Keeping a Hansvedt sinker productive comes down to three things: identifying the exact model and boards, isolating the failed component, and sourcing a replacement that matches the original specification. Most legacy Hansvedt ram machines can keep running for years on stocked, reconditioned or newly manufactured parts, and good records make every repair faster than the last one.

Many Hansvedt EDM machines still hold respectable mechanical accuracy. What wears out is the support around the frame: servo boards, hydraulic valves, pumps, contactors and capacitors. With factory support long gone for many models, owners often have to do more of the detective work themselves. This guide shows how to do it efficiently.

Start With an ID Sheet

Wrong orders cost more time than slow ones, so pin down exactly what you have before calling anyone.

Hansvedt built both ram-type sinkers and CNC wire machines, and the two share very few parts. A sinker has a ram head, a work tank and an electrode holder, and feeds a shaped electrode into the part. A wire machine cuts with a moving wire and uses wire guides, power feed contacts and a wire transport system that a sinker does not have. If you run more than one Hansvedt, label them clearly in your records.

Build a one-page ID sheet for each machine:

• Machine model, serial number and supply voltage from the nameplate
• Power supply model and serial number
• Board part numbers and revision letters, photographed in place
• Nameplate data from the servo valve, pump motor and transformer
• Any field changes, jumpers or non-original wiring

Keep a copy of the sheet in the electrical cabinet and another in your maintenance system. When a machine goes down at the end of a shift, the person on the phone with a supplier rarely has time to climb behind the cabinet with a flashlight, and the sheet answers the first five questions any supplier will ask.

Revision letters matter. Two boards with the same part number but different revisions can use different jumpers or component values, so the photos of each board edge and label are worth the five minutes they take.

Tracing the Fault

On older sinkers, most failures fall into three groups: ram motion, flushing and the electrical system. Cast iron and ways cause far less downtime than any of them.

The ram will not move

Work through the servo chain in order: control board, servo valve, then hydraulic pressure. A pump that runs only proves the hydraulics have power. Oil, wax and dust on old boards can cause shorts and overheating, so look for heat damage around transformers and resistors. If you have two identical machines, swapping one board or valve at a time is the quickest way to isolate the fault.

Burns are unstable or arcing

Weak flushing leaves debris in the gap, which causes DC arcing and unstable cutting. Check pump rotation, filter condition, cracked hoses and leaking seals. A clogged filter can starve the gap while the pump sounds perfectly normal, which is why changing EDM filters on schedule prevents one of the most common flushing faults.

The machine trips or drops power

Pitted contactors cause dropped power and random shutdowns. Old electrolytic capacitors dry out, swell or leak, weakening the power circuit. Boards develop cracked solder joints, burned traces and failed relays. If the machine shuts down the moment gap power comes on, the fault is almost certainly electrical.

Is it a part or the process?

Rough finish, high electrode wear and slow burns often come from settings, electrode choice or dielectric condition. A failed part is more likely when changing the settings changes nothing at all: no ram motion, no spark, tripped breakers or visible heat damage. Change one variable at a time and write down the result.

Is your Hansvedt powering up but refusing to move the ram, or tripping as soon as gap power comes on? Our engineers can help narrow down the board, valve or electrical fault before you start replacing parts. Talk to an Engineer.

Sourcing Parts That Fit

Match every part to the manual, schematic, part number and board revision for your exact machine. You generally have three routes:

• Original parts: new old stock or tested used OEM components, which are ideal when available
• Reconditioned parts: your own board, valve or pump, repaired and tested
• Equivalent parts: a current contactor, capacitor or pump that meets the original electrical and mechanical ratings

Equivalents have to match voltage, current, mounting and response. A pump with the wrong flow rate or a capacitor with a lower voltage rating can create a new problem while fixing the old one.

Some Hansvedt parts are simply no longer made. Brackets, fittings and electrode holders can be reproduced from the original part, a sample or drawings, and boards can often be repaired at component level or rebuilt from a working example. EDM Zap supplies components and accessories for Hansvedt platforms and can source or manufacture parts to the original spec when they are no longer on the shelf. Our article on EDM machine parts lists the items that tend to fail first and are worth stocking.

When you send a parts or repair request, include your ID sheet, photos of the failed part and its label, the exact symptom and when it started, what you have already tested or swapped, and whether you need a part, a shop repair or on-site service.

Before It Goes Back Into Production

A repaired sinker should prove itself before it touches a customer's part.

Isolate safely. Troubleshooting involves high voltage and stored energy, so only qualified people should open the cabinets. Lock out and tag the main disconnect, let capacitors discharge and confirm zero energy with a meter.

Check motion, flushing and interlocks. Jog the ram and confirm smooth travel with no hunting, then run a light burn and watch the servo back off and recover cleanly. Check pump flow, pressure and every fitting for leaks. Test the fluid level switch, door and tank interlocks and fire detection. Never bypass an interlock to finish a job.

Confirm accuracy. Indicate the ram for squareness, check positioning against a known reference and run a test burn on scrap with a known electrode and settings. Compare depth, finish and wear with past results.

Write it down. Log the date, part numbers, revisions and test results for every repair, and keep a small stock of fuses, contactors, filters and, if you can get one, a known-good servo board.

A Hansvedt sinker stays useful for as long as someone keeps accurate records and sources parts carefully. If yours is down with a failed board, a sticking servo or a part you cannot find, EDM Zap's EDM repair and maintenance team can diagnose it, repair it or build a replacement to the original spec. We have supported legacy EDM equipment since 1971 and respond within 24 hours. Talk to an Engineer, or call (630) 852 1699.

Frequently Asked Questions

Where can I find parts for an older Hansvedt EDM machine?

Independent EDM service companies that stock legacy components are the usual source. Bring your model, serial and board numbers so the supplier can match the right revision, and ask about reconditioning or manufacturing if a part is out of stock.

Why does my Hansvedt ram not move when the pump is running?

The hydraulics have power, but the servo board, servo valve or feedback circuit may have failed. Dirty or heat-damaged boards are a common cause on machines that have sat idle.

Can an obsolete Hansvedt component be reproduced?

Many mechanical parts can be reproduced from the original, a sample or drawings, and many boards can be repaired at component level. Electrical replacements must match the original voltage, current and response ratings.

What should I include in a Hansvedt repair request?

The model, serial number, voltage, power supply details, board part numbers and revisions, photos, a clear description of the symptom and any tests you have already run.