Reflow oven drivers#
Reflow oven code#

This is the quicky ‘oven’ of choice for folks like Sparkfun. Alternativesīefore getting into the hot plate, a short discussion of alternatives. Melting temperature must be exceeded by approximately 20 ☌ to ensure quality reflow. Solder reflow is accomplished in the reflow zone, where the solder paste is elevated to a temperature greater than the melting solder point. The dryout section is used primarily to ensure that the solder paste is fully dried before hitting reflow temperatures.

The most critical point in the preheat section is to minimize the temperature rise rate to less than 2 ☌/second, in order to minimize thermal shock on the semiconductor components. Reflow curves showing safe ranges and results of bad curvesĪ typical profile consists of a preheat, dryout and reflow sections.

Below is a generic reflow temperature curve (courtesy STMicroElectronics): The temperature across the circuit board should be uniform during the phases.The oven must accurately follow the right temperature curve for reflow.GoalsĪ good reflow oven is distinguished by only two characteristics. There’s a startup issue so it’s kind of kludgy but it works reliably.

Reflow oven code#

The source code for the hot plate is here. I ended up with a simple unit made up of a Raspberry Pi controller that used two easy to obtain heating cartridges and the results are outstanding. This is a pretty long article so the results are first. So, I’m building my own reflow hot plate from scratch.Ī reflow oven is a device for melting solder paste on a circuit board such that the paste smoothly melts and surface mount components self-align. I looked into buying a reflow oven but after reading reviews of inexpensive ovens - poor temperature regulation, bad interfaces, dangerous construction - and looking at alternatives (hot plates, toaster ovens, …) I finally just decided that nothing had the necessary attributes. We would also ensure that high quality standards are met at reasonable costs.I’ve been building surface mount circuit boards by hand with a hot air gun. Trying to manage your SMT production? Nex PCB might be able to help.Īt NexPCB, we have the necessary technologies and expertise for your SMT, PCB and PCBA production. This has the benefit of reducing nitrogen consumption during this process.

Today's solder manufacturers are working to develop products with a higher oxygen content that can be well welded without washing the solder paste. Since different welding products require different nitrogen levels, it's important to choose the right flux to match the process, heat and component tolerances. To obtain better welding quality, it is particularly important to use solder paste with less active flux to improve solder joint performance and reduce discoloration. Most of the furnaces used at present are the forced hot air circulation type. (3) Reduces the generation of solder balls, bridging and obtain better welding quality (2) Improves the wetting power of welding and speed up the wetting speed (1) Prevents oxidation in components during heating

Using a nitrogen reflow technique has the following advantages: Since nitrogen is lighter than oxygen, it forces the oxygen to the bottom of the chamber and reduces the exposure of the reflowing parts to oxygen. This is done by pumping nitrogen into the chamber. As the name suggests, this is achieved by filling the reflow chamber with nitrogen during the heating process. This process is mainly used to enhance the weld quality where oxidation can affect the ability of components to adhere to the flux. The main purpose of nitrogen reflux welding is to limit the amount of oxygen in the reflow furnace thereby decreasing the oxidation that is common during this process.

Reflow oven drivers#

These improvements are the main drivers for many of the technologies that we have been discussing in o ur SMT series. With the increase of assembly density and the appearance of fine spacing assembly technology, Nitrogen filled reflow welding processes and equipment were created to increase the quality and yield of reflow welding.