Start with the powder charge and production cycle

At DONGXIN, we select a high-frequency melamine preheater by powder charge, material grade and available heating time. The charge means all powder heated in one batch, including material for every mould cavity. Press tonnage alone cannot determine the required power. For MMC or UMC processing, confirm charge dimensions, starting temperature and the material supplier's recommended preheating conditions before comparing machines.

Evaluate 5 kW and 7 kW for lighter or mixed workloads

For lighter charges used in small bowls, cups or saucers, a 5 kW preheating machine can be a trial candidate when preparation time is sufficient. A 7 kW preheater is worth evaluating for larger charges or a tighter production rhythm. These are selection starting points: a multi-cavity mould can make small products a substantial batch, so product size alone is insufficient.

Consider 10 kW when charge or throughput increases

For large serving trays, heavier batches or demanding production schedules, include 10 kW in the comparison of our 5 kW to 10 kW configurations. Higher rated output may provide heating headroom, but chamber size, material response and loading arrangement still matter. If one preheater serves several presses, assess their combined demand. Approve the configuration through representative trials, rather than assuming a fixed kilogram capacity per kilowatt.

A practical example of matching the press cycle

In an illustrative case, a four-cavity mould needs 0.25 kg of powder per cavity, giving a 1.0 kg charge per press cycle. At a 60-second press cycle, the line needs one ready charge each minute. Check the complete preheater cycle, including loading and unloading. A 75-second preparation cycle would fall behind this schedule; a higher-power candidate must demonstrate that it closes the gap.

Verify heating quality and handling together

Our automatic cover preheater offers motorised opening and closing with three-stage voltage switching. During trials, check the heating result across the charge, repeatability and transfer to the press, using conditions approved for the compound. Avoid overheating that starts curing before moulding. Include handling time in the comparison and inspect moulded-part quality. A faster heating result is useful only when the complete process remains stable.

Confirm electrical requirements and running cost

Ask whether a quoted kW figure describes high-frequency output or total electrical input; input capacity in kVA is a separate specification. Compare measured energy per acceptable finished piece, not nameplate power alone. Send DONGXIN your MMC or UMC grade, batch weight, mould cavities, press cycle, number of presses and factory voltage, frequency and phase. We can then discuss a suitable configuration and material trial.