Three options, not two
Most discussions jump straight to “repair or replace”. There are three, and the middle one is where most of the value sits.
| Keep running | Remanufacture | New build | |
|---|---|---|---|
| What changes | Shims, stops, clamp pads | Datum faces re-cut, locators and wear parts replaced, hydraulics rebuilt | Design resets |
| Typical cost | 5–10% of new | 30–45% of new | 100% |
| Lead time | Days | 3–5 weeks | 5–8 weeks |
| Works when | Wear is uniform and tolerance still holds | Base is flat and the design is still right | Tolerance is tightening, or the design is the problem |
| Main risk | Hides an error that reappears as scrap | Repeats a design weakness | Cost and lead time for capability you may not need |
The first check is the base, not the locators
Put a straight edge across the full working area and check with a feeler gauge, or mount a dial indicator on a surface plate and sweep. Our acceptance is 0.02 mm over 500 mm. Beyond that, replacing locators buys a fixture that will drift again within months, because the error is now built into the foundation and cannot be shimmed out per station.
A cast iron base moves for two reasons: residual stress releasing over years, and thermal cycling if the fixture sits near a heat source or is washed at temperature. A welded steel base moves for a third — it was probably never stress-relieved after welding. If the base fails the flatness check, stop the rebuild discussion there; you are comparing a new fixture against a new fixture.
What a remanufacture actually includes
Quotes are not comparable unless the scope is the same list. A quote that only replaces locators is a repair, not a remanufacture, and it will come back. The full list:
- Strip and clean; document the condition before touching anything.
- Re-machine the datum faces that locate the locators — not only the locators themselves.
- Replace locators with hardened, ground parts; replace wear pads, rest buttons and bushings.
- Rebuild or reseal hydraulic cylinders, replace hoses, and re-test hold pressure over 30 minutes with the circuit at working temperature.
- Re-qualify with a test bar per station, then run a first article on each station and record the result.
- Re-issue the datum sheet. The next person to touch this fixture needs to know what was cut and by how much.
The break-even belongs in parts, not in money
Compare per remaining part, not per fixture. Downtime is the term people forget, and it is usually the largest.
Worked example — rebuild 26,000 CNY against new 78,000 CNY, downtime three days against six, lost contribution 4,000 CNY per day:
| Rebuild | New build | |
|---|---|---|
| Fixture | 26,000 | 78,000 |
| Downtime | 12,000 | 24,000 |
| Total | 38,000 | 102,000 |
| Per part, 10,000 remaining | 3.80 | 10.20 |
| Per part, 60,000 remaining | 0.63 | 1.70 |
On pure cost the rebuild wins at both volumes. That is the honest conclusion, and it is why rebuild is the right answer more often than suppliers admit. New build wins only when one of three conditions holds.
The three conditions where new build wins
- The tolerance class is tightening. Moving from ±0.05 to ±0.02 mm is a design change, not a wear repair. A rebuild preserves the original intent; if the original intent was looser than the new requirement, no amount of re-cutting closes the gap.
- The design is the constraint. If the real problem is changeover time, chip evacuation, or the operator reaching over the fixture, a rebuild copies that weakness faithfully. Rebuild fixes geometry; it does not fix concept.
- Volume above roughly 20,000 parts and cycle time matters. A new fixture designed around multi-station clamping or a hydraulic circuit can take 15–25% out of the cycle. At that volume the cycle saving dominates the price difference within a year.
How rebuilds go wrong
- Replacing locators without re-cutting the datum faces that locate them. The new locator is accurate and installed on an inaccurate surface.
- Reusing hydraulic cylinders without a pressure-hold test. The fixture leaks slowly, clamping force drifts, and the first indication is a dimensional trend nobody plots.
- Skipping first article because “it is the same fixture”. It is not — the geometry moved by however much material was removed, and the datum is new.
- No documentation. A rebuilt fixture with no datum sheet is a fixture that will be rebuilt again, badly.
How we quote it
Liuzhou Dongben Machinery Equipment Co., Ltd. quotes rebuild and new build side by side on the same sheet, with the downtime assumption stated, so the comparison is a calculation rather than an argument. Send the part drawing, the current fixture photographs, and the tolerance you need to hold — the two numbers come back together.