Wire-erosion is a machining process that cuts metal by
creating an electrical spark between the workpiece and a thin
brass wire. As the wire moves along a computer-controlled path
the spark removes material, similar to cutting with a very thin
piercing saw but without the mechanical contact.
We can cut thicknesses up to approximately 150mm. Very thin
materials may need to be sandwiched in layers to increase
rigidity and prevent them from deforming.
We can cut through a stack of sheets to produce multiple
identical items. This can work out more economical in many cases;
however, the increased thickness of the stack increases cutting time,
and so the extra items are not zero cost. There is also a limit
to the size of the stack, particularly for items with small
holes and apertures.
The heat generated by wire-erosion is very localised and does
not cause a general work-hardening of the part. It may cause the
production of a small amount of tarnish on the metal surface that
is easily removed from most metals.
You are welcome to supply your own metal. We do not hold
stock of precious metals and so you would need to supply those.
We can supply other metals if required; however, certain
materials may have extended lead times and can therefore delay
production. Advance payment may also be necessary.
A 0.3mm diameter cut can produce fairly detailed work. While
internal corners will, by necessity, have a small radius,
external corners will remain sharp.
Some paths cannot be cut because the workpiece itself may
become too fragile as the supporting material is removed. Other
designs may fail because the material that falls away when an
internal hole or aperture is cut may get trapped within the
machine. If a design seems problematic then we will advise you
beforehand.
The approximate width of the cut is 0.3mm. This material is
reduced to microscopic particles by the process and cannot be
reclaimed. While we do try to retrieve all other scrap some small pieces may get flushed into the filtration system. Also, if holes or apertures have to be cut in the workpiece then this
material may be lost as swarf.
All scrap metal is available for collection from our
workshop. Non-precious metal scrap is not automatically returned
by post; however, it can be returned to you if you wish to pay
any additional carriage charge.
In addition to any material costs, several factors contribute
to the overall price. These include:
Setup time
Cutting time
Material type — different metals cut at different
speeds: aluminium, copper and silver cut faster than steel
and titanium.
Material Thickness — increasing the metal thickness
also increases the cutting time.
Internal holes and apertures — For each internal
hole or aperture it is necessary to drill a hole in the
workpiece before cutting can begin. This is to allow the wire
to be threaded through the workpiece. The machine must also
be manually stopped and started for every aperture, with a
consequent increase in the time required. Reducing the number
of internal apertures in a design can be a major factor in
reducing cost.
Very small apertures — tiny apertures require more
accurate drilling and setup to ensure that they cut
correctly, with a corresponding increase in the time
required.