Self-cleaning lower contact
View Patent ↗An electrical component handler that tests electrical circuit components and includes a self-cleaning lower contact offers reduced yield loss and mean time between assists. A preferred embodiment of the electrical component handler includes multiple sets of upper and lower contacts, each set of which is spatially aligned to electrically contact a single device-under-test (DUT). Each DUT is seated in a test plate that transports the DUT to and from a test measurement position between the upper and lower contacts. The lower contact includes a contact tip that a biasing mechanism urges against the electrical component as it undergoes a test process and against a surface of the test plate as it transports the electrical component. The lower contact rubs against the test plate, thereby contributing to removal of contaminant material acquired by the contact tip during component handler operation.
1. A contact assembly configured for use in an electrical component handler and performance of electrical measurement of electrical components, the electrical components seated in a component holder that has a surface and advances relative to a contact tip of a contact element to successively place the electrical components in contact with the contact tip to perform the electrical measurement and to impart sliding contact of the surface of the component holder against the contact tip when none of the electrical components is in contact with the contact tip, comprising:
a housing having a length and an interior slot formed along the length of the housing, the interior slot defined by interior walls that form bearing surfaces;
a contact element sized to fit in the interior slot and slide lengthwise in the housing along the bearing surfaces, the contact element including opposite ends, one of which terminating in a contact tip formed of electrically conductive contact tip material; and
the electrically conductive contact tip material exhibiting wear characteristics such that, in response to the sliding contact of the contact tip against the surface of the component holder as the component holder advances to successively place the electrical components to perform the electrical measurement, the electrically conductive contact tip material undergoes removal and thereby results in purposeful progressive shortening of the contact element to present a refreshed electrically conductive contact tip to the electrical components during the performance of electrical measurement.
2. The contact assembly of claim 1 , in which the contact tip has a sloped edge that provides a slide ramp for the electrical component.
3. The contact assembly of claim 1 , in which the other one of the ends of the contact element terminates in a contact tip formed of electrically conductive contact tip material exhibiting wear characteristics such that, in response to the sliding contact of the contact tip against the surface of the component holder as the component holder advances to successively place the electrical components to perform the electrical measurement, the electrically conductive contact tip material undergoes removal and thereby results in purposeful progressive shortening of the contact element to present a refreshed electrically conductive contact tip to the electrical components during the performance of electrical measurement.
4. The contact assembly of claim 1 , in which the contact element has a length and includes a slot having a slot length that extends along the length of the contact element, the slot length defining a travel limit for the contact element when it is placed in the housing.
5. The contact assembly of claim 1 , in which the housing has an end surface into which a chamfer is formed adjacent an edge of the interior slot, the chamfer providing a ramp along which an electrical component can slide away from and not catch on the edge of the interior slot.
6. The contact assembly of claim 1 , in which the housing is formed as a one-piece unitary article.
7. The contact assembly of claim 1 , in which the housing includes first and second component parts of complementary shape that, when assembled as a unitary article, form the interior slot.
8. The contact assembly of claim 7 , in which the first and second component pans are in the shapes of generally cylindrical segments.
9. The contact assembly of claim 1 , in which the contact element constitutes a member of a set of multiple contact elements, the housing includes a set of multiple interior slots formed along the length of the housing and defined by interior walls that form bearing surfaces, and the interior slot constitutes a member of the set of multiple interior slots, the multiple interior slots sized to receive different ones of the contact elements.
10. A double-sided contact element configured for placement in a contact assembly of an electrical component handler and performance of electrical measurement of electrical components, the electrical components seated in a component holder that has a surface and advances relative to a contact tip of a contact element to successively place the electrical components in contact with the contact tip to perform the electrical measurement and to impart sliding contact of the surface of the component holder against the contact tip when none of the electrical components is in contact with the contact tip, comprising:
a body including first and second opposite end portions terminating in respective first and second contact tips, the first and second end portions being of generally rectangular cross-section, and each of the first and second contact tips formed of electrically conductive contact tip material exhibiting wear characteristics such that, in response to the sliding contact of the contact tip against the surface of the component holder as the component holder advances to successively place the electrical components to perform the electrical measurement, the electrically conductive contact tip material undergoes removal and thereby results in purposeful progressive shortening of the contact element to present a refreshed electrically conductive contact tip to the electrical components during the performance of electrical measurement.
11. The contact element of claim 10 , in which each of the first and second contact tips has a sloped edge that provides an electrical component slide ramp.
12. The contact element of claim 10 , in which the body has a length and includes a slot having a slot length that extends along the length of the body, the slot length defining a travel limit for the contact element when it is placed in a housing.
13. The contact element of claim 10 , in which the body includes a resilient body portion positioned between the first and second end portions.
14. The contact element of claim 10 , in which the first and second end portions constitute opposite distal ends of a unitary body portion of generally rectangular cross-section.