The Cost of Doing Business - IPC

By Laura Oppenheimer

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Lead-free SMT reflow ovens can cost tens of thousands of dollars, and that's only for the oven itself. Inputs, energy requirements, cooling systems and labor also contribute to the overall cost of running a reflow oven and keeping it in top shape. By understanding the daily costs of using one of these machines, companies can make more educated choices about the type of machine that best suits their needs.

The Initial Purchase

It's worth it to take some time to research an oven before diving in and making a purchase. A cheaper oven can cost as little as a few thousand dollars, while a more technologically advanced and fully loaded machine can more than $100,000. It's important to know what you are getting for your money, says Jim Hall, a principle consultant with Durham, N.H.-based ITM Consulting.

"The reality is there's a lot of inexpensive ovens coming out of China," Hall says. "They look nice on the outside, but there's a concern they aren't going to function as efficiently as U.S. or German models." By researching your needs upfront, it's possible to save money in some areas in the long term. The type of product you are manufacturing can help determine how much initial investment you should make. A toy manufacturer, for example, may have different quality requirements than a medical equipment manufacturer.

The Inputs

With the complex work SMT reflow ovens perform, it's no surprise the necessary inputs don't come cheaply. Mark Peo, president of Florham Park, N.J.-based Heller Industries, estimates an average oven accounts for $1 to $2 per hour in electricity costs, a few cents per hour for exhaust, and between $4 and $6 per hour in nitrogen costs.

Nitrogen adds significant costs to running an oven. While process requirements, not the oven, determine the necessity for nitrogen, some ovens utilize nitrogen more efficiently than others. Hall recommends avoiding nitrogen when you can. "Often nitrogen is a Band-Aid [for non-optimized materials and processes]," Hall explains. "You should only use nitrogen if you absolutely have to." If nitrogen is required, it's important to determine the purity level required by your specific process. It might be possible that a lower purity level of nitrogen (for example, 500 ppm instead of 100 ppm) could provide a finished product of equal quality.

In addition to the inputs needed to run the ovens, there are additional requirements to ensure they run smoothly and properly. Some ovens need a water chiller, which cost about $5,000. Finally, "ovens create heat and emit heat and exhaust air from the production floor, so in many ways, they create an air-conditioning load," Peo says. Although it's difficult to quantify the amount of additional air conditioning needed to keep things cool, Peo estimates it could add an additional cost of $500 to $1,000 per year.

Spend Now, Save Later

Hall says keeping cost-saving measures in mind during the initial investment for an oven can significantly cut costs down the road. "An oven at a low price might have a much higher operating cost," Hall says.

At the same time, a more expensive oven will do a much better job of handling nitrogen loss. "You can spend an extra $10K, $15K, $20K, and that money will be paid back quickly," Peo says. "There's a definite return on investment with nitrogen."

Another area where an initial investment may save money in the long term, is with exhausting. Hall says optimizing an oven by minimizing exhaust flows is the best and sometimes only parameter an operator can adjust to save money when running their oven.

Peo also recommends investing more money upfront on a flux collection system, which can save on overall cleaning costs. With less cleaning time required - eight hours per week - a company can not only save money on cleaning man-hours, but also can manufacture eight hours of additional product.

Ultimately, reliability is most important in choosing an SMT reflow oven - reliability that you sometimes, but not always, can find by paying a little bit more upfront. And if that saves some money in the daily costs of running a reflow oven down the road, it's an added bonus.