Profiled punches and inserts
Show the working contour, stock thickness and the surfaces used to locate the part. Keep edge radii and any taper explicit on the drawing.
EDM Machining Services
EDM profiles, openings and cavities
Discuss wire EDM for through-profiles and sinker EDM for blind cavities in conductive materials. We confirm the machining route, manufacturing responsibilities and inspection requirements against your drawing.
Die plates with internal openings
For a closed opening, include the permitted wire-start location and identify the opening relative to the mounting or locating features.
Slotted plates and comb features
Mark slot width, depth through the plate and the webs that must remain. Include any restrictions on holding or supporting delicate sections.
Tapered through-features
Provide both face profiles, material thickness and the intended taper or angular relationship. These details belong in the process review together.
Blind cavities in tooling inserts
Send the cavity model with its depth, floor shape, corner radii and location. Identify areas already machined and surfaces that must stay untouched. For a tooling insert, mold component machining also covers interfaces with the surrounding mold assembly.
Narrow recessed details
Include the full insert, not just a close-up of the recess. Electrode access, remaining wall thickness and the required surface condition need to be considered together.
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Send the complete part drawing to review the EDM route and inspection requirements.
Wire EDM or sinker EDM?
Electrical discharge machining (EDM) removes material from conductive workpieces through controlled electrical discharges. Wire EDM is used for through-profiles; sinker EDM can form blind cavities with a shaped electrode. The choice depends on the feature, material, access and inspection requirements. [1]
Wire EDM for through-contours
A continuously fed wire electrode follows the programmed profile through the stock. Think of a die opening, an external contour or a slot that runs through a plate.
Send the stock thickness, entry access and any difference between the top and bottom profiles. Wire selection, flushing and the finishing route affect the cut. [3]
Sinker EDM for blind, shaped recesses
Sinker, die-sinking and ram EDM refer to the shaped-electrode approach. The electrode works into an accessible cavity; it does not need to pass through the part.
Include the cavity model and the required floor, corner and surface details. The electrode, its wear and the controlled discharge gap have to be considered in the manufacturing plan. [2]
Combining EDM with milling and turning
A part can be milled or turned first, then sent for EDM on selected features. Open material removal and reference faces may be handled earlier, leaving an internal profile or difficult recess for EDM.
Mark those features and any mandatory heat-treatment sequence. Quote the complete route—or just the remaining EDM work—so preparation and final inspection are assigned clearly.
Wire entry and electrode access
Wire start holes and edge access
For a closed die opening, identify where a start hole is allowed. For an open contour, show the available edge access. Also mark areas where an entry witness or a temporary holding feature would be unacceptable.
If the two faces have different profiles, supply the geometry for both and name the reference face. A single top-view outline can leave the taper or lower opening undefined.
Blind cavity: include the electrode approach
The cavity floor, side walls and entrance all belong in the model. Show the recess in the full part so the electrode holder and workholding can be reviewed, not just the cavity in isolation.
For supplied electrodes, include their drawing, reference system and identification. Agree who checks the electrode and who is responsible for any roughing or finishing electrodes needed for the job. [4]
Conductive materials and incoming condition
Tool steel and hardened steel
Give the exact grade, hardness and treatment history. State whether EDM comes before or after heat treatment, and whether finished datums or ground faces are already present.
Review steel machining →Stainless steel, titanium and nickel alloys
Identify the actual alloy and condition, plus any final surface-integrity requirements. Discuss the material and feature together rather than treating every conductive alloy as the same job.
Browse metal materials →Aluminum, copper and other conductive stock
Include the grade, coatings and any dissimilar materials in the blank. For other conductive materials, send the material specification for review.
Compare materials →Conventional wire and sinker EDM require electrical conductivity. Ordinary insulating plastics belong in a mechanical machining review, not a standard EDM quote. [1] Explore plastic CNC machining →
EDM in the machining sequence
Confirm the blank
Match the drawing revision to the incoming part. Record stock size, hardness, existing datums and the features still to be made.
Plan access and tooling
Agree wire entry or electrode preparation, support for removable sections and the surfaces available for clamping.
Machine the marked features
Keep the required profile, depth and final surface condition tied to the released drawing. Separate roughing from finishing where the route calls for it.
Inspect and protect
Check the agreed characteristics, identify the parts and package delicate edges or finished surfaces for the next operation.
EDM tolerances, surface integrity and inspection
Profile, finish and surface integrity are separate checks
A profile can meet its size limits yet still need a specified surface-finishing step. Where recast-layer or crack limits apply, state the acceptance requirement and test method before the job is quoted. EDM can leave a thermally altered surface; the required follow-up depends on the material and application. [5]
Keep edge treatments on the drawing too. Polishing, blending or removing a surface layer may affect a fit or small radius, so the final inspection state should include that work.
| Requirement | Drawing details | Verification |
|---|---|---|
| Through profiles | Contour, reference face, thickness, taper | Top, bottom, specified intermediate sections |
| Blind cavities | Depth, floor, radii, datums | Access; replica or sectioning if agreed |
| Fits | Mating geometry and limits | Final condition after finishing |
| Roughness | Surface, parameter, units, limit | Numeric measurement and visual criteria separately |
| Surface integrity | Recast layer, cracks, specified limits | Agreed test, sampling, report |
| Material and lot | Certificate, treatment, identification | Sample and batch records |
EDM on supplied parts or a complete part order?
