Best DIY reflow oven controller? - Page 1
Forum section: electronics / general

author: irpheus
author_rank: Contributor
timestamp: August 20, 2019, 09:30:05 am
content: Hi all,I have a likely "simple" question that I hope you may help answer.As it is I am considering making a DIY reflow oven and I would like to be able to control temperatures across the surface(s) and the temperature profile quite well.It seems to me that the controleo3 is a controller that is well-considered, and by default I would use this one, but if there are better/cheaper alternatives I would appreciate hearing about it.Thanks for any help in thisJesper

author: Gary.M
author_rank: Regular Contributor
timestamp: August 20, 2019, 08:40:31 pm
content: I can vouch for ControLeo. Most important is the oven you convert. It needs to be very well insulated and have plenty of power. Convection, which mine has, helps. And if I didn't say it already... Insulation and power.

author: mrpackethead
author_rank: Super Contributor
timestamp: August 20, 2019, 09:34:42 pm
content: The controller is only part of teh story. You need a really good 'oven' as well. Vouch for what Gary said. Lots of power.I rewired my first one, so it ran 4000W.

author: irpheus
author_rank: Contributor
timestamp: August 21, 2019, 10:41:26 am
content: Hi both & thanks for your feedbacksAs it is I intend to make the oven from scratch likely with an internal insulation similar to this which is mechanically stable and also an excellent insulator with a quite low heat capacity so that it can also be cooled quite rapidly:https://www.vitcas.com/ceramic-fibre-board?gclid=CjwKCAjw1_PqBRBIEiwA71rmtQRSp5bEAQOuECJj7HKwxywG5vxKAOoLqEtCVP9-5tx2ECFpocZfcRoCdboQAvD_BwEI would then cover the entire oven probably with either wood or a thin steel plate - mainly to prevent the ceramic insulation from "dusting" as it is in itself rigid. The front would have a cut-out for a glass plate.The heating would be scrapped heat plates - top and bottom - from a ceramic kitchen stove with a perforated aluminum sheet in-between to ensure equal heat distribution. The temperature sensors would then be mounted in the aluminum plates e.g. together with a bit of stainless steel wire so as to make them movable. This way they can be placed in relevant spots just over the PCB to be reflowed.One open design aspect though is convection or not convection ... ? I likely can mount a blower on the top plate which will then blow down through the perforated aluminum sheet. I reckon it could be used to cool the PCB after having reached the max reflow temperature. I would guess though that the perforated aluminum sheet in itself would ensure equal heat distribution across the PCB surface (also given that there likely would be two heat plates both top and bottom). But I do wonder if this convectioncoolingis actually needed ... ? Any of you have experience with this?Cheers,JesperCheers

author: TIOUK
author_rank: Contributor
timestamp: August 21, 2019, 07:55:50 pm
content: Fiber board is fragile, will crack over time. I would always use bio-soluble blanket, it's safer and a better insulation value as it's less dense. I covered my oven with aluminium foil and kaptan tape and put the stainless cover back on the oven.If you need extra heat add something like thishttps://www.ebay.co.uk/itm/6-x-COMPLETE-KITS-JACKETED-FOOD-SAFE-GANTRY-HEAT-LAMPS-300W-BULBS-LIGHT/140973042068mines been going strong for a couple of years.Don't know about the ControLleo, I used one fromhttp://reflowcontroller.com/the only positive thing I can say is it was cheap. As long as you don't include the MS Office software needed to load a profile and no, I've not had any luck with libreoffice. Don't even understand the need for excel, it should be a simple two column csv list of time v temp as that's all you need in the spreadsheet. Apart from that it has an interesting idea for a school boy interface, you need to load the profile speadsheet every run, you can't get rid of the unused temperature displays when not using a 10mv/C probe (pt1000?), but that's all they seem to be as they don't effect the ramps and the graph displaying the profile temperature axis gets narrower each time you run it until it looks like a piece of 8mm paper tape with a wiggly line on it!Don't let me put you off buying though, you may like the idiosyncracies, it's only $50. Nearly forgot, you'll need to but a very small screwdriver for the 0.1" pitch screw terminals, so a couple of $$ for that too.

