Write the duty first, not the geometry
Start with what the mechanism has to survive over its working life, in the place it will actually be used. For a fixed steam cleaning machine that means the duty it repeats every day: how long a machine runs in a shift, how many start-stop cycles that produces, whether the surrounding air is damp or carries grease and cleaning agents, and whether operators push, drive or hose the unit while it works. Geometry, material choice and motor size are all answers to that statement — they should not be treated as the statement itself.
A useful duty statement is short and testable. "Frame and handles survive daily handling in an outdoor parking area, and the wetted parts tolerate tap water over repeated heating cycles" gives a designer something to dimension against. A buyer reviewing two competing machines can then check both against the same words instead of comparing brochure layout.
State the operating conditions as ranges
Single-point numbers hide risk. Temperature, supply conditions and ambient humidity all drift in real installations, and a mechanism usually fails at the edge of the range, not the middle. PowerDe's own published data is written this way, which is a good model: the Fixed Steam Cleaning Machine PowerDe HW02 page lists a 6 kW heating power, a 160° steam temperature, 0.8 MPa vapor pressure, an 80 L SUS304 tank, a footprint of 1,200 × 800 × 1,200 mm including handles, and a 220 V working voltage, with tap water entering through a 4-point internal-tooth joint, 1/2 inch. Every one of those lines is a documented target a purchasing engineer can verify against a sample, and each one answers a question about the machine's structure as well as its function.
Where a value is not published, treat it as open rather than assumed. On the same product family, steam temperature and pressure are given for the HW02 entry but not for the hand-pushed PowerDe HMW3 listing, which publishes its dimensions, 4.5 kW PTC semiconductor heater, 50 L clean-water tank, 48 V battery working supply and high-pressure water gun instead. Ask for the missing numbers in writing before you compare designs — a supplier that can produce them has usually documented them somewhere.
Turn reliability into named checks, not a promise
"Robust" cannot be inspected. Break it into the protective functions the machine is supposed to have and record what each one must do. The PowerDe HW02 page lists leakage, short-circuit, high-temperature, high-voltage, water-shortage and high-voltage-explosion protection. A performance document goes one step further for each item: what condition triggers it, what the machine does when it triggers, and how a test engineer proves that it triggered. That converts a safety claim into a set of pass/fail checks that survive staff turnover and supplier changes.
Wear parts deserve their own line. Seals, hoses, nozzles and tanks age at different rates, and the material behind each matters: an 80 L SUS304 tank, for example, is a documented material choice, not a marketing word. Note what the part is made of, what it is exposed to, and how it will be judged when it is replaced during service.
Record the human interface in the same document
Most field complaints about machinery are about handling, not strength. A hand-pushed machine needs its movement method and footprint on record; PowerDe's HMW3 entry documents both, listing hand push and L1150 × W520 × H1030 mm. Driving-style units in the same cleaning series are described for indoor garages and narrow outdoor parking spaces, which is a dimensional and access requirement as much as a marketing description. Write down how an operator reaches the controls, connects water, moves the machine and stores it, then let the design answer those constraints.
Include cleaning and servicing access in the same list. A machine used where hygiene is checked has to come apart far enough to be cleaned, and that requirement changes bolt patterns, panel joints and cable routing long before production.
Make the document part of the enquiry
For an equipment manufacturing automation project or a machine built around an automated line, the performance target list is what an engineering team designs against and what an acceptance test measures afterwards. Send it with your enquiry rather than after the quotation. A supplier asked to confirm or challenge specific duty figures responds very differently from one asked for a catalogue.
Where your own numbers do not match a standard configuration, that is also worth putting in writing. PowerDe lists engineering services covering product development, hardware testing and customized steam cleaning equipment, alongside non-standard automation — routes that exist precisely because documented targets sometimes point at a machine the catalogue does not carry.
Check the paper before the machine
Before a sample arrives, ask for the target sheet in whatever form the supplier keeps it: duty statement, published parameter table, list of protective functions, materials of wetted and wearing parts, and the tests used to confirm each one. Compare what you receive against the installation you actually have — supply connection, floor area, ambient conditions, shift pattern. Any field that cannot be filled in is a question to resolve before an order, not after.
A performance target document earns its keep twice: once when a design team uses it to size the mechanism, and again when a buyer uses it to decide whether the delivered machine was ever meant for the job.
