Chemical machining of copper
Abstract
Copper and its alloys are major engineering
materials that is extensively used particularly in
electronics industry due to their eletrical properties.
The importance of these materials attracted many
researches for investigating various production
methods. Chemical machining is one of them. This
machining process is widely used in various
industries to produce complex components from flat
materials. The process is called controlled corrosion
operation of workpiece material in acidic or alkaline
environment. The major advantage of chemical
machining is the manufacture of high precision parts
in a short machining time with low production cost.
Moreover, the process does not need a special tool
and product parts are burr free. However, chemical
machining is not environmentally friendly machining
process due to chemical etchants which have advers
effect on environment. This problem is almost
overcomed by using regeneration of waste etchant
and recovery of etched material simultaniously.
The chemical machining of copper is vital process in
the electronics industry. It is a major production
step in the manufacture of printed circuit boards.
Various chemical etchants can be used to shape in
chemical machining of copper, one of them is cupric
chloride (CuCl2). The advantages of this etchant
over other etchants are numerous; high etch rate,
compatible with etching maskant, cost effective,
possibility of etched material recovery and full
regeneration of waste etchant. These properties
make the etchant possible the most environmetally
friendly chemical solution in the chemical
machining of copper.These properties make this
etchant more attractive in case of chemical
machining of copper.
In the present study, chemical machining of copper
with CuCl2 was examined. The selected material
was 99.9% pure copper (DIN EN 1652). The
experimental study was completed in beaker as
immerse chemical machining method. The selected
etchant concentrations and temperatures were 2.04,
2.33 and 2.65 Mol; and 30°C, 50°C and 70°C.
Most of the parameters were related to literature
survey, but the highest temperature (70°C) was not
widely used. The prepared etchant solution was
placed on hot plate with magnetic stirrer. The
chemical machining temperature was kept at ± 2°C.
The total machining time was 20 mins and each
measurement of thickness and surface
roughness were taken at every 5 mins.
The aim of this study was to examine the effects of
selected etchant concentration and temperature on
depth of etch and surface roughness in chemical
machining of copper. It was concluded that etchant
concentration is important factor on depth of etch,
higher etchant concentration increased depth of
etch. Surface roughnes was affected by etchant
concentration and temperature.
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