author: irpheus
author_rank: Contributor
timestamp: August 22, 2019, 04:32:35 am
content: Hi TIOUK,Thank you also for your feedback ... sounds very interesting with the bio-soluble blankets although I still would prefer it to be a fibre board (I haven't any experience with the one I'm using cracking. It is normally used for pizza ovens - also outside I think - so I reckon it is quite sturdy). Doing an internet search I found bio-soluble fibre blanket and boards from Silca (www.silca-online.de) but they don't seem to have distribution in Denmark. Can you say what brand you use - or if you should happen to know of one that is distributed in Denmark I'd appreciate hearing about it ...Thanks also for mentioning the light bulbs ... I will keep them in mind should the heat plates for some reason not work.And then your description of the reflowcontroller actually made me smile... Not least the thing about the graph getting narrower ... I reckon it may not be that funny using it but - admittedly being an outsider - I couldn't help but smile. Anyway, I don't think it would be something for me, then. I prefer the controller to just simply work all the time without any hassles.Cheers,Jesper

author: Gary.M
author_rank: Regular Contributor
timestamp: August 23, 2019, 01:02:00 am
content: You need elements that heat quickly and cool quickly. Hence quartz elements. The oven has to ramp up fast, and the elements shouldn't retain heat.It will be much easier to buy a bench top pizza oven with quartz elements (at least 2kw in total) and convection and adapt that.ControLeo kit is what I used. The result is very good indeed.Sent from my MI 8 using Tapatalk

author: Gary.M
author_rank: Regular Contributor
timestamp: August 23, 2019, 01:07:35 am
content: My oven is very similar to this one. This already had ceramic fibre insulation between the outer skin and oven wall on top and one side. With the material in the ControLeo kit and some additional ceramic fibre board this oven achieved a rating of over 90% in the ControLeo benchmark assessment.https://www.noelleeming.co.nz/shop/whiteware-kitchen-appliances/kitchen-whiteware-and-white-appliances/ovens/benchtop-ovens/breville-bov845bss-the-smart-oven-pro-brushed-stainless/prod139393.htmlSent from my MI 8 using Tapatalk

author: irpheus
author_rank: Contributor
timestamp: August 23, 2019, 05:48:44 am
content: Hi Gary,Thank you also for your input & suggestions. Hmmmm ... I happen to have a quite capable CNC mill so making things from scratch in many cases is a time-saving solution compared with buying something that I then have to adapt - and where I may not place and mill some of the parts in the CNC. And I think that if I have ceramic insulation as the innermost material - and e.g. use distributed nichrome wire as the heating elements, or a stove heating plate - then the overall heat capacity of this setup could be very low.Quote... That is good to hear... Of the solutions I know of I'm also most inclined to use the Controleo kit.Cheers,Jesper

author: Gary.M
author_rank: Regular Contributor
timestamp: August 23, 2019, 06:24:21 am
content: A stove heating plate is completely the wrong choice. It is slow to heat, and stores energy. You will never track the required profile with it...Sent from my MI 8 using Tapatalk

author: Zucca
author_rank: Unknown
timestamp: August 23, 2019, 12:10:21 pm
content: Quote from: mrpackethead on August 20, 2019, 09:34:42 pm3 phases 380VAC?

author: SWR
author_rank: Regular Contributor
timestamp: August 23, 2019, 09:21:21 pm
content: Quote from: irpheus on August 20, 2019, 09:30:05 amI don't know the Controleo3 so I can't compare it, but the cheapest thing that comes to mind is a $3 ESP32 interfacing directly to a bi-metal temperature sensor using the LNA. The LNA was earlier documented but removed in the later manuals, but you can Google it. The cold junction temperature could be made with an NTC resistive divider into an ADC channel, and a 25A SSR with 3V input can be controlled directly from a digital output.I paid $1,65 including shipping for a 25A SSR on Aliexpress, but even if you don't need 25A keep in mind that these are "chinese" amps - somehow they don't compare to european amps, and you'll have to derate it quite a bit. It works ok for 10A = 2300W where I live.The cheapest 230V to 3,3V supply i could find was $0,90 for 700mA on Aliexpress.The ESP32 will give you WiFi and Bluetooth so you can make a nice UI with an app on your phone. Otherwise you'll have to add UI components.