Placement capability: an update of IPC's Surface-Mount Equipment Characterization standard sets the record straight.Looking back at articles published in Circuits Assembly over the last couple of years, one in particular captured my attention and prompted me to give readers an update on a currently developing standard: IPC-9850, Surface-Mount Equipment Characterization. What it Does IPC-9850 exists to standardize stan·dard·ize v. 1. To cause to conform to a standard. 2. To evaluate by comparing with a standard. the parameters, measurement procedures and the methodologies used for the specification, evaluation and continuing verification of assembly equipment characterization parameters, while maintaining a placement accuracy to placement speed relationship. The standard also provides standardized standardized pertaining to data that have been submitted to standardization procedures. standardized morbidity rate see morbidity rate. standardized mortality rate see mortality rate. reporting documentation. The standard simplifies the evaluation process by standardizing the performance parameters describing a placement machine's capabilities. Placement throughput and quality are coupled, so speed and accuracy parameters are dependent on each other. IPC-9850 also specifies the methodologies by which capability parameters are measured--reducing potential user/vendor friction created when the user believes the equipment is not functioning properly. While the standard's ultimate goal is to evaluate a machine's capability to place components in paste on printed wiring boards (PWBs), such measurements at the required precision and speed cannot currently be obtained. Many anticipate that future in-line inspection systems will improve the ability to measure component location and orientation. What it Doesn't Do Due to the convergence of high-speed and fine-pitch machines, the standard makes no attempt to separate machines by placement type or function. The user can decide if a particular model is the best solution for the application based upon needs and the data reported by the supplier. The standard is comprised of a set of parameters representing the lowest common denominator low·est common denominator n. 1. See least common denominator. 2. a. The most basic, least sophisticated level of taste, sensibility, or opinion among a group of people. b. for surface-mount placement equipment. One must recognize that additional metrics may be of value in certain instances. This core set may change in future revisions as technology dictates. Simply stated, the IPC-9850 data is the bare minimum--users and equipment vendors may find value from additional metrics. The standard cannot address every possible combination of hardware and software features unique to individual machine types that exist--too many exist. Such features and options affect the overall value of a specific equipment model, and the user must understand all options. Standard Component Types One goal of the standard is to assess the error induced by the placement machine. To isolate the contribution of the surface-mount equipment to placement error, other effects, which may contribute to the placement error evaluation process, must be reduced. Five component types--QFP-100, QFP-208, BGA-228, 1608C capacitor capacitor or condenser, device for the storage of electric charge. Simple capacitors consist of two plates made of an electrically conducting material (e.g., a metal) and separated by a nonconducting material or dielectric (e.g. and SOIC-16--were selected to represent a minimum range of component types typically placed by surface-mount equipment. Using components with nearly perfect dimensions and shape can best reduce the effect of components on placement error evaluation. Such components minimize the error associated with surface-mount component-to-component variation. For instance, 1608C capacitors were chosen as test components because the sides of the capacitors are very precisely and squarely fabricated fab·ri·cate tr.v. fab·ri·cat·ed, fab·ri·cat·ing, fab·ri·cates 1. To make; create. 2. To construct by combining or assembling diverse, typically standardized parts: . SOIC-16 integrated circuits Integrated circuits Miniature electronic circuits produced within and upon a single semiconductor crystal, usually silicon. Integrated circuits range in complexity from simple logic circuits and amplifiers, about 1/20 in. (1. were selected because of their relatively low cost and sturdy construction. These components are believed to be representative of a broad class of coarse-pitch leaded surface-mount components. Almost all surface-mount placement machines are capable of processing SOIC-16 devices, and this component allows the user to compare the performance of various machine models. For the standard, one ball grid array “BGA” redirects here. For other uses, see BGA (disambiguation). A ball grid array (BGA) is a type of surface-mount packaging used for integrated circuits. (BGA (Ball Grid Array) A popular surface mount chip package that uses a grid of solder balls as its connectors. Available in plastic and ceramic varieties, BGA is noted for its compact size, high lead count and low inductance, which allows lower voltages to be used. ) and two quad flat pack (QFP (Quad FlatPack) A square, surface mount chip package that has leads on all four sides and comes in several varieties. PQFP (Plastic QFP) may refer to all of the following QFP types. All quad flatpacks use gull-wing leads, except for the CQFP, which stick straight out. ) slugs See State and local government series. were selected. Specifically, the QFP-100, QFP-208 and BGA-228 components permit the comparison of an extended range of chip-shooters with that of specialized IC-placers and multifunctional placement systems. IPC-9850 was circulated for industry acceptance balloting in late 2001. For more IPC (1) (InterProcess Communication) The exchange of data between one program and another either within the same computer or over a network. It implies a protocol that guarantees a response to a request. Standards updates from IPC's Annual Meeting in Orlando, please visit www.circuitsassembly.com. Jack Crawford Jack Crawford may refer to:
|
|
||||||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion