Beta Layout reflow kit, first experiences

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Beta Layout reflow kit, first experiences

Postby JuKu » Tue Aug 28, 2012 10:06 am

As noted in the "what did you buy" thread, I decided to get my own reflow facilities. I bought:
Beta Reflow Kit: http://www.beta-estore.com/rkuk/order_product_details.html?p=13
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The controller for it: http://www.beta-estore.com/rkuk/order_product_details.html?p=242
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and a vacuum pick-up tool: http://www.pcb-soldering.co.uk/aoyue-932-vacuum-pick-up-station.html
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I bought some leaded solder paste, too. In my lab, I like to work on lower temperatures. Besides, I think a 300€ SMD line might not be as tightly controlled as the factories I'm used in the past, so it is good to have some leeway here.

First the vacuum: Ok for the price, but sucks too much. The local aquarium store sold me a magnetic valve and the local electronic store a footswitch, so less than 100€ and some work I have tool that ready-made would have cost me about 500€. I'm happy with that, even though I needed to file the end of the suction needle to fit my hand angle and squeeze it to third of the original size so it does not eat 0603 parts.

The oven and controller should be seen as one unit. The controller can be programmed with several soldering profiles and you can tune the parameters. And you should, the oven does not heat or cool very fast, therefore the set times are not very accurate, even though there is a "learn" feature on the controller. The "kit" adds some experimental boards, a stencil, some parts, paste etc. My first real board board will be fairly complex with 200€ worth of parts on it. I didn't want that to be the first try, so I bought the kit.

I haven't done a teardown nor do I plan to. The build quality of the oven is what you expect from a sub-50 pizza oven. But it works, good enough. The controller is just as you see, a plastic box. The packaging and instructions is fine, so there is some care put in to the product. I connected the supplied multimeter, my Extech and the controller temperature sensors to a scrap board and run some tests. all the meters appear to show similar temperatures and the controller sensor seems to react the fastest. After I came to this conclusion, I used the controller temperature readings.

It took me several tries to get the profile close to paste manufacturer specification. But there were no issues, the controller is able to log the temperatures to serial port in a format that excel has no trouble plotting curves, so it only took a couple of hours before I was ready to try a board. (The oven needs to cool between cycles.) Buying the kit was a good idea, I feel confident about my work flow now. (For example, I realized the vacuum would suck in 0603 components only at this stage...)

If you search "beta reflow" on YouTube, you'll find some videos about the kit and how to put paste on the sample board. I did just that and baked the board. Most of joints were perfect. The SOIC part did not sink in to the solder as much as I would have liked; maybe my profile is not perfect yet? More soak time? More reflow time? A bit higher reflow temperature? We'll see; I'm sure I'll get it perfect after a few real boards. The test result was good enough that I'll do a real board tomorrow.

There was also some small loose solder balls. I think there was too much paste on some of the pads, but it looked that way to me from the beginning. I would not have put that big pads on 0805 or 1206 parts.

Bottom line: about the cheapest SMD system you can buy, so it is not perfect. But value for the money is excellent. The purchase pays for itself tomorrow when I build first real board with it. That board is complex enough that I would not do it by hand. Without this system, I would have paid more that the price of the kit for assembly of this one board alone. This is perfect for my few boards per year.
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Re: Beta Layout reflow kit, first experiences

Postby JuKu » Wed Aug 29, 2012 10:28 am

Update: First real board turned out to be perfect, as far as soldering goes. No touch up required, other than for one poorly placed resistor. I wouldn't have noticed anything unusual if I would have got that board back from a real factory. Very happy! :)
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Re: Beta Layout reflow kit, first experiences

Postby bearmos » Thu Aug 30, 2012 7:00 am

Hey Juku, thanks for the overview. It's always nice to see what others are doing in this space.

Do you have any screen shots of the captured temp profiles (or excel sheets), details on where the temp probes were placed, etc? I'm always curious to see that kind of stuff.

I'm glad your first board worked out. I can't remember - what do you use for dispensing solder paste (syringe or stencil)? If you use a stencil, what material do you use and who's your favorite source?
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Re: Beta Layout reflow kit, first experiences

Postby JuKu » Fri Aug 31, 2012 12:57 am

bearmos wrote:Hey Juku, thanks for the overview. It's always nice to see what others are doing in this space.

Do you have any screen shots of the captured temp profiles (or excel sheets), details on where the temp probes were placed, etc? I'm always curious to see that kind of stuff.

This is the recommendation (Amtech NC-559 paste):
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After few tries, I decided this is close enough, and I didn't bother to to tweak it anymore. This is assuming the temperature reading of the controller is accurate (I have no reason to believe that there are significant measurement errors):
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When tuning the oven, I used a similar size scrap board. I put a piece of wire trough holes of that, and attached the sensor to the board, like shown in the controller manual, page 8: http://www.beta-estore.com/download/rk/RK-10215_212.pdf. When soldering, the scrap board and the real board were both in the oven.

I'm glad your first board worked out. I can't remember - what do you use for dispensing solder paste (syringe or stencil)? If you use a stencil, what material do you use and who's your favorite source?

No way I would try to put paste manually with a syringe to 1000+ pads! :) (I said it was fairly complex...) This was my first board with this method, so I don't have a favorite stencil source yet. I first placed an order to http://www.smtstencil.co.uk/, but his printer broke. I was getting in a bit hurry, so I ended up getting the first stencil from the same place where I got the PCB, http://www.eurocircuits.com/, 49€ for a 195 x 140mm steel stencil.

(The stencil method turned out to be so easy, with perfect result! Assuming the polyester stencil guy gets back to business, I consider syringe method to be rather foolish. Ok, maybe, just maybe if your board is very simple (say, 50-100 pads), and you happen to have the tools (I have no reason to buy them). For me, there is no room between the stencil+oven method and hand soldering for a syringe. See http://www.youtube.com/watch?v=4gFVkOptv-c to see the system in action. My first board was exactly like that, except it had 450 components on it.
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Re: Beta Layout reflow kit, first experiences

Postby SAElectroNerds » Fri Aug 31, 2012 5:30 am

Grrr, just lost my previous post so here is my second effort. Thanks for the report JuKu, you helped make my mind up as I was considering getting one of these Reflow kits. Luckily Beta LAYOUT have recently set up shop in Cape Town as it's near impossible to order internationally from South Africa. And I think I will also get the controller.
Anyhow, just wanted to let you know that you can also get a free stencil if you order PCBs from Beta LAYOUT via their PCB POOL service online. Yes, 100% Free stainless steel stencil and they will even give 2 stencils if there are SMDs on both sides. I've used them a few times now and although they are cheap (compared to local suppliers) the quality has been perfect. I assume they offer the same service in the UK. Thanks, Paul.
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Re: Beta Layout reflow kit, first experiences

Postby bearmos » Fri Aug 31, 2012 6:59 am

Thanks a lot for the graphs Juku, this is really encouraging.

JuKu wrote:No way I would try to put paste manually with a syringe to 1000+ pads! :)

I tried it once, since someone recommended it, and found that I preferred hand soldering.

It sounds like the stainless steel stencils are the way to go for fine pitch components (based on the size of the size of your board and number of components, I'm guessing you had some very small SMD's). I've only tried using a stencil on one set of boards, using Mylar - I had to rework all of the 0.5mm pitch QFN's.
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