Spark erosion machines: electrodes, tooling and service records
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Before offering a die-sinking EDM machine for sale, find out who owns the electrodes beside it. Their presence in the workshop does not prove that they can be included, and their value to the next owner depends on what they are.
Makino's description of sinker EDM explains the basic arrangement: a shaped electrode works on conductive material within a dielectric fluid. That makes electrode identity and job history relevant to the sale. A box labelled only “EDM tooling” leaves too much unanswered.
The machine itself still needs a complete specification. Record the model, serial number, control, documented working envelope and fitted electrode-handling equipment. Use documents for the actual build.
Separate reusable holders from job electrodes
A general-purpose holder and a shaped electrode made for a customer's component are different assets. They may have different owners, confidentiality restrictions and future uses.
Use a schedule like this while deciding the lot contents:
| Sale reference | Item type | Identity or job reference | Ownership evidence | Proposed treatment |
|---|---|---|---|---|
| E01 | Shaped electrode | Internal reference only | Customer agreement to check | Hold outside sale pending decision |
| H01 | Electrode holder | Manufacturer and interface | Purchase record held | Include if compatible package confirmed |
| S01 | Spare holder components | Markings incomplete | Seller stock record | Identify before grouping |
| F01 | Workpiece fixture | Associated job identified | Ownership unresolved | Obtain release or exclude |
These are hypothetical entries. Keep confidential job references out of public photographs and descriptions unless their release has been authorised.
Do not describe a used electrode as ready for another job merely because it appears intact. The sale record should identify it and its known history, leaving suitability for future use to the buyer's assessment.
Record the machine's supporting systems
The dielectric equipment, filtration and any separate temperature-control unit may form part of the package. Identify what is fitted and what is shared. For loose holders and tooling, the tooling lotting guide helps compare a combined package with separate lots.
List the electrode changer or magazine, supplied holders, relevant controller and loose accessories separately. If one component is excluded, describe the resulting package honestly. Avoid suggesting that a machine is complete for a buyer's intended production simply because the base unit is present.
A wire EDM sale involves different wire-handling and supporting-system questions. Do not reuse a wire-machine checklist and assume it covers a die-sinking machine.
Request the service information that matters
An orderly service enquiry is more useful than asking for “all paperwork”. Ask the owner or service provider for:
- The most recent machine service report and the faults it addressed.
- Reports concerning the generator, control and axis systems.
- Records for electrode handling or changing equipment.
- Dielectric-system service information identifying the fluid and relevant equipment.
- Filter, pump or temperature-control work recorded in the service file.
- Any unresolved fault or recommendation following the latest visit.
A date on an invoice establishes a transaction. The accompanying report may establish more about the work performed and its result. Keep both where available.
Where fluid identity or condition is uncertain, tell the specialist directly. The fluid and swarf handover guide provides preparation questions, but EDM fluid requirements must come from the relevant machine and fluid documentation. Do not drain, mix or replace fluids merely to improve the sale presentation.
Agree the release and removal boundaries
An electrode may still be needed for a final job even when the machine has a proposed sale date. Put release dates against those items individually.
The contractor also needs to understand the installed machine, associated tanks or units and site conditions. Use the foundation and anchoring questions to gather building information without prescribing a removal method.
HSE's guidance on second-hand products explains supply responsibilities in Great Britain. Clear ownership and service records support a sale; they do not replace competent advice about equipment condition.
Send the agreed electrode schedule, machine record and supporting-equipment list to UK Auction Group. The engineering and CNC hub links the other preparation guides.
Sources
- Makino: Sinker EDM technology Checked
- HSE: Second-hand (re-supplied) products Checked
This guide gives general information. Equipment-specific, legal, tax and safety decisions may need a qualified adviser or competent specialist. The guides do not promise sale prices, fees or results.