![]() ![]() The conductive properties of aluminum in the PCB tray and insulation (Floor & Tunnel Shield II) is more effective at eliminating temperature differentials than moving air. A convection fan is nice to have but most convection ovens are larger, cost more and are more difficult to modify. The oven in this guide may be unavailable in your area, or you may want to use a different oven - perhaps with a convection fan. Tip: click on any photo to see the high-resolution version. The door servo does not use any of the outputs it is controlled separately. In this guide only 3 of the outputs are used: bottom element, top element and boost element. The internal volume is small at 10 liters. There are 2 heating elements - 600W on top and 550W on the bottom. The "low" power consumption means we can add an additional heating element without blowing fuses. It doesn't have a convection fan and the power consumption is 1150W. ![]() These may have different controls, color or handle design but the chassis is the same. Newer ovens works too, like the TO1705SB, TO1750SB and TO1760SS. It was a brand new Black & Decker TO1303SB toaster oven for just $30 shipped! Black & Decker ovens similar to the one in the guide are the TO1322SBD, TO1332SBD and TO1313SBD. If you convert a convection oven, you may need a 20A outlet or a 240V circuit.įor this guide we found a suitable oven on. This give a 10% safety margin, which is fine because it is rare that all elements are on at the same time during a reflow, and reflow durations are short. The oven in this guide starts out at 1150W and a 350W boost element is added. This means that 110V x 15A = 1650W is available, though that should be derated by 20% if the oven is on continuously. Available power - Most USA outlets are rated at 110VAC 15A.Consider using a low-temperature lead-free paste like Chip Quik SMDLTLFP10. Even then, you'll need a lot of insulation and for best performance your should consider buying a 2nd oven and donating its elements to the first. We have done a huge amount of testing on both oven types, and only recommend convection ovens if more PCB space is needed. However, convection ovens are typically much larger and have less power for the volume. Convection fan - there is no doubt that a convection fan is a good thing.Avoid those - you need to be able to control where the heat is coming from. Ability to heat top and bottom independently - some cheap ovens turn the top and bottom elements on together, with no way to control them individually.Also, Controleo3 will limit how much the top element is used to further reduce uneven heating. They are typically shielded with a perforated steel sheet which limits direct radiation. The compromise is to use quartz infrared elements which emit less IR. Commercial ovens use infrared elements, but only to heat the air which is then blown onto the boards. Infrared elements are usually a poor choice because they heat up dark components before lighter or shiny ones. Resistive heating elements are extremely slow to heat up and cool down, and make it difficult to follow a reflow profile. ![]() Type of element - the elements should ideally be quick to heat up and cool down.We add an extra heating element to bring the total power up to 1500W. Power - a lot of power is required to get the right rate-of-rise at high temperatures.Get the smallest oven that will work for you. Larger ovens require significantly more power to heat up. The oven in this guide is just 10 liters. Size - a small oven has less metal and air to heat up (less thermal mass).To choose the right oven, a number of things need to be considered: If you're looking for the Controleo2 build guide, click here.Ĭhoosing an oven to convert to a reflow oven If you use solder paste with a lower liquidus temperature - some go as low as 138☌ - you can get away with a lesser oven. Typically, prototyping conditions should mimic the production environment to avoid mass-produced surprises. This is what is typically used by contract manufacturers making commercial PCB's. This oven is designed to reflow lead-free solder paste with liquidus temperature around 217☌ (max temp around 250☌). It uses Controleo3, a 6-relay programmable reflow oven controller. The entire tray can be filled with PCB's, and all will reflow perfectly. The reflow oven build described here is fully capable of fine pitch lead-free soldering at very high temperatures, and can do it consistently and reliably. Building it yourself will give you a better indication of what to look for, how it works and how to tune it to get excellent results. It isn't difficult to build your own oven, and the result can be equal or better than commercially available ovens. This guide will show you how to build a great toaster reflow oven. ![]()
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