MI CNC Parts vs Xometry vs Protolabs

Who this comparison is for

The buyer with a print in hand who is deciding whether to upload it to a platform or send it to a person. Both are legitimate. Xometry and Protolabs both publish instant or near-instant quoting from an uploaded model, and plenty of parts fit that model. This page does not argue about the quality of anyone’s parts, because there is no honest way to do that from a website. It compares the terms each company publishes: how you get a quote, what the minimums are, who you talk to, what lead times each one claims, and what files each one takes.

How each one quotes

Xometry: an instant quote. Its site says the Xometry Instant Quoting Engine "prices parts and generates lead times instantly based on the 3D geometry of uploaded CAD files, market pricing, and the buyer’s choice of the manufacturing process, material, finish, quantity, and other specifications" (source 2). A material the engine does not list can be submitted for manual review (source 1), and technical drawings are accepted alongside the model (source 1).

Protolabs: an automated quote with design analysis. Its CNC machining page says "Upload a 3D CAD file of your machined part and in seconds to hours, we’ll send you manufacturing analysis and quote specific to your request," and that "our automated design analysis identifies any features that may be difficult to machine" (source 3). Its FAQ puts the turnaround as "an interactive quote within hours with free design feedback" (source 4). Within the quote, materials and quantities can be changed with pricing updating in real time (source 3).

MI CNC Parts: a person reads the files. Send a STEP model and a PDF print through the quote form (or by email) and Evan reads the model and the drawing: the tolerances, the material callout, the quantity, and the manufacturing problems on the print. The reply comes within 24-48 hours with price, material, and lead time. A free design review comes with every quote and flags any callout that adds cost. There is no portal and no account. The trade is a day or two instead of seconds, in exchange for a quote from someone who read the print and will be the same person on every email that follows.

Minimums and quantities

Xometry: its FAQ describes handling "everything from one-offs to high-volume production," so a single part can be quoted (source 2). Protolabs: its FAQ says that because there are "no up front non-recurring engineering (NRE) costs," purchasing "quantities as low as 1 to 200 parts" is cost effective (source 4), and its production page states "1 to 1,000,000 parts. No minimum" (source 5). MI CNC Parts: no minimum order, one piece is a normal job, production runs go to 10,000, and there is no minimum-charge line on the quote; the price for one piece carries its setup and shows it. By their own pages, all three quote a quantity of one. Ask for more than one quantity, such as 1, 25 and 100, and the quote shows each. At Protolabs, the quote itself lets you change quantities with pricing updating in real time (source 3).

Lead times, as each one states them

These are the companies’ own claims, not measurements. Xometry: its CNC page lists a standard lead time of "3-7 business days" in its tolerances table and says "many parts available in 3-4 days" for quick-turn work (source 1), and its FAQ says many custom parts have "expedited, standard, and economy options" (source 2). Protolabs: "machined prototypes and production parts in as fast as 1 day" and "parts ready in as fast as 4 days" (source 3), and production orders "shipped in as fast as 5 days" (source 5).

MI CNC Parts: Rush: 1-2 weeks. Standard: 4-6 weeks (typical). Extended: 6-8 weeks, for jobs that aren't time-sensitive. Rush 1-2 weeks applies to machined parts with no secondary operations. Heat treat, grinding, EDM and finishing add time, and the quote gives the real date. Lead time starts at order approval. Put your need date in the part description and the quote answers it. That is slower than both platforms’ fastest claims, and this page will not pretend otherwise: where the date is the deciding factor, the days each platform states are the ones to check against your part. How long custom machined parts take explains where the weeks go: sourcing, finishing, and inspection.

