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Printed Circuit Board Terminology
Published in Robert P. Hedden, Cost Engineering in Printed Circuit Board Manufacturing, 2020
After fluxing, the actual soldering takes place by hand, dip pot, or wave-solder machine. Hand soldering uses a soldering iron and a piece of core solder or a preformed shape of solder. A variety of wattages and iron tips are available and must be matched to the task. Hand soldering may be used to repair or touch up individual joints that are faulty from automated soldering. Also, some components cannot stand the heat or cleaning process used with automated or dip pot soldering. In the dip pot method the board is placed in a hand holder and the lead side is placed on the surface of the pot of solder. Skill and dexterity are required by the operator. An automated wave-solder machine includes a flux applicator. Boards are placed in a holding fixture (pallet) and then on a moving track in the machine, which carries them over the flux applicator and over a solder wave. The solder wave is molten solder pumped to form a wave. There are various theories and designs of solder waves to achieve ideal soldering.
Installing and Using the Hybrid Assembly
Published in Fred W. Kear, Hybrid Assemblies and Multichip Modules, 2020
The printed conductors on the thick-film substrate are relatively durable and will permit desoldering and resoldering of components with very little risk of failure. However, good repair procedures should be used to remove and replace components. This includes the use of soldering irons with the correct wattage rating. The soldering iron tip should be kept clean and tinned. Solder should be wicked from the joint before an attempt is made to remove the component. Proper tools should be used to grasp the component as it is detached from the substrate. Needle-nose pliers or forceps are suitable for this task. Force must not be used to remove the component, but rather it should be lifted free after the solder is removed or melted. In some cases, component spacing or other layout constraints may preclude complete removal of solder before the component is lifted. If done with care, this is an acceptable procedure.
From Circuit Schematics to PCB
Published in Julio Sanchez, Maria P. Canton, Embedded Systems Circuits and Programming, 2017
Julio Sanchez, Maria P. Canton
Although more difficult than through-the-hole parts, surface-mount components can also be hand-soldered to boards and adapters. For this purpose, the general-purpose soldering iron is not suitable and its use will only lead to damaged components. The soldering must be performed with a temperature-controlled station with a temperature readout. Additionally, it is necessary to use special soldering tips that are designed for SMT pins and have the adequate form and dimensions. These are usually furnished with the soldering station or are available separately from the station manufacturer. The following items would be required in a minimal toolkit for soldering SMT components: Temperature-controlled soldering stationSoldering tips appropriate for the SMT typeSolderSoldering flux and flux removerSpecial heat gun for desoldering componentsDesoldering wick (braided)Exacto knifeWater in a spray bottleTin foil heat shieldMagnifying glasses and 10X jeweler’s loupeA steady hand
Small chamber study of lead exposures from manual soldering of microelectronics
Published in Human and Ecological Risk Assessment: An International Journal, 2021
Brent D. Kerger, Anne E. Loccisano, Russell Gerads, Matthew J. Glassman
The set of ten nitrile finger cots and two nitrile gloves from each trial were removed using clean nitrile gloves and transferred to two separate acid-cleaned plastic bottles for outside laboratory determination of Pb mass adhered (including parallel analysis control gloves and cots). The chamber was cleared of equipment following each experimental trial, and visible solder debris was collected into a sample vial with the aid of a Kimwipe for later determination of total mass and particle size distribution. The chamber floor was wiped for analysis of any remaining residues (or small solder debris) with a pre-certified batch of lead-free Ghost Wipes, which was transferred to an acid-cleaned plastic bottle for Pb mass determination. For each trial, the solder debris on the tip cleaning sponge was manually separated for determination of total mass and particle size distribution of dross removed from the soldering iron tip during the intensive soldering activity. Samples were labeled and shipped to the lab under chain-of-custody documentation. There was no attempt to quantify the Pb mass deposited on interior surfaces or bulk items other than the chamber floor, the cleaning sponge, and the finger cots and gloves.
Small-angle measurement in laser autocollimation based on a common-path compensation method
Published in Journal of Modern Optics, 2019
Yan Guo, Haobo Cheng, Yongfu Wen, Hengyu Wu, Yumin Wu
Among the many air parameters leading to the beam drift, the temperature is dominant according to the Edlen formula (25). A heat source can generate a circular temperature gradient field around itself. The closer the heat source is, the faster the refractive index of the air medium changes. When a light beam passes near a heat source, the direction of the beam will bend with the change of the refractive index, and then the drift will occur. To test the compensation effect for the temperature-induced drift, the electric fan was turned off and replaced by a soldering iron. The experiment was performed as soon as the soldering iron was energized. The soldering iron was slowly heated to 200°C in the first 40 min, and then a fluctuation range of ±1°C was maintained over the next hour. The compensation results are presented in Figure 8. In the first 40 min, the red drift curves shown in Figure 8(a) and (b) significantly increased or decreased by approximately 3 arcsec, and then changed in a relatively gentle manner by less than 2 arcsec. Throughout the measurement process, the PV values of the angular drift of the TM in the x- and y-directions were 3.581 and 5.137 arcsec before compensation, while 0.154 and 0.193 arcsec after compensation, respectively. It can be seen that the angular drift caused by temperature was more severe than that caused by the air current, particularly in the y-direction. With compensation, the measurement stability was increased by 95.7% and 96.2% in the x- and y-directions, respectively. In this experiment, the compensation rates were higher than those in the air current experiment.
Using conductive fabrics as inflation sensors for pneumatic artificial muscles
Published in Advanced Robotics, 2021
Arne Hitzmann, Yanlin Wang, Tyler Kessler, Koh Hosoda
In this section, we will elaborate on the final production process of our design. Figure 3 illustrates the key steps during production. One of our sensors is created by the following steps. First, the conductive fabric is cut to the appropriate length for a given muscle circumference. Through empirical trials, we found that a well-performing length of EeonTex LTT-SLPA-20K is 5% shorter than the empty muscle's circumference plus 6 mm for the bonding area. Next, an area of 3 mm on one of the short edges is covered with adhesive before the fabric is folded, and the bonding area is clamped for curing. After the adhesive is cured, the now gauntlet-like sensor can be turned inside out, producing a smoother seam. In the next step, two magnet wires are prepared by removing the enamel with a soldering iron. This method leaves a rough surface on the wire, which makes the fixation in the next step easier than sanding off the enamel. The two wires are then stitched into the fabric, leaving a gap of 1 cm. The gap size of 1 cm was chosen as it could be considered to be a unit size of one. The resulting test specimen also fits very well into our motorized test stand mount. While other gap sizes are possible, to allow for sensors with comparable feedback, the distance should be the same on all sensors. To secure the exposed ends of the magnet wires in the fabric, conductive adhesive that can cure at room temperature (KAKEN TECH TK Paste CN-7120) is then used to bond the magnet wires to the fabric. After the adhesive has cured, the sensor can be sheathed over the PAM. Due to being intentionally undersized, no additional measures are needed to secure the sensors on the PAM.