Sourcing, Services and Outsourcing
Making in-house or buying a service, equipment payback, requesting quotes and protecting your design.
Make it yourself or buy the service?
Almost every prototype uses a mixture: you make the quick, cheap parts yourself and buy the ones that need a machine you do not have, or a skill you do not have. The decision depends on how often you need the process, how fast you need the result and what your time is worth.
| Factor | Favors making it yourself | Favors buying |
|---|---|---|
| Speed of iteration | Same-day changes | Several days of waiting per round |
| Quantity | One to a few parts | Larger batches, repeat orders |
| Capability | Processes you own and know | Metals, fine tolerances, special processes (SLS, sheet-metal, anodizing) |
| Cost | Cheap consumables, owned machine | Expensive machine or skill needed rarely |
| Confidentiality | Secret design | Under a non-disclosure agreement |
| Learning | You want to learn the process | You want the result, not the process |
Equipment payback
Worked example: is a $600 3D printer worth it?
- Depreciate the printer over 3 years at 500 printing hours a year: $600 ÷ 1 500 h = $0.40 per hour; add filament ($1.20 per hour), power ($0.15) and maintenance ($0.20): $1.95 per printing hour.
- A 4-hour part costs $7.80 to print yourself, against a service price of $25 and 7 days (yours: 1 day).
- Counting only the marginal cost (filament and power: $5.40 per part), the printer pays for itself after $600 ÷ ($25 − $5.40) = 31 parts. If you value your own time at $10 per part (30 minutes of tending at $20/h), it is 63 parts.
- The faster iteration is often worth more than the money: a design that takes five tries is done in five days instead of five weeks.
Types of service
| Service | Examples | Strengths | Watch for |
|---|---|---|---|
| Online manufacturing platforms | Xometry, Protolabs, Hubs, Fictiv, JLC3DP | Instant quotes, many processes, DFM feedback | Price at small quantities; lead times; shipping |
| Local machine shops and fabricators | Machine shops, sheet-metal and laser shops | Talk to a person; quick turnaround; no shipping | Minimum charges; set-up cost |
| Makerspaces and university labs | Shared workshops | Machines and advice; low cost | Waiting lists; skills needed |
| PCB fabrication and assembly | See PCB Prototyping | Cheap boards and assembly | Lead time, parts availability |
| Casting, molding and finishing | Urethane casting, anodizing, painting, plating | Production-like parts and finishes | Master models and molds; minimum quantities |
| Contract engineers and designers | Consultants, freelancers | Skills you lack; flexible | Scope, cost and who owns the result |
| Contract manufacturers | Assembly and product manufacturers | Production runs | Minimum quantities; qualification (see From Prototype to Production) |
Names are examples only: services change. Check current capabilities, prices and reviews before you choose.
Asking for a quote
- Send a complete package: a 3D model (STEP), a drawing with the critical dimensions and tolerances (see GD&T), the material and grade, the finish, the quantity and the date you need it.
- State what matters: mark the dimensions that must be held and leave the rest at the standard tolerance; tight tolerances everywhere cost money (see Tolerances by Process and Surface Finish).
- Ask for several quantities (1, 10, 100) to see the price breaks.
- Ask what is included: set-up, tooling, finishing, inspection report, packaging, shipping and tax.
- Ask for a design review (DFM feedback): a good supplier tells you what could be cheaper to make.
- Confirm the lead time in working days and whether it starts from your approval or your payment.
Worked example: price breaks for a machined bracket
With the illustrative CNC model of Rapid Fabrication: Choosing a Method ($120 set-up, $28 per part):
| Quantity | Total | Per part |
|---|---|---|
| 1 | $148 | $148.00 |
| 5 | $260 | $52.00 |
| 25 | $820 | $32.80 |
| 100 | $2 920 | $29.20 |
The set-up is spread over more parts: five parts cost 1.8 times one, not five times. Ask for the break at 10 or 25 and order the spares at the same time.
Comparing suppliers
Worked example: scoring three suppliers
Weights: price 0.30, lead time 0.25, quality 0.30, communication 0.15; scores 1 to 5.
| Supplier | Price | Lead time | Quality | Communication | Weighted score |
|---|---|---|---|---|---|
| Supplier A (cheap, overseas) | 5 | 2 | 3 | 2 | 3.20 |
| Supplier B (local shop) | 3 | 5 | 4 | 5 | 4.10 |
| Supplier C (online service) | 4 | 4 | 4 | 3 | 3.85 |
The cheapest supplier (A) scores lowest overall because of its lead time and communication; the local shop (B) wins. As with any matrix, choose the weights before you score, and check how the result changes if you shift them (see Rapid Fabrication: Choosing a Method).
