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Frequently Asked Questions - Conventional

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Black residues are any combinations of flux, plating wear particles, lubricant, and or contaminants from the environment. Unless these contaminants are extremely heavy or washed down into the probe tube through improper cleaning, the black residues do not adversely affect the electrical resistance of the probe. As a fixture is cycled, air is continuously drawn across and into the probes. Contaminants in the air and from the Unit Under Test (UUT) collect on the probes’ surfaces and by combining these with the plating wear particles formed during sideloading from fixture cycling, create a black residue. By maintaining filters in wave soldering and reflow ovens and by using filters on the vacuum release port and covering the fixtures when not in use, contaminants will be reduced. Maintaining fixture alignment, selecting the proper point style for the intended contact, and performing proper probe and fixture maintenance will reduce sideloading.

The 120°C temperature limit is for lubricated probes. The temperature limit is increased to 204°C by selecting an unlubricated probe that is assembled with stainless steel springs.

No-clean fluxes can be hard and very abrasive. Steel tips, due to their increased hardness (58-60 HRC) over BeCu (38-42 HRC), will remain sharper longer and resist abrasion better than BeCu. Note that not all tip styles are available with the steel (-S) option.

No, they are designed to remove headed probes only. These tools are ideal in cases where a large number of headed probes must be removed quickly without damaging the probe. For headless probes and probes on closer centers, tweezers or miniature precision long nose pliers are recommended. Care must be taken when removing probes that are to be reused as pliers and tweezers can damage the plating and or bend the plunger.

The -D stands for decreased stroke. When a -D option is selected in these series, the total stroke is reduced from .400 [10.16] to .250 [6.35]. This is accomplished by using the springs from their .250 [6.35] stroke counter part series. This option is used when longer reach probes with higher spring forces are required.

In probe designs where the spring is highly stressed, the mechanical life is reduced. All of our probes are routinely cycled in a controlled environment to the mechanical life indicated. When running probes in a production environment there are many factors that will reduce the life cycle expectations of a probe such as: contaminants on the UUT and in the environment, side-loading during actuation, damage to the probe’s tip, plating, etc. These factors make it virtually impossible to determine how long a probe will last in a specific test environment. The best method to determine probe life is to monitor probes in the test environment and to develop a maintenance program for your specific application.

Yes, the tail is a gold and nickel plated phosphor bronze part and is easily soldered to. When feeding solder onto the tail, care must be taken not to flow additional solder into the socket/tail junction. This junction is also a soldered connection. Flowing additional solder into this joint will cause solder to wick into the bottom of the socket either causing a probe to be soldered into the tube or preventing a probe from being fully installed in the socket.

Yes, although not recommended, the probe tube can be directly soldered to the termination. Probe tubes are typically made from nickel silver and this material is easily soldered to. Precautions must be taken to prevent the solder from flowing into the probe tube ID. Solder in the probe tube ID could cause the plunger to stick or prevent the plunger from compressing fully (not obtaining full plunger stroke). This application is common when installing probes directly into PCB’s or similar.

No, the pin is press-fit into the tube, so even without solder holding the pin, it takes a minimum of 10 pounds (of axial force) to move the square pin and about 1 pound to move the round pin. After the socket cools, the solder will solidify and the integrity of the joint will remain unchanged.

The main difference is that the 050-R25 Series has a longer overall length 1.700 [43.18] versus 1.362 [34.59] for the 050-T25 Series. The increased length allows springs with a higher force and longer life to be installed in the probe tube. As a result, the maximum spring force for the 050-R25 Series is 10.1 oz [286 gms] versus 8.0 oz [227 gms] for the 050-T25 Series.

In general, any nonconductive material is suitable with the most popular socket mounting plate made from an epoxy fiberglass AT7000, G10 or FR4. This is the same material used in the manufacturing of printed circuit boards. Other suitable materials include but are not limited to Acrylic, polycarbonate, PVC, and Delrin. The socket retention forces will vary between materials and must be considered in fixture design.

There is no maximum recommended voltage limits for test probes and sockets. However, the spacing between the probes and the dielectric properties of the probe plate must be taken into consideration. Avoid probe plate materials that have hygroscopic tendencies. Finally, the voltage must not be present while the probes are actuating against the DUT as arcing will occur, damaging the probes tip contact surfaces.

The B option for QA test probes is designed for use with the old style Pylon brand sockets that do not incorporate a probe retention indent in the socket body. Because the Pylon socket was basically made up of a straight tube, the –B (bend) in the probe is the retention method to hold the probe in the socket. As a general rule, we do not recommend that the –B option be used with QA sockets as our sockets incorporate probe retention indents in the socket tube. For older sockets where the probe retention indent has been damaged, or if the probes are loose or are being pulled out during test, using the –B option is a suitable solution until a permanent repair to the socket can be made.

A: Yes, Hipot testing is an abbreviation for High Potential Testing and is also called Dielectric Withstanding Voltage (DWV) test. This test applies an over voltage condition to the device and is used to verify that the electrical insulation in the device does not break down and is sufficient to protect the operator from electrical shock in PCB’s, transformers, electric motors, finished appliances, cables or other wired and wireless assemblies. When test probes are used as the interface between the Hipot Tester and UUT, the following are recommended:

  • The probes must be contacting the terminals on the UUT and compressed before the test is run.
  • The probes must not be retracted from the UUT until the test is complete and the voltage has been cut off.
  • Any contaminants between the tips of the probes and UUT will act as insulation causing high resistance at this junction. In-turn, the higher resistance will cause localized heating and possible arcing at the tip.
  • Sufficient distance and or insulation between the conductors must be maintained to prevent the electricity from arcing between the bare plungers.
  • Over time, the sliding plated surfaces will degrade faster compared to low voltage applications and may require increased maintenance.
  • Use the largest probe you can with High to Extra High spring forces.