Handing over design data properly: what a manufacturer actually needs

We receive enquiries every day consisting of one file and one sentence of text. Some can be quoted immediately, some cost two days of back and forth. The difference is almost never the quality of the design, it is which information came with it. If you know what a manufacturer needs, you get a solid quote faster and a usable part on the first print.

STEP rather than STL where possible

An STL only describes a triangle mesh. Radii are faceted, dimensions are approximate, threads and hole axes are no longer identifiable as such. For a print that is often enough, for a change it is not. As soon as a dimension needs compensating, a hole needs machining allowance or a split line has to be added, working from an STL means fighting the format.

STEP keeps the exact geometry. That lets us compensate holes cleanly, evaluate radii for orientation and split a part when needed without distorting the shape. If you only have an STL, that is not a blocker. Just say so, so we know that changes can only go through your CAD.

The two or three dimensions that must be right

No FDM part is equally accurate across every dimension. That is not a weakness of the process but a property of it: shrinkage, extrusion width and orientation affect directions differently. This is why the most useful information in an enquiry is not a full drawing but a short list of the functional dimensions.

• Which hole takes a bolt, a bearing or a pin
• Which face locates against a mating component
• Which outside dimension has to fit an existing envelope
• Which fit should slide and which should clamp

Three named critical dimensions immediately change production: build orientation, which faces sit on the plate, whether machining allowance is added and what gets measured on the first article. Without them we decide from experience, and that is right nine times out of ten. On the tenth the critical face ends up on supports, and nobody could have known.

Load direction beats infill

In FDM parts, strength across layers comes close to moulded material while strength along the Z axis is noticeably lower. A bracket printed standing up can fail far earlier than the same bracket printed flat, with identical geometry and material. This is the biggest lever a manufacturer has, and it costs nothing.

One sentence is enough: where the load is applied and in which direction it acts. Ordering 100 percent infill instead pays for print time and material without fixing the weak point. The layer plane stays the layer plane, even in a solid cross section.

Operating conditions instead of a material request

Many enquiries name a material directly, often PLA or PETG because that is what is familiar in the office. The reverse order is usually more useful: operating temperature, load, environment, appearance. Those four points nearly determine the material on their own, and sometimes it is a different one than expected.

• Permanently above 60 degrees, for example in an engine bay or an enclosure with electronics: PC, PA12 or PPA-CF instead of PETG
• Direct sun over months: ASA or ASA-CF instead of PETG, painted additionally if needed
• Loaded brackets and fixtures: PA12-CF or PA6-CF with heat-set inserts
• Flame retardancy to UL94 V-0: PC FR or ABS FR, where the datasheet rating is what counts

If you state the conditions we will propose the material, and we will also say when the cheaper one is sufficient. That happens more often than people expect. Not every enclosure needs carbon fibre.

Quantity and outlook belong in the enquiry

Ten parts now and ten parts a month for two years are two completely different orders, even if the first delivery looks the same. With recurring demand it is worth locking profile and material lot, optimising nesting and filling the build volume. That lowers unit cost permanently and keeps parts comparable over time.

So tell us what you expect: a single sample, a pilot run, ongoing demand or a call-off order. That determines how we quote and how much effort goes into locking the process.

An enquiry that can be quoted immediately

• STEP file, plus an STL if handy
• Quantity now and expected follow-up demand
• Two to four critical dimensions, a marked screenshot is fine
• Load direction in one sentence
• Operating temperature, environment and whether the part is visible
• Target date if there is a fixed one

With that information a response usually comes within a few hours, including design feedback where we have any. If it is missing that is not a problem, it just costs one more round. And in development a round is rarely cheap.