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BTU International provides advanced thermal processing equipment and processes to the electronics assembly markets, focusing on SMT reflow ovens and high temperature custom-built furnaces. A wholly owned subsidiary of the Amtech Group, BTU has operations in Billerica, Massachusetts, in the United States, and in Shanghai, China.
In an interview with I-Connect007 at the recent IPC APEX EXPO event in Las Vegas, Bob Bouchard, corporate marketing manager at BTU, talks about the latest developments in their products, how their technology is helping users reduce their setup times, and the impact of Industry 4.0 in the electronics assembly industry.
Stephen Las Marias: Bob, tell us about your latest technologies.
Bob Bouchard: Sure. One of the things that we’ve been working on with our partner, Electronic Controls Design (ECD), is RecipePro. ECD is well known for their thermal profiling and analytical software solutions. RecipePro is a recipe generator tool. The recipe generator is used to create a starting group of settings or what we call a recipe to be used in the oven. It allows a user with limited knowledge about thermal profiling an oven to enter some simple attributes about the PC board, and the recipe generator will create a starting recipe. It dramatically reduces the oven setup for a specific printed circuit. What’s unique about it and how it differentiates us is we have other competitors that actually have a similar tool that they’ve contracted with third parties. One of the things that we found and is critical to the success of a tool like this is that it has the correct algorithms, so the background technology needs to be right. One of the things missing from the competitive solutions is the convection rate for the heat transfer is not included in competitive algorithms.
When we selected ECD to come up with a new tool to do this, we wanted to find a partner that would include the convection rate in the algorithm technology so that we had a more accurate prediction to provide our customers a better tool.
Las Marias: What is the importance of knowing that convection rate?
Bouchard: In a reflow oven, the heat transfer is created by a handful of things. To keep it simple, we have radiation, conduction and what’s called forced convection. Forced convection is the dominant heat transfer method inside the oven that is directed onto the product.
The convection rate, in particular, is one of the major heat transfer components. By not including the convection rate, the algorithm has to use a fixed heat transfer rate that doesn’t reflect the convection rate that’s in the oven. For example, in our systems, the convection is very tightly controlled. Changes in convection can impact a number of things—like the uniformity on the PCB—or it can impact the actual heated zone set points and conveyor speed.
All these things work together, and in particular BTU has a very precise convection control system that creates very repeatable process. From one machine to another, or one site to another, you dial in a recipe in our equipment and it can be transferred anywhere in the world. This is the importance of a convection rate. By changing the convection rate, it allows us to have a very accurate prediction of the thermal profile.
Editor's Note: This article originally appeared in the May 2016 issue of SMT Magazine.