Know Everything About ICT Test Fixtures

ICT Test Fixtures

A device used to check the open and short circuit conditions of individual components and circuit networks online.

ICT test fixture is the abbreviation of Integrated Circuit Tester, which is an on-line inspection and test fixture. It is a standard test equipment for testing the electrical properties and electrical connections of in-line components to check for manufacturing defects and defective components.

ICT test fixtures can be analog device function and digital device logic function test, high fault coverage, for each kind of veneer need to make a special needle bed, this needle bed in industrial production is called it ICT test fixtures.

Functionality

ICT test cure with single-sided and double-sided points, universal ceiling to facilitate the exchange of machine species, the use of adjustable Perrin seat, easy to maintain, the use of acrylic & bakelite & FR-4 material (or specified), direct gerber file processing to generate drilling files, to ensure the accuracy of drilling. The test program is generated automatically, avoiding the possibility of manual input errors Applicable to tri, jet, newsys, okano, tescon, takaya, gwposhell, src, concord, PTI816 and other ICT models. Center distance between two measured points or measured points and pre-drilled holes shall not be less than 0.050" (1.27mm). A distance greater than 0.100" (2.54mm) is preferred, followed by 0.075" (1.905mm). The test points of the fixture should be distributed as evenly as possible to ensure that the board does not change shape after being pressed on to avoid damage to the product.

Functions

ICT test fixtures are capable of checking the electrical performance of in-line components on manufactured boards and the connection of circuit networks. It can quantitatively measure resistors, capacitors, inductors, crystals and other devices, and functionally test diodes, transistors, photocouplers, transformers, relays, operational amplifiers, power supply modules, etc. It also functionally tests small and medium-sized integrated circuits, such as all the 74-series, Memory-type, commonly used driver-type, switching-type and other ICs.

ICT test fixtures detect defects in manufacturing process and bad components by directly testing the electrical performance of in-line devices. Components can be checked for over-value, failure or damage, and Memory can be checked for program errors. For the process category can be found such as solder short circuit, component insertion error, insertion of the reverse, leakage, pin warping, false soldering, PCB short circuit, broken wires and other faults. Test faults are directly positioned in the specific components, device pins, network points, fault location is accurate. Fault repair does not require more specialized knowledge. The use of program-controlled automated testing, simple operation, fast and rapid testing, single-board test time is generally a few seconds to tens of seconds.

On-line test is usually the first test process in production, which can timely respond to the manufacturing situation, and is conducive to process improvement and enhancement. ICT test fixtures tested faulty boards, due to the fault location accurate, easy to repair, and can significantly improve production efficiency and reduce maintenance costs. Because of its specific test items, it is one of the important test means for modernized mass production quality assurance.

Selection of test plates

Test fixtures in the selection of the plate generally have acrylic (plexiglass), epoxy resin plate and so on. Ordinary probe aperture greater than 1.00 mm fixture.

Its plate to plexiglass mostly, plexiglass is cheap, while plexiglass is relatively soft drilling with expansion and contraction of the probe casing and the combination of holes tight, the plexiglass is transparent.

As the plexiglass is a transparent fixture, the problem is very easy to check. But ordinary plexiglass in the drilling of holes is prone to melting and broken drill bit, especially when drilling holes smaller than the diameter of the hole.

Especially when drilling holes less than 0.8 mm in diameter is a big problem, general drilling holes less than 1 mm in diameter are used in epoxy resin plate, epoxy resin plate drilling Epoxy resin plate is not easy to break the drill bit, its toughness and rigidity are good, but the price is more expensive, the epoxy resin plate has no expansion and contraction, so if the drilling hole diameter is not accurate, it will result in the probe sleeve and the hole is very loose between the tube and the hole.

The tube and the hole is very loose between the resulting shaking. Epoxy resin plate is opaque if the fixture problem checking is more difficult, in addition to the plexiglass temperature deformation than the Epoxy resin plate is larger, if the test density is very high need to use epoxy resin plate. The selection of the board and drilling accuracy of the entire test fixture of the precision of the entire test fixture plays a key role.

Fixture base

Most fixture bases are made of bakelite or plexiglass. When measuring PCBAs, there are ESD requirements, and generally ESD materials are selected, such as black FR4, synthetic stone, etc. Bakelite and plexiglass do not belong to ESD materials. Most manufacturers produce fixture base is based on the size of the test plate temporary production, so the quality of the base and the base of the repeated use of the rate is not very good, so it is recommended to unify the size of the base and the standard, equipped with several different standard sizes, so that in the design of the choice will be of great help, do not need to repeat the design of the action part of the fixture. Fixture production should be based on the actual situation of the selection of appropriate materials, which can significantly reduce costs, while the universal reusable base can also significantly reduce costs, and make the standardization of the production of fixtures to facilitate the production and improve the quality of fixtures.

Selection of the box of the fixture

Most of the fixtures have a box under the base to install some electronic devices, we usually choose to make the box material is bakelite, plexiglass and metal, in this part of the box, also standardize the size and standards, and the base to match. In the market there will be some good production of different sizes of the metal box, the price is relatively cheap, in the production can save a lot of time.