Can not believe my eyes, gently pressed, when the bump pressed down, like a whole simply can not see the gap, so precise zero-tolerance products in the end how to process out of it.
Before, I had always thought it was cut from a single piece of steel and then assembled. But actually, it’s cut from two separate steel plates and then put together. If it were cut from just one place directly, there would always be a gap no matter how carefully it’s done. According to the data, the highest precision of this size can be controlled within 1μm. This really shows how extremely precise it is.
This manufacturing process is slow walking wire, that is, one of the EDM electric discharge machining, also known as wire cutting.
Wire cutting can be grouped into fast – speed wire cutting, medium – speed wire cutting, and slow – speed wire cutting.
Fast walking wire and medium walking wire use molybdenum wire.
Slow walking wire is the most accurate, using copper wire.
The principle is to pass a copper wire through a steel plate. With power on, the desired shape is slowly cut out.
The copper wire can be inserted directly from the side of the steel plate to start cutting. Another way is to first drill a hole on the top of the steel plate. Then, thread the copper wire through the hole, and after that, the cutting process can begin.
Before ah, I always think that the copper wire with the saw like, directly hard on the workpiece to saw, now think about it really funny, completely their own brain drama, think carefully about the copper wire is not hard, there is no teeth, how can it be directly sawing it, it is really curious, this cutting is not like a saw as back and forth friction, but the use of metal wire as the electrode, the workpiece for the impulse spark discharge melting of the metal, To achieve the purpose of cutting and molding.
In layman’s terms, this wire is electrically connected to the negative pole, the workpiece is connected to the positive pole, the formation of a circuit between the two and access to the pulse power supply.
Under the action of the pulse current, the gap between the electrode wire and the workpiece to produce spark discharge, can instantly produce thousands of degrees of high temperature, the discharge of that part of the melting or gasification, that is how to cut, not hard to cut, not the wire itself to produce high temperature to cut, but through the high temperature generated by the spark discharge to remove the material.
Then there’s a question: why doesn’t this copper wire melt? It’s because there’s a pulse power supply. The current is like a series of small bursts, not flowing continuously. So, each time, there’s just a quick flash between the electrode wire and the workpiece. The time is extremely short, which prevents the electrode wire from overheating and melting. Also, the power supply can precisely control the energy of each discharge. This way, it can melt or vaporize the material without harming the electrode wire. The copper wire used is a special alloy copper wire made specifically for cutting.
Finally, when the workpieces are cut and put together, you can actually still see the joint. So, it is ground on a surface grinder. In the end, for the finished product, you can’t see even the slightest gap.
Rapid Protos, your trusted parts manufacturing partner
We have advanced wire EDM equipment and can provide customized processing of zero-tolerance high-precision parts. If you need, please contact us for a free quote. Contact Us >>
About the Author: Gavin Xia
