SMD & SMT Rework Pre-heater        Bottom-Side Pre-heating       Ramping & Preheating for Soldering & De-Soldering

1996 "Vision Award" Awarded to Zephyrtronics for
the AirBath™
 "Best New Product of the Year"

Real Preheat Power Now in Compact Units: We've heard the your voices! Our engineers have now packaged our patented preheating technology into two amazingly powerful, yet compact systems. Packing more than double and triple the preheating air volume capacity than any other small profile pre-heater on the market, our new ZT-1-CLS AirBaths™ are available from Zephyrtronics.

Two Compact Models: Digital & Analog!  Our ZT-1-CLS Compact AirBaths™ are available in two popular choices:

The ZT-1-CLS-DPU Deluxe Digital AirBath™ packs over 15CFM (430 liters/minute) of forced-convection preheat power: Over 3 times preheating/post-cooling™ power of others in its size and class!

And the ZT-1-CLS-MIL Analog AirBath™ which, while not quite as powerful as the Deluxe Model, still packs over a whopping 10 CFM (285 liters/minute) of forced convection preheating and post-cooling™ which is up to twice the output of other compact pre-heaters in size and class.

Key to PCB Preheating:  Successfully preheating a PCB is done, not with higher temps of low-volume preheated air, but lower temps with effective volumes of preheated air. Beware of imitative pre-heaters with less than 10CFM (285 liters/minute) that crudely attempt to compensate for their lack of air volume with higher temp settings! Keep in mind that the critical glass transition of a FR-4 PCB is only 170°C (338°F)! You don't want higher preheat temps, you want a higher volume of safe preheated (100°C to 170°C) air for your PCB's. (See more below.)

More Details:

* Please note that our T-Series of ABC Adjustable Board Cradles only fit the two CLS-Compact AirBath™ Preheaters shown on this web page and will not straddle our larger AirBath™ Preheaters which utilize our standard (larger) ABC Cradles.

Loaded With Premium Features: The ZT-1 AirBaths™ get into all the nooks and crannies of the PCB assembly where hot plates and IR pre-heaters can't go (more below).  It is ESD-safe; features illuminated indicator lights (blue: cooling; red: preheating); it is self-contained with an internal air supply (no hookups); all inside a  durable, steel housing for industrial use and long production life.

Critical Thermal Ramping: The ZT-1AirBaths™ have the industry standard, built-in temperature ramping at 2° to 4°C per second preventing thermal shock to sensitive chips, ceramic caps and glass diodes. The ramp is "built in" by design into every Zephyrtronics AirBath™ Preheating System. Our ramping was essential to Motorola® and Boeing® with their space applications.

The Many Benefits of Preheating Your PCB: The benefits from preheating are multiple and compounding. 1.) Preheating or "soaking" the assembly prior to initiating reflow helps to activate the flux, removing oxides and surface films from the leads and pads to be soldered, thereby enhancing the wetting process and solder joint quality.  2.) Preheating the board permits lower soldering reflow temperatures.  3.) Preheating reduces the final "dwell time" during the final reflow stage.  4.) Preheating reduces thermal stresses to the PCB substrate and its components when localized reflow is made with soldering irons, de-soldering tools and hot air systems. 5.) Preheating provides the thermal boost needed when working with RoHS lead-free solders without damaging the work!

For Thru-Hole, SMT & BGA Preheating Tasks: The The ZT-1AirBaths™ are ideal for all PCB challenges from low-volume production runs, prototyping during design or during rework with all component packages such as BGA, CSP, QFP, QFN, TSOP, PLCC, SOIC, SOL, LCC, Flip Chip and Glob Top components. And it easily handles all substrates including FR-4, polyimide, composites, flex circuits and ceramic boards.

Zephyrtronics' AirBath Spotlighted in Ray Prasad'sText
"Surface Mount Technology"

Comparing The 4 Methods of Preheating:

Pre-heating PCB assemblies falls into four categories: Use of hot plates, use of ovens, IR systems, and the use of forced convection (warm air) up under the PCB: While any preheating of your PCB's prior to solder reflow is certainly better than none, an objective analysis of the various methods of preheating quickly reveals that all preheating methods are not equally effective or beneficial:

1.) The Oven: The use of an oven to pre-heat the substrate before reworking and initiating solder reflow for either removal and/or replacement of components can yield the most uniform temperature profile as it warms both the top and bottom of the PCB assembly as ovens also do in high volume production equipment such as conveyor ovens and wave solder machines. But obviously, it's just a wee bit problematic to crawl inside an oven to preheat a PCB while your perform selective soldering or desoldering tasks on one side of the board. Of course, one can preheat in an oven and then race with it in your high-gloved hands back to the bench, but it's hardly a solution either.

2.) The Hot Plate: The obvious limitation to the hot plate is that not all PCB assemblies are single sided. In fact, in today's world of hybrid and mixed technologies, the PCB that is entirely flat or plane on one side is an exotic and rare creature indeed. PCB's typically can carry heat sinks, connectors, jumpers and transformers on both sides of the substrate. These uneven surfaces on the board present an indirect path of heat conduction from the hot plate to the board assembly.

3.) The IR Preheater: There are many drawbacks to IR which is why it really never completely caught on. That is not to say that, as with hot plates,  there are some applications that work with IR pre-heaters.  Some of drawbacks which have been enumerated in articles in SMT Magazine, Circuits Assembly and in white papers at electronic conventions are the difficulty in ramping temps (some are better than others); shadowing caused by high profile components on PCB's; and if the IR preheat grid is very large it can make working on small PCB's very uncomfortable for the technician (this is a very common complaint). Still another great disadvantage to IR preheaters is that they can not ever truly be "temperature controlled" without the technician having to always pre-assemble an external thermocouple into every board before working on it. And that's a continuous hassle and headache replete with quality pitfalls, questionable temperature readings, and problems with inconsistent results. There are more, but these are some of the key setbacks.

NASA & JPL: 'IR Preheaters Are Risky': Addressing the critical preheating process during rework of plastic and other heat sensitive components in their 49-page published report, two JPL engineers, Dr. Rajenshuni Ramesham and Dr. R. David Gerke, wrote "Hot plates and infrared preheaters are not recommended for this type of rework. The reason that they should not be used is that the thermal reaction times, energy transfer rates and efficiency are never consistent. However, they can be used for large metal and ground-plane boards in limited applications, e.g., where the size of the board matches that of the preheater in area." And citing the late William Scheu, the authors pointed out the superiority of bottom-side forced convection preheating systems. Moreover, the NASA Survey by JPL spotlighted still more of the deficiencies of IR preheating devices: "They (IR preheaters) have little capacity to ramp and soak to perform properly engineered repair scenarios or to support the creation and application of complicated thermal profiles. They also are limited in their ability to preheat beyond the physical dimensions of the heating surface. Hot-air preheating can be ramped, soaked and, on some systems, synchronized with the reflow process, permitting duplication of the actual profile used in manufacturing the assemblies. BGAs and photoelectrical parts are sensitive to higher temperatures and any attempt to preheat with marginally controllable sources is risky."---NASA & JPL: Survey of Rework Methods & Equipment for Various Packaging Technologies." -- August 2005.

 A Comparison of Two Popular PCB Preheating Methods