Selecting the right 3D printing vendor can make or break your project timeline, budget, and final product quality. Whether you're prototyping a consumer product, manufacturing replacement parts, or producing custom fixtures, asking the right questions upfront prevents costly mistakes and revisions. Here's exactly what to dig into before signing a contract.
What 3D Printing Technologies Do They Actually Operate?
Not all 3D printers are created equal. FDM (Fused Deposition Modeling) is affordable and fast for prototypes but produces rougher surfaces. SLA/DLP (resin-based) delivers higher detail but costs more and requires post-processing. SLS (Selective Laser Sintering) handles complex geometries without support structures. BINDER JETTING and multi-material systems serve niche applications.
Ask your vendor which technologies they own and operate in-house. If they outsource your job to a third-party facility, you lose quality control and add lead time. Confirm they have the specific printer type your design needs—don't accept vague assurances.
What Materials Are Available, and What Are Their Properties?
The wrong material choice makes a beautiful 3D print useless. Ask for a complete list of materials they stock: standard resins, engineering-grade thermoplastics, metals (aluminum, titanium, steel), composites, and flexible polymers. Request material datasheets for tensile strength, shore hardness, temperature tolerance, and chemical resistance.
For production parts, don't settle for "standard white resin." Specify whether you need flame-retardant properties, UV stability, biocompatibility, or thermal endurance. Many vendors charge 15–40% premiums for specialty materials, so nail down exact costs per material option before comparing quotes.
What's the Timeline from File to Finished Part?
Lead times vary wildly. Quote turnaround depends on equipment availability, post-processing complexity, and current queue depth. A resin print might ship in 3–5 days; an SLS job could take 2–3 weeks; metal printing stretches to 4–6 weeks plus finishing.
Ask:
- How many days does your current queue have?
- Do you offer rush pricing, and what's the realistic 48-hour turnaround cost?
- How long does post-processing typically take (curing, support removal, cleaning, surface finishing)?
- If I order 10 units, do all parts finish together or staggered?
Get this in writing. Many vendors quote production time but underestimate finishing, causing delays your timeline can't absorb.
What's Your Quality Control and Accuracy Range?
3D printing tolerances depend on technology and material. Resin prints typically hold ±0.5 mm; FDM is looser at ±1–2 mm; SLS lands around ±0.3 mm on average. But "typical" doesn't mean "guaranteed."
Ask your vendor:
- What tolerance class can you certify (ISO 286)?
- Do you measure critical dimensions with calipers, CMM, or visual inspection only?
- Can you provide a test coupon or accuracy report for my specific design?
- What's your rework or scrap rate on similar projects?
Request a sample print of your part, even if you pay $50–200 for it. Seeing actual quality beats any promise.
Do You Handle Post-Processing, and What Does It Cost?
Raw prints aren't always usable. Post-processing includes support removal, UV curing (resin), sanding, vapor smoothing, painting, plating, and assembly. These steps add 30–60% to lead time and 20–50% to cost.
Clarify whether post-processing is included in the base quote or billed separately. Ask:
- Which finishing options do you offer in-house versus outsource?
- Can I get a finished part looking like a commercial product, or will it have visible layer lines?
- What's the cost delta between minimal finishing and full aesthetic/functional finishing?
What's Your Pricing Model and Minimum Order?
Get a transparent breakdown: setup/software prep (usually $50–300), per-unit material cost, machine time, and post-processing fees. Some vendors quote "per-job" with no clarity; demand itemized estimates.
Confirm minimum order quantities. Many shops have $200–500 minimums to justify setup labor, while others accept single units at premium rates. For Mercoly customers, you can compare multiple vendors' pricing and capabilities in one place to avoid the back-and-forth email hunt.
Do You Offer Revisions and Reprints?
Ask what happens if your first sample doesn't meet specs. Do they reprint free if it's their error, or charge half-rate? What's the revision limit before you pay full price again? Get revision policies in writing.
Frequently Asked Questions
Q: What's a realistic budget for a 25-unit batch of custom plastic parts using SLS printing? Expect $1,500–$4,000 depending on part complexity, size, and whether post-processing is included; setup typically runs $300–500, and per-unit material and labor ranges $40–150.
Q: How do I know if my 3D printed part will survive actual use in a high-temperature environment? Request material property datasheets, ask the vendor for parts made in your exact material that survived similar conditions, and consider ordering a stress-tested prototype sample before committing to production.
Q: Should I send my CAD file to multiple vendors for quotes? Yes—different shops have different equipment, pricing, and lead times; comparing 3–5 quotes ensures you're not overpaying and that your design is producible.
Start comparing vetted 3D printing vendors today and get quotes tailored to your exact project.