EDM on your supplied parts
Send the finished-part drawing and current measurements. Point out existing coatings, treated layers and protected surfaces. Agree incoming acceptance and responsibility for a damaged or undersized blank.
Machining, electrodes and EDM in one request
List the complete delivery scope: blank supply, pre-machining, heat treatment where required, EDM, finishing and records. For repeat work, agree electrode or fixture storage and the revision each item belongs to.
Agree the manufacturing site and any outside processors before the order is placed. Kevin can discuss coordination through VETCNC or a direct introduction to a suitable partner; the quotation should name the responsibilities for machining, inspection and delivery.
What affects EDM machining cost?
Preparation and electrodes
A sinker job may need electrode design, machining and checking before the first part is burned. For wire work, entry preparation and holding the component are part of the route. [4]
Cut length, depth and access
Stock thickness, narrow or deep features and access for flushing affect process planning. Send the full blank dimensions as well as the finished feature. [3]
Finishing and inspection
Final size, roughness and material-integrity checks can require additional operations or records. Quote these alongside the part quantity and required delivery date.
For samples and repeat batches, separate the sample quantity from the released production quantity. Ask which one-time tooling costs are included, what can be reused and what must be reviewed when the drawing changes.
EDM machining questions
When is EDM a better fit than CNC milling?
It is worth reviewing for conductive parts with hard-to-reach recesses, intricate through-profiles or difficult hard-material features. Milling often handles open stock removal more efficiently. The useful comparison is the complete route for your drawing, not a rule that one process is always better. [1]
What is the difference between wire EDM and sinker EDM?
Wire EDM follows a through-profile with a wire electrode. Sinker EDM uses a shaped electrode for an accessible cavity, including a blind recess. Send a section view when it is unclear whether a feature breaks through the part. [2]
Which materials can be machined by EDM?
Conventional EDM needs an electrically conductive workpiece. Send the exact material grade, hardness and treatment condition so the route can be reviewed. Ordinary insulating plastics are outside that process scope. [1]
Does every internal wire-cut opening need a start hole?
A closed internal profile normally needs a through start hole to thread the wire. An open feature may allow entry from an edge instead. Agree the start location and lead-in so they remain compatible with the finished contour.
Can EDM produce a perfectly square internal corner?
Specify a measurable radius rather than “perfectly sharp.” Wire diameter and the discharge gap influence a wire-cut corner. Sinker EDM also has electrode geometry, wear and gap effects. The attainable corner has to be reviewed against the actual feature. [2]
Can EDM be carried out after heat treatment?
Yes, EDM is used on hardened conductive materials. Include the actual incoming hardness, treatment records and finished datums. Any further treatment or surface finishing must stay in the agreed process sequence. [2]
What tolerances and finishes can you hold?
Send the contour, cavity or fit tolerances, surface-finish limits, part size and material. Achievable limits and inspection methods are confirmed for your drawing and the proposed machining route before an order.
Will an EDM surface need more finishing?
That depends on the required final state. EDM can leave a recast layer, and visual smoothness alone does not establish surface integrity. Specify any removal, crack, roughness or test requirements before machining; agree how later finishing affects the dimensions. [5]
Can I supply partly machined parts or my own electrodes?
You can include either in the request. Supply current dimensions, material records and a clear identification system. For electrodes, include drawings and references, then agree incoming checks, usable condition and responsibility for any replacements.
What do you need for an EDM quote?
A dimensioned drawing, 3D model where available, material and condition, blank dimensions, quantity and delivery requirement. Mark through versus blind features, allowed start holes, datum faces and any surface-integrity requirements. State whether you need EDM only or a complete machined part.
PROJECT SUPPORT
Send your EDM drawing
Mark the opening, cavity or local detail that needs EDM. Include the surrounding part so access, stock condition and references can be reviewed.
Show the feature and send the complete part
A first request can leave the wire-versus-sinker route open. Tell us the required result rather than guessing an electrode size, wire diameter or spark gap.
For an existing component, send the current revision and identify the surfaces already finished.
Technical references
References for wire EDM, sinker EDM, electrode preparation and surface integrity. The machining scope, inspection requirements and manufacturing responsibilities are confirmed for each order.
- Makino — electrical discharge machining and its process types
- Makino — sinker EDM, electrodes and flushing
- Sodick — wire selection and wire-EDM process considerations
- Sodick — electrode preparation and the milling/sinker-EDM workflow
- Able Electropolishing — EDM recast layers and subsequent finishing