Used Injection Molding Machine Acceptance Test: Agree the Trial Before Payment

Short answer: agree the exact machine, test scope, intended application, measurement method and pass criteria in writing before a used injection molding machine trial. A single good sample or an unloaded dry cycle cannot prove that the offered press will meet your production requirement. The test report must identify what was actually run and which questions remain open.

Use the acceptance run to compare the particular machine against a buyer-defined requirement. It is not a universal certification, a warranty of future uptime or proof that another mold, resin or factory will produce the same result.

Why the test must be agreed before the machine is warmed up

“The machine runs well” is not a measurable acceptance criterion. The buyer and seller first need to specify what satisfactory operation means for the intended job: for example, the identified mold and material, a stated operating mode, acceptable part criteria, agreed measurements, and how a failed or interrupted run will be handled.

EUROMAP 10 (1975) is a historical technical recommendation for preparing and reporting injection machine tests. It says test scope, place and timing should be agreed in the supply contract; its proposed test programme covers measurements, methods and instruments, machine adjustments, measurement points and the number and duration of readings. Treat it as a useful planning reference, not as a statement of current law or a mandatory standard for every used-machine sale.

Write the test sheet around four identities

Identity	Record before the run	Why it matters
The press	Manufacturer, model, serial or machine number, nameplate details, control version, injection unit and installed options.	Evidence must attach to the exact machine and configuration being offered, not another press from the same brand or series.
The mold	Tool number, cavity count, sprue or hot-runner arrangement, core pulls, ejector needs and any auxiliary connections used.	A substitute mold can exercise the press but does not prove the intended tool will fit or run.
The material	Resin identification and grade, colour or additives, lot, drying or conditioning steps, and relevant supplier data.	Different materials and preparation can change filling, recovery and part quality. Do not compare trials as equivalent if these inputs changed.
The result	Part drawing or agreed acceptance points, sample identification, cavity-by-cavity criteria, target output and reject treatment.	“Good parts” needs a shared definition. Preserve the actual samples and measurement results where practical.

EUROMAP 5 (1994) provides a manufacturing-report format intended to make production results reproducible. Its record includes the molded part, shot and part mass, mold and material, machine identity, operating conditions, temperatures, cycle times, pressures, clamping force and energy boundary. The document describes measurements after the machine and mold reach stable running conditions and over a continuous period of at least 15 minutes comprising at least 25 cycles. Treat those figures as the 1994 recommendation’s test method, not as an automatic acceptance threshold for a different job; agree a representative sample for your actual production requirement.

Define the run and the evidence before the trial

1. Agree what the run is meant to prove. Separate machine function checks from application proof. A safety interlock check, platen measurement or injection-unit test answers a different question from whether a target part meets its drawing.
2. Use the target tool and material when application fit is the claim. If the actual mold, resin, hot runner, dryer or robot is unavailable, write down the substitute and limit the conclusion to that setup. A video or a few sample parts cannot fill in missing machine-specific data.
3. Agree stabilization and sampling. Define the warm-up or stabilization point, the run duration, number of cycles or samples, how cavities will be represented, and which stops or alarms invalidate or restart the measurement window. Choose a representative duration for the job rather than treating any historical recommendation as a universal threshold.
4. Agree measurements and tools. Name each instrument, measurement point, unit, method and acceptable uncertainty. Check that the instrument is suitable and its calibration status is documented if the result depends on measured dimensions, force, pressure or energy.
5. Freeze the operating record. Capture the relevant process settings, actual values, alarms, manual interventions, cycle-time distribution and any changes made during the run. If the settings are adjusted, label the before-and-after runs separately.
6. Agree how the result changes the transaction. Put pass, conditional pass and fail criteria, responsibilities, retest costs and timing, and the payment or collection consequence in the purchase agreement. The test report should be signed by people authorized to represent both parties.

Separate a dry cycle from production evidence

A dry cycle can show that selected movements operate without the production process under the observed conditions. It does not show that the intended resin fills the target mold, that parts meet specification, or that the required saleable output is achieved. Conversely, an acceptable sample from a short run does not independently establish long-term reliability, machine history or remaining component life.

For each test item, record the result as observed and passed against an agreed criterion, not tested, or inconclusive. Avoid converting “not observed during this short run” into “no defect exists.” If the mold or resin differs from your production setup, list the difference beside the result.

Buyer acceptance checklist

• Does the report show the same serial number and configuration as the machine offered?
• Are mold, resin, auxiliaries, settings, stabilization, duration and sample selection recorded?
• Are product requirements and measurement methods written down before testing?
• Are machine-function tests distinguished from part-quality and output claims?
• Are alarms, adjustments, stops, rejected samples and excluded measurements visible in the record?
• Do both parties know which outcomes trigger payment, retest, repair or rejection?
• Are open points stated plainly instead of being presented as successful tests?

If mold suitability is still uncertain, compare the mold and machine dimensions in the used-machine mold-fit checklist. For the injection unit, review shot size and resin matching. To discuss a specific used-machine requirement, send the mold, resin and acceptance criteria with your inquiry. Current configuration, availability and trial arrangements must be confirmed for the particular offer.

Questions buyers ask

Does EUROMAP 10 mean the seller must test a used machine this way?

No. The 1975 document is a technical recommendation and should not be represented as current law or an automatic contractual obligation. Use its test-planning ideas to agree the scope and report with the other party; confirm any legal or contractual requirements for your transaction separately.

Can the seller use a different mold for the acceptance run?

A different mold may help demonstrate selected machine functions, but it cannot establish that your production mold fits or meets the part requirement. Record the substitution and narrow the conclusion accordingly.

Is one acceptable sample enough to approve the press?

Not by itself. The sample should be linked to the identified machine, mold, material, settings, measurement method and agreed sampling plan. A sample also cannot prove long-term reliability or future output under changed conditions.