File handling

Xometry: its FAQ page lists STEP, STP, SLDPRT, STL, DXF, IPT, X_T, X_B, 3DXML, CATPART, PRT, SAT, 3MF, and JT for the quoting engine (source 2), and its CNC page says "We accept technical drawings" (source 1). Protolabs: its FAQ accepts "native SolidWorks (.sldprt) or ProE (.prt) files as well as solid 3D CAD models from other CAD systems output in IGES (.igs), STEP (.stp), ACIS (.sat) or Parasolid (.x_t or .x_b) format," and .stl files, and "2D drawings can be submitted with your 3D CAD file" (source 4). STEP is on both lists; Wikipedia describes the STEP-file as a widely used data exchange form (source 6). MI CNC Parts: the form accepts any file type; a STEP model plus a PDF print is the ideal package, and a dimensioned sketch, a photo, or a new sample part is enough to start, with the CAD quoted as its own line. The sample ships back with the parts. What file to send covers the formats and what a good print includes.

Who you talk to

Xometry: the quote is generated by software; its FAQ says that for parts sooner or a quote that beats its times you can "reach out to support@xometry.com or your dedicated sales rep" (source 2), and its CNC page lists a support phone line (source 1). Protolabs: its FAQ gives an applications engineer phone line for discussing a design revision (source 4), and its production page describes a "dedicated point of contact" (source 5). MI CNC Parts: one contact. The person who read the print and quoted the job is the person who answers the reply, and stays with the job from quote through delivery. MI CNC Parts is a Michigan-based business that quotes the job, gets the part made, ships it and stands behind it. Every part inspected against your print before it ships. If a part doesn’t match the print, it’s remade or credited. There is no portal and no account; the quote form and an email thread are the whole of it. Vendor setup in a day: W-9, NDA, net terms available.

How to choose

Choose a platform when what you want is a number in seconds or hours and a date stated in days: Xometry and Protolabs publish exactly that, and where speed and lead time decide it, they fit better. Choose a person when you want the drawing read by one person before a number exists, the material or finish needs a conversation, or the part will come back: a second run, a revision, a family of parts. Reorders at the same revision: send the last quote or PO number and it’s requoted. That is the work MI CNC Parts is built around, though one piece is a normal job and there is no minimum. If you are holding a competing number, meet-or-beat pricing says what to do with it. The Xometry, Protolabs and Fictiv comparisons each go deeper on one platform; this page is the three-way view.

Sources

All accessed 30 September 2026. Where a figure here differs from your print, the print governs. Competitor terms change; if a line here is out of date, the source is the authority and the line gets corrected.

1. Xometry, "Custom Online CNC Machining Services - Metal and Plastic Instant Quotes", xometry.com/capabilities/cnc-machining-service/, accessed 30 September 2026, no date shown on the page (instant quotes, manual review for a custom material, "We accept technical drawings", standard lead time 3-7 business days, many parts in 3-4 days, support phone).

2. Xometry, "Answers to the Most Frequently Asked Questions About Xometry", xometry.com/resources/blog/answers-to-most-frequently-asked-questions/, page dated updated 26 August 2026, accessed 30 September 2026 (how the quoting engine prices, accepted file types, one-offs to high-volume production, expedited, standard and economy options, support contact).

3. Protolabs, "Online CNC Machining Service", protolabs.com/services/cnc-machining/, accessed 30 September 2026, no date shown on the page (quote and analysis in seconds to hours, automated design analysis, as fast as 1 day and 4 days, materials and quantities changed in the quote).

4. Protolabs, "Digital Manufacturing FAQs", protolabs.com/resources/faqs/, accessed 30 September 2026, no date shown on the page (accepted file formats, 2D drawings with the 3D file, quantities as low as 1 to 200 parts with no NRE costs, interactive quote within hours, applications engineer phone line).

5. Protolabs, "Production CNC Machining", protolabs.com/services/cnc-machining/production-capabilities/, accessed 30 September 2026, no date shown on the page (1 to 1,000,000 parts and no minimum, shipped in as fast as 5 days, dedicated point of contact).

6. Wikipedia, "ISO 10303-21", en.wikipedia.org/wiki/ISO_10303-21, last edited 29 July 2026, accessed 30 September 2026 (STEP-file as a widely used data exchange form).

MI CNC Parts’ own terms are stated on the quote page, the FAQ, quotes in 24-48 hours, and no minimum order.