Why Structure Decisions Belong Before Motors And Controls Are Chosen
Most buyers start a machine project with the drive system: how fast, how accurate, which servo. On the shop floor, the structure usually decides whether those choices survive. A linear module with perfect repeatability can still miss tolerance if the frame deflects under load, and a well-specified process can fail because the housing has no path for the residue, heat, or vibration it produces. PowerDe works from a base of equipment R&D, non-standard automation, and integrated engineering services, which means the mechanical structure is treated as a specification to be written and verified, not as a shell drawn around the parts later.
The list below is ordered the way our engineers fill it in during a design review. Each item has a definition, and the definition is what a supplier needs to quote, test, and accept the machine against.
1. Envelope, Mass Budget, And Load Path
Define the outer footprint first, including clearances for loading, maintenance access, and any ancillary equipment. Then state the mass budget: total moving mass per axis, payload range, and where that mass sits. A load path drawn from the point of force application to the base tells you whether a frame will bend and where stiffening belongs. Write the static and dynamic load each interface carries, plus the moment loads, because a structure sized only for weight will still twist.
2. Stiffness, Flatness, And Datum Scheme
Specify the deformation you will accept under the defined load, and state the datum surfaces every other feature is measured from. Flatness, parallelism, and perpendicularity tolerances for mounting surfaces matter more than the general frame tolerance, since rails, plates, and guides bolt to those surfaces. If a machine has more than one axis, the alignment between axes belongs in the drawing as a geometric tolerance rather than a note in a quotation.
3. Material And Surface Treatment
Name the material per part and the reason for it: aluminium profile for a light frame, welded steel where damping is needed, stainless where the environment is wet or cleaning is frequent. State the treatment, since this controls corrosion and wear — anodising, plating, painting, or passivation. For cleaning equipment this decision is direct: our steam cleaning machines run hot water, steam, and high pressure, so frames, tanks, and fittings are chosen and finished to survive repeated wet duty. The fixed steam cleaning machine page lists an 80 L SUS304 tank as an example of that material call being written into the specification instead of left to the supplier.
4. Interfaces: Electrical, Pneumatic, Fluid, And Data
Every connection through the structure needs a definition on the drawing. That means connector type and location, cable routing with a bend radius, strain relief points, pneumatic fitting size, water inlet and outlet connections, drain points, and any sensor or fieldbus wiring path. In PowerDe's own equipment listings a water inlet is recorded as a specific fitting rather than as “water connection”, and the driving style steam cleaner is documented as a battery variant and a without-battery variant. Recording the interface that way is what lets two variants share one frame and lets a buyer compare offers on the same basis.
5. Environment, Protection, And Safety Requirements
State where the machine will live and what it will meet there: ambient temperature range, humidity, dust, splashing water, cleaning agents, and any washdown. From that follow the enclosure rating, the sealing details, and the drainage design. Safety requirements are part of the structure as well — guarding, interlock mounting points, accessible emergency stop, pinch-point geometry, and stable base fixing. PowerDe equipment pages list protection functions such as leakage, short-circuit, high-temperature, high-voltage, and water-shortage protection; each of those needs a physical home inside the machine, so the structure has to be drawn with them rather than adjusted after the enclosure is cut.
6. Movement, Ergonomics, And Handling
For mobile equipment, movement is a structural specification: how the unit is pushed, driven, or lifted, the height and grip of handles, wheel or caster choice, the centre of gravity when the tank is full and when it is empty, and the turning behaviour in the space it works in. Indoor garages and narrow outdoor parking areas are the working spaces for our mobile cleaning machines, so handle geometry and wheelbase are set against those aisles, not against an open workshop. Weight limits for the people who will move the unit belong in the specification, along with any lifting points for service.
7. Maintenance Access And Wear Parts
Write down which parts are expected to be replaced, how often, and with what tools. Then design the access: panel openings, fastener type, whether a component can be pulled out without removing a neighbouring assembly, and whether a filter, pump, or heating element can be reached without draining the whole machine. A machine that is quick to clean but slow to open transfers its cost onto the operator every day.
8. Manufacturing Method And Tolerance Reality
State how each part will be made and what the process can hold. Tolerances written tighter than the process produces buy inspection time, not quality. For welded parts, note stress relief and where machining happens after welding. For sheet metal, note bend radii and tooling limits. For extruded profile frames, note the connector system and the achievable squareness. A structure specification that matches the shop's normal capability is the one that arrives consistent across batches.
9. Verification And Acceptance
Each number in the specification needs a check: the measurement method, the instrument, and the pass criterion. Typical structural checks are dimensional inspection of datum surfaces, a deflection measurement under a defined load, a run-in on a dummy cycle, a vibration or noise observation, and for wet equipment a leak and function check through the full fluid path. Put the acceptance test in the same document as the drawing so both sides sign off against the same list. Where performance figures such as cycle time or fit error are published on a product page, they are stated with the conditions they were measured under — a useful habit to copy into your own specification.
10. Cost, Availability, And Change Control
Specify what may be substituted. Standard fasteners, bearings, rails, and profile sections can usually be exchanged with an equivalent; frames, machined plates, and sealed assemblies cannot. Record the parts that must keep their source, the lead time the structure carries, and the rule for approving a change. A one-page change-control note prevents the quiet substitutions that show up as alignment drift three months into production.
How PowerDe Approaches Structure Work
Our range runs from cleaning equipment to non-standard automation equipment, and the structural questions are handled the same way across them. A buyer can send the process requirement and the working environment and receive back a machine structure, an interface list, and an acceptance checklist; or bring their own concept and have it reviewed against production and testing. The services side of the site covers product development, hardware testing, and integrated engineering team support, which is where a structure specification gets checked before tooling is committed.
A Short Checklist Before You Send The Drawing
- Envelope, mass budget, load path, and the deformation you accept
- Datum surfaces with geometric tolerances, not just overall dimensions
- Material and surface treatment per part, with the environment it serves
- Every electrical, pneumatic, fluid, and data interface named by type and position
- Protection and safety features drawn into the structure, not added afterwards
- Handling, handles, casters, and lifting points defined for the people who move it
- Wear parts, service intervals, and the access needed to reach them
- Tolerances matched to the manufacturing method that will produce the part
- Acceptance test with method, instrument, and pass criterion for each figure
- Substitution rules and a change-control note
Send the working condition and the duty cycle, and the structure can be specified against them. That is the question to put to any supplier: not “what frame will you build”, but “which numbers will you sign the acceptance test against”.
