and that was OK for most stuff but the SX-100 is a totally other class. I use it for repair work and because I also repair defect industrial boards you can not power up and benchtest. For those repairs I often remove a lot of parts to test them out of circuit (IC's, caps, relais, semi conductors etc. I have a lot of component testing test gear) So I do a lot of desoldering. Some days I desolder a few hundered pins and I the last 2 years it was able to desolder everything. Some extreme cases I used a slodering iron for extra heat and often I first add some fresh solder first. For most because I want the lowest possible risk for the PCB.My MBT250 is over 25 years old and 2 or 3 years ago updated it with the SX-100, A new normal handpiece and opened it to clean the pump. It was clean and still like new.I made the mistake a few years ago to buy a Metcal to replace my pace because my SX70 was totally worn but I wore down 2 pumps in 1 year, a desolder handpiece and 2 soldering handpieces. The tips lasted something like 2 months and their warranty is very very very bad. My pace tips last a whole lot longer. I use 8 different sizes but the most used one last over a year.

author: Smith
author_rank: Frequent Contributor
timestamp: November 10, 2019, 09:37:55 am
content: Maybe a Weller WR3M rework station or equivalent? Served me right for years. When it comes to really big obnoxious ground planes and SMD components with power pads (with only rarely happens) I use the WHP 3000 pre-heater. I use it to pre-heat anywhere from 75-125C depending on the components and board type.Remember you can also use a fast soldering iron instead of a high power soldering iron. I use a very small 50W Weller WRMP that easily solders components on reasonably big planes compared to the 80-120W giant irons I used before. The temperature of the Weller drops a little, but goes back up again in seconds. The older irons seemed to take much longer to heat back up to operating temperature.

author: kaffine
author_rank: Newbie
timestamp: November 16, 2019, 03:30:02 pm
content: Thank you for the suggestions.One of the common supplies we use is an Ericsson BMR456 it has 10 signal pins and 5 power pins. Sorry I don't have a picture of one of the boards. Other parts they will just cut the pins on then remove the pins one at a time, these supplies they normally cant reach the pins to cut them.It is lead free solder.

author: Shock
author_rank: Super Contributor
timestamp: November 17, 2019, 01:38:50 am
content: Difficult to remove multiple pins through vacuum desoldering when the interconnecting side is partially surface mounted and the pins are a tight fit. If you had side access you can use tweezers to greatly improve the heating of individual pins with vacuum desoldering, preheating additionally effective.That is always the scourge of multi pin removal, I think if you are dealing with multiple sweated joints you are going to have problems unless you reflow all of the pins at once and then you have to smoothly separate the boards.Yes I think it can be vacuum desoldered but it's a question of if it can be cleanly desoldered that way. If you encounter those problems and replacement pins can be be sourced I'd consider the destructive route to be more effective.