- Test a new supplier with a small order before a big one.
- Keep a second supplier for anything important.
- Check certification where it matters (ISO 9001, material certificates, RoHS).
Protecting your design
- Keep dated records: notebooks, CAD file history and emails show when you made the design.
- Use a non-disclosure agreement (NDA) before sharing the details with a supplier, investor or consultant; most platforms have terms that cover uploaded files, so read them.
- Know what you can and cannot protect: patents (new, non-obvious inventions), copyright (software, drawings), designs and trademarks. Public disclosure (a website, a trade show) can prevent patenting in many countries.
- Talk to a patent attorney early if you may want a patent.
- Agree who owns the result when a contractor or a student helps: in writing.
- Split the work if a supplier should not see everything: one makes the case, another the board.
This is general information, not legal advice: the rules differ by country and by situation.
Incoming inspection
Check what you receive before you build on it. A sample inspection with zero allowed defects can show that the defect rate is below a limit.
Worked example: how many parts to inspect?
- To be 95 % sure that the defect rate is below 5 %, inspect n = ln 0.05 ÷ ln 0.95 = 59 parts with no defect found; below 10 %: 29; below 2 %: 149.
- For small prototype orders (five parts) inspect all of them; for large ones sample.
| Defect rate limit | Confidence | Parts to inspect (zero defects) |
|---|---|---|
| 10 % | 95 % | 29 |
| 5 % | 95 % | 59 |
| 2 % | 95 % | 149 |
| 10 % | 90 % | 22 |
- Check the critical dimensions, the finish and the material certificate against the drawing.
- Keep the first articles as references and record the results.
- Report problems promptly with photographs and measurements.
Lead time and logistics
Worked example: ordering a machined part
- Request and receive quotes 3 d, Approve and order 1 d, Manufacture (service) 7 d, Shipping 4 d, Incoming inspection 1 d: 16 working days from the first request to a checked part.
- Parts and shipping: $200 of parts plus $45 shipping and 8 % duty on the total is $265 landed: 32 % above the part price.
- An overseas price quoted in another currency can move by 5 % or more between quote and payment.
- Order before you need it: add a week for the unexpected.
- Check the import rules and duties for the country; some processes (and materials) need export paperwork.
- Use tracked shipping for anything important and insure the parcel.
- Check the parts on arrival and keep the packaging until you have.
Troubleshooting
| Problem | Likely cause | Try |
|---|---|---|
| Parts arrive wrong or out of tolerance | Unclear drawing; a supplier error | Mark critical dimensions; ask for an inspection report; use the supplier’s remake policy |
| Quote much higher than expected | Tight tolerances, hard material, set-up for one part | Relax tolerances; ask for a DFM review; order more |
| Late delivery | Queue, shipping, customs | Confirm dates; track; keep a local backup |
| Supplier will not sign an NDA | Platform terms | Read the terms; split the design; use a local shop |
| Hard to repeat an order | No records of the specification | Keep the drawing revision, the quote and the part numbers |
Related
- Prototyping Techniques: the overview of this guide.
- Rapid Fabrication: Choosing a Method: choosing a method.
- From Prototype to Production: when you move to a manufacturer.
- Shop Tools: equipping a workshop.
FAQ
When is it worth buying a 3D printer instead of using a service?
When you expect to print dozens of parts and value the speed of iteration: the payback is typically 30 to 60 parts. For a few parts, a service is cheaper.
How do I get the best price for a machined part?
Relax tolerances where they are not needed, choose a standard material and finish, order several at once and ask for a design review.
Do I need an NDA?
Before sharing a design that matters, with a supplier or consultant who is not covered by the platform’s terms. It is a sensible habit, not a guarantee.
How many parts should I inspect?
All of a small order; for larger ones, about 59 with no defects shows a rate below 5 % at 95 % confidence.
Should I use an overseas supplier?
For price at volume and when time allows. For prototypes, a local or online service with short lead times is often better.
References
- Ulrich, K. T. and Eppinger, S. D., Product Design and Development, McGraw-Hill (make-or-buy, supplier selection).
- Platform and supplier terms of service (confidentiality); national patent office guidance (WIPO, USPTO, UKIPO).
- Kalpakjian, S. and Schmid, S., Manufacturing Engineering and Technology (process capabilities and costs).
Last reviewed: October 2026. Prices, lead times and legal points are general: check your own situation and get advice where it matters.