Reflow Ovens

I'm thinking of buying one of these "T962" reflow ovens. It looks like they all come from the same place, but are resold by a thousand different guys, all named "Honest Chen". I have visions of getting some piece of Chinese crap and no satisfaction about getting things fixed if it breaks.

Here's a link to an example on Amazon:

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Has anyone out there got one of these? Did it work?

And most importantly -- does anyone know of a place that ships these from the US, and backs them from a place staffed by US citizens, or at least people with US green cards?

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Tim Wescott 
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Tim Wescott
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Den torsdag den 12. februar 2015 kl. 01.31.10 UTC+1 skrev Tim Wescott:

afaict most say it is crappy but will work

this one is a bit and seems to get better reviews

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how about a hot plate

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less stuff that can break

I doubt it, at that price what you see it what you get and if it doesn't work you have to fix yourself it or bin it

-Lasse

Reply to
Lasse Langwadt Christensen

You do know how small 180 x 235 in millimeters is, right?

Reply to
DecadentLinuxUserNumeroUno

Hi Tim,

I bought one, but did not get good results. I only managed to burn up a few boards. It could have been (probably was) operator error on my part.

I settled on one of these:

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from which I've had good results. It's large and flat with only a slightly raised rim near the edge. For double-sided boards I use the hotplate for one side and hot air on the other side.

ChesterW

Reply to
ChesterW

I have the 962-A, the larger version. I actually have 2 of them, one for a spare. I have run 100s of boards through it of various sizes and layer counts. A few cautions, operational tips:

1) You cannot use the full size of the tray. Subtract at least an inch from the total dimensions so you have about a 1/2 inch on both sides. If your boards are less than, say, 9x10 (962A) you probably wont have any issues. 2) You need to run a "warm up" cycle before the first board. It will help with temp control. 3) You will most likely have to program your own profile. It's not hard to do but does take some tweaking. I use Amtech 4300LF which works well with a pretty straight line ramp to liquidus and then a 240C peak. 4) I have not been able to get reliable results with large bulky EMI filters. Maybe I could use a longer pre-heat early on. 5) Ramp to temp and then board soak for a long duration does not work well. I just use a linear ramp for the 4300LF. 6) Component height might be an issue. There are a couple of thermocouples that hang down from the top. I'd have to go measure but it is only an issue if you have very tall components. 7) Double sided boards are no problem. Of course it's a 2 pass procedure. 8) The firmware keypad debounce is a little flaky. 9) Dont open it up unless you really want to see how the sausage is made. The control board is nicely done but the rest of the unit is, well, China. There is really not much in it. There is the control board and keypad,LCD up front with connections to the thermocouples. Connections to a couple of SSRs in the back that control the exhaust fan and the IR lamps (4 of them). There is a small fan that runs all the time that provides airflow for the control board. 10) Dont expect this thing to hold +/- a few C of the temp profile. It's not a megabuck oven. 11) It does work for me. I load a board, hit the go button and come back about 6 minutes later when the thing is beeping at me.

As far as shipping goes, both units I got were very well packaged and worked right out of the box. I'd have to go back and look to see who I bought them from. One may have been ebay the other alibaba. The user manual is typical Chinese converted to bad English. There is enough there to make it work and program it.

If you want a phone number you can call and get support you are way above the price range of these things. You are going to spend $400 to $500 to get one of these to your door. Or you can spend a few thousand on a better unit and get some support or you can DIY but how much is your time worth.

I could have DIY'd a setup for a lot less but for me, I had the money and cobbing together a reflow oven using a toaster oven was not high on my bucket list.

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Chisolm 
Republic of Texas
Reply to
Joe Chisolm

I use a big GE toaster oven, and a thermocouple ramp-and-soak temperature controller. I poke a micro-sized thermocouple into a through-hole on the board to measure the actual board temperature.

