Explain the intended use
Describe the purpose of the part, approximate size, quantity and the features that matter. Distinguish a display model from a part expected to fit, carry load or operate in a demanding environment. Let the provider assess suitability.
Say what you already have
List the file format and units, or explain that you have only drawings or an idea. Ask whether the quote includes CAD work, file repair, print preparation and revisions. Do not upload confidential files to a public listing.
Ask for comparable quotes
Use the same specification with each provider. Request separate line items for design, production, finishing, shipping and taxes. Confirm deadlines in writing and ask what happens if the design needs changing.