| 摘要 |
A method for determining the quality of metal coatings of hole units in a circuit board. Well centered hole units are punched and secured in a container provided with grooves, said holes being aligned, whereafter the container is filled with material for moulding-in the hole units. Thereafter the hole units and filling material are milled down to alignment with the centers of the holes, and the material is milled down additionally around the holes so that the hole unit centers have raised portions. The raised portions comprising the hole plating are thereafter ground and the latter can be examined. The invention also concerns apparatus for performing the above-mentioned method.
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