Temperature uniformity is a bit of a problem, one corner of the oven always runs a little colder, so sometimes I have to reheat a few pads on the corner of the board that was over there. I usually run 6 or 8 small boards in the oven at once, or it can handle one up to 8 x 11 inches.

Jon

Reply to
Jon Elson

For double-sided boards, I do them twice. I have a piece of stainless wire about 3mm diameter bent in a rectangular ring, this sits on top of the sliding grill in the toaster oven. I apply the solder paste and do the P&P on the back side, reflow in the oven, then repeat for the front side of the board. Only trick is to make sure the board has cooled to less than 120 C or so before removing from the oven, to be sure all back-side component soldering is well below solidus temp, or you can disturb the back side components.

The ring of stainless wire was sized such that most boards sit on it with the back side components touching nothing. I've never had a back side component fall off when reflowing the top. I do NOT use any glue for back-side parts.

Jon

Reply to
Jon Elson

What model, and is it convection or plain ol'?

Given how my toast comes out in the mornings, I was worried that uniformity would be more than a bit bad with a toaster oven.

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Tim Wescott 
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Tim Wescott

I looked at those, and some reviews, which were horrorshow -- masking tape used to hold things in place, so the first few runs were smoky and stinky... A number of recommendations to basically disassemble and reassemble the unit before use doing things such as replacing masking tape with kapton.

I settled on a $30 on-sale Black & Decker toaster oven from Target. I added pieces of adhesive-backed auto exhaust heat shielding from the kid's stash of car stuff. Runs on an arduino-based PID controller using a k-type thermocouple in the oven. Reasonable results, stay away from the edges.

I like being able to see the boards; I put heat shielding tape on most of the glass door leaving a slit about 3/4 inch high to view what's going on.

Total investment on the project was around $60 -- the toaster oven, I2C thermocouple interface SSR and heatsink, k thermocouple in stainless shell.

Reply to
artie

I tried a toaster; everything soldered great but when the board popped up at the end, all the bits flew off.

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John Devereux
Reply to
John Devereux

Model doesn't matter, as you won't be able to get the same model, I bought this one 7 years ago. Although the front says GE, the bottom says WALMART model 169055, so it must be made only for Walmart. It does have the convection fan, but I have not been able to tell much difference between on and off.

It has two linear elements left to right across the top, and two on the bottom. I set the selector so it uses all the elements.

While uniformity is not perfect, the central area is QUITE good. If I stuff the whole oven with boards right to the edge, then the right rear corner runs a little cooler, and I sometimes have to touch up the board that was there.

The trick is to poke the controller's thermocouple into a plated through hole in the board. Without that, the boards overheat greatly while the thermocouple senses air temp which lags way behind the heat absorbed by the boards. I learned this trick the first time I tried it.

Jon

Reply to
Jon Elson

Mine works fine, the button response time is a little iffy, and takes getting used to, but so far no problems, and at the price, I could buy another one while waiting for parts for a broken one.

Reply to
WangoTango

I have a broken toaster you could try. ;)

Cheers

Phil Hobbs

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Phil Hobbs

Ian from Dangerous Prototypes went over to China to acquire a Qinsi QS-5100 (

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). Qinsi doesn't answer my emails. (They may not understand English.) Here's what Ian says about T-962s:

The T-962, commonly found on eBay for around $300, is slightly larger than the Qinsi QS-5100. Both the Qinsi and the T-962 use only two infrared heating tubes. Two seem barely enough for the smaller work area of the QS-5100, so we chose it over the T-962. The larger Qinsi with 4 tubes and greater vertical separation between tubes and boards probably heats more evenly. Given unlimited money and space we'd choose a four tube oven instead.

Some mention (and others, and others) that various T-962s exhaust bad fumes, timers are off by double or more (5 minutes becomes 12 minutes), menus are buggy, buttons are not debounced, or that the heat doesn't ramp up fast enough. These were all nagging concerns we had buying this oven, but we have not run into a single one of these issues.

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Reply to
Don Kuenz

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