EDM Process

innomolding.com > EDM Process

Before we introduce EDM process, we would like to have an overall introduction to injection mold structure. An injection mold consists of mold base, cavity, core, injection channel, ejection system, and other mold components if needed(hot runner system).

We out-source mold base and other components(like sleeve, ejection pins, nut), but the mold cavity and core must be manufactured by our-self.

In the mold making industry, there are lots of different type of mold making machines to use, like CNC milling, wire cutting, grinding machining, drilling, and EDM machining.  

EDM is known as electrical Discharge Machining, plays a very important roles in the mold making technology, which mainly used to achieve some deep and narrow profile that a normal CNC machining could not work for.

At Inno molding, we are well-equipped with 10 sets of normal EDM and 5 sets of mirror EDM that exported from Switzerland and Japan.

Prior to EDM machining, all of our electrode tool must be fully measured to ensure accurate dimension we will obtain. Here below you can review our EDM manufacturing process.

What do We do with EDM Machining?

In today’s mold making market, it requires mold manufacturers to serve customers with high quality, low cost, flexible service, and short lead-time. Therefore a good combination use of high-speed CNC milling and EDM machining is necessary. So when do we use EDM machining?

Generally speaking, we use EDM machining to obtain slots, ribs, arcs, webs, grid, etc. Here below are some examples


ribsThere are many different features existing on a plastic parts, like hole, pillar, cutout, window, platform, web, grid, etc. We machine most of them via CNC milling and wire cutting process. But for some complex cutout that requires precision dimensions and excellent finish, we will do it by EDM process. For different requirement, we might choose either conventional EDM or mirror EDM. Normally a conventional EDM works fast but with worse finish quality, but a mirror EDM deliver extremely good finish even through it works much slower. 


mold profile

In order to obtain an overall smooth profile, we make this kind of mold core and cavity with mirror EDM process. it delivers us accurate dimension and extremely excellent finish. Even through it takes about 8~12 hours to finish such a single mold cavity, but we always choose this type of EDM for most of our mold tool.

When perform a EDM process, the most important things is to have an accurate electrode, as well as  experienced operator. Before EDM process, we use CMM to measure full dimension of it. Ensuring the most precision mold tool we will obtain.


corePlastic part shape gives customer a touch and looking feel, it requires us to makes accurate dimension and excellent surface finish, we emphasize our work to deliver best EDM result as possible. Our EDM operators mount electrode, align work-piece, perform EDM, and check out finished mold part. 


If any deviation found, we will re-make an new electrode for rework. Our aim is to meet total customer satisfaction.

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