LGA QFN soldering without hot air station on already populated board. Help? - Page 1
Forum section: electronics / projects

author: BurnedResistor
author_rank: Regular Contributor
timestamp: October 01, 2016, 04:50:44 pm
content: Dear All,A while back I designed a PCB that contains a number of very tiny lga and qfn packages. More specifically:MPU9250 (Super tiny 3x3mm 24 pin qfn imu)MCP2200 (20 pin qfn usb to serial bridge)MPL3115A (A relatively large LGA 8 pin absolute pressure sensor)and a microusb port that has the two main support pins under the connector.And then my cheap chinese hot air rework station broke.The problem is, that half the PCB is already assembled with an arm processor, a zigbee module, and a million small capacitors, resistors and other chips. Buying a new hot air station is out of the budget right now as I will not buy another crappy cheap one.Any ideas on how I could get these parts onto my PCB?Regards,

author: stj
author_rank: Super Contributor
timestamp: October 01, 2016, 05:10:54 pm
content: you fix your cheap hot air station.

author: BurnedResistor
author_rank: Regular Contributor
timestamp: October 01, 2016, 05:29:30 pm
content: Quote from: stj on October 01, 2016, 05:10:54 pmI wish, something in the controller smoked, left a hole in the pcb, and the heatgun burned out.Beyond Economical Repair...As much as I agree that a cheap rework station would be a solution I would much rather put that money into the "Get a good hakko in 2 years" fund!Any other ideas?

author: ovnr
author_rank: Frequent Contributor
timestamp: October 01, 2016, 05:58:26 pm
content: If you don't care about melting things by accident? Buy a cheap heat gun.

author: KL27x
author_rank: Super Contributor
timestamp: October 01, 2016, 07:59:17 pm
content: In US, 858's are <33.00 on eBay, shipping included. Got mine in 3 days. I have it as backup. Seems like a no brainer, if your expensive first-line hot air station ever needs servicing/maintenance/repair. Assembly was inserting the holder. Two screws. Very satisfied... even if I never end up using it.Sure I have other ideas. But top of the list would be to buy a hot air station. Your board and your time is worth more than that. But if you must have it completed today, you could spend 3 hrs doing hot plate method by trial and error. God forbid it doesn't work on the first try, though. haha. Removing parts by hot plate doesn't sound as convenient.Anyhow, you can buy more expensive, but it doesn't mean it is better. A hot air device is a toaster with a fan/pump. Evolution has spoken. 858 is the pinnacle of efficiency, regarding cost and ergos and utility. I'm convinced it will be around for the next 20 years, at least. Time tested design is at least as good if not better than smart design. At the price, is easy to maintenance a 858. The customer service/support is bar none. Buy a new one.

author: nctnico
author_rank: Super Contributor
timestamp: October 01, 2016, 08:29:25 pm
content: I second the suggestion for the Atten 858D+. I bought an extra one in case the one on my desk fails.

author: KL27x
author_rank: Super Contributor
timestamp: October 01, 2016, 08:46:06 pm
content: Of course, I have no idea what one costs in Austria.At the current US cost, anyway, I don't know if I will ever fix/service a hot air station, again.

author: stj
author_rank: Super Contributor
timestamp: October 01, 2016, 09:05:53 pm
content: 858's on ebay are about 45Euro